FR2988563A1 - Ludwigia grandiflora plant extract, useful as antibacterial agent against e.g. Clostridium botulinum for treating e.g. skin infections and as antimicrobial agent in product for cleaning, decontaminating and disinfecting surfaces of human - Google Patents

Abstract

Ludwigia grandiflora plant extract useful as an antibacterial agent against gram-negative bacteria, is claimed. ACTIVITY : Antibacterial; Fungicide; Immunosuppressive; Cytostatic; Gastrointestinal-Gen.; Antiinflammatory; Cardiant; Respiratory-Gen.; Antileprotic; Antianginal. The antibacterial activity of the Ludwigia grandiflora plant extract was tested against Bacillus megaterium in vitro The result showed that the extract exhibited antibacterial activity of 100%. MECHANISM OF ACTION : None given.

Description

Field of the Invention The present invention relates to the antimicrobial activity of Ludwigia grandiflora. The invention relates in particular to extracts of this plant, and their use in different sectors such as, for example, pharmacy, medicine, cosmetology, aquariology, the field of food or industrial preservatives, and the field of products. maintenance and hygiene. Background of the Invention Ludwigia, more commonly known as Jussies, are invasive hydrophytes of the Onagraceae family originating in South America or the southern United States. There are about 82 different species of Ludwigia. Some of these species are ubiquitous in freshwater ecosystems, or even adjacent wetlands, in several parts of America, Australia, and Europe (including France, Spain, Italy, the Netherlands, Switzerland and the Balkans). In France, there are two highly invasive species: Ludwigia grandiflora subsp. hexapetala (large flowering plant with an aerial system up to 1 meter high) and Ludwigia peploides subsp. montevidensi (creeping plant with small flowers). Introduced in France in the nineteenth century as ornamental plants of aquariums or basins of botanical gardens, Ludwigia have become formidable invaders of calm natural and aquatic environments. These plants multiply rapidly and completely colonize the available aquatic area. Invasion by Ludwigia is responsible for significant ecological changes related, inter alia, to the reduced penetration of light into the body of water and the decantation of organic matter at the level of root entanglement. These organic substances undergo, as soon as the temperature becomes favorable, a degradation which causes the creation of an anoxic environment unfavorable to the life of the fauna and the flora, thus disturbing the equilibrium of the ecosystem. In addition, Ludwigia form very dense seagrass beds that slow down the flow of water, clogging the canals, causing significant nuisance to human activities such as tourism, hunting, fishing and agriculture. The eradication of Ludwigia is impossible. The uprooting of these plants, the most used means of control against invasion, is only effective in the short term. It is delicate, expensive, and generates tons of polluting biomass that must be completely eliminated, by incineration to avoid the risk of proliferation by cuttings. Many research works have concerned Ludwigia. They are mainly focused on the conditions of development and reproduction patterns of the plant, the survey of seagrasses and the impact of invasion and clogging of contaminated waterways (Dandelot et al., Hydrobiologica, 2005, 551). 131-136, Dandelot et al., Rendus Biologies, 2005, 328: 991-999, Ruaux et al., Aquatic Botany, 2009, 90: 143-148). Numerous studies have also reported medicinal properties of Ludwigia, in particular diuretic, anti-dysenteric, antiseptic, anti-inflammatory, anti-tumor, anthelmintic and antidiarrheal properties (Perry, Medicinal Plants of East and South East Asia: Attributed Properties and Uses, 1980, The MIT Press, USA, Yusuf et al., "Medicinal Plants of Bangladesh," 1994, BCSIR Laboratories, Bangladesh, Kirtikar et al., "Indian Medicinal Plants," 1999, Second Ed., International Book Distributors, India, pp. 1088-1089, Ghani, "Medicinal Plants of Bangladesh", 2003, Second Ed., Asiatic Society of Bangladesh, Dhaka Bangladesh, Murugesan et al., Phytotherapy Research, 2000, 14: 381-383). Antibacterial properties have also been demonstrated in Ludwigia octovalvis (Chen et al., J. Ethnopharmacol., 1989, 27: 285-295), Ludwigia adscendens (Ahmed et al., Fitoterapia, 2005, 76: 473-475). , Ludwigia hyssopifolia Linn. (Das et al., Pak, J. Pharm Sci., 2007, 20: 128-131), and Ludwigia repens (Castillo-Juarez et al., J. Ethnopharmacol., 2009, 122: 402-405). Moreover, Dandelot et al. (Aquatic Botany, 2008, 88: 311-316) mention allelopathic properties of Ludwigia grandiflora, that is to say of 2 capacities to synthesize molecules having a positive or negative influence on the biology of organisms that live within of its ecosystem. A development route for Ludwigia grandiflora, and more particularly for Ludwigia grandiflora subsp. hexapetala, one of the invasive species found in Europe, would exploit these properties. In a preliminary study, the present inventors have demonstrated that extracts of Ludwigia grandiflora have antibacterial effects on Gram-positive bacteria (Gram +) (Smida et al., "Study of the impact of Ludwigia grandiflora on micro-organisms in order to the restoration of ecosystems and the valorization of plant biomass ", 7th European Conference on Ecological Restoration, 23 to 27 August 2010, Avignon, France). SUMMARY OF THE INVENTION In general, the present invention is based on the demonstration of the antibacterial properties of Ludwigia grandiflora against Gram-negative bacteria (Gram-), on the observation that extracts of Ludwigia grandiflora which exhibit the highest antibacterial activity are those obtained from plants taken during their flowering period exhibited particularly interesting antibacterial effects, and on the demonstration of antifungal properties of Ludwigia grandiflora. Accordingly, a first aspect of the present invention is an extract of a plant of the species Ludwigia grandiflora for use as an antibacterial agent against Gram-negative bacteria. The invention also relates to an extract of a plant of the species Ludwigia grandiflora for use as antifungal agent. The invention also relates to an extract of a plant of the species Ludwigia grandiflora, characterized in that the plant is harvested during the flowering period of Ludwigia grandiflora, preferably in June, July and / or August. In some embodiments, an extract according to the invention is an entire plant extract. In other embodiments, an extract according to the invention is an extract of a plant part selected from roots, stems, leaves, flowers and any combination of said parts, preferably an extract of the leaves and or flowers, more preferably an extract of flowers.

In certain embodiments, an extract according to the invention is obtained by: washing the sampled plant with water, drying the sampled plant or a portion of the washed plant, crushing the plant or a part of the plant to reduce it to powder, - extraction of the powder with a solvent, preferably water or dimethylsulfoxide. Another aspect of the invention relates to an extract of a plant of the species Ludwigia grandiflora, characterized in that the plant is harvested during the flowering period of Ludwigia grandiflora, preferably in June, July and / or August for its use. as a medicament, and in particular as an antibacterial agent in antibiotic therapy, antibiotic therapy may be directed against a gram-positive bacterium or a gram-negative bacterium. Another aspect of the invention relates to a pharmaceutical composition comprising at least one extract according to the invention and at least one physiologically acceptable vehicle or excipient. The invention also relates to a cosmetic composition comprising at least one extract according to the invention and at least one cosmetologically acceptable vehicle or excipient. Another aspect of the present invention relates to the use of an extract according to the invention. In particular, the invention relates to the use of an extract according to the invention as an antimicrobial agent for cleaning, decontaminating or disinfecting surfaces. The invention also relates to the use of an extract according to the invention as an agent for the preservation of a cosmetic product, a food product or a pharmaceutical product. The invention also relates to the use of an extract according to the invention for clarifying and / or purifying stagnant water. Another aspect of the present invention relates to products comprising an extract according to the invention. In particular, the invention relates to a cleaning product, decontamination or disinfection containing an extract according to the invention. This product may be intended to clarify and / or purify stagnant water. The invention also relates to a food product comprising an extract according to the invention. The invention also relates to an agricultural product comprising an extract according to the invention. A more detailed description of some preferred embodiments of the invention is given below.

DETAILED DESCRIPTION OF THE INVENTION In general, the present invention relates to Ludwigia grandiflora extracts, their antibacterial properties, and their use in various fields ranging from pharmacology to aquariology. I - Extracts of Ludwigia Grandiflora As used herein, the term "Ludwigia grandiflora" refers in particular to the subspecies Ludwigia grandiflora subsp. hexapetala found in many parts of Europe, among others. An extract of Ludwigia grandiflora according to the invention can be obtained from plants taken from a wild herbarium (that is to say from a body of water invaded by plants of the species Ludwigia grandiflora). In particular, the plants used in the preparation of such an extract can result from a procedure of eradication by pulling, thus making it possible to promote the polluting biomass of the meadows. However, it is not excluded that an extract of Ludwigia grandiflora according to the invention can be obtained from plants specially grown for this purpose. In the context of the present invention, the term "Ludwigia grandiflora extract" means any substance obtained by at least one physical, chemical, and / or biochemical operation carried out on a plant of the species Ludwigia grandiflora. In certain embodiments, the plants used in the preparation of an extract according to the invention are taken at any stage of their development, that is to say from the state of seedling to that of flowering completed. . However, preferably, the plants are taken during the flowering period of Ludwigia grandiflora which extends from June to September. More preferably, the plants are taken in June, July and / or August. It is understood that these months correspond to the usual flowering period of Ludwigia grandiflora in the South of France. Those skilled in the art will recognize that due to weather conditions, the flowering period of Ludwigia grandiflora may vary from year to year and, for example, start earlier (as early as April) and / or end later. (in September or October). It is also evident that the flowering period of Ludwigia grandiflora in another geographical region than the south of France or in another country will take place at a different time and / or for a different duration.

In some embodiments, the extract is obtained from whole plants. In other embodiments, the extract is obtained from one or more specific organs or parts of the plant (e.g., roots, stems, leaves, flowers, or a particular combination of these organs). or parts). Preferably, an extract of Ludwigia grandiflora is prepared from leaves and / or flowers, in particular from leaves and / or flowers of plants taken during the flowering period. More preferably, an extract of Ludwigia grandiflora is prepared from leaves and / or plant flowers taken in June, July and / or August. Preparation of an Extract of Ludwigia grandiflora Plants may be removed by any suitable method, for example by manual or mechanical pulling and / or cutting. Immediately after collection, the plants are placed in watertight glaciers. The collected plants are then washed under running water. In some embodiments, once the plant is washed, it is allowed to dry as removed, i.e., as a whole (root, stem, leaves and flowers). Drying can be carried out by any suitable method. Plants can, for example, be air dried, protected from light, protected from dust, and at room temperature (ie between 18 ° C and 25 ° C). ). However, it is possible to carry out the drying at a temperature higher than the ambient temperature, for example between 25 ° C. and 30 ° C., or between 30 ° C. and 35 ° C. It is also possible to dry the plants by lyophilization. In other embodiments, once the plant is washed, the various organs or parts of the plant (roots, stems, leaves and flowers) are separated and then dried separately as described above. After drying, the whole plants or all the separate organs or only some of them (eg flowers and / or leaves) are crushed and reduced to a fine powder. The grinding can be carried out by any suitable technique, including mechanical milling (using, for example, a mortar and pestle system, a Potter-Elvelijhem type mill, or a Dounce type mill), or by shredding mechanical (using, for example, a Waring BlenderTM, or a Virtis crusher). Any suitable combination of these methods can also be used in the preparation of a Ludwigia grandiflora extract according to the invention. The powder obtained by grinding serves as starting material for the extraction. The extraction can be carried out immediately after drying. Alternatively, before extraction, the dried powder can be stored at a low temperature (for example at 4 ° C.) in the absence of light and moisture or else be frozen (for example at -20 ° C.). It is also conceivable to freeze the dried plants or organs to preserve them and to reduce them to powder thereafter only before extraction. The extraction of the vegetable powder is carried out using a solvent. The solvent may be chosen from organic solvents of different polarities from water to cyclohexane, or any combination of these solvents. In some embodiments, the solvent is selected from water, methanol, ethanol, dimethylsulfoxide (DMSO), acetone, dichloromethane, and ethyl acetate. In some preferred embodiments, the extraction solvent is water or DMSO. The addition of the solvent to the vegetable powder is followed by vigorous stirring and centrifugation. The supernatant, which is generated by centrifugation, is recovered and constitutes an extract of Ludwigia grandiflora according to the invention. In some embodiments, the solvent of the supernatant is evaporated. In preparations of the order of a few grams of Ludwigia grandiflora extract, the solvent is preferably added in a ratio ranging from 1 to 50 ml of solvent per gram of vegetable powder, for example from 2 to 30 ml or from 2 to 20 mL, preferably 3 to 10 mL of solvent per gram of plant powder, and more preferably about 5 mL of solvent per gram of plant powder. A person skilled in the art will know how to determine optimal ratios in the case of larger scale preparations. The vigorous stirring can be carried out by any suitable technique (for example by vigorous vortex agitation or vigorous magnetic stirring or by sonication). The person skilled in the art will know how to determine the optimal conditions of the agitation (duration, temperature, etc.). In particular, the stirring time will vary depending on the amount of starting vegetable powder, the nature of the solvent, and the powder / solvent ratio. Likewise, the optimal conditions of centrifugation (temperatures, rotation speed, and duration) will be determined according to the extraction solvent used and the amount of starting vegetable powder. In some embodiments, centrifugation is performed at 15,000 rotations per minute (rpm). In some embodiments, successive centrifugations can be performed. The extract of Ludwigia grandiflora obtained (in liquid form in the extraction solvent) can be stored at a low temperature (for example at 4 ° C.) and protected from light or else be frozen. Alternatively, the extract can be put into powder form after spray drying, evaporation and / or lyophilization, and stored at room temperature or at low temperature (for example at 4 ° C.) and protected from light or else still be frozen (for example at -20 ° C).

II - Uses of Extracts of Ludwigia grandiflora Because of their antimicrobial properties, the extracts of Ludwigia grandiflora according to the invention can find application in many fields where the absence of bacterial and / or fungal contamination is sought. As used herein, the term "antibacterial" refers to a substance that kills and / or prevents the growth of bacteria. The term "bactericidal" here has its usual meaning and refers to a substance having the ability to kill bacteria. As used herein, the term "antifungal" refers to a substance that kills and / or prevents the growth of fungi (also called fungi), and the term "antimycotic" refers more specifically to a substance that kills and / or prevents the growth of fungi in the treatment of fungal infections, that is to say infections caused by fungi in mammals. Thus, the extracts of Ludwigia grandiflora according to the invention, and more particularly the extracts obtained from plants taken during the flowering period as described above, can be used in any field where the absence of contamination by Gram + bacteria. is sought. A "Gram + bacterium" is a bacteria that has a unimembrane structure and appears mauve by the Gram stain technique. Gram + bacteria against which an extract of Ludwigia grandiflora according to the invention can be used include, without limitation, bacteria belonging to the genera Staphylococcus, Micrococcus, Lactococcus, Lactobacillus, Clostridium, Bacillus, Streptococcus, Enterococcus, and Listeria. In particular, an extract of Ludwigia grandiflora can be used against Gram + bacteria that are pathogenic or potentially pathogenic to humans or another mammal, such as, for example, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Staphylococcus hyicus, Staphylococcus intermedius, Clostridium tetani , Clostridium botulinum, Clostridium perfringens, Clostridium difficile, Bacillus cereus, Bacillus anthracis, Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus pneumoniae, Enterococcus faecalis, Enterococcus faecium, Listeria monocytogenes, and Listeria ivanovii. The extracts of Ludwigia grandiflora according to the invention can also be used in any field where the absence of contamination by Gram-bacteria is sought. A "Gram-bacterium" is a bacterium that has, with the exception of one, a bimembrane structure and appears pink by the Gram staining technique. The Gram-bacteria against which an extract of Ludwigia grandiflora according to the invention can be used include, without limitation, bacteria belonging to the genera Bordetella, Salmonella, Enterobacter, Klebsiella, Shigella, Yersinia, Escherichia coli, Vibrio, Pseudomonas, Neisseria, Haemophilus, and Agrobacterium. In particular, an extract of Ludwigia grandiflora can be used against gram-pathogenic or potentially pathogenic bacteria for humans or another mammal, such as, for example, Bordetella pertussis, Bordetella parapertussis, Bordetella bronchiseptica, Shigella boydii, Shigella dysenteriae, Shigella flexneri , Shigella sonnei, Enterobacter aerogenes, Enterobacter cloacae, Enterobacter sakazakii, Klebsiella pneumoniae, Yersinia pestis, Yersina enterocolitica, Yersina pseudotuberculosis, Salmonella enterica, Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio fluvialis, Neisseria meningitidis, Neisseria gonorrhoeae, Haemophilus influenzae, Haemophilus aegypticus, and Haemophilus ducreyi. The extracts of Ludwigia grandiflora according to the invention therefore find application in medicine (human or veterinary), in particular in antibiotic therapy. Antibiotic therapy currently faces the need for a renewal of antibiotics on the market as a result of the emergence of significant resistance of major pathogenic bacteria in hospitals. This phenomenon is at the origin of the numerous nosocomial diseases observed. The search for new molecules synthesized by living organisms, in particular, plants, appears as a particularly interesting strategy.

The present invention thus relates to an extract of Ludwigia grandiflora, as defined herein, for its use as a medicament, particularly as an antibacterial agent (antibiotic or antiseptic). The term "antibiotic" refers here to a substance that kills and / or prevents the growth of bacteria within the human or animal body while the term "antiseptic" refers here to a substance that acts similarly on surfaces external of the human or animal body. According to the same aspect, the present invention also relates to a method of treatment comprising a step in which an effective amount of a Ludwigia grandiflora extract or a pharmaceutical composition comprising such an extract (see below) is administered to a patient or to a subject. This method can, in particular, be used for the treatment of a bacterial infection, such as an infection caused by a Gram + pathogenic bacterium or a gram-pathogenic bacterium. In the context of the present invention, the term "treatment" means a method that aims to (1) delay or prevent the onset of a disease or clinical condition; (2) to slow or stop the progression, aggravation or deterioration of the symptoms of the disease; (3) to make improvements in the symptoms of the disease; and / or (4) to cure the disease. A treatment can be administered before the onset of the disease for preventive action, or it can be administered after initiation of the disease, for therapeutic action. The term "subject" refers here to a mammal, particularly a domestic mammal, such as sheep, cattle, goats, horses, cats, dogs, etc., while the term "patient" is preferably used. when the subject is a human being An extract of Ludwigia grandiflora according to the invention (or a pharmaceutical composition comprising such an extract) can be administered by any appropriate route of administration (oral, parenteral, rectal, pulmonary, nasal, cutaneous, transdermal, mucosal, etc. ) and can be local or systemic. The optimal route of administration may be determined depending on the nature and / or location of the bacterial infection. Bacterial infections that can be treated by administration of a Ludwigia grandiflora extract according to the invention include, without limitation, bacterial urinary tract infections, bacterial skin infections, bacterial intestinal infections, bacterial lung infections, osteoarticular infections. bacterial genital infections, bacterial tooth infections, sepsis, nosocomial infections, bacterial meningitis, bacterial gastroenteritis, endocarditis, endocarditis pneumonia, leprosy, typhoid, tetanus, bacterial angina, bacterial otitis, salmonellosis, etc. The extracts of Ludwigia grandiflora according to the invention can also be used in any field where the absence of contamination by fungi is sought. As used herein, the term "mushroom" includes microorganisms of the Fungi kingdom including yeasts. Fungi against which an extract of Ludwigia grandiflora according to the invention can be used include, but are not limited to, fungi belonging to the genera Candida, Cryptococcus, Aspergillus. Trichophyton, Microsporum, and Epidermophyton. In particular, an extract of Ludwigia grandiflora can be used against fungi that are pathogenic or potentially pathogenic to humans or other mammals, such as, for example, Candida albicans, Candida pseudotropicalis, Candida tropicalis, Candida parapsilosis, Candida guillermondii, Cryptococcus neoformans, Cryptococcus laurentii, Cryptococcus albidus, Cryptococcus gattii, Aspergillus fumigatus, Aspergillus dip, Aspergillus nidulans, Aspergillus ochraceus, Aspergillus versicolor, Microsporum audouinii, 12 Trichophyton rubrum, Trichophyton interdigitale, Trichophyton violaceum, Triphophyton schoenleini, Epidermophyton floccosum, Microsporum canis, Trichophyton mentagrophytes, and Trichophyton ochraceum. The present invention therefore also relates to an extract of Ludwigia grandiflora, as defined herein, for its use as antifungal agent, particularly antimycotic. According to the same aspect, the present invention also relates to a method of treating a fungal infection comprising a step wherein an effective amount of a Ludwigia grandiflora extract or a pharmaceutical composition comprising such an extract (see further low) is administered to a patient or a subject. As already mentioned, the administration of a Ludwigia grandiflora extract according to the invention (or a pharmaceutical composition comprising such an extract) can be carried out by any appropriate route of administration (oral, parenteral, rectal, pulmonary, nasal, cutaneous, transdermal, mucosal, etc.) and may be local or systemic. The optimal route of administration may be determined depending on the nature and / or location of the fungal infection. Fungal infections that can be treated by administration of an extract of Ludwigia grandiflora according to the invention include, without limitation, candidiases such as cutaneous, oral, and vaginal candidiasis, and deep or systemic mycosis which affects the entire body of the body; cryptococcosis, which in the vast majority of cases affects immunocompromised patients and whose most frequent and most serious clinical form is meningoencephalitis; aspergillosis, in particular bronchopulmonary aspergillosis, dermatophytosis such as ringworm, trichophytosis, microspora, and epidermophytosis. The extracts of Ludwigia grandiflora according to the invention also find application in the field of cleaning and hygiene products as a disinfecting agent. The term "disinfectant" as used herein refers to a substance that kills and / or prevents the growth of bacteria and / or fungi on the surface of inanimate objects. Such objects may for example be medical instruments; floors, surfaces, furniture or devices of laboratories or operating sites; floors, surfaces, furniture or devices in private homes or in public or industrial installations. The present invention thus relates to the use of an extract of Ludwigia grandiflora, as defined herein, as a disinfecting agent. According to this same aspect, the present invention also relates to a method for cleaning, decontaminating or disinfecting a surface of an object comprising a step of contacting the surface of the object with an effective amount of an extract Ludwigia grandiflora or a composition comprising such an extract. An extract of Ludwigia grandiflora may be included in a composition or a cleaning product, or may impregnate a tampon or wipe for cleaning, decontamination and / or disinfection. The invention encompasses such compositions, products, pads and wipes. The extracts of Ludwigia grandiflora according to the invention also find application as preservatives. The term "preservative" as used herein refers in particular to a substance which prevents the development of bacteria and / or fungi in a product and ensures the preservation of this product. The present invention thus also relates to the use of an extract of Ludwigia grandiflora, as defined herein, as a preservative. An extract of Ludwigia grandiflora may be included in a cosmetic product, a food, a beverage, a pharmaceutical product to avoid contamination of the product by bacteria and / or fungi. The invention encompasses such products. According to this same aspect, the present invention also relates to a method for preserving a cosmetic, food, or pharmaceutical product comprising a step of incorporating an effective amount of a Ludwigia grandiflora extract into a cosmetic, food or pharmaceutical product. . With regard to cosmetology and agri-food, the replacement of chemical preservatives with biological products in creams or lotions is in line with the requirements of the legislation. An extract of Ludwigia grandiflora according to the invention, because of its antibacterial properties, can also be used to maintain the clarity and purity of the stagnant water of aquariums, flower vases, basins, etc. An extract of Ludwigia grandiflora may be included in a stagnant maintenance product. The invention encompasses such products. The invention also relates to a method for maintaining the clarity and / or purity of stagnant water comprising the step of adding an effective amount of Ludwigia grandiflora extract to stagnant water. Finally, an extract of Ludwigia grandiflora can also be used against bacteria, fungi and / or oomycetes that are pathogenic or potentially pathogenic to plants, for example, Phytophthora infestans, Phytophthora destructor, Phytophthora cactorum, Fusarium spp., Botrycis cinerea, Pythium spp., Armillariella mellea, and Plasmodiophora brassicae. An extract of Ludwigia grandiflora according to the invention therefore finds application as antifungal agent in the field of agriculture, fruticulture, vegetable cultivation, horticulture and / or arboriculture. The invention therefore relates to the use of an extract according to the invention for preventing and / or inhibiting the growth of bacteria, fungi and / or oomycetes on or in edible plants (vegetables, fruits), trees, ornamental plants (plants, flowers) and / or soils on which these plants or trees grow and / or packaged agricultural products. According to this same aspect, the present invention relates to a method for preventing or inhibiting a bacterial, fungal or parasitic infection of a plant and / or the substrate on which it develops, the method comprising a step of bringing the surface of the plant into contact with one another. plant and / or substrate with an effective amount of a Ludwigia grandiflora extract or a composition comprising such an extract. The contacting can be done by any suitable method, for example by dusting or liquid spraying. An extract of Ludwigia grandiflora according to the invention may be included in a composition or a product intended to promote and / or allow the development of the plant, for example watering water or fertilizer. III - Pharmaceutical, Para-pharmaceutical and Cosmetic Compositions The invention also relates to pharmaceutical, para-pharmaceutical or cosmetic preparations or compositions comprising at least one Ludwigia grandiflora extract as defined above, and in particular an extract prepared with from plants taken during the flowering period. Because of their antimicrobial properties mentioned above, extracts of Ludwigia grandiflora can be used as preservatives in cosmetics to prevent their contamination by bacteria and / or fungi. A cosmetic composition according to the invention comprises at least one Ludwigia grandiflora extract as defined above and at least one cosmetologically acceptable or appropriate excipient. A composition according to the present invention may be used as such, or alternatively may be incorporated in a cosmetic product, or in a personal care or hygiene product. Thus a cosmetic composition of the invention can be added to creams or lotions for the face, hands, feet or body (for example, day creams, night creams, body milks, detergents and soaps, lotions, milks, gels or mousses for skin care, deodorants or antiperspirants); makeup products; creams, gels, oils or lotions of self-tanners; sunscreens; hair products (for example, shampoos, conditioners, coloring products, creams, gels or styling mousses); shaving and aftershave products, lip balms, etc. A cosmetic composition according to the present invention can be formulated in solid, semi-solid, or liquid form. The choice of the formulation will generally be according to the application for which the composition is intended. Formulations suitable for cosmetic use are known in the art and include, for example, simple emulsions (e.g., oil-in-water or water-in-oil emulsions), multiple emulsions, microemulsions, aqueous or hydroalcoholic gels. , oils, aqueous solutions or hydroalcoholic solutions, foams, creams, milks, oils, lotions, pastes, sticks, powders, pencils, etc. For the preparation of such formulations, an extract of Ludwigia grandiflora may be mixed with at least one cosmetologically suitable excipient (for example, vegetable or mineral oils, vegetable or mineral waxes, silicones, alcohols, fatty acids, lanolin, water, etc.) or be incorporated into vectors of the liposome, macrosphere, microsphere, nanosphere, macroparticle, microparticle, nanoparticle, macrocapsule, microcapsule or nanocapsule type, or be absorbed onto powdery organic polymers, talcs, bentonites and other mineral supports. A cosmetic composition according to the invention may also contain additives such as other antibacterial adjuvants, perfumes, extraction and / or synthetic lipids, gelling and viscosity polymers, surfactants, emulsifiers, etc. In general, a cosmetic composition of the invention comprises an effective amount of Ludwigia grandiflora extract, i.e., an amount of extract that is sufficient to fulfill the desired role or action ( for example, provide, to the cosmetic product that contains the extract, protection against contamination by bacteria and / or fungi). For example, in some embodiments, a cosmetic composition of the invention may comprise from about 0.01% to about 50% by weight powdery extract, or from about 0.01% to about 90% by weight. extract weight in encapsulated form.

The cosmetic compositions of the present invention may further contain at least one additional cosmetic active ingredient (i.e., in addition to Ludwigia grandiflora extract). The term "cosmetic active ingredient", any compound or substance that can be used in the care for the body, skin, hair, etc ..., and which is generally applied locally.

The cosmetic active principles that can be used in the context of the present invention may belong to various families of compounds and substances, including plant extracts, marine extracts, tissue extracts, synthetic molecules, and the like. Such active ingredients are known in the art. For example, a suitable cosmetic active ingredient may be advantageously selected from substances which increase skin protection (for example, vitamins, ceramides, anti-radical substances, UV filters, etc.), substances which have a healing effect (for example , proteins, hyaluronic acid, amino acids) or an anti-inflammatory effect on the skin, substances that limit the harmful effects of the sun (UVA and / or UVB filters), bronzing and self-tanning products, substances that facilitate the good condition of the scalp and that of the hair (for example, minerals, vitamins, ceramides, protein extracts, mucopolysaccharides, flower and / or fruit acids), anti-aging and / or anti-wrinkle substances, tonics, detergents, substances that have an activity on skin sensitivity, etc. In such cosmetic compositions of the invention, each additional active ingredient is generally present in an amount sufficient to exert its activity. Because of its antimicrobial properties, an extract of Ludwigia grandiflora according to the invention can be used as a therapeutic agent. Such an extract may be administered as such or in the form of a preparation or pharmaceutical composition in the presence of at least one physiologically acceptable carrier or excipient. In the context of the present invention, the term "physiologically acceptable vehicle or excipient" means any medium or additive that does not interfere with the effectiveness of the biological activity of the active ingredient (here, Ludwigia grandiflora extract), and which is not excessively toxic to the patient or subject at the concentrations at which it is administered. A physiologically acceptable vehicle or excipient may be a vehicle or excipient suitable for administration to humans and / or animals (particularly to domestic mammals). The pharmaceutical compositions of the present invention may be administered using any combination of dosage and route of administration effective to achieve the desired therapeutic effect. The exact amount to be administered may vary from one patient to another, depending on the age, weight, general condition of the patient, the nature and severity of the bacterial or fungal infection, etc. The route of administration (oral, parenteral, rectal, pulmonary, nasal, cutaneous, transdermal, mucosal, etc.) may be chosen depending on the nature and / or location of the bacterial or fungal infection. Administration can be local or systemic. The formulation of a pharmaceutical composition of the present invention may vary depending on the route of administration and dosage for which the composition is to be used. After formulation with at least one physiologically acceptable vehicle or excipient, a pharmaceutical composition of the invention may be in any form suitable for administration to a mammal, including humans, for example in the form of tablets, tablets, dragees , capsules, syrups, ointments, injectables, suppositories, etc. Those skilled in the art can select the most suitable vehicles and excipients for the preparation of a given type of formulation. Thus, for example, excipients such as water, 2,3-butanediol, Ringer's solution, isotonic solutions of sodium chloride, synthetic mono or diglycerides, and oleic acid are often used for formulation injectable preparations. Liquid compositions, including emulsions, microemulsions, solutions, suspensions, syrups, elixirs, etc., may be formulated in the presence of solvents, solubilizers, emulsifiers, oils, fatty acids, and the like. other additives such as suspending agents, preservatives, sweeteners, flavors, viscosities, colorants, etc. Solid compositions for oral administration may be formulated in the presence of an inert excipient such as sodium citrate, and optionally additives such as binding agents, humectants, disintegrating agents, accelerators and the like. absorption, lubricating agents, etc. In some embodiments, a pharmaceutical composition of the present invention is formulated for immediate release of the active ingredient (s) of the extract. Alternatively, a pharmaceutical composition may be formulated for sustained release of the active ingredient (s) of the extract. Many strategies are known in the art for inducing prolonged release of an active ingredient, such as, for example, increased residence time in the stomach, using pH-sensitive coatings and / or enzymatic actions, or bioadhesive coatings that cling to the walls of the stomach or intestine, or by using encapsulation systems as mentioned above. The pharmaceutical compositions according to the present invention may further contain at least one additional active pharmaceutical ingredient (i.e., in addition to Ludwigia grandiflora extract). The term "pharmaceutical active principle" is understood to mean any compound or substance whose administration has a therapeutic effect or an effect beneficial to the health or general condition of a patient or a subject to whom it is administered. Thus, a pharmaceutical active ingredient may be active against the bacterial or fungal infection that is to be treated by administration of the pharmaceutical composition; may be active against a condition or symptom associated with the bacterial or fungal infection (e.g., inflammatory reaction); or may increase the availability and / or activity of the active ingredient (s) of the pharmaceutical composition.

Examples of pharmaceutical active ingredients that may be present in a composition of the present invention include, without limitation, anti-inflammatories, antibiotics, antipyretic agents, antipruritic and / or antihistaminic agents, vitamins, etc. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by an ordinary specialist in the field to which this invention belongs. Likewise, all publications, patent applications, patents and all other references mentioned herein are incorporated by reference. The following examples and figures are presented to illustrate certain embodiments of the procedures described above and should in no way be considered as a limit to the scope of the invention. Examples The following examples describe some embodiments of the present invention. However, it is understood that the examples are presented for illustrative purposes only and in no way limit the scope of the invention. MATERIAL AND METHODS 1. Obtaining the plants of Ludwigia grandiflora The plants were taken from a herbarium of Ludwigia grandiflora found in Siagne, at a place called Ecluset in Pégomas (Alpes Maritimes, France). This herbarium is bulky; it colonizes the banks of the river and a collection of the bank in which the flow of water is lenient (slow flow).

Six sampling campaigns were carried out in April, May, June, July, August and September, by manual pulling or section at the stem of the plant, without dispersal in the ecosystem of pieces of plant. The plants were immediately placed in sealed glaciers. The different parts of the plants (stems, leaves and flowers) were separated and dried in the dark, protected from dust, and at room temperature. Once dried, the biomass was crushed and reduced to a fine powder, using a laboratory mill (Labortechnik IKA®). The powders of the different parts of the plant were stored in glass containers, protected from light and moisture. 2. Preparation of extracts of Ludwigia grandiflora For each type of organ (stem, leaf and flower), 10 ml of DMSO were added to 2 g of vegetable powder, the whole being crushed in a glass or ceramic mortar and the resulting mixture stirred vigorously with Vortex® for 10 minutes. Centrifugation at 15,000 rpm was then performed for 21 minutes at 20 ° C. The supernatant (i.e. the extract) was collected and stored at 4 ° C protected from light. 3. Bacterial Strains The 14 bacterial strains used were provided by the Microbial Ecology Laboratory of IMEP and are presented in Table 1. 4. Antibacterial Activity Tests The antibacterial activity of each extract was tested on medium agar using the disk diffusion method, the antibiogram method (Janssen et al., Pharmaceutische Weekblad (Scientific Edition), 1987, 9: 193-197, Bayero et al., J. Pure Appl. Sci., 2008, 2 : 149-153, Loubaki et al., Science and Medicine, Journal, CAME-Series A, 1999, 01:67). The medium used is that of Mueller Hinton Agar, which is non-selective and suitable for testing antibiotic sensitivity. Flood seeding. The bacterial suspensions were obtained by suspending colonies isolated from the strains in sterile distilled water. The absorbance of each bacterial suspension was adjusted to an optical density (OD) of 0.5 at 450 nm. Dilutions were then carried out for each bacterial strain in order to obtain a microbial mat suitable for the study: suspensions of S. typhymurium strains, S. aureus, K. Oxytoc, L. grayi, L. lactis, E. aerogenes , and E. faecalis were diluted 1/100, the suspensions of the 3 E. coh strains, and the P. rettgeri, P. aeruginosa, P. putida, and B. megaterium strains were diluted 1/1000. The boxes were inoculated by flooding. 2 mL of bacterial suspension was needed to cover the surface of each box. The surplus was recovered by aspiration. After inoculation, the dishes were incubated for 15 minutes at 37 ° C. for rapid fixation of the bacteria on the agar medium. Table 1. Bacterial strains used. Bacteria Name Gram + Notes strain or Gram- Escherichia coli IP 105242 Gram - bacterium of mammalian digestive tract IP 6221 IP 6224 Enterobacter aerogenes CIP 60.86 Comensal commensal gram- bacterium responsible for urinary tract infection and nosocomial infections Enterococcus faecalis IUP U1 Gram + commensal bacterium of the gastrointestinal tract, responsible for nosocomial infections, multidrug-resistant commonly used in particular, semi-synthetic penicillins Klebsiella oxytoca LMD7265 col Gram- bacterium responsible for urinary tract infections, pulmonary and sepsis, resistant to penicillins bl Lactobacillus lactis IUT Gram + bacterium used in the production of dairy products Providencia rettgeri CIP 69.24 Gram- bacterium responsible for human gastro- enteritis and chicken cholera Pseudomonas aeruginosa IP100720 Gram-pathogen opportunistic nosocomial, responsible for pulmonary, urinary infections, burns and p lariae, susceptible to carboxipenicillins but resistant to all other penicillins Pseudomonas putida IP521917 Gram- bacterium used for the bioremediation of hydrocarbon-contaminated soils such as compounds derived from naphthalene Listeria grayi Gram + bacterium responsible for foodborne infection, can reach central and fetoplacental nervous system Salmonella typhymurium Gram- infective agent of the digestive tract Staphylococcus aureus Gram + Part of the skin flora, responsible for nosocomial infections, skin infections and life-threatening diseases such as endocarditis, pneumonia and meningitis, resistant to many antibiotics Bacillus megaterium Gram + soil bacterium, produces penicillineamidase for the production of penicillin Application of disks. The disks used are sterile Whatman filter paper disks, 6 mm in diameter. In each dish (two dishes per extract), two disks impregnated with 15 g of extract and a control disc impregnated with 30 g of DMSO were carefully placed on the agar, using a sterile forceps. The dishes were incubated at 30 ° C for 24 hours. The appearance of a halo around the disks reflects the inhibition of bacterial growth. The diameter (measured in millimeters) of the halos is proportional to the antimicrobial activity.

Legends of the Figures Figure 1 is a photo showing the inhibition halos obtained with a crude extract of leaves of Ludwigia grandiflora harvested at least in August on Candida albicans. Results 1. Antibacterial activity of Ludwigia grandiflora extracts The antibacterial activities are expressed in terms of diameter, in mm, of the zones of inhibition, calculated from 3 diameters determined for each halo, ie 6 diameters in total. Antibacterial properties of leaf extracts of Ludwigia grandiflora. The results obtained are shown in Table 2. Table 2. Effects of leaf extracts of Ludwigia grandiflora on the development of bacterial strains. The results presented are the diameters expressed in mm (n = 6). Month April May June July August September Bacillus megaterium 0 17.08 ± 1.16 13.17 ± 0.83 0 15.28 ± 1.33 13.28 ± 1.76 Enterobacter aerogenes 0 9.33 ± 0.89 15 , 50 ± 1.78 10.00 ± 1.04 0 9.00 ± 0.00 Enterococcus faecalis 0 9.00 ± 0.00 21.42 ± 1.24 10.50 ± 0.52 11.00 ± 0.00 10.43 ± 0.75 Escherichia coli 1052 12.08 ± 1.08 11.83 ± 2.72 17.08 ± 2.11 21.75 ± 1.54 15.33 ± 0.89 12.00 ± 0.00 Escherichia coli 6221 12 , 50 ± 2.43 12.00 ± 2.76 15.75 ± 4.22 12.50 ± 1.17 16.42 ± 1.73 0 Escherichia coli 6224 0 0 17.89 ± 1.17 15.22 ± 1.20 22.33 ± 1.58 16.11 ± 1.05 Klebsiella oxytoca 9.17 ± 0.37 10.17 ± 0.37 15.00 ± 0.00 18.33 ± 1.70 21, 39 ± 1.42 15.11 ± 5.26 Lactobacillus lactis 0 0 0 13.00 ± 0.00 12.83 ± 0.37 13.44 ± 0.90 Listeria grayi 0 0 0 12.00 ± 0.00 17.28 ± 1.52 14.67 ± 0.47 Providencia rettgeri 10.67 ± 1.49 10.00 ± 0.00 19.83 ± 1.67 16.50 ± 1.50 17.67 ± 1, 11 14.25 ± 0.43 Pseudomonas aeruginosa 0 0 14.00 ± 2.53 19.93 ± 0.25 14.27 ± 0.44 14.93 ± 1.34 24 Pseudomonas putida 0 0 16.75 ± 2 , 12 16.17 ± 6.36 19.93 ± 0.25 18.33 ± 2.12 Salmonella typhymurium 0 7.50 ± 0.52 24.75 ± 0.87 23.00 ± 0.00 27.00 ± 0.00 24.00 ± 0.00 Staphylococcus aureus 0 11.00 ± 0.00 21.92 ± 1.24 18.83 ± 0.39 22.58 ± 0.51 19.00 ± 0.00 Antibacterial properties of the flower extracts of Ludwigia grandiflora. The results obtained are shown in Table 3. Table 3. Effects of flower extracts of Ludwigia grandiflora on the development of bacterial strains. The results presented are the diameters expressed in mm (n = 6). Month June July August Bacillus megaterium 0 0 10.33 ± 0.75 Enterobacter aerogenes 12.58 ± 2.23 22.75 ± 0.62 10.00 ± 0.00 Enterococcus faecalis 10 ± 0 10.08 ± 1.16 11.33 ± 0.49 Escherichia coli 1052 17.83 ± 2.25 18.17 ± 2.08 0 Escherichia coli 6221 25.5 ± 3.55 17.25 ± 4.69 15.5 ± 0.80 Escherichia coli 6224 16.17 ± 0.98 16.89 ± 1.62 18.89 ± 0.60 Klebsiella oxytoca 18.67 ± 1.60 15.83 ± 069 18.39 ± 1.38 Lactobacillus lactis 0 11.00 ± 0.00 17.83 ± 3.32 Listeria grayi 10.00 ± 0.00 11.00 ± 0.00 20.00 ± 0.00 Providencia rettgeri 19.17 ± 0.37 15.92 ± 0.95 17.42 ± 1.19 Pseudomonas aeruginosa 16.73 ± 1.24 0 14.00 ± 0.00 Pseudomonas putida 17.67 ± 0.00 13.67 ± 1.41 16.50 ± 2.12 Salmonella typhymurium 26 , 00 ± 0.00 25.00 ± 0.00 25.50 ± 0.52 Staphylococcus aureus 23.17 ± 0.94 21.00 ± 0.00 23.92 ± 1.38 Antibacterial properties of stem extracts Ludwigia grandiflora. The results obtained are shown in Table 4. Table 4. Effects of stems extracts of Ludwigia grandiflora on the development of bacterial strains. The results presented are the diameters expressed in mm (n = 6). Month April May June July August September Bacillus megaterium 0 11.46 ± 0.50 0 0 0 0 Enterobacter aerogenes 0 12.92 ± 1.24 14.00 ± 4.49 10.67 ± 0.49 0 0 Enterococcus faecalis 10 , 17 ± 0.41 11.17 ± 0.39 10.00 ± 1.04 10.0 ± 1.04 9.33 ± 0.77 9.17 ± 0.77 Escherichia coli 1052 14.08 ± 1, 73 17.92 ± 4.23 15.92 ± 3.34 15.67 ± 2.06 9.00 ± 0.00 9.25 ± 0.45 Escherichia coli 6221 0 18.83 ± 3.04 14.00 ± 5 , 01 14,42 ± 1,16 0 0 25 Escherichia coli 6224 0 0 16,22 ± 1,17 0 18,00 ± 0,87 0 Klebsiella oxytoca 0 9,17 ± 0,37 10,00 ± 0,00 14.00 ± 0.00 9.17 ± 0.37 9.50 ± 0.50 Lactobacillus lactis 0 0 0 10.00 ± 0.00 11.00 ± 0.00 11.00 ± 0.00 Listeria grayi 0 0 0 0 10.33 ± 0.47 10.00 ± 0.00 Providencia rettgeri 0 11.75 ± 1.30 16.33 ± 1.55 16.50 ± 0.50 10.50 ± 0.50 12, 50 ± 0.87 Pseudomonas aeruginosa 0 0 16.80 ± 2.29 14.33 ± 2.09 9.00 ± 0.00 0 Pseudomonas putida 0 0 13.17 ± 2.83 17.00 ± 3.54 0 0 Salmonella typhymurium 0 0 18.00 ± 0.00 21.00 ± 0.00 10.00 ± 0.00 10.00 ± 0.00 Staphylococcus aureus 0 0 15.92 ± 0.90 17.50 ± 0 52 10.50 ± 2.15 8.75 ± 0.45 The results obtained states (see Tables 2, 3 and 4) show that the antibacterial activity of the extracts varies according to several parameters: - the period of development of the plant: the antibacterial properties appear from June, and their effect increases until August. Young plants that develop in May do not show any activity. - the organ of the plant (stems, leaves or flowers): the highest antibacterial activity is observed for leaf extracts and flower extracts. - The bacterial strains to which the extract is applied: the activity is manifested, more or less intense depending on the nature of the bacterial strain. But the measured activities do not depend on the Gram + or Gram- character of the strain, which tends to suggest that the action of the extracts is not specifically at the level of the synthesis of peptidoglycan, an essential component of the Gram + bacterial wall. Out of all the results obtained, the strains most sensitive to extracts of Ludwigia grandiflora were found to be the strain of Salmonella typhimurium and the strain of Staphylococcus aureus.

For most of the extracts studied, a bactericidal effect, even bacteriolytic, but rarely bacteriostatic was observed. 26. Antifungal activity of extracts of Ludwigia grandiflora An activity on a strain of Candida albicans, pathogenic yeast, causing intestinal infections, oral or gynecological, was observed with an extract of leaves of Ludwigia grandiflora harvested in August (Figure 1). The mean diameter of the inhibition halos is 30.00 mm ± 0.00 mm. 3. Fractionation of a Ludwigia grandiflora extract Silica column splits were performed on an extract of Ludwigia grandiflora leaves harvested in August. A first fractionation carried out with a petroleum ether / ethyl ether (not 10) gradient made it possible to eliminate non-active apolar fractions on the strain of Staphylococcus aureus, bacterium taken to witness an antibacterial activity. On the active part of the extract, a gradient of ethyl ether / dichloromethane / methanol polarity, for a total volume of 400 ml, led to the production of 29 samples which were named subfractions (Table 5). Depending on the characteristics of the spots observed in thin layer chromatography, these subfractions were combined into 7 fractions (F1 to F7) according to the distribution specified in Table 6. An antiobiogram was performed on the strain Staphylococcus aureus with disks. impregnated with 15 μL of each of these fractions (as described above). The results obtained are shown in Table 6. Table 5. Fractionation of the active part of the leaf extract of Ludwigia grandiflora in a gradient of ethyl ether - dichloromethane - methanol No. subfractions Ethyl ether (%) Dichloromethane (%) Methanol (%) 0 100 0 0 1 0 99 1 2 0 98 2 3 0 97 3 4 0 96 4 5 0 95 5 6 0 94 6 27 0 93 7 8 0 92 8 9 0 91 9 10 0 90 10 11 0 89 11 12 0 88 12 13 0 87 13 14 0 86 14 15 0 85 15 16 0 84 16 17 0 83 17 18 0 82 18 19 0 81 19 20 0 80 20 21 0 79 21 22 0 78 22 23 0 75 25 Table 6. Diameters of the S. aureus strain inhibition halos, expressed in millimeters, obtained by the method of US Pat. antibiograms with fractions F1 to F7, and with unfractionated extract. Staphylococcus aureus extract fractions and subfractions of Table 5 (Inhibition halo diameters expressed in parentheses mm) F1 (1-6) 17.00 ± 0.00 F2 (7-11) 27.17 ± 1 , 17 F3 (12-15) 25.00 ± 0.00 F4 (16-19) 36.00 ± 0.00 F5 (20-25) 34.00 ± 0.00 F6 (30-75) 23.50 ± 0.55 F7 (100 - 100) 0.00 ± 0.00 Unfractionated extract 22.58 ± 0.51 Purification of the extract seems to demonstrate that the action of all the antibacterial molecules it contains does not not act in synergy. The bacterial activities of the fractions F4 and F5 (diameter of the inhibition halos 28 respectively equal to 36.00 mm ± 0.00 and 34.00 mm ± 0.00) are 1.5 times greater than those of the crude extract (Inhibition halo diameter = 22.58 mm ± 0.51) and therefore contain the molecules that would be more active, and / or would be in higher concentration. 29

Claims (6)

REVENDICATIONS1. Extract of a plant of the species Ludwigia grandiflora for its use as an antibacterial agent against Gram-negative bacteria. 2. Extract of a plant of the species Ludwigia grandiflora for use as antifungal agent. 3. Extract from a plant of the species Ludwigia grandiflora, characterized in that the plant is harvested during the flowering period of Ludwigia grandiflora, preferably in June, July and / or August. 4. Extract according to any one of claims 1 to 3 characterized in that the extract is an entire plant extract or part of a plant selected from roots, stems, leaves, flowers and any combination of said parts, preferably an extract of the leaves and / or flowers, more preferably still an extract of flowers. 5. Extract according to any one of claims 1, 2 and 4, characterized in that the plant is taken during the flowering period of Ludwigia grandiflora, in June, July, August or September, preferably in June, July and / or August. 6. Extract according to any one of claims 1 to 5, characterized in that the extract is obtained by: - washing with water of the sampled plant, - drying of the plant or part of the washed plant - grinding the plant or part of the plant to reduce it to powder, - extraction of the powder with a solvent, preferably water or dimethylsulfoxide.30. An extract as claimed in any one of claims 3 to 6 for use as a medicament. 8. Extract according to any one of claims 3 to 6 for its use as an antibacterial agent in antibiotic therapy. 9. Extract according to claim 8, characterized in that the antibiotic treatment is directed against a Gram-positive bacterium or a gram-negative bacterium 10. Pharmaceutical composition comprising at least one extract according to any one of claims 1 to 6 and at least one physiologically acceptable vehicle or excipient. 11. Cosmetic composition comprising at least one extract according to any one of claims 1 to 6 and at least one cosmetologically acceptable vehicle or excipient. 12. Use of an extract according to any one of claims 1 to 6 as an antimicrobial agent for cleaning, decontaminating or disinfecting surfaces. 13. Use of an extract according to any one of claims 1 to 6 as an agent for the preservation of a cosmetic product, a food product or a pharmaceutical product. 14. Use of an extract according to any one of claims 1 to 6 for clarifying and / or purifying stagnant water. Cleaning, decontamination or disinfecting product containing an extract according to any one of claims 1 to 6. 16. Product according to claim 15, characterized in that the product is intended to clarify and / or purify a stagnant water. . 31. Food product containing an extract according to any one of claims 1 to 6. 18. Agricultural product containing an extract according to any one of revendicatios 1 to 6. 32