WO2005072529A1

WO2005072529A1 - Compositions for use as biocides and biostatics and uses of said compositions

Info

Publication number: WO2005072529A1
Application number: PCT/GB2005/000338
Authority: WO
Inventors: Peter Whitton
Original assignee: Phyto-Research Ltd
Priority date: 2004-01-29
Filing date: 2005-01-31
Publication date: 2005-08-11
Also published as: GB0401964D0; GB2410435A

Abstract

A composition for use as a biostatic or biocide comprising one or more lactones and, wherein said one or more lactones is/are compounds of the general Formula (I) or Formula (II) below, wherein R1, R2, R4, R5 and R6 are independently selected form H, -OH, C1-10 alkyls, C6-10 arylalkyl, C6-10 aryl, C6-10 alkylaryl, halides, and R3 is a C1-C40 alkyl, C6-40 arly or arylalkyl or C6-C40 arylalkylene group.

Description

Compositions' for use as biocides and biostatics and uses of said compositions

The present invention relates to compositions for use as a biostatic or biocide, and in particular to fungistatic and/or bacteriostatic compositions suitable for the treatment and prevention of diseases such as crown rot in plants . Fungal diseases among fruit plants can be detrimental to their fruit production and may be fatal to the affected plants. Due to the damaging effect the diseases have commercially on crop growers, much research has been focussed on finding effective fungicides that selectively target the deleterious fungus, without harming the plant or affecting its fruit production.

A particular fungal disease that is detrimental to plants is that of crown rot. Crown rot is caused by fungal strains such as those from the Phytophthora species and those selected from Fusarium pallidoroseum, Colletotrichum musae, Verticillium theobromae, Ceratocytis paradoxa, Lasiodiplodia theobromae. Crown rot has been found to affect many fruit trees, such as, for example, banana trees, apple trees, pineapples trees, cherry trees, peach trees. Crown rot is somewhat similar to root rot.

Prior methods used to prevent crown rot include treating plants with poly-aromatic hydrocarbons, organophosphates and organochlorides . However, the disadvantages of these methods of the prior art are that the fungicides may be detrimental to human health if consumed in large quantities. There is also concern that these synthetic compounds could be harmful to the environment. In addition, some of the fungicides of the prior art are not readily biodegraded which means that they remain harmful in the environment long after they have been applied. Many of the environmentally harmful compounds of the prior art either have been banned in the US or Europe or will be banned under impending EU and US legislation. The present invention aims to address at least some of the problems presented by the prior art.

The present invention provides a composition for use as a biostatic or biocide comprising one or more lactones, wherein said one or more lactones is/are compounds of the general formula (I) and/or formula (II) below:

(i) in) wherein Rl, R2 , R4 , R5 and R6 are independently selected from H, -OH, OMe, OEt, Cl-10 alkyls, C6-10 aryl or arylalkyl, C6-10 alkylaryl, halides, and R3 is a C1-C40 alkyl, C6-40 aryl or arylalkyl or C6-C40 arylalkylene group. The present invention also provides a use of a composition of the present invention as a biocide and/or as a biostatic.

The present invention also provides a method for protecting a plant or its propagation material from a fungal disease, or treating a plant having a fungal disease or its propagation material having a fungal disease, said method comprising contacting a plant or its propagation material with an fungicidally effective amount of the composition of the present invention.

The present invention further provides use of a composition of the present invention in the manufacture of a medicament for the treatment of fungal infections of humans or animals.

Figure 1 shows formula (I) and formula (II), as described above, illustrating the two possible structures of the lactones of the present invention.

Preferably, for the compound of formula (I) above, the stereochemistry is as shown in the compound of formula (III) below, wherein the substituents are defined as above or as in the description below:

( I I I )

Preferably, the Cl-10 alkyl is CI to C6 alkyl, more preferably, CI to C4 alkyl, most preferably CI to C2 alkyl.

Preferably, the C6-10 arylalkyl is C7 to CIO arylalkyl, more preferably, C8 , C9 or CIO arylalkyl, most preferably C8 arylalkyl .

Preferably, the Cβ-10 alkylaryl is C7 to CIO alkylaryl, more preferably, C8, C9 or CIO alkylaryl, most preferably C8 alkylaryl . Preferably, the alkyl or alkylene group in the arylalkyl or arylalkylene group, respectively, is a C2 to C5 alkyl or C2 to C5 alkylene, respectively, more preferably C2 to C4 alkyl or C2 to C4 alkylene, respectively, even more preferably C2 to C3 alkyl or C2 to C3 alkylene, respectively, and most preferably C2 alkyl or C2 alkylene, respectively.

Preferably, the alkyls are straight-chain alkyls, meaning that there are no carbon atoms attached as a side group to the chain of carbon atoms in the alkyl group.

Preferably, R4 and R5 are independently selected from H and OH . "Biostatic" includes, but is not limited to, a substance able to prevent growth of one or more types of microorganisms . "Biocide" includes, but is not limited to, a substance able to kill at least one or more types of microorganism. "Microorganism" includes, but is not limited to, bacteria, fungi and yeasts.

"Fungicidally effective amount", as would be appreciated by the skilled person, would be dependent on the nature of the fungal disease, the extent to which the plant or its propagation material was affected by the fungal disease, and the amount (i.e. concentration or percentage) of lactone(s) in the composition. To be "fungicidally effective", the composition must act to some extent on the fungus being treated as a fungicide or a fungistatic.

In the composition of the present invention, preferably -R3 is a group of the formula (IV) or formula (V) below

where x, y and z are independently any number from 0 to 5, preferably 1 to 4, more preferably 1 to 3 , still more preferably 1 to 2 and most preferably 1 and R7 , R8 , R9, RIO and Rll are independently selected from H, -OH, Cl-10 alkyls, Cl-10 arylalkyl, Cl-10 alkylaryl, and halides.

The aryl groups in any of the compounds defined above may be phenyl or napthyl , most preferably phenyl . Preferably, Rl is Me; R2 , R4 and R5 are each H.

Preferably, x is 0, z is 0 and y is 1.

Preferably, when R3 contains the HRC=CHR double bond, wherein R indicates a continuation of connected atoms at either end of the bond, the R groups are 'trans' with respect to one another, rather than a cis configuration.

Preferably, the one or more lactones are a compound (s) of any one of the formulas (VI) to (IX) below:

(see next page)

(VI ) (VI I )

wherein Rl is a Cl-4 alkyl, preferably a Cl-2 alkyl and most preferably methyl; R2 , R4 , R5 , R6, R7, R8 , R9, RIO and Rll are independently selected from H, OH, OMe, OEt, halides, NMe2 , NMeEt , NEt2 C02H, C02Me . Any two adjacent carbon atoms on the phenyl ring may be joined by means of the group -0- (CH2) -O- .

"Halides" includes fluorine, chlorine, bromine and iodine . Preferably, the lactone is obtainable from the Piper methysticum plant. The lactones obtainable from the Piper methysticum plant may be produced by extraction of the lactones from the plant. Methods of extraction are known to those skilled in the art. Extraction is often carried out using solvents such as ethanol, water, dichloromethane, and acetone, and combinations thereof. However, the invention is not intended to be limited to use of lactones prepared by solvent extraction. Most preferred is ethanol or acetone. The ethanol may be laboratory strength ethanol, that is ethanol containing around 96% ethanol. Techniques of extraction of lactone from Piper methysticum are described in Phytochemistry 64 (2003) 673-679, hitton et al . It should be noted that Piper methysticum is sometimes referred to as kava kava or the Kava plant in the literature.

Alternatively, the lactones may be synthesised from other chemical compounds. By way of example, syntheses of Kavain, Dihydro-kavain, di-hydromethysticin, methysticin, 5 , 6-dehydromethysticin, demethoxyyangonin, limethoxyyangonin, 11-methoxynoryangonin and yangonin are documented in the following paper and book: Israili ZH, Smissman EE, Synthesis of kavain, dihydrokavain, and analogues, J. Org Chem 1976, Dec 24, 41 (26) : 4070-74 and

Lebot, 1992 and Lebot, V., Merlin, M. , Lindstrom, L. 1992. Kava: The Pacific Drug. New Haven: Yale University Press.

Other lactones of the general formula (I) or (II) above are also obtainable by chemical synthesis, as would be appreciated by the skilled person.

Preferably, the lactone (s) is/are selected from kavain, 7 , 8-dihydrokavain, 5, 6-dehydrokavain, yangonin, 5,6, 7,8- tetrahydroyangonin, methysticin, dihydromethysticin, 5,6- dehydromethysticin, 5,6 -dihydroyangonin, 7,8- dihydroyangonin, 10-methoxyyangonin, 11-methoxyyangonin, 11- hydroxyyangonin, hydroxykavain and ll-methoxy-12- hydroxydehydrokavain .

The composition of the invention may further comprise a polar solvent. The polar solvent may comprise one or more of water, ethanol, dimethylsulphoxide and dimethylsulphoxone . The dimethylsuphoxone may be obtained by aqueous extraction from Equisetum Arvense and related species. Most preferred is dimethylsulphoxide . Dimethylsulphoxide is particularly preferred as the solution has been found to penetrate the skins of fruit, particularly bananas, only to a very limited extent, if at all in some cases. Hence, if the composition of the present invention was dissolved in dimethylsulphoxide, the composition would not accumulate to any significant degree, if at all, in the interior of the treated fruits, that is in or beneath the skin of the fruit .

Further, it has been found that dimethylsulphoxide is able to dissolve the lactones up to a concentration of 20% weight/volume . This allows for transportation of large quantities of the lactone-containing solvent to the site of intended use. The solvent may then be diluted at the site, preferably with water, to a preferred usage concentration of from 0.1% to 5% w/v, preferably of from 0.1 to 1 w/v, and most preferably of from 0.2% to 0.5%, w/v.

Preferably, if the composition comprises a polar solvent, the total amount of one or more lactones in the solvent is from 0.01 to 50%, w/v. More preferably of from 0.1 to 5%, w/v, and most preferably of from 0.2 to 0.5%, w/v.

In a most preferred embodiment, the present invention also provides a biostatic or biocidal composition comprising an extract of one or more lactones from the Piper methysticum plant and a polar liquid comprising or consisting essentially of dimethylsulphoxide . Preferably, the composition of the present invention further comprises one or more other insecticides, fungicides, nematocides, bactericides, acaricides, growth regulators, chemosterilants, semiochemicals, repellents, attractants, pheromones, feeding stimulants or other biologically active compounds to form a multicomponent biocidal or biostatic composition. This may give an even broader spectrum of agricultural protection.

The composition may be in the form of, inter alia, a paste, liquid, paint, spray or aerosol or solid. Said solid includes, but is not limited to, powdered, pelletised, tablet and compressed form.

The present invention also provides a plant, or part thereof, coated at least in part with the composition according to the present invention. Preferably this plant is a fruit tree. Most preferably, this plant is a banana tree, apple tree, cherry tree, peach tree, pear tree, plum tree, pineapple tree or coffee tree.

The present invention also provides the use of a composition of the present invention as a biocide or biostatic. Preferably, the use of composition of the present invention is as a biostatic, most preferably fungistatic. It is believed from preliminary tests that the composition of the present invention acts as a fungistatic against some bacteria, yeasts and fungi. However, it is conceivable that it may act as biocide against a small proportion of the tested bacteria, yeasts and fungi.

Preferably, the fungus being targeted is crown rot, root rot, or any disease caused by the Phytophthora species of fungus .

The present invention also provides a method for protecting a plant or its propagation material from a fungal disease, or treating a plant or part thereof or its propagation material having a fungal disease, said method comprising contacting a plant, a portion thereof, its propagation material or its growth medium with a fungicidally effective amount of a composition of the present invention.

Preferably, the fungal disease being treated or prevented is crown rot, root rot, or any disease caused by the Phytophthora species of fungus. The fungal disease may be caused by a fungal strain that is selected from Fusarium pallidoroseum, Colletotrichum musae, Verticillium theobromae, Ceratocytis paradoxa, Lasiodiplodia theobromae. Disease control in plants may be effected by applying an effective amount of the composition, either pre- or post- infection with the disease to a portion of the plant to be protected. The portions of the plant to be treated include, but are not limited to, the roots, stems, foliage, fruit, seeds, tubers or bulbs, or to the media (e.g. soil, sand or water) in which the plants are growing. The composition may also be applied to the seeds or seedlings.

The site of application on the plant, the amount supplied and the treatment schedule may vary depending on the nature of the disease it is intended to treat or prevent.

Propagation material includes seeds, cuttings, spores, fruit separated from a plant, or any other part of a plant that will allow reproduction or growth of a new plant.

The amount of the composition applied to plants may be in the range of from lOg per hectare to 5000g per hectare.

The amount of the composition applied to seeds may be in the range of from one kilo per tonne to ten kg per tonne,

The composition of the present invention is applicable in a wide variety of circumstances and to any substance in which or on which fungus has grown or may grow. Various uses of the present invention will be discussed below.

The present invention also provides a coating composition comprising a composition of the present invention. The composition may be used as an additive to any coating composition in order to provide protection against fungal growth, e.g. it can be used as the active ingredient in anti-fungal paints. Said paint may be a paint for use in domestic environments, such as a top-coat, undercoat. Surface forming paints typically comprise a film-forming component, a solvent or thinner, an organic or inorganic pigment and optionally one or more additives such as fillers and extenders. The typical components of a paint are well known to those skilled in the art. Said paint may be unpigmented. Said coating composition may be an anti- fungal paint designed specifically and only for the purpose of treating fungus and/or bacteria.

The composition of the present invention is generally useful as an anti-fungal or anti-bacterial agent. Thus, the present invention provides a method for the prevention of growth of, or treatment of, fungi or bacteria in a liquid or on or in a substrate, said method comprising contacting a composition according to the present invention with said liquid or substrate. A substrate in the present context includes, but is not limited to, any solid or semi solid object .

The liquid may be selected from any one of: water for use as coolant in mechanical industrial processes, water in cooling towers for air conditioning systems, water in papermaking, water in recycling rinse water for washing processes, water from a human effluent treatment plant.

The liquid or substrate may be a pharmaceutical product a precursor to said pharmaceutical product, and any object upon which fungi or bacteria may grow. Such objects may be those found in a medical or surgical environments, for example a surgical or medical device or part thereof. Examples of objects that may be treated include, but are not limited to, surgical implements, gloves, storage receptacles, furniture and face masks typically worn in a medical environment. The present invention may also be used to treat clothes.

The pharmaceutical product may be suitable for consumption, topical application, or application to the ocular region of an animal or human. A substrate for application to the ocular region includes, but is not limited to, a contact lens. The composition could also be added to a contact lens solution to prevent the growth of fungi therein.

The liquid or substrate may be a cosmetic product or a toiletry for use by humans or animals, or a precursor to said cosmetic product or toiletry. Cosmetic products include, but are not limited to, lipsticks, make-up, moisturisers, eye-liner and nail applications. As mentioned above, the present invention also provides use of a composition of the present invention as biostatic or a biocide. Said use may be as a biostatic or a biocide in or on a cosmetics product, a pharmaceutical product, a food product, a cleaning product, a paint, staining product, a varnish, clothing, footwear, a plant, a medium for the growth of bacterial or fungal cultures .

The present invention also provides a method of preparing a biostatic or biocidal composition, said method comprising providing a Piper methysticum plant, extracting an extract comprising kava lactones from the Piper methysticum plant with a polar solvent removing more than 95 % by weight of the polar solvent from the extract to form the biostatic or biocidal composition.

The composition thus obtained may be combined with dimethylsuphoxide to form a concentrate of the biocidal composition. Said concentrate can either be used without further dilution to treat fungi or bacteria or it may be diluted with a polar solvent to a desired concentration, as would be appreciated by the skilled person.

The present invention also provides a cosmetics product, a pharmaceutical product, a food product, a cleaning product, a paint, staining product, a varnish, a plant, a medium for the growth of bacterial or fungal cultures, all of which comprise a composition of the present invention.

The present invention also provides a method for the treatment of fungi or bacteria in a liquid, said method comprising contacting a composition of the present invention with the liquid. By "treatment of fungi or bacteria", this includes using the composition to kill at least some of the fungi or bacteria in a liquid or act as a biostatic against at least some of the fungi or bacteria in a liquid.

The liquid to be treated may be, for example, cooling water, soap solutions or other industrial liquids. While not being bound by theory, it is believed that the lactones prevent the functioning of Cytochrome P450 enzymes within the fungi or bacteria.

The invention may be further understood with reference to the following non-limiting experimental Examples.

Examples

The kavalactones may be extracted as a mixture from the kava kava plant by a number of ways including maceration of the root in a suitable solvent (ethanol or acetone) and then by evaporation of the solvent, or by supercritical carbon dioxide extraction. The lactones are available commercially as a paste produced by either of these techniques . The pastes commercially available typically contain 60 to 75% by weight of kavalactones. In order to treat crown rot the product is diluted to the correct level (approximately 0.25% of the concentrate in water) and applied directly to the crown of the fruit either by painting or spraying or dipping the fruit in a bath of the solution. Ideally, for maximum efficacy, the entire crown affected by the fungus has the solution applied to it.

The paste used in the present Examples contained 70% kavalactones, by weight.

The compositions of the present invention are typically solution stable in bottle, with no deposit forming in the original bottle. When mixed with a culture medium a yellow/brown suspension is seen to be formed.

Storage of substance

The preparation was stored at room temperature in the original container, tightly capped in an uncontaminated atmosphere, in the dark in a locked cupboard in a locked room. - li

Materials and methods

Microbial species used:

The three species of bacteria, one yeast and one mycelial fungus are tabulated as follows:

Media and Growth conditions

Complex media (as per BP Appendix XVI) Casein-Soybean Digest Agar BP USP (Oxoid CM131 batch no 260257) was used for purity tests on the bacteria Sabouraud Broth BP, USP (Oxoid product no CM147 batch no 46613) for inhibition tests on yeast and fungus

Defined medium (as per Kelsey-Sykes test) ( Kelsey & Maurer, 1974) AOAC synthetic broth (Difco product no 235220 lot no 0054005), used for inhibition tests on all microbes. For the growth of bacteria in AOAC medium glucose was added aseptically to the medium to give a final concentration of 0,1% w/v. For the growth of fungi and yeast, glucose was added to a final concentration of 2% w/v.

Recovery medium (as per Kelsey -Sykes test) (Kelsey & Maurer, 1974)

For solid media, Agar No 1 (Oxoid product Lll, batch no. 127 40182) was added to a final concentration of 12g/ .

Liquid cultures were incubated with shaking at 32 °C for bacteria and at 26 °C (the lowest temperature achievable) for yeast and fungus .

The preparation of the composition of the present invention (20% w/v kavalactones) was diluted to give concentrations in Sabouraud and AOAC culture media ranging from 20mg/mL to 2μg/ml.

Four sets ^'of dilutions in both media were prepared, and duplicate sets were inoculated with Aspergillus and Candida at the densities indicated below. Cultures of organisms and in each medium were incubated both with aeration by shaking and statically, without shaking.

Media containing concentrations of substance greater than an 0,06% v/v dilution (120μg/mL) were turbid, so that growth could be determined unequivocally only by subculture. This was done semi -quantitatively by using calibrated disposable loops of lOμL capacity, with an intermediate dilution step of 10-3 and plating on Sabouraud agar to estimate the number of yeast growing and on TSA to check for purity (i.e. absence of bacteria).

Results The growth of S. aureus was delayed for 24h by dilutions of 0,03% v/v antifungal preparation (MIC 3 μg/ml) , This effect appeared to a bacteriostatic rather than a bactericidal activity, as subculturing of the tubes showing inhibition into recovery medium (though not into nutrient broth) showed rapid growth.

Bold = >10 x growth above inoculum; unbolded numbers approximately equal to inoculum

In summary mould and yeast growth was only apparent after sub-culturing and so the fungi-static properties of the preparation have been demonstrated at the dilutions shown in the table above.

Toxicity tests

Toxicity testing was undertaken using human liver cells as the only ever reports of possible toxic reactions to the compounds present in these extracts has been in liver tissue. The other benefits of using human liver cells in culture is that they are extremely sensitive to any toxins and so give good indications of the potential toxicity of the substance. A review of toxicity data on humans compiled by the Medicines and Health Related Products Agency (UK) has shown that toxicity is only possible in humans ingesting above the equivalent of 1.2 litres of the product per day (this data is from patients with damaged livers) . In a normal healthy person the toxicity is far lower and equates to a person ingesting 1400 litres in one dose. The IC50 is calculated at 1200g/KG bodyweight .

In conclusion it can be stated that the composition of the present invention is an effective and safe method of providing protection against fungal attack to many products.

The composition of the present invention is a new form of anti-mould and anti-fungal treatment designed to work in many different applications ranging from agriculture and fresh food use to prevention of mould and athletes foot in footwear applications.

The composition of the present invention may also be used in the treatment of timber and plaster for the building and construction trades and also in anti fungal paints, stains and varnishes to be used in the remediation of contaminated buildings . The composition of the present invention is also effective in the manufacture of soaps and cleaning materials as it provides the products with anti-fungal capabilities. It can also be used as an effective natural preservative in cosmetics and toiletries.

The effects of the composition of the present invention can be diluted out to allow growth of bacteria and fungi if desired and so it can be used for storage and preservation of scientific library samples of fungi.

The composition of the present invention is unique in its mode of action and it is believed will not prove toxic to marine life.

Unlike the toxic anti-fungal products of the prior art the composition of the present invention is not apparently toxic to the fungi, at least in the concentrations used in the Examples above, in the accepted sense i.e. it does seem not kill the fungus.

In order to control mould and fungi, it is not necessary to kill them, only to render them inactive. Without being bound by theory, it is believed that the composition of the present invention acts by inhibiting the metabolism of the fungi at the level of the cytochrome P450 enzymes so the fungi are unable to grow. This means that as long as the fungi are in contact with the composition of the present invention they will not be able to grow or reproduce. This mechanism of control is preferable to toxic methods as danger from fungi is not necessarily due to the presence of the fungi. Therefore a toxic anti-fungal can be used to treat a food substance that is contaminated with Aspergillus which will kill off the fungus but leave the potentially fatal aflatoxins intact. The reason that this fungus is dangerous is purely because it produces these toxins .

Any method of controlling moulds must only prevent the growth of the moulds and this is precisely what the composition of the present invention is believed to do. It performs this function via natural biological pathways and so is not toxic in the conventional sense. In fact tests have shown that in order for an average person to be harmed by the product they would have to drink 1400 litres of the finished product for it to be harmful to them. Obviously it would be impossible for this amount of the product to be ingested in one sitting and our tests show that the product is not accumulated in the body so in order for the product to be toxic to humans then they would have to consume this amount of the product in one dose .

Evaluation of the product has also shown that the composition of the present invention works well at preventing the growth of the major classes of plant pathogenic fungi and also has some effect against bacteria although this is not its primary function.

Claims

CLAIMS:

1. A composition for use as a biostatic or biocide comprising one or more lactones and, wherein said one or more lactones is/are compounds of the general formula (I) or formula (II) below:

(i) (ID wherein Rl , R2 , R , R5 and R6 are independently selected from H, -OH, Cl-10 alkyls, C6-10 arylalkyl, C6-10 aryl, C6-10 alkylaryl, halides, and R3 is a C1-C40 alkyl, C6-40 aryl or arylalkyl or C6-C40 arylalkylene group .

2. A composition as claimed in claim 1, wherein --R3 is a group of the formula (IV) or formula (V) below

wherein x, y and z are independently any number from 0 to 5 and R7, R8 , R9, RIO and Rll are independently selected from H, -OH, -OMe, -C02H, C02Me, C02Et, Cl-10 alkyls, Cl-10 arylalkyl, Cl-10 alkylaryl, and halides.

3. A composition as claimed in claim 1 or claim 2, wherein Rl is Me and R2 , R4 and R5 are each H.

4. A composition as claimed in claim 2 or claim 3, wherein x is 0, z is 0 and y is 1.

5. A composition as claimed in any one of the preceding claims, wherein the lactone is obtainable from the Piper methysticum plant.

6. A composition as claimed in any one of the preceding claims, wherein the lactone is selected from kavain, 7, 8-dihydrokavain, 5, 6-dehydrokavain, yangonin, 5,6, 7, 8-tetrahydroyangonin, methysticin, dihydromethysticin, 5, 6-dehydromethysticin, 5,6 -dihydroyangonin, 7,8- dihydroyangonin, 10-methoxyyangonin, 11-methoxyyangonin, 11- hydroxyyangonin, hydroxykavain and ll-methoxy-12- hydroxydehydrokavain.

7. A composition as claimed in any one of the preceding claims, said composition further comprising a polar solvent .

8. A composition as claimed in claim 7, wherein the polar solvent comprises one or more of water, ethanol and dimethylsulphoxide .

9. A composition as claimed in claim 7 or claim 8, wherein the lactone (s) is/are present in the solvent in a amount of from 0.01 to 50%, w/v.

10. A composition as claimed in claim 9, wherein the lactone (s) is/are present in the solvent in an amount of from 0.1 to 2%, w/v.

11. A composition as claimed in claim 9, wherein the lactone (s) is/are present in the solvent in an amount of from 0.2 to 0.3%, w/v.

12. A composition as claimed in any one of the preceding claims which further comprises one or more other insecticides, fungicides, nematocides, bactericides, acaricides, growth regulators, chemosterilants, semiochemicals, repellents, attractants, pheromones, feeding stimulants or other biologically active compounds

13. A composition as claimed in any one of the preceding claims in the form of a liquid, paint, spray or aerosol.

14. A composition as claimed in any one of claims 1 to 6 and 12 in the form of a solid.

15. A plant coated at least in part with the composition as claimed in any one of the preceding claims.

16. Use of a composition as claimed in any one of claims 1 to 13 as a biostatic or a biocide.

17. Use of a composition as claimed in claim 16, wherein the composition is used as a fungistatic or a fungicide .

18 Use of a composition as claimed in claim 17, wherein the composition is used as a fungistatic or a fungicide against the Phytophthora species of fungus.

19. A use as claimed in claim 17, wherein the composition is used as a fungistatic or a fungicide against crown rot or root rot.

20. A method for protecting a plant or part thereof or its propagation material from a fungal disease, or treating a plant having a fungal disease or its propagation material having a fungal disease, said method comprising contacting a plant or part thereof, its propagation material or its growth medium with a fungicidally effective amount of a composition as defined in anyone of claims 1 to 13.

21. A method as claimed in claim 20, wherein the fungal disease is crown rot.

22. A method as claimed in claim 20 or claim 21, wherein the fungal disease is caused by a fungal strain that is selected from Fusarium pallidoroseum, Colletotrichum musae, Verticillium theobromae, Ceratocytis paradoxa, Lasiodiplodia theobromae.

23. A method as claimed in any one of claims 20 to 22, wherein the propagation material is a seed.

24. A coating composition comprising a composition as defined in any one of claims 1 to 14.

25. A coating composition as claimed in claim 24, wherein said coating composition is a paint.

26. A method for the prevention of growth of, or treatment of, fungi or bacteria in a liquid or on a substrate, said method comprising contacting a composition as claimed in any one of claims 1 to 14 with said liquid or substrate.

27. A method as claimed in claim 26, wherein the liquid is any one of water for use as coolant in mechanical industrial processes, water in cooling towers for air conditioning systems, water in papermaking, water in recycling rinse water for washing processes, water from a human effluent treatment plant.

28. A method as claimed in claim 26, wherein the liquid or substrate is a pharmaceutical product, a precursor to said pharmaceutical product, a medical or surgical device or part thereof .

29. A method as claimed in claim 26, wherein the liquid or substrate is a cosmetic product or a toiletry for use by humans or animals, or a precursor to said cosmetic product or toiletry.

30. A biostatic or biocidal composition comprising an extract of one or more lactones from the Piper methysticum plant and a polar liquid comprising or consisting essentially of dimethylsulphoxide .

31. A use of a composition as claimed in claim 16, wherein the composition is used as a biostatic or a biocide in or on a cosmetics product, a pharmaceutical product, a medical or surgical device or part thereof, a food product, a cleaning product, a paint, staining product, a varnish, a plant, a medium for the growth of bacterial or fungal cultures.

32. A product comprising a composition as claimed in any one of claims 1 to 14, said product being selected from a cosmetics product, a pharmaceutical product, a food product, a cleaning product, a paint, staining product, a varnish, clothing, footwear, a plant and a medium for the growth of bacterial or fungal cultures .

33. A method of preparing a biostatic or biocidal composition, said method comprising providing a Piper methysticum plant, extracting an extract comprising kava lactones from the Piper methysticum plant with a polar solvent removing more than 95 % by weight of the polar solvent from the extract to form the biostatic biocidal composition.

34. A method as claimed in claim 33, wherein the composition is combined with dimethylsuphoxide to form a concentrate of the composition.

35. Use of a composition as claimed in any one of claims 1 to 14 in the manufacture of a medicament for the treatment of fungal or bacterial infections of humans or animals .