GB2624905A - Stable allyl sulfide compositions - Google Patents

Abstract

Storage stable agricultural composition comprising one or more allyl sulfide compounds (e.g. diallyl sulfide, diallyl disulfide, diallyl trisulfide, diallyl tetrasulfide) and at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment wherein the composition is characterised by a pH of less than 6.5. The allyl sulfide compounds may be extracts of garlic. The composition may be aqueous-based and/or a concentrate. Also claimed is a storage stable composition garlic extract oil, water, an emulsifier and/or surfactant (ethoxylated castor oil) and an acid (e.g. phosphoric acid), wherein the composition is characterised by a pH of less than 6.5. Such a composition may further comprise an antifreeze agent (silicone emulsion) and an antifoam agent (e.g. polypropylene glycol). Most preferably, such a composition has a pH of 5.5 and is more chemically stable to degradative processes as compared with a similar aqueous-based composition at a pH of ≥ 6.5.

Description

Stable Ally' Sulfide Compositions

Background

Essential oils have been used since ancient times as pesticides and repellants. Garlic has been used for many years as an animal and insect repellent and its antimicrobial, pesticidal and fungicidal properties have been extensively studied.

Garlic Essential Oil is a natural repellent against sucking mid plowing insects, it has a dissuasive action on the feeding habits of insect infestations and it obstructs the action of natural pheromones causing disorientation to insects during their reproduction stage. The success of Garlic Essential Oil, as an agricultural pesticide, etc. has been apparently limited due to the low storage stability of its active components, particularly allyl sulfide compounds which may account for its reportedly relatively low efficacy.

Field of the Invention

This invention relates to the field of pesticide control, and to stable, and particularly, storage stable, compositions and methods useful for controlling pests including insects, arthropods, mites, lepidopterous larvae, thrips etc., and fungi without limitation, especially in agricultural environments.

Summary

The present invention provides stable and storage stable agricultural compositions comprising one or more allyl sulfide compounds and at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment characterized by a pH less than 6.5.

The one or more allyl sulfide compounds are typically those extracted from natural sources exemplified by extracts of garlic, a notable example being Garlic Essential Oil.

The present invention provides stable agricultural compositions comprising one or more organosulfur compounds (OSC) comprising at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment characterized by a pH measured in aqueous environment of between 3.7 ±5% and and about 6 with the proviso that the pH remains less than 6.5 at the time of compounding and over the period of storage.

The organosulfur compound is preferably one or more allyl sulfide compounds. The organosulfur compounds are typically those extracted from natural sources exemplified by extracts of garlic.

The present invention provides stable aqueous compositions comprising organosulfur compounds (OSC) comprising at least one acid, wherein the composition is characterized by a pH less than 6.5. In notable embodiments the composition is an emulsion, microcmulsion or nanocmulsion.

The present invention provides stable agricultural compositions comprising diallyl disulfide comprising at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment characterized by a pH less than 6 5 The present invention provides storage stable agricultural compositions comprising diallyl disulfide comprising at least one acid, wherein the composition is acidic measured in aqueous environment is between 3.7 +5% and and 6 with the proviso that the pH remains less than 6 5 at the time of compounding and over the period of storage.The present invention provides storage stable agricultural compositions comprising organosulfur compounds (OSC) comprising at least one AO sulfide compound selected from the group of, diallyl sulfide (DAS); diallyl disulfide (DAS2) and combinations thereof, and at least one acid, wherein the composition comprises greater or equal to 90%, preferably 95%, of undegraded organosulfur compounds (OSC) after storage at so-called "Accelerated Storage" conditions as exemplified by storage at 54°C for 14 days or at 40°C for 80 days, or any comparable accelerated storage conditions, as compared to the organosulfur compounds (OSC) content after compounding, most typically measured immediately prior to storage.

The storage stable agricultural compositions comprising organosulfur compounds (OSC) of the invention are characterized in that they comprise an extract of garlic and the organosulfur compounds comprise one or more of, diallyl sulfide (DAS), diallyl disulfide (DAS2), diallyl trisulfide (DAS3) and diallyl tetrasulfidc (DAS4).

The present invention provides stable agricultural compositions comprising organosulfur compounds (OSC) comprising at least one of, diallyl sulfide (DAS) and diallyl disulfide (DAS2), and at least one acid, wherein the compositions of the invention, are more chemically stable to degradative processes as compared to similar aqueous-based compositions characterized by pH >6.5. The term similar aqueous-based composition, refers to compositions having the equivalent ingredients but lacking the acid or including an amount of acid insufficient to provide a pH below 6.5.

The present invention provides storage stable agricultural compositions comprising organosulfur compounds (OSC) comprising at least one of, diallyl sulfide (DAS) and diallyl disulfide (DAS2), and at least one acid, wherein the composition comprises greater than or equal to 90%. preferably 95%, of undegraded organosulfur compounds (OSC) after storage at 54°C for 14 days or at 40°C for 80 days, or any comparable accelerated storage conditions, as compared to the organosulfur compounds (OSC) content after compounding, most typically measured immediately prior to storage.

The invention provides inter al/a, compositions wherein the pH (measured in aqueous systems), is below 6.5 and preferably between 3.7 ±5% and about 6 with the proviso that the pH of the composition remains below 6.5 over the period of storage. As detailed below, generally numbers in this disclosure prefixed by the tenn "about", will be understood to include +10% of their value, unless clearly otherwize based on the context or if specifically defined otherwize. Thus, "about 6" will include values greater than 6 but less than 6.5, even though it is slightly less than +10% based on the context.

Extracts from Allium spp. (Garlic essential extract or Garlic Essential Oil), comprise organosulfur compounds (OSC), including Methyl methanethiosulfinate, S-methyl 2-propeneI -thiosulfinate, Allicin and derivatives thereof. Alliin and derivatives thereof, Di-allyl trisulfide, Ajoene, S-Allyl-L-cysteine, Diallyl disulfide, S-Ethyleysteine, N-Acetyleysteine, 5-allylmercaptocysteine, Captopril and 5-allyl-mercapto-captopril. These compounds have the following stmctures.

ZcHtfo'i e., In particular, extracts from Allium spp. sometimes referred to as garlic essential oil, comprise organosulfur compounds (OSC), including diallyl sulfide (DAS); diallyl disulfide (DADS); diallyl trisulfide (HATS), tetra-sulfides and sulfift dioxide (SDO).

It is worth mentioning some Organic Sulfur Compounds (OSC) derived from Allicin and AlliM produced due to enzymatic process after smashing e.g., other Thiosulfinates with important fungicide and bactericide action. There is no intention that this disclosure should be taken as limiting the range of useful Organic Sulfur compounds (OSC) derived from All icin and Alliin.

Thus, the present invention provides stable agricultural compositions comprising Garlic essential extract comprising at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment characterized by a pH less than 6.5.

Often the inorganic acids have been preferred in preparing the inventive products simply due to their case of use. Some non-limiting examples employing phosphoric acid arc usefully described but, no inference should be drawn by this choice other than convenience.

The organosulfur compounds in the stable and storage stable compositions of the invention are most typically components of garlic essential oil which is reported to be a natural repellent against sucking and plowing insects, it has a dissuasive action on the feeding habits of insect plagues and it obstructs the action of natural pheromones causing disorientation to insects during their reproduction stage.

Garlic essential oil has several modes of action including though not limited to, A) The garlic extract is absorbed by the plant through the vascular system, this alters the enzymatic system of the plant, causing an alteration in perspiration, causing a change in the intracellular juices.

B) The masking effect on the pheromones produced by the insects is increased, breaking the life cycle of the insects.

C) It alters eating habits due to ingestion and contact with garlic.

D) The presence of sulfur substances known as allomones attack the central nervous system of insects.

The compositions of the invention are suitable to be applied in a wide variety of crops such as: eggplant, onion, chili, peas, cucurbits, cabbage, cauliflower, broccoli, beans, lettuce, corn, watermelon, tobacco, tomato, citrus, peach, apple, pear and ornamentals and many more.

Some useful preventative control indications include: sorghum brown bug, lygus bug, small cereal bug, fast bug, fast bug or conchuela green: apply at 7-14 day intervals. In the nymphal and adult stage, it causes disorder in eating habits.

Leafrniner: apply at 8-12 day intervals. In the larval stage it causes disorder in eating habits and in the adult stage it causes layperexcitation and reproductive disorientation.

White fly, cotton midge or white midges: apply at intervals of 7-14 days, in the nymph stage it causes disorder in eating habits and in the adult stage it causes repellency and reproductive disorientation.

Chili borer or cotton boll weevil: apply at intervals of 6-10 days. In the adult stage it causes repellency and reproductive disorientation Thrips, bean thrips, black thrips, thrips: apply with intervals of 8-12 days, in the adult stage it causes disorder in eating habits, hyperexcitation and reproductive disorientation.

Thus, in some embodiments, the invention provides storage-stable compositions for use in controlling pests including insects, arthropods, mites, lepidopterous larvae, thrips etc., microbes, fungi etc., comprising: a carrier comprising water; a surfactant; an emulsifirer a wetting agent or similar ingredient; and an acid and said compositions are characterized as having a pH in a range of 1 to less than 6.5; and an allyl sulfide compound.

A storage-stable composition for use in controlling pests including insects, arthropods, mites, lepidopterous larvae, thrips etc., microbes, fungi etc., comprising: a carrier comprising water, a surfactant, an emulsifirer a wetting agent or similar ingredient, and an acid and characterized as having a pH in a range of 1 to less than 6.5; and at least one organosulfur compound selected from Methyl methanethiosulfinate, S-methyl 2-propene-1 -thiosulfinate, Allicin and/or derivatives thereof Alliin and/or derivatives thereof. Di-allyl trisulfide, Ajoene, S-Allyl-L-cysteine, Diallyl disulfide, S-Ethylcysteine, N-Acefiicysteine, 5-allylmercamocysteinc, Captopril and S-allyl-mercapto-captopril and combinations thereof, with the proviso that said composition contains at least one ally' sulfide compound.

The present invention provides stable aqueous Garlic essential extract compositions comprising at least one acid, wherein the composition is characterized by a pH less than 6.5. In notable embodiments the composition is a storage stable emulsion, microemulsion or nanocmulsion.

In some embodiments present invention provides Garlic essential extract compositions comprising at least one acid, wherein the composition is for pesticidal or repellent use after dilution in an aqueous medium characterized by a pH less than 6.5 after dilution. In some embodiments the composition is an emulsifyable concentrate and the diluted composition comprises a stable emulsion, microemulsion or nanoemulsion.

In one aspect the instant invention relates to storage stable Garlic extract oil compositions comprising at least, Diallyl Disulfide, Diallyl Sulfide and combinations thereof In at least one aspect, the instant invention relates to aqueous compositions of Garlic extract oil comprising at least, diallyl disulfide, diallyl Sulfide and combinations thereof characterized by their stability mediated by the acidic character of the aqueous composition.

In some aspects, the invention relates to stable aqueous emulsion compositions of Garlic extract oil comprising at least, Diallyl Disulfide, Diallyl Sulfide and combinations thereof characterized by their stability mediated by the acidic character of the aqueous composition.

The term stability is understood to include both chemical stability often measured by lower rates of degradation of any of the active components, as well as physical stability of the composition including though not limited to, color and emulsion stability and the like.

The process by which an emulsion coalesces (completely breaks i.e., the system separates into bulk oily and water phases), is generally considered to be governed by four different droplet loss mechanisms: Brownian flocculation, creaming, sedimentation flocculation, and disproportionation, shown schematically in Figure 1 Reproduced from "Emulsion Stability and Testing" found at, The first three are the primary methods by which emulsions are destabilized, though all four processes may occur simultaneously and in any order.

Figure 1 The processes of creaming, flocculation, and coalescence arc well demonstrated by taking an emulsion of limited stability and centrifuging it at low speeds or various lengths of time. For oils with a density less than water (which will be assumed unless otherwise noted), an initial "rising" of the cream is observed. Then, as larger droplets rise and concentrate, they begin to appear at the top. Finally, the drops coalesce to fonn a separate layer of oil on top.

Creaming derives its name from the most commonly known example of a de-emulsification process -the separation of milk into its separate cream (curd) and skim milk (whey) components. Creaming is not an actual breaking but a separation of the emulsion into two emulsions, one of which (the cream) is richer in the disperse phase than the other. Creaming is the principal process by which the disperse phase separates from an emulsion and is typically the precursor to actual coalescence.

Table 2 lists properties that are typically used to assess quality an emulsion formulation. Ideally, all these tests should be conducted on a final formulation but it is not practical, nor necessary, to conduct the total battery' of tests on all preliminary formulations. Typically, initial formulations are screened for changes in pH, and physical separation at elevated temperatures. It is at least the stability of these emulsion characterists which are referred to.

Table 2

The aqueous emulsion composition embodiments of the invention display emulsion storage stability as regards at least creaming and/or sedimentation and preferably also as regards flocculation, and coalescence, both after storage at at 54°C for 14 days and at 40°C for 80 days, and other comparible accellerated storage conditions.

The aqueous emulsion composition embodiments of the invention display emulsion storage stability as measured by a reduced creaming rate, such that no more than 30inm creaming and/or sedimentation is measured after storage at either 54°C for 14 days or at 40°C for 80 days. Preferably the aqueous emulsion compositions display a creaming rate of less than 20mm and more preferably less than 15mm, and most preferably less than lOmm after storage at 54°C for 14 days or at 40°C for 80 days.

In general, a "creaming rate" of less than 1 mm per day is considered negligible In an aspect of the invention a stable aqueous composition is provided comprising Garlic essential extract and an acid wherein the composition comprises greater or equal to 90%, preferably 95%, of undegraded organosulfur compounds (OSC) after storage at 54t for 14 days or at 40°C for 80 days, as compared to the organosulfur compounds (OSC) content, measured either imediately, after compounding, or at initiation of storage.

The stable aqueous composition comprising Garlic essential extract has a pH below 6.5, and notably between 3.7 ±5% and about 6. The composition is typically an emulsion, microemulsion (or similar), or an emulsifyable or microemidsifyable concentrate wherein the pH is measured in the aqueous product.

In noted embodiments the stable aqueous composition comprising Garlic essential oil has a pH below 6, and excellent results were obtained with stable aqueous compositions comprising Garlic essential oil that were formulated to display a pH of 5.5 at the time of compounding by judicious use of the acid content to adjust the pH. For convenience, ease of use, etc. a mineral acid is sometimes preferred. Excellent results were recorded using phosphoric acid but there should not be any inference that this choice is in any way essential other than for practical purposes.

In an aspect of the invention a stable aqueous emulsion composition is provided comprising Garlic essential extract and an acid wherein the color hue of the composition is not visibly changed or darkened when measured by visual inspection, after storage at 54°C for 14 days or v!s.cutTleter letr; oq51-Natr-rn11.o?Tv.t.::-$ EMULSION PROPERTIES TO E N1ONITOREB* DURING STABILITY TESTING P.tverri j That Method EEktetninn,53 PmpF';F sire NSlitIrcaX.;:.3:: anc: tFtNF at 40°C for 80 days, as compared to the color hue imediately after compounding. The stable aqueous composition comprising Garlic essential extract has a pH below 6.5, and notably between 3.7 ±5% and about 6. The composition is typically an emulsion, microemulsion (or similar), or an emulsifyable or microemulsifyable concentrate where the pH is measured in the aqueous product. Often the pH of a concentrate is usefully measured after it is diluted in water for ease of measurement.

While typical emulsion compositions of the invention are often microemulsions the inventors envision stable nanoemulsions comprising Garlic essential extract and an acid being within the scope of the invention as conceived.

It has proven conveient to measure chemical stability of by the rate at which the component Diallyldisulfide (DADS) degrades.

No inference should be drawn by this choice of stability indicating component and no assumption should be made that the invention is limited in anyway by the acitive component measured. However, as will be abundantly clear, the invention will clearly include methods by which the rate of degradation of diallyl disulfide in aqueous systems containing it, is reduced by modulating the pH of the aqueous environment to be below 6.5 and preferably equal or less than 6 In an aspect of the invention stable aqueous-based compositions are provided, comprising diallyl disulfide and an acid wherein the compositions of the invention, are more chemically stable to degradative processes as compared to similar aqueous-based compositions characterized by pH >6.5.

In an aspect of the invention a storage stable aqueous composition is provided comprising diallyl disulfide and an acid wherein the composition comprises no less than 90% of undegraded diallyl disulfide after storage at 54t for 14 days, or at 40°C for 80 days, as compared to the diallyl disulfide content imediately after compounding, or at the start of the storage period. The stable aqueous composition comprising diallyl disulfide has a pH below 6.5, and notably between 3.7 +5% and about 6, though even more preferred, below pH 6, In an aspect of the invention a storage stable aqueous composition is provided comprising diallyl disulfide and an acid wherein the composition comprises no less than 95% of undegraded diallyl disulfide after storage at 54t for 14 days, or at 40°C for 80 days, as compared to the diallyl disulfide content imediately after compounding or immediately prior to storage. The stable aqueous composition comprising diallyl disulfide has a pH below 6.5, and notably between 3.7 ±5% and about 6 though even more preferred, below pH 6.

In an aspect of the invention a stable aqueous emulsion composition is provided comprising diallyl disulfide and an acid wherein the color hue of the composition is not visibly changed or darkened when measured by visual inspection, after storage at 54°C for 14 days, or at 40°C for 80 days as compared to the color hue imediately after compounding. The stable aqueous composition comprising diallyl disulfide has a pH below 6.5, and notably between 3.7 +5% and about 6 though even more preferred, below pH 6.

Formulating a chemically and physically stable composition comprising garlic extract oil (Garlic essential extract), is very challenging. This is the case both from point of view of the stability of the active components to chemical degradation as well as the physical stability of the composition.

It was found that the stability of these compositions is mediated by the acidity of the composition and in particular, the acidic pH of aqueous compositions can determine the degree of stability of the composition.

S

It is well understood that the choice of composition ingredients can influence the stability of all compositions, however all things being equal, the acidity of garlic extract oil compositions will determine the relative stability of otherwize equivalent compositions. Acidity for the inventive compositions is most usefully defined by the pH measured when the compositions are in aqueous systems.

Most notably emulsion compositions, and particularly, aqueous-based microemulsion compositions have been found to benefit from the implementation of the invention, whereby the garlic extract oil emulsion compositions of the invention, are not only found to be more chemically stable to degradative processes during storage, but the stability of the physical parameters of the emulsion (Emulsion stability), are also improved as compared to similar emulsion compositions characterized by pH >6.5.

A typical emulsion stability test is a test done to see what happen when the product is diluted in water. In these tests it is common for a concentrated produt to be diluted to the end-use concentration (Field rate) and tested for physical parameters including Creaming and Sedimentation. in addition, it was observed that as the acidity of the compositions (as measured by pH), increased, the color of the emulsions over periods of storage became unacceptably compromised and discloration was clearly visable.

Moreover, inventors have established that acidic compositions, and noteably aqueous compositions characterized by a pH below 6.5, and noteably a pH of approximately 6 and preferably below, are significantly more stable than more basic or alkaline compositions. As defined later, all numbers (figures) in this disclosure, and especially' numbers prefixed by the term "approximately" or "about", will most commonly be understood to include +10% of their value, unless clearly otherwize based on the context or if specifically defined otherwize. As an example, because the stable pH of a composition is herein defined as being "below" 6.5, it is clear that there was no intention of including values that would be include 6.5 and above, and thus the +10% range is inappropriate for the upper limit of "about 6" and would be clearly understood as such, while including values higher than 6 but less than 6.5 exemplified by a pH of 6.4 while a clear preference for a pH of 6 limit, and even more preferably below 6 is clear from this disclosure.

Thus a possible rephrasing of the inventive stability-related pH of the stable aqueous compositions may be, a stable composition of Garlic essential extract displaying an aqueous pH of less than or equal to about 6, with the proviso that the pH of the composition in aqueous media is less than 6.5.

It is understood that pH is a characteristic which only has any meaning in aqueous systems, however the invention clearly encompasses non-aqueous preparations which are intended to be incorporated in aqueous systems. These non-aqueous compositions could be water dispersible solid granules or powders, or emulsifiable concentrates to name a few.

Such incorporation of the non-aqueous compositions in aqueous systems can involve simple dilution, or dissolution of the non-aqueous composition in water or emulsification and similar processes. It would seem that the stabilizing characteristic of such non-aqueous systems that might be important is "acidity" while recognizing that measurement and providing useful numerical ranges are more practical in terms of pH of those systems dispersed in water.

In all events, the inventive compositions of the invention are characterized by' the pH measured while they are within an aqueous system.

It has been convenient in experimentation, to evaluate stability using so-called accelerated stability storage conditions exemplified by a storage protocol of 14 days at a temperature of 54, These accelelerated protocols are generally predictive of the stability of the test sample for much greater periods of time at more moderate conditions, exemplied by storage at ambient conditions.

The agriculturally useful activities of Garlic essential extract including its repellent (e.g., for insects), or pesticidal qualities, are largely attributed to the high contents of bioactive compounds and particularly organosulfur compounds (OSC) found within.

Thus, maintaining the amount of those OSC by reducing the rate of their degradation will clearly have a positive effect on maintaining the efficacy of the compositions particularly over extended periods of storage.

As agricultural compositions are most frequently applied by the end-user (e.g., farmer), after a significant period of storage, acidic agricultural Garlic essential extract compositions according to the invention will often display higher levels of efficacy in the field than equivalent compositions which are more basic or alkaline.

Inventors surmise without being bound by any theory that, aside from any efficacy enhancement that may be related to the acidity of the composition, the fact that more of the active components remain undegraded after periods of storage will undoubtably be reflected in higher relative efficacy.

As it was found that due to the increased stability of the inventive compositions there is a concomitant increase in efficacy as explained above, the amount of the active components can in principle, be reduced while maintaining the levels of efficacy achieved in previous non-storage stable compositions of Garlic essential extract.

While it is common to consider unlikely and creative solutions to known problems having known causes, to be the most surprising, in notable cases, as here, it is the elucidation of the cause of the problem which is most unexpected, after which the solution to that problem might seem trivial to the novice, while nothing could be further from the truth. If the source of the problem is unknown, (or even that the problem exists), then the solution to the problem is surprising, it is only with hindsight that a problem might be suggested.

In some embodiments the compositions of the invention are formulated to display increased storage stability by including components that will lower the pH of the compositions in aqueous media. These components are often acids. Inventors have no doubt that other ingredients not typically called "acid"per se, that lower the acidity of such compositions are useful, and fully conceive of these compounds as being within the scope of protection being sought, it is enough to have provided the source of the problem and exemplified solutions to provide sufficient guidance to those skilled in these compounding arts for suggesting the range of stabilizing additives.

In some embodiments the acid component of the compositions may typically or usefully include but are certainly not limited to mineral acids or inorganic acids.

Other examples of acids can be organic acids, such as citric acid, acetic acid, alpha-hydroxy acid, beta-hydroxy acid, salicylic acid, lactic acid, glycolic acid, natural fruit acids, or combinations thereof. Often it will be fomunating considerations that will determine the choice of acid, as it is envisaged that while many garlic extract oil compositions are more easily formulated with mineral acids exemplified by phosphoric acid, some e.g., entirely oily or solid preparations, may be easier to prepare with organic components.

In addition, inorganic acids, for example hydrochloric acid, nitric acid, sulfuric acid, sulfamic acid, phosphoric acid, and combinations thereof can be utilized to reduce the pH value of the composition and stabilize the compositions. Inventors have noted the ease and/or speed by which a desired pH can be achieved using mineral acids, making them convenient for some compositions.

Mention is made of formic acid, acetic acid, oxalic acid, tartaric acid, phosphoric acid, phthalic acid, bcnzoic acid, boric acid, cthylcnediaminc tctra-acetic acid, gluconic acid, glutamic acid, glutaric acid, lactic acid, malic acid, succinic acid, hydrochloric acid, sulfuric acid, acetic acid, citric acid, ascorbic acid, sorbic acid, propanoic acid, butyric acid, oxalic acid, succinic acid, malic acid, tartaric acid, fiimaric acid, aconitic acid, dipicolinic acid and mixtures thereof Given the disclosed methods of compounding and testing as well as the most useful range of acidity, any researcher will easily be able to choose their most preferred example most suitable for a proposed formulation.

In some embodiments, the acid is phosphoric acid (Ortho phosphoric acid) . In some embodiments the inventive composition is an emulsion or micoemulsion. In some embodiments the inventive composition is a concentrate which forms an emulsion or microemulsion when combined with water or aka emulsifyable or microemulsifyable, concentrate. In some embodiments the emulsion formed on combination with water is a microemulsion. Although of course nanoemulsions and nanoemulsifyable concentrates are clearly envisaged.

The compositions of the invention will typically include non-biologically active components or excipients, and/or auxiliary components useful in compounding agricultural compositions. For emulsions or EC compositions an emulsifyer, exemplified by an ethoxylated vegetable oil, is typically included, often accompanied by a surfactant. The surfactants if present can be exemplified by ethoxylated sorbitan esters, ethoxylated oils or fatty acids, ethoxylated fatty acid alcohols arylsulfosuccionate salts, arylbenzene sulfonate salts, or ethoxylated aryl alkyl phosphate esters. But the inventors stress that the invention is not dependent on the choice of surfactant which is well within the skills of a person ordinarily skilled in these agricultural composition formulating arts, as long as they do not adversly affect the acidity and importantly the stability of the compositions. It must be stated (though self-evident) that emulsifyers and surfactants that destabilize the active component organosulfur components arc not generally chosen as ingredients.

Inventors however, can evision instances in which one or more destabilizing non-biologically active components, excipients, compatibilizing or auxiliary components must be included for formulating purposes, and thus the invention in these cases is understood to providing composition components that can ameliorate the deliterious effect of inclusion of these necessary though destabilizing components, in these aforementioned situations it is the reduction in degradation rather than a specific target rate of degradation that indicates increased stabilization.

In some embodiments the present invention provides a combination comprising (I) an amount of garlic extract oil, (2) water, and (3) an amount of acid.

In some typical embodiments the present invention provides a composition comprising (1) an amount of garlic extract oil, (2) water, (3) emusifier and (4) an amount of acid.

Thus, in an embodiment of the invention, a stable aqueous emulsion composition of the invention can contain the following igredients.

Garlic Oil (Garlic extract), Emulgator/Emulsifier (e.g., ethoxylated castor oil), Antifreeze (e.g, Propylene Glycol) Acid (e.g., Phosphoric acid) Antifoam (e.g., emulsions of siloxanes, polyorganosiloxanes silicones silica etc.), and Water In an exemplified embodiment the acid is orthophosphoric acid and it is conveniently introduced into the composition as Phosphoric acid 85%, to adjust the pH, and might comprise 0.05% of the composition. Similarly in particular instances the compositions are adjusted to a pH of 5.5 during manufacture.

As must be abundantly clear, the acid component is a very important component in the compositions of the invention, while ingredients other than the organosulfur compounds in the compositions are chosen from a wide army of both inactive and biologically active components having their own acidity and/or alkylinity, and thus the exact amount of acid used by the formulator to adjust the pH of the formulated composition is not as important as the pH that is achieved by modulating the acid.

In an exemplary method of manufacture the composition is compounded and the pH adjusted by the inclusion of the acid. In a particular embodiment the pH is adjusted to about 5.5. While stability is proven over the entire range of pH of about 6 and below, it is sometimes reported that the pH value might change over the storage period. For this reason and others the inventors have exemplified a pH of 5.5 for the composition at the time of its manufacture as being a useful value. Similarly although compositions with a pH of greater than 6 though less than 6 5 at the time of compounding, is well within the values contemplated by inventors, it is useful to monitor the pH during storage to ensure that the pH does not reach 6.5 or greater.

It should be noted that pH measurements often vary at least slightly, between measurements and between instruments, it is not uncommon to find that a particular sample may have a pH reading which is +0.2 of a reading of the same sample using a different device, or between devices calibrated at different times by different technicians.

The inventive compositions include a wide range of formulation types including concentrates, emulsions, including microemulsions, nanoemulsions, etc. as well as diluted ready to use compositions. Thus the content of Garlic Essential oil can be upto 25% of the composition, more commonly up to 20%, often upto 15% and in some cases up to 10%. A useful emulsifiable concentrate may comprise 12.5% +10% Garlic Essential Oil.

In an example of an aqueous microemulsion, the content of garlic oil extract (Garlic Essential Oil) might be less than 5% and often approximately 2% w/w of the composition and in an exemplified embodiment about 1.8% w/w of the composition or 1.75% w/w (18 g/L). In a dilute embodiment a composition might contain 1.8 g/L Garlic Essential oil which translates as 0.18% by weight of the composition, obviously thither dilutions would lower this value.

When chemical degradation processes are being addressed it is often noted that the chemical degradation problem is more pronounced in dilute systems.

The exemplified components and the detailed examples relate to dilute systems, no inference should be drawn from this choice of % content of Garlic Essential Oil in the examples of the inventive compositions other than the inventors using the most challenginging dilute systems which at the same time have concentrations well within the level to actually be useful for their real world application.

Garlic Essential oil has a typical Diallyl Disulfide content of about 30-45% but has been reported to contain between 30% and 55% of Diallyl Disulfide. There is a preference for using Garlic Essential oil having a Diallyl Disulfide concentration of about 35%-40%.

In general those skilled in the agricultural compounding arts e.g., formulation technicians, will be well aware of the other useful components of aqueous agricultural compositions and their methods of production and the instant inventive compositions are not limited by the identity or percentage content of these components other than the stipulation that the pH of the compounded composition is lower than 6.5 and preferably between 3.7 +5% and about 6 with the proviso that the pH remains less than 6.5 over the period of storage.

It should be abundantly clear that compositions that include components that accelerate the chemical degradation of the active components or destabilize die physical form of the composition, are very much less favored, however the inventors note that in extenuating circumstances where such ingredients need to be included for compounding-based reasons, the addition of an acidifying component particularly an acid, can compensate the deliterious effects of these unfavoured ingredients to at least some degree.

In some embodiments the stable agricultural compositions comprising organosulfur compounds (OSC) comprising at least one acid, also comprise ingredients that improve their efficacy. One example of many such ingredients, include the incorporation in the compositions of a penetration enhancer. These ingredients are well known to the agricultural formulation technician and will be chosen based on common compounding principles, including chosing such ingredient that do not adversely effect the biological activity of the composition, for example by accelerating the degradation of the organosulfur compounds (OSC).

In some embodiments the stable compositions comprising Garlic Extract oil (Garlic essential extract), an advantage can be achieved by the compositions also containing one or more additional agriculturally active ingredients. In cetain embodiments the additional active ingredients would unfavorably interact with the Garlic Extract oil in the absence of the stabilization afforded by the adjustment of the composition p1-1. These multi-component compositions comprising Garlic Extract oil (Garlic essential extract) are clearly within the scope of the invention as envisioned by the inventors.

While inventors have found that addition of particular amounts of specific acids are particularly useful, inventors do not wish to limit the invention by the quantity or content of the acidic component so long as the stabilizing pH is achieved. With that said, inventors have exemplified phosphoric acid (Ortho phosphoric acid) as the stabilizing acid and thus although expressing no specifically articulated preference for this acid, the amounts of phosphoric acid are more fully optimized. Inventors' choice of acid was based on ease of use rather than preferance based on being a more stabilizing variety.

In some emebodiments where the acidifying ingredient is an acid, the amount of the acid in the composition is defined as the amount of acid that will ensure the pH of the composition in an aqueous environment is below 6.5 and preferably about equal or less than 6.

While it is often useful to provide numerical ranges for the content of an inventive ingredient, in this case, limiting the stabilizing component by its percentage content or weight content, might exclude some acceptably stable compositions from being encompassed, the inventors have no wish to do so. However some non-limiting examples are provided as guidance but no inference should be drawn as to the range of options of acceptable ingredients or their amount.

Non-Limiting Examples Example 1 IVlicroemulsion Compositions of Garlic Extract Oil (Essential Oil) Ingredient Chemical Name w/w w/v % [gin Garlic extract oil Garlic extract 1.8 18 Eumulgin R-400 Castor oil, ethoxylated 28 290 Propylene glycol Propane-1,2-diol 5 51.5 Phosphoric acid 85% Ortho phosphoric acid -0.05 -0.5 Antifoam 30% active Silicone/Silica Emulsion 0.01 0. I Water(2) Water 65.4 674 Density approximately 1.03 Seven lots of the lots of the composition were prepared and the pH of each was adjusted with more or less acid to achieve compositions displaying pH of 4; 5, 5.5; 6; 6.5, 7, and 8 respectively.

Example 2 Stability

1. Chemical stability The garlic essential extract micro emulsion contains Garlic extract. The major active constituents are diallyl disulfide and diallyl sulfide. As can be seen from the results presented below, there is a very close con-eleation between the Active ingredient chemical stability and the level of acidity in the microemulsion system.

As represented in the Table and the Graph below as the pH increases the active is degraded and the degradation can start immedeatly after prodcution and continue during storage at 54°C. As a useful indicator of chemical stability, the amount of diallyl disulfide is measured immediately prior to and at the end of the storage period. As represented in the Table and the Graph below, as the pH increases the diallyl disulfide is degraded immedeatly after prodcution and cotinuing during storage at 54°C. As with all naturally derived multicomponent compounds the (1/1O content of one component, e.g., diallyl disulfide in the garlic extract can vary, and thus in order to compare the stability of different batches or lots, it is convenient to address the % of undegra.ded diallyl disulfide after the period of storage in comparison to the percentage content at the time of initiating storage.

Table 3 -Diallyl Disulfide Content of Compositions Stored At 54°C Emulsiontable 0 Days 3 Days 7 Days 14 Days pH To T3d 17d T14d g/L % To g/L % To g/L % To g/L % To 4.0 5.2 100 5.2 100.4 5.1 98.8 5.3 102.3 5.0 5.2 100 5.2 100.0 5.1 98.1 5.2 99.2 5.5 5.3 100 5.2 98.1 5.1 96.4 5.2 97.4 6.0 5.1 100 5.2 102.2 5.1 99.6 5.1 100.2 6.5 5.1 100 5.1 100.6 5.0 97.4 4.5 89.2 7.0 5.1 100 5.0 98.0 4.6 90.2 3.7 73.3 8.0 5.0 100 4.7 94.0 3.5 70.9 3.3 66.9 Time Ways) Figure2 -pH Stability of the Tested Compos t ons pH Stability Data PH 0 Days 3 Days 7 Days 14 Days Compounded TO 1734 T74 T14t1 4 3.8 4.4 4.1 4.9 5.0 4.9 4.9 4.7 5.5 5.5 5.3 5.3 5.0 6 6.0 5.8 5.9 5.8 6.5 6.6 6.4 6.4 6.5 7 7.1 6.9 6.9 7.0 8 7.9 7.1 7.4 7.4 pH vs ACCELERATED AGING cibjeutte 2. Composition Physical Stability The stability of the composition may also be assessed by visual observation Color test A particular phenomenon was observed after storage of the compositions for 14 Days at 54°C In the stability samples a color change was observed which was a function of pH e ar: hH Ott A:ft Ac* pues.

At: 7 0 the pH of the composition product. It is possible that there is a direct relationship between color and the content of degradants which may visually indicate degradation of the active components.

In the picture below it is evident that the composition with a pH of 7 and above are significantly darker than the compositions with pH <6.

The lighter colored samples are very pale yellow, the higher pH compositions have become dark brown in color.

3. Physical Stability Test -Emulsion stability.

This emulsion stability test is performed to assess what happen when the product is diluted in water at the concentrations used for end-use application (Field).

The Product sample is diluted according to the Field rate and is evaluated for "Creaming-and Sedimentation. The results obtained from the emulsion stability testing performed it was observed that as the pH of the compositions increased above 6 the emulsion quality clearly degraded after storage for 14 Days at 54°C Incidentally, the color change seen in the above concentrated compositions are also reflected in the diluted compositions although it is difficult to see in the black and white image.

* 1%..\* * \ ***A-

Claims (27)

1. Claims 1 A storage stable agricultural organosulfur composition comprising one or more allyl sulfide compounds and at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment wherein the composition characterized by a pH of less than 6.5.
2. 2. The composition of claim 1 wherein the one or more allyl sulfide compounds are extracts of garlic.
3. 3. The composition of claim I wherein the composition is an aqueous-based composition.
4. 4. The composition of claim I wherein the composition is a concentrate adapted to be diluted with an aqueous media prior to use.
5. The composition of claim 1 wherein the composition is any one some or all of, an aqueous emulsion, microemulsion nano emulsion, and/or an emulsifiable concentrate which forms an aqueous emulsion, microemulsion, or nano emulsion when diluted with an aqueous media
6. 6. The storage stable agricultural composition of any one of claims 1-5, wherein the composition contains greater or equal to 90% of undegraded organosulfur compounds (OSC) after storage at 54°C for 14 days as compared to the organosulfur compounds (OSC) content after compounding measured immediately prior to storage.
7. 7. The storage stable agricultural compositions of any one of claims 1-6 wherein the allyl sulfide compound is one or more extracts of garlic comprising, at least one, some, or all of, diallyl sulfide (DAS), diallyl disulfide (DAS2), diallyl trisulfide (DAS3) and diallyl tetra sulfide (DAS4).
8. 8. The storage stable agricultural composition of any one of claims 1-7 wherein the allyl sulfide compound comprises diallyl disulfide.
9. 9. The storage stable agricultural composition of any one of claims 1-8, wherein the composition contains greater or equal to 90%, preferably 95%, of undegraded diallyl disulfide after storage at conditions selected from, a. 54"C for 14 days; and b. 40"C, for 80 days; as compared to the diallyl disulfide content after compounding, measured immediately prior to storage.
10. 10. The storage stable agricultural composition of any one of claims 1-9, comprising one or more extracts of garlic wherein the composition contains greater or equal to 95% of undegraded diallyl disulfide after storage at conditions selected from, a. 54-C for 14 days; and b. 40-C for 80 days; as compared to the diallyl disulfide content after compounding, measured immediately prior to storage.
11. 11 The storage stable agricultural composition of any one of claims 1-9, comprising one or more extracts of garlic wherein the composition is an aqueous emulsion and the compositions display a emulsion stability as measured by a creaming rate resulting in no more than 30mm creaming and/or sedimentation, preferably less than 20mm creaming and/or sedimentation, after storage at 54°C for 14 days or at 40'C for 80 days.
12. 12. The storage stable agricultural composition of claim 1 comprising organosulfur compounds (OSC) comprising at least one a11y1 sulfide compound selected from the group of diallyl sulfide (DAS), diallyl disulfide (DAS2) and combinations thereof, and at least one acid, wherein the composition comprises greater or equal to 90%, preferably 95%, of undegraded organosulfur compounds (OSC) after storage at conditions selected from, a 54-C for 14 days; and b 40;C for 80 days; as compared to the organosulfur compounds (OSC) content after compounding prior to storage.
13. 13. The storage stable agricultural compositions comprising organosulfur compounds (OSC) according to any one of claims 1-12 characterized in that it comprises an extract of garlic and wherein the organosulfur compounds comprise one or more of, diallyl sulfide (DAS), diallyl disulfide (DAS2), diallyl trisulfide (DAS3) and diallyl tetra sulfide (DAS4).
14. 14. The storage stable agricultural composition of claim 13 comprising at least one of diallyl sulfide (DAS) and diallyl disulfide (DAS2), and at least one acid, wherein the composition comprises greater or equal to 90%, preferably 95%, of undegraded organosulfur compounds (OSC) after storage at 54°C for 14 days or at 40-C for 80 days, as compared to the organosulfur compounds (OSC) content after compounding prior to storage
15. 15. The storage stable agricultural composition of claim 1 comprising diallyl disulfide, wherein the composition comprises greater or equal to 95% of undegraded diallyl disulfide after storage at 54°C for 14 days or at 40'C for 80 days, as compared to the diallyl disulfide content after compounding prior to storage.
16. 16. The storage stable agricultural composition of claim 1 comprising diallyl disulfide, wherein the composition is an aqueous emulsion or microemulsion wherein storage stability is emulsion stability as measured by a creaming rate of no more than 30mm creaming and/or sedimentation, preferably less than 20mm creaming and/or sedimentation, after storage at 54°C for 14 days or at 40T for 80 days.
17. 17. The storage stable agricultural organosulfur composition of claim I comprising, a. garlic extract oil (Garlic Essential oil), b. water, c. emulsifier and/or surfactant, and d. an acid wherein the composition is characterized by a pH of less than 6.5.
18. 18. The storage stable agricultural organosulfur composition of claim 17 when the composition is an aqueous emulsion composition comprising, a. garlic extract oil (Garlic Essential Oil, Allium spp.), b. emulsifier or emulgator and optionally, surfactant, c. antifreeze agent, d. antifoam agent e. an acid, and f. water wherein the composition is characterized by a pH of less than 6.5.
19. 19. The storage stable agricultural organosulfur composition of claim 17 wherein the composition is an aqueous emulsion composition comprising, a. 1.75% w/w garlic extract oil (Garlic Essential Oil, Allium spp.), b. 28% w/w ethoxylated castor oil, c. 0.01% w/w active silicone emulsion (30 percent) d. 5% w/w Propylene Glycol e. Phosphoric acid 85%, and f Water up to 100% wherein the amount of the phosphoric acid is modulated to adjust the pH of the composition to a pH of less than 6.5 at the time of compounding.
20. 20. The storage stable agricultural organosulfur composition of any one of claims 17 -19 wherein % content of acid added to adjust the pH is about 0.05% w/w.2L The storage stable agricultural organosulfur composition of any one of claims 17 -19 wherein the % content w/w of Garlic Essential Oil (Allium spp) in the composition is selected from the group comprising: a.
21. Up to 25%; b. up to 20%; c. up to 15% d. up to 10%; e. 12.5% +10%; f 2+10%; g. 1.8% +10%; and h. 0.18%+10%, based on the total weight of the composition.
22. 22. The storage stable agricultural organosulfur composition of any one of claims 1-21 wherein the pH of the composition, measured in aqueous environment is between 3.7 +5% and about 6 with the proviso that the pH remains less than 6.5 at the time of compounding and over the period of storage.
23. 23. The storage stable agricultural organosulfur composition of any one of claims 1-22 wherein the pH of the composition, measured in aqueous environment is adjusted to a pH of 5.5 during manufacture by modulation of the acid content.
24. 24. A stable aqueous-based composition comprising diallyl disulfide and an acid wherein the composition, is more chemically stable to degradative processes as compared to similar aqueous-based compositions characterized by pH >6.5.
25. 25. The storage stable agricultural organosulfur composition of claim I for use in controlling pests including insects, arthropods, mites, lepidopterous larvae, thrips, microbes, fungi, comprising: a. a carrier comprising water, b. a surfactant, c. an emulsifier d. a wetting agent, and e. an acid, characterized by a pH as measured in an aqueous environment between 1 to less than 6.5, and at least one organosulfur compound selected from Methyl methane thiosulfinate, S-methyl 2-propene-I -thiosulfinate, Allicin, Allicin derivatives, Alliin, Alliin derivatives, Di-allyl tri-sulfide, Ajoene, S-Allyl-Lcysteine, Diallyl disulfide, diallyl sulfide, S-Ethylcysteine, N-Acetylcysteine, S-allyl mercapto-cysteine, Captopril and S-allyl-mercapto-captopril and combinations thereof, with the proviso that said composition contains at least one allyl sulfide compound.
26. 26. The storage stable agricultural organosulfur composition of claim 1 for a use selected from the group, a. as a natural repellent against sucking and plowing insects; b. causing a dissuasive action on the feeding habits of insect infestations; and c. obstructing the action of natural pheromones causing disorientation to insects during their reproduction stage; characterized by a pH as measured in an aqueous environment between 1 to less than 6.5, comprising at least one compound selected from diallyl disulfide; diallyl sulfide and combinations thereof, wherein the composition comprises greater or equal to 95% of undegraded organosulfur compound after storage at 54°C for 14 days, or at 40:C for 80 days, as compared to the content of the same organosulfur compound after compounding prior to storage.
27. 27. A storage stable agricultural organosulfur composition comprising one or more allyl sulfide compounds and at least one acid, wherein the composition is acidic as measured by pH in an aqueous environment wherein the composition is characterized by a pH of less than 6.5.