TECHNICAL FIELD OF THE INVENTION:

The present invention relates to compositions comprising sugar esters and sugar alcohol esters of short chain fatty acids and their use in pest management. These compositions possess antiviral, antimicrobial, insecticidal, pesticidal and herbicidal properties which results in their potential use in controlling, Lepidoptera, Hemiptera and Thysanoptera insects, Tomato spotted wilt viruses, Tobacco mosaic viruses.

The present invention also relates compositions of sugar esters and sugar alcohol esters of short chain fatty acids as potential agents for treating oral and dermatological problems of microbial origin.

The present invention further relates to the synthesis of novel sugar esters and sugar alcohol esters of short chain fatty acids.

BACKGROUND OF THE INVENTION:

The potent insecticidal activities of naturally occurring sucrose esters against the persistent and damaging whiteflies have shown that, sugar esters are a new class of “natural” insecticides that should be exploited for commercial use. This was further demonstrated in articles titled ‘Polyester insecticides’ and ‘Characterization and insecticidal activity of sucrose octanoates’ where composition of sorbitol esters with sucrose esters enhances the insecticidal properties. It is believed that the reported esters i.e. sucrose laurate or sucrose octanoate act as surfactants to de-wax the insect's protective coating. The insect then either dehydrates or is readily attacked by microbes results in their death. The insecticidal/antimicrobial properties of the sugar esters are affected by the sugar head group, length of the fatty acid and degree of substitution. Another article titled ‘Structure-function relationships affecting the insecticidal and miticidal activity of sugar esters’published by Gary et al in Journal of Economic Entomology , 2003, 96 (3), discloses synthetic sugar esters such as xylitol or sorbitol hexanoate, octanoate, decanoate and dodecanoate esters as synthetic pesticides.

Whilst, most of the research works were focused on the preparation of sugar esters based on sucrose, sorbitol and xylitol using fatty acids of medium and long chain, there is no literature or reports available on the sugar esters of short chain fatty acids and its use against various insects/microbes including Eepidoptera, Elemiptera and Thysanoptera insects, Tomato spotted wilt viruses, Tobacco mosaic viruses.

Therefore, there remains a need in the art to provide effective antimicrobial/bio- pesticidal compositions with reduced toxicity and cost by exploiting hither to unreported sugar esters and sugar alcohol esters of short chain fatty acids. The present invention therefore provides sugar esters and sugar alcohol esters of short chain fatty acids and compositions thereof which have not been reported in the prior art as having potential antiviral, antimicrobial, insecticidal, pesticidal and herbicidal properties and their potential use in controlling Eepidoptera, Hemiptera and Thysanoptera insects, Tomato spotted wilt viruses, Tobacco mosaic viruses.

OBJECT OF THE INVENTION:

In accordance with the above, it is an object of the present invention to provide compositions comprising sugar esters and sugar alcohol esters of short chain fatty acids and compositions thereof. These compositions are useful for pest management and also useful as potential agents for treating oral and dermatological problems of microbial origin. It is another object of the present invention to provide a process for the preparation of compositions of sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids.

Another object of the present invention is to provide a bio-pesticide composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids optionally with insecticidal soap and other excipents.

It is yet another object of the invention to provide antimicrobial composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids optionally with pharmaceutically acceptable excipients for use in the tretament of oral and dermatological problems of microbial origin.

SUMMARY OF THE INVENTION:

In accordance with the above objects, the present invention provides a composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids useful in the management of various microbes such as bacteria, algae, fungi, protozoans, virus and other pathogens in plants, humans and animals.

In another aspect, the present invention provides antimicrobial/biopesticide composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids along with other active and inactive ingredients.

In another aspect, the present invention provides a composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids wherein, the sugar/sugar alcohol and C2 to C6 linear or branched chain fatty acids is present in a variable ratio of 1 : 1 to 1 :7.

In another aspect, the present invention provides a composition comprising sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids wherein, the C2 to C6 linear or branched chain fatty acid esters of sugars and sugar alcohols are isomeric mixtures due to degree of acylation based on the number of available hydroxyl groups in the sugar moieties and the ratio of the acid to sugar/sugar alcohol.

In an aspect, the present invention provides a process for preparing environmentally friendly sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids comprising combination of sugar/sugar alcohol: C2 to C6 linear or branched chain fatty acids in a variable ratio of 1 : 1 to 1 :7.

In an aspect, the invention provides composition comprising hither to unreported novel short chain C2 to C6 linear or branched chain fatty acid esters of sugars and sugar alcochols. The short chain fatty acids of C2 to C6 are selected from the group consisting of acetic acid, propionic acid, butyric acid, 2-methyl propanoic acid, 2-methyl butanoic acid, 3 -methyl butanoic acid, pentanoic acid, 3 -methyl pentanoic acid and caproic acid.

In another aspect, the sugar and sugar alcohol may be selected from the group consisting of sucrose, lactose, glucose, galactose, maltose, isomaltose, mannitol, fructose, cellobiose, globabiose, trehalose, myo-inositol, psicose, sorbitol, xylitol, erythritol etc. either in their chiral form or racemic form and any polyhydroxy compounds which are of synthetic or natural in origin.

In yet another aspect the present invention provides an environmentally friendly antimicrobial/biopesticide composition C2 to C6 linear or branched chain fatty acids of sugars and sugar alcohols along with agriculturally acceptable excipients which will have better phytotoxic tolerance.

In yet another aspect, the present invention provides antimicrobial composition comprising C2 to C6 linear or branched chain fatty acids of sugars and sugar alcohols optionally with pharmaceutical excipients useful as potential agents for treating oral and dermatological problems of microbial origin. In another aspect, the present invention provides an environmentally friendly biopesticide composition comprising short chain fatty acid esters of sugar/sugar alcohol for inhibiting the growth of various insects such as fall army worm (S podoptera frugiperda)., cotton pink bollworm, aphids, mealy bugs, white flies, thrips, and fungi such as Pyricularia oryzae, Fusarium oxysporum, Alternaria solani, Colletotrichum gloeosporioid.es etc.

In yet another aspect the present invention provides an environmental iy acceptable non-toxic seed treatment agent which cart enhance the quality of seed vigor, germination and protection of seedling from various soil pathogens and insects from germination to seedling stage (0 to 14 days).

DESCRIPTION OF DRAWINGS:

Figure 1 IR spectroscopic data of short chain fatty acid esters with sucrose Figure 2 IR spectroscopic data of short chain fatty acid esters with glucose Figure 3 GC chromatogram of erythritol butyrate Figure 4 GC chromatogram of xylitol propionate Figure 5 GC chromatogram of sucrose butyrate

DETAILED DESCRIPTION OF THE INVENTION:

The invention will be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.

The pressent invention provides a composition comprising C2 to C6 linear or branched chain fatty acid esters of sugars and sugar alcohols, useful in the management of various microbes such as bacteria, algae, fungi, protozoans, virus and other pathogens in plants, humans and animals.

In an aspect, the present invention provides a composition comprising environmentally friendly sugar esters and sugar alcohol esters of C2 to C6 linear or branched chain fatty acids wherein, the combination of sugar/sugar alcohol : C2 to C6 linear or branched chain fatty acids are present in a variable ratio of 1 : 1 to 1:7.

In an embodiment, the invention provides hither to unreported C2 to C6 linear or branched chain fatty acids of sugars or sugar alcohols. The short chain fatty acids are selected from the group consisting of acetic acid, propionic acid, butyric acid, 2-methyl propanoic acid, 2-methyl butanoic acid, 3 -methyl butanoic acid, pentanoic acid, 3 -methyl pentanoic acid, phenyl acetic acid, caproic acid or combinations thereof.

In an embodiment, the sugars and sugar alcohols are selected from the group comprising of sucrose, lactose, glucose, galactose, maltose, isomaltose, fructose, cellobiose, globabiose, trehalose, myo-inositol, psicose, sorbitol, mannitol, xylitol, erythritol etc. either in their chiral pure form or racemic form and any polyhydroxy compounds which are of synthetic or natural in origin.

In another aspect, the present invention provides an environmentally friendly biopesticide composition comprising short chain fatty acid esters of sugar/sugar alcohol for inhibiting the growth of various insects such as fall army worm, cotton pink bollworm, aphids, mealy bugs, white flies, thrips, and fungi such as Pyricularia oryzae, Fusarium oxysporum, Alternaria solani, Colletotrichum gloeosporioides etc., which comprises; a) C2 to C6 linear or branched chain fatty acid esters of sugars or sugar alcohols in a concentration ranging from 0.05% to 4.0% w/w; b) Inactive excipients in a concentration ranging from 96% to 99.5% w/w; and c) water in a concentration ranging from 0 to 90%.

In yet another aspect the present invention provides an environmentally friendly antimicrobial/biopesticide composition comprising C2 to C6 linear or branched chain fatty acids of sugars and sugar alcohols and agriculturally acceptable excipients which will have better phytotoxic tolerance.

In one of the preferred embodiments, the sugar that is esterified is sucrose and the fatty acid is butyric acid that results in the formation of isomeric composition of sucrose butyrate.

In an embodiment, the invention encompasses hitherto unreported novel butyrate esters of sucrose. The fact that there are 8 hydroxyl groups that can be esterified in sucrose means, that in principle one can make 8 mono esters, 28 diesters and 56 triester isomers. There is no means to isolate and analyse each isomer from the reaction mixture as there is no structure and activity relative evidences that particularly proves whether the composition of mono or di or tri or tetra esters having insecticidal activity.

Therefore, this invention concerns a mixture of isomers of sugar esters, which have insecticidal activity and are environmentally friendly.

In another embodiment, the said esters can also be prepared using acid catalyzed trans-esterification employing the use of acid catalyst such as phosphoric acid, sulfuric acid, p-toluene sulphonic acid, pyridinium sulphonate, or base catalyzed reactions employing the use of metal carbonate selected from the group of sodium carbonate, potassium carbonate or metal alkoxides selected from the group consisting of sodium methoxide or sodium ethoxide or using metal salts such as zinc chloride, iron chloride, or by Mitsunobu coupling, carbodimide coupling, lipase, lews acids selected from the group of salts of zinc, copper, tin, iron, scandium, gallium, with the potential anions selected from the group of chlorides, bromides, triflates etc. In a preferred embodiment, the present invention provides a process for preparing C2 to C6 linear or branched chain fatty acids of sugars or sugar alcohols comprising;

(i) adding sugar or sugar alcohol to C2 to C6 linear or branched chain fatty acids in a ratio of 1:1 to 1:7 and heating the resultant mixture at a temperature ranging from 110 °C to 180 °C,

(ii) Adding 10% - 30% moles of Phosphoric acid (with respect to sugar/sugar alcohol) into the mixture of step (i), followed by heating for 8 to 48 h,

(iii) Cooling the mixture of step (ii) to 60-70 °C, followed by diluting with ethyl acetate,

(iv)Treating the mixture of step (iii) with Ca(OH)2 for 10 min at 60-70 °C and

(v) Filtering the hot solution through celite bed followed by concentrating the filtrate under vacuum to obtain ester of C2 to C6 linear or branched chain fatty acids with sugar/sugar alcohol.

The C2 to C6 linear or branched chain fatty acids are selected from the group consisting of acetic acid, propionic acid, butyric acid, 2-methyl propanoic acid, 2- methyl butanoic acid, 3 -methyl butanoic acid, pentanoic acid, 3 -methyl pentanoic acid and caproic acid.

The sugar and sugar alcohol may be selected from the group consisting of sucrose, lactose, glucose, galactose, maltose, isomaltose, mannitol, fructose, cellobiose, globabiose, trehalose, myo-inositol, psicose, sorbitol, xylitol, erythritol etc. either in their chiral form or racemic form and any polyhydroxy compounds which are of synthetic or natural in origin.

The esters of C2 to C6 linear or branched chain fatty acids with sugar/sugar alcohol thus obtained after drying under vacuum was further evaluated for its insecticidal properties. In a specific embodiment, the addition of 1.0 to 1.5 equivalents of sugar to 1.0 to 5 equivalent of C2 to C6 linear or branched chain fatty acids is sufficient to achieve the esters of C2 to C6 linear or branched chain fatty acids with sugars or sugar alcohols in very good yeilds . Accordingly, in an embodiment, C2 to C6 linear or branched chain fatty acid esters of sucrose are selected from the group consisting of sucrose propionate, sucrose butyrate, sucrose 2-methyl butyrate and sucrose 3 -methyl pentanoate, Erythritol butyrate, Xylitol Propionate, Glucose propionate, Glucose 2-methyl butyrate, Glucose 3 -methyl pentanoate, Glucose butyrate, Sorbitol butyrate, Arabinose butyrate, Arabinose propionate, etc.

In another embodiment, the short chain fatty acids can be used either alone or in combination with other C2 to C6 linear or branched chain fatty acids.

The process comprises reaction of sugar or sugar alcohol with C2 to C6 linear or branched chain fatty acids to obtain isomeric mixtures. The isomeric mixtures are obtained due to degree of acylation having mono, di, tri, tert- or higher order based on the number of available hydroxyl groups in the sugar moieties and the ratio of the acid to sugar/sugar alcohol.

In another embodiment, the said esters can also be prepared using N,N-carbonyl diimidazole (CDI). To a solution of C2 to C6 linear or branched chain fatty acid (0.9 to 5 eq) in DMF was added CDI (1.2 eq with respect to fatty acid) in aliquotes under nitrogen atmosphere. The temperature of the reaction mixture was maintained at 0-5 °C during the addition of CDI. After the complete addition of CDI, the reaction mixture was stirred for 10 min at 0-5 °C under nitrogen atmosphere. Into this was added sugar/sugar alcohol (1.0 eq) in aliquots. Reaction mixture was stirred for 24 h, treated with ice cold water and extracted with ethyl acetate. Organic phase separated, washed with saturated brine solution and dried over anhydrous sodium sulfate. Volatiles were removed under reduced pressure to give a mixture of fatty acid sugar/sugar alcohol esters as light brown material. In another embodiment, the said esters can also be prepared using Lipase enzyme as follows: Sucrose (1.0 eq) and butyric acid (1.0 to 5 eq) were heated together at 50 °C under mechanical stirring. Sodium butyrate (1.5 eq) was added and the reaction was then started by adding Candida antarctica component B lipase (1.5 ml of an aqueous solution containing 5000 LU/mL). The resulting reaction mixture which comprised two clear phases was stirred at 50 °C for 15 min after which the stirring was stopped. The phases were separated and the isomeric mixture of sucrose butyrate was recovered from the the top phase.

In an alternative embodiment, C2 to C6 linear or branched chain fatty acid esters of sugars or sugar alcohols were made using acid chloride method where in 1.0 eq of acid chloride was added to a hot and stirred solution of sugar/sugar alcohol (1.1 eq) in dry DMF and pyridine. The reaction mixture was stirred at 80 °C until all the acid chloride was consumed. Reaction mixture was cooled to room temperature and diluted with ethyl acetate (5 v), washed with water, followed by dilute HC1, then with cold bicarbonate solution and finally with brine solution. Organic phase was separated and dried over anhydrous sodium sulphate, filtered and evaporated under vacuum. The residue thus obtained was used as such for the further studies.

In another embodiment, the said esters can also be prepared using acid catalyzed trans-esterification employing the use of catalyst such as phosphoric acid, sulfuric acid, p-toluene sulphonic acid, pyridinium sulphonate, or base catalyzed reactions employing the use of metal carbonate selected from the group of sodium carbonate, potassium carbonate or metal alkoxides selected from the group of sodium methoxide or using metal salts such as zinc chloride, iron chloride, or by Mitsunobu coupling, carbodimide coupling, lipase, lews acids selected from the group of salts of zinc, copper, tin, iron, scandium, gallium, and the potential salts selected from the group of chlorides, bromides, triflates etc. In an embodiment, the antimicrobial composition comprises C2 to C6 linear or branched chain fatty acids of sugars and sugar alcohols optionally with pharmaceutical excipients useful as potential agents for treating oral and dermatological problems of microbial origin.

In another embodiment, the antimicrobial/biopesticide composition comprises C2 to C6 linear or branched chain fatty acid esters of sugars and sugar alcohols with silica, nano silica diatomaceous earth for the control of pest and insects.

In another preferred embodiment, the present invention provides an antimicrobial/biopesticide composition comprising C2 to C6 linear or branched chain fatty acid esters of sugars or sugar alcohols along with other agriculturally acceptable ingredients selected from the following:

• oxidation pathway inhibitors such as gallic acid or tannic acid for reducing resistance,

• other insecticides/pesticides of natural or synthetic origin,

• plant nutrients, stimulants, hormones, PGR etc.

• pheromones,

• surfactants, spreaders, stickers, penetrants, silica, nano silica diatomaceous earth etc.

• carrier oil, anti-oxidants such as ethoxyquin, a tocopherol, BHT, etc.

• Arginine, Lysine, Glycine, nitrosglutathione, sodium nitrospruside, sodium hydrogen sulphide which may act as adjuvents

• Methyl xanthines such as caffiene, theacrine, theophyline, theobromine, paraxanthine, methyl liberine

• Nonionic, Cationic and Anionic surfacts such as Tween (Poly sorbate), or any secondary alcohol ethoxylate, Tergitol (anionic sulfonate), SDS, spreading agents such as Silwet (Polyalkyleneoxide modified heptamethyltrisiloxane), xanthum gum and long chain alcohol ranging from C 8 to C 20. Accordingly, the present invention provides an antimicrobial/biopesticide composition comprising a) C2 to C6 linear or branched chain fatty acid esters of sugars or sugar alcohols in a concentration ranging from 0.05% to 4.0% by weight of the composition; b) inactive excipients present in a concentration ranging from 96% to 99.5% by weight of the composition and c) water in a concentration ranging from 0 to 90%.

The present composition can be formulated as powder, soaps, pellets, granules, suspensions, gels, solutions and aerosol sprays.

The present invention is explained further in detail by illustrating examples below. Some typical examples illustrating the embodiments of the present invention are provided; however, these are exemples only and should not be regarded as limiting the elements of the present invention.

Example 1: General procedure for the preparation of sugar/sugar alcohol esters using acid catalysis:

Preparation of Erythritol butyrate

Butyric acid (72.3 g, 2.0 eq) was charged into a three necked RB flask (250 ml) fitted with a short distillation head and a mechanical stirrer. Into this was added erythritol (50 g, 1.0 eq) in aliquots. The reaction mixture was heated to 120 °C. Into this was added phosphoric acid drop wise (10 mole percent, with respect to Erythritol) under stirring. The temperature of the reaction mixture slowly raised to 150 °C and stirred for 30 h. It was allowed to reach rt, diluted with ethyl acetate (150 mL) and treated with calcium hydroxide (3 g). It was filtered through celite bed and the filtrate was dried over anhydrous sodium sulphate, evaporated under reduced pressure to give an amber colored viscous liquid. The isomeric compostion of esters of erythritol butyrate thus obtained was used as such for the preparation of insecticidal formulation; GC analysis (below table) shows the formation of mixed esters as expected. Yield: 92.0 g.

Example 2: General procedure for the preparation of sugar/sugar alcohol esters using acid chloride method:

Preparation of Xylitol Propionate

A solution of propanoyl chloride (27.76 g, 1.0 eq) in acetonitrile (115.0 mL) was added to a suspension of xylitol (50.0 g, 1.1 eq) in DMF (250 mL) and pyridine (32.0 mL) at rt. It was stirred for 24 h during which TLC showed the disappearance of the starting materials. It was treated with cold water (400 mL) and extracted with ethyl acetate (2 x 100 mL). The organic phases combined, combined phase washed with cold dil. HC1 (10 mL x 3) followed by brine (50mL x 2) and then dried (anhydrous sodium sulphate). It was filtered and the filtrate evaporated to dryness to give amber colored viscous liquid. The isomeric composition of esters of xylitol butyrate used as such for the preparation of insecticidal formulation; GC analysis (below table) shows the formation of mixed esters as expected. Yield: 65.0 g

Example 3: General procedure for the preparation of sugar/sugar alcohol esters using N, N’ Carbonyl diimidazole:

Preparation of Sucrose Butyrate

To a stirred solution of butyric acid (64.3 g, 5.0 eq) in DMF (350 mL) was added N,N‘ carbodiimidazole (CDI) (142 g, 6.0 eq) in aliquots at 0-5 °C. After 10 min, was added sucrose (50.0 g, 1.0 eq) in small portions. The reaction mixture allowed to reach rt and stirred for further 24 h, during which TLC showed the disappearnce of the starting materials. Reaction was quenched by the addition of ice cold water and the content was extracted with ethyl acetate (200 mL x 3). The organic phases combined and washed with saturated brine solution and dried over anhydrous sodium sulfate. Volatiles were removed under reduced pressure to yield a light brown syrupy material. The composition of fatty acid esters of sugar/sugar alcohol thus obtained were used as such for the insecticidal formulation.GC analysis (below table) indicates the formation of mixed esters. Yield 91 g.

GC analysis data of Sucrose butyrate:

Example 4: General procedure for the preparation of sugar/sugar alcohol esters using Lipase enzyme: sucrose (5 g, 0.014 moles) and butyric acid (5.2 g, 0.073 mol) were heated together to 50 °C under mechanical stirring. Sodium butyrate (2.4 g, 0.021 mol) was added and the reaction was then started by adding Candida antarctica component B lipase (1.5 ml of an aqueous solution containing 5000 LU/mL). The resulting reaction mixture which comprised two clear phases was stirred at 50 °C for 15 min after which the stirring was stopped. The phases were separated. The top phase contains isomeric mixture of sucrose butyrate. GC analysis shows the formation of mixed esters as expected.

Yield:7.2 g Analytical Data:

The density of fatty acid sugar esters prepared in accordance with the invention varies between 0.98 to 0 1.02 g/mL @ 30 °C.

Table: 1

I.R specrtal Data

The composition was analyzed by IR concluded that all sugar/ sugar alcohol fatty acid esters contain ester carbonyl stretching frequency atl735-1750 cm ¹ , C-H stretching frequencyat 2850-3000 cm ¹ , OH stretching frequency at 3500-3600 cm ¹ and C-0 stretching at 1000-1150 cm ¹ .

GC ANALYSIS DATA

GC analysis was done for isomeric composition of short chain fatty acid sugar esters. The column used is ZB5 30m X 0.25 mm X 0.25 pm, Make Phenomenex. Injector temperature 250 °C, Detector temperature 300 °C, Column Flow 1 mL/min, Carrier gas Nitrogen, Injection volume is lpL.

From G.C analysis data it is evident that polyhydroxy sugar and sugar alcohols undergone esterification with short chain fatty acid either partially or fully leading to the formation of mixtures of mono, di, tri and tetra esters in varying proportions.

The fact that there are multiple hydroxyl groups in sugars that can be esterified which means that in principle multiple isomers of sugar esters were formed during the synthesis. As there is no structure and activity relative evidences to establish that particularly whether mono or di or tri or tetra easters alone having insecticidal activity, which also has no means to separate each isomer and predict the chemical structure. Therefore, a mixture of isomers of sugar fatty acid esters have been tested as such for insecticidal activity.

Entomological studies

The composite mixture of sugar/ sugar alcohol fatty acid esters in different proportions is very powerful insecticidal agents, whose activity is clearly explained in entomological studies.

Entomological studies were carried out on different pests using various short chain fatty acid esters of sugar/sugar alcohols @ 0.1%; 0.25% and at 0.5% concentrations and the mortality rate is observed after 48 h, as shown in tables 2 to 4. The following pests were selected for entomological studies:

1. Spodopterafrugiperda (Fall army worm)

2. Rhopalosiphum maidis (Com leaf aphid)

3. Maconellicoccus hirsutus (Hibiscus mealybug)

Table: 2

Table: 3 Table: 4

Note: Efficacy categories based on mortality rate; Minimal: 0 to 50% mortality, Good: 50 to 70% mortality, Very Good: 70 to 90% mortality, Excellent: 90 to 100% mortality. While the market control Delegate is 11.7 % SC concentration; the claimed formulations were tested with 0.1 to 0.5% concentration.