RU2619249C1 - Composition for seed treatment and method of its production - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: composition comprises tebuconazole and water-soluble derivatives of glycyrrhizic acid in the form of the acid itself, its salts or licorice root extract at the weight ratio of 1:(1-10), respectively. The composition is obtained by mechanochemical interaction of the mixture of said components. The method for producing the composition comprises the mechanochemical treatment of the mixture, in which tebuconazole is mixed with water soluble derivatives of glycyrrhizic acid at the ratio of 1:(1-10), respectively.

EFFECT: increased penetration of tebuconazole into the internal volume of the grain, increased fungicidal activity, decreased retardant effect of tebuconazole.

6 cl, 1 dwg, 5 tbl, 7 ex

Description

The invention relates to agriculture, in particular to means for combating diseases of crops and increasing their productivity, in particular to the creation of fungicidal preparations, and may find application in the protection of crops from root rot and other diseases.

Tebuconazole (TBA) - the technical name of the active substance is 4,4-dimethyl-3- (1H-1,2,4-triazol-1-ylmethyl) -1-n-chlorophenylpentan-3-ol, belongs to the class of organic compounds (a namely, to the class of triazoles), and according to biological activity, to systemic fungicides of a wide spectrum of action for combating diseases of leaves and ears of grain (fusarium, septoria, rust, powdery mildew and others), gray rot of grapes, some diseases of soy, rape, sunflower, vegetable and fruit crops by spraying and seed dressing for more ribs with solid and dusty smut, Septoria of cereal crops [1. Melnikov N.N., Novozhilov K.V., Belan S.R. Directory. Pesticides and plant growth regulators. M .: Chemistry, 1995].

TBA is a broad-spectrum systemic fungicide. It has protective, healing and eradicating properties [2. Belov D.A. Chemical methods and plant protection products in forestry and landscaping: a textbook for students. - M .: MGUL, 2003. - 128 p.]. It quickly penetrates into the plant and is evenly distributed in it [3. Andreeva E.I., Zinchenko V.A. Systemic fungicides inhibitors of ergosterol biosynthesis. Magazine "AgroXXI", No. 4, 2002, p. 14-151]. When processing seeds, it effectively suppresses root rot pathogens, smut fungi and moldy seeds [4. Popov S.Ya. Fundamentals of chemical plant protection. Popov S.Ya., Dorozhkina L.A., Kalinin V.A. / Ed. Professor S. Ya Popov. - M.: Art-Lyon, 2003. - 208 p.].

TBA has a growth-regulating effect, which can turn into a retardant under adverse conditions: lack of moisture, waterlogging of the soil, too deep seeding of seeds, their low germination energy and field germination, high herbicidal load, which can slow the emergence of seedlings (the same properties are inherent to diniconazole, triticonazole and to a lesser extent other azoles). [5. Tyuterev S.L. Grain seed dressing. All-Russian Research Institute of Plant Protection of the Russian Academy of Agricultural Sciences. Moscow: Journal of Plant Protection and Quarantine (Appendix), 2005].

Seed disinfectants should be toxic to pathogens, well kept on the surface of the seeds, not to reduce their germination. When seed dressing, relatively small amounts of active substances must be applied evenly to the seeds to ensure their protection against external and internal infections, from damage by pathogens in the soil. In order to achieve an optimal biological effect against diseases, seed dressers must be in good formulation.

Such forms for TBA are formulations in the form of suspension concentrates (Barrier-Color, Vial-Trust, Stinger, Alt-Force) and microemulsions (Tebu, Scarlet) [6. The state catalog of pesticides and agrochemicals approved for use on the territory of the Russian Federation. M., 2010, 840 pp.]. To prepare suspension forms, the substance of the preparation is dispersed in ball and bead mills in an aqueous (or aqueous-organic) medium with the addition of surfactants, stabilizers and other fillers. Oil emulsions are prepared by dissolving the substance of the drug in an organic solvent (or mixture of solvents) with the addition of a surfactant, which forms a stable emulsion with water [7. Guidelines for the quality control of preparative forms of CSF and feedstock for their preparation. Cherkasy, NIITEKHIM, 1984, 48 pp.].

As an analogue for the invention described below, the preparative form of TBA in the form of the drug "Raksil", KS (60 g / l), which is recommended for the treatment of seeds of grain crops in the fight against root rot [8. The state catalog of pesticides and agrochemicals approved for use on the territory of the Russian Federation. M., 2010, 840 pp.]. This formulation is obtained by wet grinding the active substance of the drug "Raxil" (TAC) with auxiliary substances (wetting agents, dispersants, emulsifiers, surfactants, etc.) in a liquid medium.

There is also known a method of obtaining a fungicidal agent [9. EP 2269581, publ. January 5, 2011], containing a fungicide in the form of nanoparticles and natural or synthetic water-soluble polymers in the ratio fungicide: polymers 1: (1-100). However, the known method requires the presence of solvents, energy-intensive processes of spray or freeze drying, characterized by a multi-stage process. In addition, excipients — emulsifiers, stabilizers, which as a rule have undesirable toxicochemical properties — are present in significant quantities in the preparative forms.

The closest technical solution chosen for the prototype is a fungicidal agent and method for its preparation [10. Pat. RF №2469536, publ. December 20, 2012]. This fungicidal agent contains TBA and water-soluble natural or synthetic polymers from the group: beta-cyclodextrin, arabinogalactan, hydroxyethyl starch, pectin, polyethylene glycol, polyvinylpyrrolidone, in a mass ratio of 1: (1-5), respectively. The tool is obtained by mechanochemical interaction of these components. The invention allows to increase the water solubility of the fungicidal agent, to increase its fungicidal activity. However, an increase in water solubility in itself is not directly related to an increase in the biological activity of the preparations. So, on the example of drugs, a fairly wide range of drugs is known that have high water solubility, but poorly penetrate biological membranes [11. Food and Drug Administration. Guidance for Industry: Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms Based on a Biopharmaceutics Classification System. Food and Drug Administration, Rockville, MD, 2000. Available at http://www.fda.gov/cder/guidance/index.htm] and thus lacking pharmacological efficacy. It follows that in order to increase the effectiveness of fungicidal compositions, it is necessary first of all to increase the penetration of TBA through the shell of the grain into its volume, the so-called "Bioavailability". Unfortunately, to date, data on the values of TBA penetration into the internal volume of grain from various formulations are not available.

The objective of the present invention is:

- increased penetration of TBA into the internal structures of the grain through the fruit and seminal membranes;

- increased fungicidal activity of TBA in the composition;

- reduction of the retardant action of TBA;

- the use of non-waste and productive technology for producing the composition.

The solution of this problem is achieved by creating a composition for seed dressing containing TBA and water-soluble derivatives of glycyrrhizic acid (HA), used in the form of the acid itself, its salts or licorice root extract in a mass ratio of 1: (1-10), respectively. Derivatives of HA can be embedded in biological lipid membranes and, presumably, are “carriers” of low molecular weight biologically active substances in transmembrane transfer. In aqueous solutions, HA derivatives form vesicles - micelles, consisting of 60-100 molecules, which include molecules of sparingly soluble TBA in water. Such micelles have membranotropic properties that increase the transmembrane transfer of TBA, thereby increasing its bioavailability. At the same time, it is far from obvious that HA will facilitate the transfer of TBA through the shell of the grain, since they have a more complex structure compared to the lipid membranes of animal cells.

The composition is presented in the form of a water-soluble powder, and when it is dissolved in water by gel permeation chromatography, the formation of the above micelles is detected. This indicates specific intermolecular interactions of TBA and HA derivatives, which are formed during the mechanochemical preparation of compositions. At the same time, the bioavailability of TBA is significantly increased, the fungicidal effect is enhanced. In addition, HA derivatives help to reduce the retardant effect of the active substance and increase cereal productivity (see examples of the invention).

The proposed composition for seed treatment have the following advantages:

- the use of affordable and cheap materials derived from HA isolated from widely distributed plant materials — licorice roots — and capable of forming mechanochemical supramolecular structures — micelles — complexes with TBA;

- increased bioavailability - the ability of TBA to penetrate through the shell of the grain into its internal volume, which allows to improve the fungicidal properties of TBA and reduce its current dose;

- the use of useful technological and biological properties of the water-soluble derivatives of HA themselves, which will not only improve the quality indicators of mechanochemical complexes / micelles, but also achieve the synergistic effect in the fungicidal and antimicrobial effects of TBA;

- the use of the biological properties of the water-soluble derivatives of HA themselves, which will reduce the retardant effect and increase the yield of grain crops.

The solution to this problem is also achieved by the fact that the claimed composition is obtained by mechanochemical interaction of TBA and water-soluble derivatives of HA in a ratio of 1: (1-10). As apparatuses for mechanochemical processing, ball roll, planetary, vibrational, vibrocentrifugal, etc. can be used. mills, i.e. shock abrasion devices. The process scales from ball laboratory mills with a load of several grams to flow vibrocentrifugal mills with a capacity of up to 100 kg / h and more.

A mixture of TAC and HA derivatives, taken in a mass ratio of 1: 1 to 1:10, is subjected to mechanochemical treatment in the above shredders-activators of shock-abrasive type. During the mechanical treatment, TBA molecules are dispersed into the volume of solid phases of auxiliary substances, forming a solid solution, which is a disordered solid phase in which TBA and auxiliary substances, in the form of water-soluble derivatives of glycyrrhizic acid, experience non-covalent non-ionic interactions. During the dissolution of this solid dispersion, HA micelles are formed, in which TBA molecules are included, which is justified by the achieved increase in its water solubility [12. A.V. Dushkin, E.S. Meteleva, et al., Complexing of Pharmacons with Glycyrrhhizic Acid as a Route to the Development of the Preparations with Enhanced Efficiency // Chemistry for Sustainable Development 18 (2010) 437-444].

Thus, the claimed advantages of mechanochemically obtained compositions are achieved - the inclusion of TBA molecules in HA vesicles / micelles and an increase in permeability through grain shells, which determines the corresponding indicator of fungicidal and antimicrobial action. At the same time, the following declared advantages of the production method are achieved — the preparation of the claimed compositions takes place in one technological stage of machining in the grinder-activator, the participation of liquid phases is not required, the energy-intensive and lengthy process of drying the material is excluded, there are no solvent wastes. In the absence of the above production conditions — for example, the use of mixing the components under “mild” conditions, only water-soluble components of the compositions pass into the aqueous solution, and the crystalline phase of the TAC remains in the sediment.

There are no special requirements for controlling the humidity of the premises, since the substances are processed in the sealed internal volume of the mills. In all cases, the process is carried out in virtually one stage, it does not require expensive equipment and is easy to implement.

It should be noted that the detected phenomenon of increased fungicidal activity, a decrease in the retardant effect, and an increase in the yield of grain crops using the inventive composition and method for producing the composition does not follow with obviousness from the existing level of scientific knowledge and was first discovered by the inventors. Thus, according to the above description, the phenomenon we discovered of an increase in fungicidal activity in combination with a decrease in the retardant effect and an increase in the yield of grain crops, as well as a method for producing such compositions providing their properties, meets the criterion of novelty.

Case Studies

Example 1. Obtaining compositions for seed treatment based on TBA and licorice extract

In a metal drum (1 liter capacity, loading grinding media - steel balls with a diameter of 23 mm, 1.5 kg) of a VM-1 roller mill (acceleration of 1 g), 6 g of TBA substance and 60 g of dry extract of licorice root (content of HA 20, 5%). Activation is carried out for 12 hours, taking and analyzing samples (see Example 4) every 2 hours. The optimal time of mechanochemical treatment is selected according to the criteria for maximum water solubility, provided that the content of TBA is not less than 95% of the initial one.

Example 2. Obtaining compositions for seed treatment based on TBA and HA

In a metal drum (0.3 L capacity, loading grinding media - steel balls with a diameter of 23 mm, 0.75 kg) of a VM-1 roller mill (acceleration of 1 g), 3 g of TAC substance and 15 g of HA substance are placed. Activation is carried out for 12 hours, taking and analyzing samples (see Example 4) every 2 hours. The optimal time of mechanochemical treatment is selected according to the criteria of maximum water solubility, provided that the content of TAC is not less than 95% of the initial one.

Example 3. Obtaining compositions for seed treatment based on TBA and sodium glycyrrhizinate

In metal drums (two twin drums of 50 ml each), the AGO-2 grinder-activator is charged with 1.0 g of TBA, 5.0 g of disodium salt of HA (Na ₂ HA) and 96 g of balls (diameter 4-5 mm). Activation is carried out at an energy intensity of 20 g for 10 minutes After activation, the product in the form of a powder is unloaded and characterized according to the analysis of its aqueous solution (see Example 4).

Example 4. Analysis of aqueous solutions of mechanochemically obtained compositions for dressing grain

To determine the solubility in water, the TBA / HA derivatives composition in an amount of 0.2 g was dissolved in 10 ml of distilled water with stirring in a shaker incubator (25 ° C, 180 rpm) for 3 hours. The concentration of TBA in the solution was determined by HPLC on an Agilent 1200 chromatograph with a Zorbax Eclipse XDB-C18 column, 4.6 × 50 mm; column temperature 30 ° C; Diode array detector. The acetonitrile - water (1: 1) system was used as an eluent, the flow rate was 1 ml / min, the sample volume was 5 μl, and detection at a wavelength of 238 nm. The concentration of TBA was determined relative to its specially prepared solution in ethanol.

To study the structure of aqueous solutions of the compositions, gel filtration chromatography using an Agilent 1200 chromatograph with a PL aquagel-OH 40 column, 300 × 7.5 mm; column temperature + 30 ° C; refractometric detector. An aqueous solution of 0.1 M LiNO ₃ or distilled water was used as a solvent and eluent; the flow rate was 1 ml / min. Calibration was performed according to Sigma-Aldrich dextran standards with molecular weights of 12, 25, 50, 80, 150, 270, and 410 kDa. Agilent GPC Date Analysis (using the linear dependence lgMM - retention time) was used to process the obtained results and calculate the MMD. In all cases, in the chromatograms of aqueous solutions of TBA compositions with HA, Na ₂ HA and licorice extract, peaks of high molecular masses with a mass of 60-100 kDa were observed. Previously, [13. A.V. Dushkin, E.S. Meteleva, et al., Complexing of Pharmacons with Glycyrrhizic Acid as a Route to the Development of the Preparations with Enhanced Efficiency // Chemistry for Sustainable Development 18 (2010) 437-444], we have shown that they belong to HA micelles consisting of from 60-100 of its molecules. No peaks of low molecular weight compounds (TBA) were found under the used analysis conditions, which, along with data on an increase in the solubility of TBA, see Table 1, indicates the inclusion of TBA molecules in micelles.

Example 5. Determination of penetration of tebuconazole in the internal volume of grain

Wheat grain (grade Omskaya 36) was treated with an aqueous suspension of the composition, as well as tebuconazole based on the amount of 0.03 g of active substance (TBA) per 100 g of grain. The suspension was prepared by mixing the calculated amount of the composition and 5 cm ^{3 of} water. The suspension was mixed with grain in a drum of a roll mill VM-1 (see example 1), however, without loading grinding media. Processing time - 1 hour.

Then the treated grain germinated for 3 days. For this, the kernels were laid out in sterile chambers on moistened filter paper and placed in a thermostat at a temperature of + 25 ° С.

Germinated grain along with the sprouts was dried to constant weight in a vacuum oven at + 60 ° C. Then, the TAC was flushed, which did not penetrate into the grain volume and remained on its surface. For this purpose, a grain sample was treated with several portions of ethanol until the peak of TBA disappeared in the HPLC chromatograms (see Example 4) in the above alcohol washes.

The grain treated in this way was dried for 24 hours in a vacuum oven at + 60 ° C and ground in an impact mill (coffee grinder). Next, a known amount of ethanol was added to a weighed sample of the obtained powder, the mixture was stirred on an orbital shaker for 20 min at + 25 ° С and filtered through a paper filter. The concentration of TBA in the resulting solution was carried out by HPLC (see example 4). Then, the mass of TAC contained in 100 g of grain was calculated. The results are shown in Table 2.

Thus, the results confirm that the claimed composition increases the penetration of TBA into the internal volume of grain by at least 2 times.

Example 6. Biological effectiveness of seed treatment with the composition Na ₂ HA / TCE 5/1

The effectiveness of the use of the Na ₂ HA / TBA 5/1 composition with a consumption rate of 0.3 kg / t of seeds was studied in a field experiment on crops of spring wheat of Omskaya 36 and spring barley of Acha. The standard was Raxil disinfectant-fungicide, KS with a consumption rate of 0.5 l / t. The experiment was repeated four times, the allocation of plots was systematic, the plot area was 23 m ² .

The biological effectiveness of the composition in suppressing the development of ordinary root rot in phase 3 of cereal leaves reached 83.2% in spring wheat crops, 49.6% in spring barley crops and was higher than when using the reference preparation - 76.6 and 37.9% respectively (table 3). The prevalence rate of the disease was also significantly reduced. On wheat, the high biological effectiveness of the composition was determined, among other things, by suppressing the development of the disease on coleoptile. By the phase of baking grain, the phytosanitary effect of dressing was 46 and 41.9% on wheat and barley, in the variant with Raksil - 44.6 and 34.9%, respectively.

Example 7. The effect of the composition of Na ₂ HA / TBA 5/1 on the productivity indicators of grain crops

A field experiment showed that the treatment of seeds with the composition had a positive effect on the growth processes of cereal plants (Fig. 1. The growth dynamics of soft spring wheat and spring barley during seed treatment with the composition Na ₂ HA / TAC 5/1).

The height of the wheat and barley plants protected by the composition in phase 3 of the leaf exceeded the pure control (23.0 and 21.8 cm) and the standard (21.7 and 21.1 cm) in the phase of three leaves by 1.6 and 0.7 cm ( control) and 2.9 and 1.3 cm (standard). In the subsequent phase of accounting, wheat plants in the variant with the composition exceeded the control by 0.2 cm, and the reference version by 2.3 cm, the corresponding indicators for barley plants were 3.0 and 5.0 cm.

Seed dressing affected the density of grain crops. To a greater extent, the effect of the protectants affected the productive stalk (Table 4). The number of productive stems of wheat exceeded the control by 137 pcs / m ² , the standard - by 8 pcs / m ² . When sowing barley seeds treated with the composition, both indicators of the sowing density significantly increased: the number of plants / m ² - by 54 (relative to the control) and 11 pcs / m ² (relative to the standard), productive stems - by 246 and 84 pcs / m ^2, respectively.

By the phase of milk ripeness, the grain of the plant grown from the seeds treated with the composition turned out to be more (11.0% - wheat; 13.0% - barley) tall (control - 86.7 and 53.8 cm), more clustered (table . 5). In wheat and barley plants, the spike length, the number of spikelets in the spike, the number of grains in the main spike, the weight of grain per plant, and the weight of 1000 grains significantly increased relative to the control. Regarding the variant with Raxil, there was a tendency to increase all of these indicators.

The grain yield increased relative to the control by 0.2 t / ha when sowing wheat and by 0.19 t / ha when sowing barley treated with Na ₂ HA / TBK 5/1, compared to Raxil, these indicators were 0.04 t / ha and 0 , 12 t / ha.

Thus, the examples of implementation of the invention confirm the claimed characteristics and a method for producing compositions for seed treatment. Achievable technical result consists in obtaining, according to non-waste and productive technology, a new composition for seed dressing, which provides a twofold increase in the penetration of tebuconazole into the internal volume of grain, an increase in fungicidal activity and a decrease in its retardant effect.

Claims (6)

1. A composition for seed dressing, comprising tebuconazole, characterized in that it further comprises water-soluble derivatives of glycyrrhizic acid in a mass ratio of 1: (1-10), respectively, and obtained by mechanochemical interaction of tebuconazole and derivatives of glycyrrhizic acid. 2. A seed dressing composition according to claim 1, characterized in that it is presented in the form of a water-soluble powder, includes water-soluble derivatives of glycyrrhizic acid selected from the group: glycyrrhizic acid, salts of glycyrrhizic acid or dry licorice root extract containing glycyrrhizic acid. 3. A seed dressing composition according to claim 2, characterized in that when dissolved in water it forms glycyrrhizic acid micelles, including tebuconazole molecules. 4. A method of obtaining a composition for seed dressing, including mechanochemical processing of a mixture containing tebuconazole, characterized in that tebuconazole is mixed with water-soluble derivatives of glycyrrhizic acid in a ratio of 1: (1-10), respectively. 5. The method according to p. 4, characterized in that the water-soluble derivatives of glycyrrhizic acid are selected from the group: glycyrrhizic acid, salts of glycyrrhizic acid or dry licorice root extract. 6. The method according to p. 4, characterized in that the mechanochemical interaction is carried out in devices of shock-abrasive action.

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