SOLVENT AND METHOD FOR EXTRACTING ACTIVE COMPOUNDS FROM PLANTS ADN USE OF SUCH A SOLVENT

Description

Technical Field

The present invention finds application in the field of chemistry for agriculture and has particularly for object a solvent and a method for the extraction of active compounds from plants utilizing said solvent. The invention also relates to the use of this solvent and of the related method for the extraction of active compounds from plants designed for use in agriculture.

State of the art

In agriculture, the use of active plant-based compounds for uses such as bio stimulants, fertilizers, nutrients, pesticides and as adjuvants for the growth of plants in general, both with a nutritive and protective function, is always increasing.

The products currently on the market are different both for the raw material, which conditions the active substances that will then be present in the final compound, and for the methods of application, which may include application in the soil or directly on a part of the plant, on the leaves and/or roots.

However, the extraction methods usually provided require the use of acids or bases or volatile organic solvents or, again, enzymatic hydrolysis.

These methods present various safety problems both for the operators involved in their handling and for the users of the final product, due to their toxicity, the high environmental impact and safety risks.

Not least, these known procedures may cause significant modifications of the extracted molecules and are also energy-intensive, so that they may be economically uneconomical.

On the contrary, there is a growing need to have natural and environmentally friendly products that can replace the common synthetic bio- stimulants, fertilizers, nutrients, parasiticides or products of animal origin and that are safe both for the technicians involved in their production and for the operators who use them, as well as for the final consumers of the treated plant products. US2013149322 describes a method for the extraction of substances from materials of natural plant origin which uses, in place of traditional organic solvents, the so-called natural eutectic solvents called NADES {Natural Deep Eutectic Solvents) which do not have the drawbacks of common solvents and have elevated environmental compatibility.

The NADES have in fact several advantages compared to traditional solvents such as solvents derived from petroleum, ethanol or similar.

In particular, NADES, in addition to good solvents properties, have low volatility and low environmental impact.

Moreover, NADES can be customized according to needs and their properties can be modified by changing the composition.

The aforementioned patent application describes, in a first embodiment, an eutectic solvent obtained starting from the combination of an organic acid with sugars, alcohol or amino acids. A second solution involves the use of inorganic compounds instead of organic acids. A third solution, finally, involves the combination of two sugars.

However, current extraction techniques using NADES are not currently suitable for obtaining products for use in agriculture, such as fertilizers, bio stimulants, plant protection products or plant care products in general.

We therefore propose to find an alternative to known eutectic solvents in order to favor their use in agriculture, such as fertilizers, biostimulants, plant protection products or plant care products in general.

On the contrary, the use of NADES as solvents is well known in pharmacology and in the so-called nutraceutical sciences.

In these sectors, different combinations of starting elements for the production of NADES were experimented, using both combinations of several organic compounds and combinations of organic compounds with inorganic compounds.

However, these solutions proved to be too complex and therefore too expensive to be used also in the agricultural sector, where, unlike the pharmaceutical sector, the economic aspect is still a relevant factor, or not very stable and therefore not suitable for general use. To this second group belong the NADES formed from a compound based on choline, which led to a final product with too high water content and therefore with low stability.

Scope of the invention

The object of the present invention is to overcome the above drawbacks by providing a solvent for the extraction of active compounds from plants which allows to obtain compounds usable in organic farming or in any case does not entail risks for the consumer of agricultural products treated with this compound.

A particular object is to provide a new use of such a solvent to obtain compounds usable in agriculture.

A particular object is to provide such a solvent whose method of production is particularly efficient and relatively cost-effective.

A particular object is to provide a method for the extraction of active compounds from plants that can be used in agriculture and that is safe both for operators and for the environment.

Still another object is to provide a method for the extraction of active compounds from plants for use in agriculture which allows to obtain a product for the care and/or nourishment of plants in general which is absolutely natural and which does not involve risks neither for the environment nor for the operators who are involved in its handling and which can also be used also in the field of organic farming or in any case does not involve risks for the consumer of agricultural products treated with this compound.

A further object is to provide a method for the extraction from plants of active compounds for use in agriculture which allows to obtain a boost extraction of the active compounds in order to have a final product relatively rich in such compounds and therefore more effective.

These objects, as well as others that will appear clearer later, are achieved by a natural- origin eutectic solvent (NADES) according to claim 6, consisting of a first organic compound of natural origin combined with a second compound of natural origin with an organic base chosen between organic acids and vitamins, urea, salts or a mixture thereof.

The solvent thus constituted will be formed starting from food grade raw materials, being able to have itself food grade, and can be used in complete safe manner, allowing to obtain extracts with high environmental compatibility and therefore usable also in organic farming and without producing harmful residues for people or the environment.

Advantageously, said first and/or said second organic compound will comprise a mixture of short chain amino acids in amounts of at least 80%.

This feature will allow to have a particularly cost-effective solvent and therefore with an easier use in agriculture, or in a sector where there is great attention to the economic aspect.

Preferably, the eutectic solvent will have a final water content between 15% and 20%, even more preferably close to 18%, so as to be particularly stable and not to precipitate. According to a further aspect of the invention a method is provided for the extraction of active compounds from plants using the above natural eutectic solvent.

The method thus configured will be particularly safe and will allow to obtain a particularly ecological end product with a particularly high pigment content.

As matter of fact, it will be possible to start from a natural raw material, extracting the pigments using both the solid part and the juice of the first extraction, in order to extract the pigments in a substantially complete manner.

The product thus obtained will also be food grade and therefore can be safely applied on plants in order to obtain safe products that do not involve risks for the operators involved in their application on plants or for the final consumer of the agricultural product.

According to still further aspects, the use of a natural eutectic solvent (NADES) is provided for the extraction of active plant compounds from plants or parts of plants, as well as the use of an active vegetable compound for use in agriculture as a biostimulant, and/or fertilizer and/or nutrient and/or pesticide and/or as products for the biostimulation and/or care of plants and/or to promote their growth, wherein said plant compound is a phytocomplex obtained by extraction from plants by at least one natural eutectic solvent (NADES).

The use of these solvents, as well as phytocomplexes extracted with these solvents, will allow to have products with high efficiency in the aforementioned areas of use and having high biocompatibility, high stability and low cost.

Advantageous embodiments of the invention are obtained according to the dependent claims.

Brief disclosure of the drawings

Further features and advantages of the invention will become more apparent in the light of the detailed description of some preferred but non-limiting embodiments of the method according to the present invention, illustrated by way of non-limiting example with the aid of the accompanying drawings wherein:

FIG. 1 is a flux diagram of a possible mode of carrying out the method of the invention.

Best modes of carrying out the invention

With reference to Fig. 1, there is shown a possible way of carrying out a method for extracting active compounds from a vegetable raw material to obtain products with a high phytocomplex content for use in agriculture, in particular as bio stimulants, fertilizers, nutrients, pesticides and in general as products for the biostimulation and/or care of plants and/or to promote their growth.

The method essentially comprises a step a) of providing a raw material M of vegetable origin having a content in phytocomplexes rich in one or more different pigments and a step b) of extracting the phytocomplexes to have one or more by-products containing one or more pigments present within the raw material.

Preferably, but not exclusively, it will be possible to start from a raw material M rich in flavonoids, in particular with high content in anthocyanins, or from a raw material rich in betalains.

Always by way of example, the raw material M may be red or yellow beet, red thistle, amaranth, cactus fruits, in particular Opuntia sp. or Hylocereus sp, rich in betalaine, or blackcurrant or black carrot, rich in anthocyanins, or parts of such plants, such as seeds, flowers, fruits, leaves, stems, roots and other subterranean organs. The choice of these raw materials was preferable due to their wide availability and high content in active principles.

In addition, anthocyanins and betalains have proven to have antioxidant properties, contrast environmental stress conditions, both in humans and in plants, may regulate a wide range of physiological and biochemical processes. Betalains increase resistance to pathogens and increase viral defenses.

However, it is also possible to use different raw materials, such as materials with a high content of tannins or other wood-derived compounds, such as oak, chestnut or exotic trees, or, again, to use green or brown algae, or other higher plants, mono or dicotyledonous.

The extraction step b) is subdivided into two distinct steps, with a first step c) for separating the liquid part or juice J from the solid part or puree P of the raw material M and a second step d) of extraction of the phytocomplexes from the solid part P to obtain a byproduct S rich in phytocomplexes.

In this way a liquid part or juice J with a high content of pigments, as well as with a sugar content, will be obtained together with a solid part or puree P, which also contains pigments.

According to a first operating mode, step c) of separation may be an essentially mechanical separation obtained by cold pressing the raw material M, or by ultrasonic treatment, or similar cold techniques, so as to preserve the integrity of the extracted phytocomplexes.

The step d) of extraction of phytocomplexes from the puree may be carried out adding to the puree P a volume of a natural eutectic solvent (NADES) so as to obtain a byproduct S rich in phytocomplexes in the form of gel.

In a preferred but not exclusive way, puree P and NADES may be added in equal volume.

In a preferred and particularly advantageous manner, NADES will consist of a first organic compound of natural origin combined with a second compound of natural origin selected from organic acids, vitamins, urea, salts or a mixture thereof. Even more preferably, the first organic compound will be selected from organic acids and may be citric acid.

The second organic -based compound may be a vitamin or tartaric acid.

Suitably, the first and second organic -based compounds may be present in equal amounts in the solvent.

By way of example, whit a raw material M containing anthocyanins it has been observed to be preferable to use NADES obtained from the mixing of citric acid and tartaric acid.

The liquid part or juice J may be suitably added with an acid, such as formic acid or other organic acid, in order to lower the pH to a value between 2 and 4, to stabilize the pigments extracted and reduce fermentation and bacterial growth.

The juice J may also be concentrated or dehydrated to obtain a raw material suitable for being stored and used for future preparations by dilution or with the addition of other active compounds.

The liquid part or juice J, after eventual rehydration, is subsequently mixed (step e) with the by-product S of the extraction step b) to obtain a final product F suitable for use in agriculture for the care, biostimulation and/or the nourishment of plant elements. The final product F will thus have a particularly high pigment content as it derives from the sum of the pigments present naturally in the liquid part J and those extracted from the solid part P.

According to an alternative operating mode, the liquid part or juice J may be added directly to the NADES, in variable amounts depending on the specific applications. Furthermore, it will be possible to mix (step f) the by-product S of the extraction through NADES with potassium or phosphorus salts Ks, Ps, for example potassium citrate or ammonium phosphate, to obtain potassium or phosphorus salts Ks', P' rich in phytoex tracts.

According to a further operating mode, a phase g) may be provided for mixing the liquid part J with potassium or phosphorus salts Ks, Ps, also in this case potassium citrate or ammonium phosphate, to obtain corresponding potassium or phosphorus salts. K', Ps' in powder form to be applied directly on the plant. The analysis of the by-products of the two extractions showed that the active principle content is comparable with that of high purity industrial dry products obtained according to the known techniques.

In particular, for the blackcurrant, an anthocyanic content was obtained in the juice equal to 617 mg/1 and 437 mg/1 in the by-product deriving from the mixing of the puree with NADES.

For the red beet there was a juice with betalaine content equal to 342mg/L and 144mg/L in the mixture of puree and NADES.

Preferably, the solvent will comprise, as one of the organic compounds, a mixture of amino acids having short chain amino acids in amounts at least equal to 80% of the total weight of the organic compound, so as to be stable and at the same time economic. Furthermore, the final water content of the solvent will preferably be between 15% and 20% and even more preferably close to 18%.

According to a first formulation, the solvent will be composed of said mixture of amino acids, urea and sucrose, and will have a final content in water close to 18%, for example equal to 18.68%.

In particular, the mixture of amino acids will be present at 25%, sucrose at 25% and urea at 50%.

According to a second formulation, the eutectic solvent will be composed of said mixture of amino acids, urea, sucrose and citric acid and will have a final content in water close to 18%, for example euqual to 18.14%.

In particular, the mixture of amino acids will be present at 25%, sucrose at 45%, urea at 5% and citric acid at 25%.

According to a third formulation, the eutectic solvent will be composed of said mixture of amino acids, sucrose and citric acid in equal parts and will have a final water content of 18%.

A further formulation may include an eutectic solvent composed of urea, sucrose and proline in equal parts and a final content in water between 15% and 16%, for example 15.64%. From above it is therefore evident that the solvent and the method achieve the intended objects.

The method and the solvent according to the invention are susceptible of numerous modifications and variations, all of which are within the inventive concept expressed in the appended claims. All the details may be replaced by other technically equivalent elements, and the materials may be different according to requirements, without departing from the scope of protection of the present invention.