Method for preparing pectin gel of elevated part of willow herb

FIELD: medicine.

SUBSTANCE: invention refers to a method for preparing a pectin gel of an elevated part of willow herb. The declared method enables dissolving pre-recovered pectin from the elevated part of willow herb in water, cooling and applying onto a frozen chitosan solution and further gel formation.

EFFECT: invention enables preparing a degradable biomaterial possessing the antimicrobial activity on Escherichia coli and Staphylococcus aureus cells.

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The invention relates to the medical industry, namely to obtain pectin preparations used in the manufacture of a prophylactic and therapeutic tools.

Gel-forming ability of pectin depends on many factors, including the degree of methylethylamine, localization ester metal groups, pH, concentration of the biopolymer, the concentration of calcium ions, ionic strength of the solution, temperature.

We can distinguish the following main directions of the use of gels in Biomedicine: designing systems for targeted drug delivery, creating selective chelators, creating materials for tissue engineering and surgery. As gelling polymers are widely used polysaccharides of animal, bacterial and plant origin, such as cellulose, dextran, chitosan, and their derivatives. It is established that pectic polysaccharides have several advantages over other gel-forming biopolymers. Unlike biopolymers animal and microbial origin pectins are characterized by higher biological security.

Usually ways to obtain gels based on plant polysaccharides include the following stages: receiving from the source plant material polysaccharide, purification of the polysaccharide or the modification of its properties, rest is increased polysaccharide in the solution under stirring, the formation of a gel, drying.

There are several technological methods, improving physiological and technological properties of the resulting gels. Thisthe improved composition of the gel exclusion from the use of toxic reagents; the expansion of raw materials sources of pectin.

A method of obtaining single-component gel on the basis of pectin by increasing its gelling ability, reaching the amidation of pectin by passing gaseous ammonia through a pectin solution (EN¹2399301, A23L 1/0524, 2010). The disadvantage of this process is the necessity of using large amounts of ammonia, as well as the use of commercial samples of pectin that does not have a pronounced physiological activity.

Another way to obtain a gel-based chitosan (EN¹2099352, IPC SW 37/08, 1997) consists in the reaction of chitosan with glutaraldehyde in acetate buffer at pH 3.5 to 5.5, ionic strength of a solution of 0.1-0.5 and the molar ratio of glutaric aldehyde: chitosan 1:6-15 with subsequent recovery of the reaction product with sodium borohydride allocation of hydrogenerators. It is necessary to use a large number of chemicals.

Way to get the gel on the basis of modified pectin by it in the pre-treatment solution of metal chloride (RU ¹2113221, A61K 9/50, 1998), involves the use of alkali for the process of gelation, which reduces the ecological purity of the product.

The disadvantage of the gel composition for the treatment of RAS (RU¹2384338, A61K 31/715, OR 17/02, 2010) is the use of high-purity beet pectin, not possessing physiological activity, and synthetic substances, the antiseptic chlorhexidine.

The closest way to obtain pectin gel to the invention is a method including dissolving purified and powdered sugar beet pectin in distilled water at a temperature of 20-30°C and stirring until smooth within 20-30 minutes the resulting solution of pectin thickness 2.0-2.5 mm is applied on the PTFE surface and dried at a temperature of 20-50°C for 24-48 hours (EN¹2342955, A61L 15/28, A61L 15/44, A61F 13/15, A23L 1/0524, 2009). The disadvantage of this method is use to get gel purified beet pectin, not possessing physiological activity, and low strength of the gel and prolonged drying at relatively high temperatures.

The aim of the present invention is to increase physical activity and improve the technological properties of the gel on the basis of pectin.

The technical result is t from the use of the invention in that, as a result of the use of the method obtained degradable biomaterial, has antimicrobial activity against cells of Escherichia coli and Staphylococcus aureus.

This result is achieved by the fact that to obtain the gel we use the pectin isolated from the aerial parts of fireweed herb with antibacterial activity against strains of Escherichia coli and Staphylococcus aureus. To improve the strength characteristics of the gel coating is provided on chitosan matrix, forming with pectin complex through ionotropic gelation.

The method of producing gel-based pectin from the aerial parts of fireweed herb involves the dissolution of pre-allocated pectin from the aerial parts of fireweed herb in water and then cooled and applied to a pre-frozen solution of chitosan and the subsequent formation of a gel; the dissolution of the pectin is carried out by heating to 70°C to obtain a 0.4%aqueous solution, followed by cooling of a solution of pectin occurs to a temperature of +4±1°C cooled solution of pectin is applied to frozen at -18±1°C for 40 minutes with 5%chitosan solution obtained preliminary dissolution of chitosan acetate buffer (pH=3,6) at 70°C with the addition of calcium chloride, the formation of a gel occurs within 6-8 hours at room temperature the re.

An example of the method.

0.4 g of pectin, previously isolated from the aerial parts of fireweed herb and lyophilized, dissolved in 100 ml of distilled water by heating to 70°C. 2.5 g of chitosan was dissolved in 50 ml of acetate buffer (pH 3,6) when heated to 70°C and was added 0.27 g of calcium chloride. A solution of chitosan was poured into the form and frozen at -18±1°C for 40 minutes. The solution of pectin was cooled to a temperature of +4±1°C. the frozen solution of chitosan poured into a chilled solution of pectin in a volume ratio of 1:1. The gel formation occurred within 6-8 hours at room temperature.

Characteristics of the resulting gel is shown in the table.

Thus, the obtained data testify that the invention allows to obtain a gel based on physiologically active polysaccharide pectin fireweed herb with antimicrobial activity against strains of Escherichia coli and Staphylococcus aureus, while by using ionotropic gelation with chitosan reduced the formation of gel and improve its technological characteristics.

The method of producing gel-based pectin from the aerial parts of fireweed herb, including the dissolution of pre-allocated pectin from the aerial parts of fireweed herb in water and then cooled and applied to a pre-frozen solution of chitosan and the subsequent formation of a gel; the dissolution of the pectin is carried out by heating to 70°C to obtain a 0.4%aqueous solution, followed by cooling of a solution of pectin occurs to a temperature of +4±1°C cooled solution of pectin is applied to frozen at -18±1°C for 40 min 5%solution of chitosan, obtained preliminary dissolution of chitosan in acetate buffer (pH=3,6) at 70°C with the addition of calcium chloride, formirovaniya occurs within 6-8 h at room temperature.