CS252039B1 - A method of isolating fl-escin from horse chestnut seeds - Google Patents

Abstract

The purpose is to improve the isolation of (3-escin from horse chestnut seeds. The stated purpose is achieved by extracting the seeds with a mixture of water and alcohol with a carbon number of Ci to C3, the extract is concentrated at a temperature of 40 to 80 °C, an acid is added to the concentrated extract at a temperature of 50 to 60 °C to a pH of 2.8 to 1.6 and the solution is set aside for crystallization.

Description

The present invention relates to a process for the isolation of β-escin from horse chestnut seeds.

[Beta] -Ecin, used as a raw material for the manufacture of pharmaceutical preparations used e.g. whilst post-traumatic and postoperative edema is bleached, it is isolated from the seeds of the horse-chestnut (Aesculus hippocastanum LI by extraction with alcohols or a mixture of alcohols with water (pat. GDR 11178, pat. NSR 1125 117), or the extract is passed through an ion exchanger in an H cycle (U.S. Pat. No. 25 30 941), or acidified to pH 1.5 to 2.0 (U.S. Pat. No. 11178), then concentrated and concentrated. f-escin is precipitated with water Other processes utilize the extraction of ground dried chestnut seeds with higher aliphatic alcohols (French Pat. No. 24 24 689, Spanish Pat. No. 455 693), or ternary mixtures such as methanol-chloroform-water (Pat. There is known a process for extracting equine grapevine seeds with aqueous ammonia, adjusting the pH in the extract and extracting the 3-escin with isopropanol (U.S. Pat. No. 483,982). water, extract is concentrated It is cooled to 10-25 ° C, strong mineral acid is added to pH 1.0, the acidified solution is heated to 40-60 ° C and the precipitated escin is isolated. The disadvantage of this procedure is that before the addition of the acid, the extract is cooled and then reheated, which is an energy disadvantage. Another disadvantage is that strong mineral acid is added to a pH of 1.0.

(S-Escin is present in the natural material in the form of a water-soluble sodium salt from which it must be liberated by the addition of acid. In aqueous solution at pH 4.2, the ratio of dissociated and undissociated form of escin is 1: 1. precipitation is necessary to reach a pH lower than <4.2, but J-Escin is a glycoside which decomposes in acidic solutions, and the rate of decomposition is proportional to the decrease in pH and the temperature rise. resulted in a partial decomposition of the product which had to be recrystallized from methanol to achieve the desired parameters.

The disadvantages of this process are eliminated by the process according to the invention, in which the horse chestnut seeds are extracted with a mixture of water and an alcohol having a carbon number of C1 to C3, the extract is concentrated at 40 to 80 ° C to 1/2 to 1/5 of the flood volume. acid to pH 2.8 to 1.6 at 5 ° C ^! 0 to 60 ° C, and the solution is allowed to crystallize. The advantage of this procedure is that the concentration of the extract is carried out at neutral pH, with both ester and glycosidic bond decomposition being minimal; in order to release escin from its sodium salt, it is sufficient to adjust the pH to a value of less than 2.8, thus consuming less acid, with a lower degree of glycosidic bond decomposition. Maintaining the temperature at 50 to 60 ° C is required for the product to precipitate in a suitable crystalline form. According to this procedure, β-escin was obtained without further crystallization of such parameters as in the previous post-purification procedure. Another advantage is easier treatment of the crystallization liquors by adjusting the pH, separating the salts and concentrating - this product can be used e.g. in cosmetics.

Further details of the method of the invention are apparent from the examples.

Example 1

100 kg of dried milled horse-chestnut seeds are stirred for 1 h in ethanol-water (1000 l, 1: 1 ratio), the suspension is filtered, the filtrate is concentrated under vacuum at 60 to 70 ° C to a final volume of 400 l at 60 ° C, phosphoric acid (2 mol / l) was added to a final pH of 2.4, and the solution was set aside to crystallize to give 2.7 kg of product, which had the following parameters without further recrystallization:

Melting point: 220 DEG-230 DEG C. (decomposition [.alpha.] D @ ²⁰ = -26.8 DEG. + -. 1 DEG (c. 5, methanol); water: 10.2%; EXAMPLE 2 kg of dried ground chestnut seeds is stirred for 1 hour in 600 l of ethanol-water (6: 4), the suspension is filtered, the filtrate is concentrated to a volume of 150 l at 60-70 [deg.] C, the concentrate is acidified (5 mol / l) to pH 1.8 and at 60-65 ° C is set aside to crystallize.

This procedure yielded 1.5 kg of product, an amount of water of 11.3% / o, an amount of β-escin in dry matter of 99.7% / o.

Example 1 and d 3

100 kg of dried ground chestnut seeds are stirred for 1.5 hours in 1 200 l of methanol-water (55:45), the suspension is filtered, the filtrate is concentrated to a volume of 600 l at 40-60 ° C under vacuum, and the concentrated solution is acidified formic acid (concentrated) to pH. 2.8 and set aside for crystallization.

This procedure produced 1.9 kg of product, an amount of water of 10.6%, an amount of β-escin in the dry matter of 98.9%.

Claims (2)

252039 PEEDMET What is claimed is: 1. A method for isolating l-escin from horse chestnut seeds extracted with a water / alcohol mixture having a carbon number of C1 to Cs, wherein the extract is concentrated to 1/2 to 1 at 40 DEG to 80 DEG C. In the case of the flood volume, acid is added to the concentrated extract at a temperature of from 50 to 60 ° C to a pH of 2.8 to 1.6 and the solution is removed for crystallization. 2. A method according to claim 1, wherein phosphoric acid, sulfuric acid or formic acid is used for acidification.