There is a permanent interest in medicinal plants around the world: about 40% of all remedies are of plant origin, while their proportion in drugs for the therapy of cardiovascular diseases amounts to 80~ One of the main reasons for this success of medicinals of natural origin is the absence of some detrimental side effects frequently inherent in synthetic drugs. By now, more than 500 plant species have been characterized with respect to their pharmacological properties, many of these representing an important source of raw materials for commercial drug production.Our attention has been attracted to plants belonging to the vetch (Vicia) genus of the legumes family. This is explained by their wide occurrence in the territory of Russia and by the fact that many species are cultivated as feeds, for decorative purposes, or for honey culturing and some plants are used in folk medicine [1,2]. Unfortunately, the chemical composition of vetch plants is insufficiently studied, although it has been established that almost all of the species studied contain flavonoids-compounds having a broad spectrum of biological activity. The object of our study was the Caucasian vetch occurring in the region of North Caucasus. As we have previously established [3], the above-ground part of the plant contains a group of diosmetin glycosides (2% of the air-dry mass) possessing hypolipidemic and eapiUary-consolidating activity [3]. According to the data of chromatographic analyses, the dominating components are diosmetin glycosides, while monoglycosides are present in trace amounts. As is known, glycosidation in most cases increases water solubility, which is a factor important for physiological activity manifestation.Our primary task was to develop an economically efficient method for extraction of the above group of active compounds. The conventional methods described in the literature (allowing the collection of glycosides, in particular-digly-I Pyatigorsk State Pharmaceutical Academy, Pyatigorsk, Russia.
595cosides, and of flavonoids in a sufficiently high yield) is based on a sequential treatment of the water-ethanol tincture, obtained upon a preliminary fat. extraction, by various extractants (diethyl ether, ethyl acetate, butanol, etc.), followed by purification of the required fractions and isolation of the target flavonoids (usually, by column chromatography). Our attempts at using these techniques were unsuccessful [3,4]. The procedure is rather time-consuming (we spent about 150 h obtaining the target group of compounds), involves the use of large solvent volumes (because of repeated operations such as multiple extraction, heating cycles, etc.), and leads to partial hydrolysis of the target glycosides (which probably explains the increase in the monoglycoside content in the total glycosides extracted-about 10% of the total yield, which by no means corresponds to the actual content of monoglycosides in the initial raw material).The proposed method of flavonoid isolation consists in extracting the air-dry material (above-ground pa...
