Strophantus – species Strophantus DC.
S. gratus Franch. – the strophant is pleasant. Grows in western tropical Africa; cultivated in Cameroon, Nigeria (Lagos).
S. hispid us DC – bristly strophanthus – Western tropical Africa (coast, Senegal, Cameroon, Gabon, Guinea); cultivated in Western and Eastern tropical Africa.
S. kombe Olive. – strophanthus kombe – Southeast Africa along the Zambezi River and its tributary Hira and north to large lakes; cultivated in Cameroon and East tropical Africa.
All species are woody vines 15-20 m long or climbing shrubs in the forest, and shrubs in open places.
The leaves are opposite, elliptical or ovoid, with a pointed apex. Flowers in semi-umbrellas; corolla yellow, regular, tubular, five-lobed, petals elongated into descending, cord-like and often twisted ends. In the pharynx there are 5 two-toothed scales. Stamens 5, ovary of 2 ununited carpels. The fruit is a complex leaflet, consisting of 2 lobes, horizontally diverging, reaching together almost 1 m in length; the lobes are fusiform, dark brown, unilocular; when ripe, they open along the ventral suture, releasing numerous seeds. The seed is oblong, rounded at one end, elongated at the other, turning into a long fragile awn, ending in a wide feathery silver-white tuft of silky hairs; in S. hispidus, the crest is almost sessile. Seeds of S. kombe are silvery-greenish, with adpressed silky hairs. Seeds of S. hispidus brown, less densely pubescent. Seeds of S. gratus are yellow-brown, glabrous.
The seeds of the listed species of strophanthus – Semen Strophanthus are very rich in cardiac glycosides. In the seeds of S. kombe (the main industrial raw material), the total amount of glycosides can reach 8-10%, but K-strophanthoside is the main one (K is the symbol of the species from which the glycoside was isolated). It is a primary glycoside, which is a trioside formed by the aglycone K-strophandidine and (subsequently) cymarose, α-glucose and α-glucose. The aglycone is characterized by an aldehyde group at the C 10 position . When glucose is cleaved, a secondary glycoside is obtained, called K-strophanthin-p (according to B-glucose remaining in the sugar chain) – a very valuable remedy. With further hydrolysis, the glycoside cyramine appears, also a drug.
Of the other glycosides in B. coche, cymarol deserves attention, which differs from cymarin in that its aglycon strophanthidol at C 10 has not an aldehyde, but a primary alcohol group (it can be used to obtain cymarin).
The composition of glycosides is the same, but their total number is less. In the seeds, the amount of glycosides ranges from 4 to 8%, with O-strophanthin in the mixture being 90–95%. O-strophanthin is distinguished by a primary alcohol group at C 10 and hydroxyl groups at C 1 , C 5 , C 11 and C 14 . C-strophanthin is a monoside with one rhamnose molecule. It is also known under the name “ouabain” (African arrow poison).
Strophanthus preparations surpass all other cardiac remedies in speed and strength of action, therefore they are especially valuable; do not accumulate. Ampoules containing 1 ml of a 0.05% solution of K-strophanthin-R are produced. In addition, tincture is used as a heart remedy; it must contain at least 200 units in 1 ml.
Other types of strophanthus are also of considerable interest to medicine, in particular, strophanthus vine-shaped. This species is distributed in Western tropical Africa (from Senegal to Congo) and in Uganda. Previously, the seeds of this species were found as an admixture with the seeds of official species. Now they are of independent interest, since sarmentocymarin was found in the seeds of botanical forms from the northern savannas, and sarmentogenin in the forms from South Tropical Africa is glycosides of high activity. This species is currently introduced into culture in Tropical Asia, the West Indies and Florida.
In the history of pharmacy, strophanthus is known as the basis of arrow poison, which was prepared from all known species of this plant. The first physiological studies of arrow poison were carried out in 1865 at the Medico-Surgical Academy in St. Petersburg.
The plant contains cardenolides.
PLANTS CONTAINING CARDIAC GLYCOsideS
For centuries, plant products containing cardiac glycosides have remained unchanged. They provide a selective therapeutic effect in heart failure. These plants are known to the peoples of different countries. The ancient Egyptians and Romans used squill as a heart and diuretic. The ancient Greeks used jaundice. Many plants containing cardiac glycosides have been used by the African people since time immemorial to make arrow poison. in Europe since the 18th century. foxglove began to be used.
The therapeutic effect of cardiac glycosides is due mainly to their aglycones (genins). The sugars that make up the glycoside molecule affect the solubility, permeability through cell membranes, the ability to bind to blood and tissue proteins; being inactive, they affect the activity and toxicity of glycoside molecules in general.
Aglycones of cardiac glycosides are derivatives of cyclopentanoperhydrophenanthrene, having at C 17 substitutes: an unsaturated five-membered lactone ring – the cardenolide type or an unsaturated six-membered lactone ring – the bufadienolide type.
The whole variety of aglycones, and hence their properties, is due to the specific features of the substituents. So, for example, a substituent at C 19 can be of different oxidation states – groups CH 3 OCH, CH 2 OH. In addition to a constant hydroxyl at C 3 (here esterification with sugars occurs) and almost constant at C 14 , hydroxyls can be C 5 and C 16 . Even greater differences in the structure are introduced by the number (up to 30) and the diversity of monosaccharides, among which most are specific for cardiac glycosides. According to the number of monosaccharides attached to genin at C 3 , bi-, trio- and tetrazides are distinguished.