Glycosides squill

Among the medicinal plants, that contain cardiac glycosides, squill is the one that has been used earliest in history. By 1500 BC squill was used in Egyptian medicine for the treatment of dropsy (oedema), a symptom of failing function of the heart. The effect of squill was known by Hippocrates and by the... 

History. For centuries man has recognized that rodent pests destroy his habitat, consume his food, and cause the spread of virulent diseases. Throughout the same centuries man has sought to eliminate these pests with a variety of poisons such as strychnine, arsenious oxide, and red squill - a steroidal glycoside extracted from the bulb of a lily-like plant, Urginea maritima. 

Types of Cardiac Glycoside. Three groups of plants produce cardenolides the Digitalis species, growing in temperate climates the Strophanthus species, of tropical provenance and Scilla (sea onion or squill), a Mediterranean plant. 

The cardiac glycosides are mainly obtained from plants e.g. digitalis, stropanthus and squill species and also present in certain other plants and animals. In 1776, William Withering, a Birmingham... 

Cardiac glycosides with bufadienohde skeleton, e.g. proscillaridin A, have been found in plants (e.g. squill, Drimia maritima). 

The distribution of cardiac glycosides in the plant varies in different species. Digitalis is obtained from the leaves and seeds strophanthus, from the seeds squill, from the bulbs Convallaria, from the flowers and ouabaio, from the wood and bark. In addition, there are saponin bodies that do not show the typical digitalis effect on the heart but which are extracted along with the glycosides, which possess the cardiac actions. 

Anorexia, nausea, vomiting, visual disturbances, and the cardiac effects seen in acute toxicity may be seen. In chronic exposures, patients may not demonstrate the classic finding of hyperkalemia, which is frequently seen in acute exposures. Decreased renal function may interfere with clearance of the glycosides. Patients may be more sensitive to the effects of their squill remedies if they are on medication that also slows AV conduction such as quinine, beta blockers, or calcium channel blockers. 

Red squill contains many cardiac glycosides, the most prominent being scillaren A and scilliroside. These glycosides produce digitalis-like effects when ingested and, like digitalis, inhibit Na/K ATPase, block AV conduction, and cause sinus bradycardia. 

Scillae buibus var. alba (3-5). The white squill samples (3,4) contain predominantly pro.scillaridin, seen as a major light-brown fluorescent zone at R, 0.6 (T/a). The glycoside scillaren A (R, — 0.4/b) dominates the standardized commercial extract 5. Three additional cardenolide zones (e.g. glucoscUlaren R, — 0.2) are detectable as yellow-browii fluorescent zones. Sciliirosidin glycosides are absent in white squill. 

Scillaren. A mixture of glycosides, scillaren A and B in the proportions in which they occur in fresh squill, Ur-ginea Scilla) maritime (L.) Baker, Liliaceue, about 2 parts of A to I part of B. Isolation of scillaren and separation of A and B Stoll et al.. Helv. Cfurn. Acta 16, 703 (1933). 

Contains cardiac glycosides or cardioactive substances (adonis, broom, devil s claw, ginger, hawthorn, oleander, squill)... 

Squill SciHa Urginea maritima 1 Cardiac glycosides (see p 155)... 

A. Digoxin-specific Fab fragments will bind other cardiac glycosides including digitoxin, ouabain, oleander glycosides, and possibly glycosides in lily of the Nile, strophanthus, squill, and toad venom Bufo species cardenolides). 

Plant extracts containing cardiac glycosides have been in use for thousands of years. The ancient Egyptians were familiar with squill (a source of proscillaridin), as were the Romans who used it as a heart tonic and diuretic. The foxglove was mentioned in the writings of Welsh physicians in the thirteenth century and features in An Account of the Foxglove and some of its Medical Uses , published by William Withering in 1785, in which he described its application in the treatment of dropsy or the oedema that results from heart failure. 

The principal cardiac glycosides (from digitalis, strophanthus, and squill) have a direct and selective action on heart muscle, increasing the force of the contraction (for details, see Section 14.1). Quinidine, which is an optical isomer of quinine (10.33), and procainamide (7.56) have a therapeutically useful depressant effect directly on the heart and are used to correct arrhythmias. This effect is shown by many other substances which have a relatively lipophilic aromatic ring linked (by an ester, ether, ketone, or carbinol bridge) to a basic group (Thomas, 1981). 

An immunogen for proscillaridin, a squill glycoside, can be prepared in the same way as that for ouabain, and the specificity is almost exclusively directed toward proscillaridin and closely related derivatives. Digoxin, digitoxin, and ouabain have only weak cross reactivity whilst steroids are totally ineffective as inhibiting antigens (Belz et al. 1973). 

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