Steroidal alkaloids pharmacology

The three most important groups of steroids are the sterols, bile acids, and steroid hormones. Particularly in plants, compounds with steroid structures are also found that are notable for their pharmacological effects—steroid alkaloids, digitalis glycosides, and saponins. 

Amiya T and Bando H (1988) Aconitum alkaloids. The Alkaloids, Chemistry and Pharmacology (ed Brossi A) Vol 34. Academic, San Diego, pp 95-179. Atta-ur-Rahman and Choudhary MI (1998) Chemistry and biology of steroidal alkaloids. The Alkaloids, Chemistry and Pharmacology (ed Cordell GA) Vol 50. Academic, San Diego, pp 61-108. Atta-ur-Rahman and Choudhary MI (1999) Diterpenoid and steroidal alkaloids. Nat Prod Rep 16, 619-635. Earlier reviews 1997, 14, 191-203 1995, 12, 361-379. 

Kvaltmova, Z., L. Lukovic, J. Machova, and M. Fatranska. 1991. Effect of the steroidal alkaloid buxaminol-E on blood pressure, acetylcholinesterase activity and [ H]quinuclidinylben-zilate binding in cerebral cortex. Pharmacology 43 20-25. 

Steroids a large class of of terpenoids (see Ter-penes) including many biologically important compounds, e.g. Sterols (see). Steroid hormones (see). Bile acids (see). Cardiac ycosides (see), Steroid alkaloids (see) and steroid saponins (see Saponins). Synthetic S, e.g. Ovulation inhibitors (see). Anabolic steroids (see) and structurally modified steroid hormones, are pharmacologically important. More than 20,000 S are known, of which about 2 % have some medical significance. 

Woody nightshade. Solarium dulcamara, has been used from the time of Galen (c. AD 180) for the treatment of cancers. Recent studies on the plant have shown that the steroidal alkaloid glycoside -solamarine is active against S 180 [344] however, its low therapeutic index precludes it from further pharmacological study. A number of steroidal alkaloid glycosides have been reported to have cytostatic activity [345], and solananine to be a mitotic poison [346]. 

Microbial metabolites contribute to the list of products as well, such as with fermentations to such major products as ethanol, acetic acid, n-butanol, or lactic acid key growth factors such as amino acids or vitamins or pharmacologically active compounds such as antibiotics, steroids, or alkaloids. Pharmacologically active agents are generally catagorized as secondary metabolites, which most often implies production in the stationary (non-growth-associated) phase of fermentation (Chap-... 

Figure 26 shows the formula, conformation, and absolute configuration of veratridine (52). The structure and conformation of the C27-steroidal base is very similar to that determined for zygacine (C32H49N08) another Veratrum alkaloid (53). Variations in the pharmacological effects of Veratrum alkaloids appear to be dependent on the substituents attached to the essentially rigid molecular framework. The numerous intramolecular hydrogen bonds that enhance the molecular rigidity are indicated in Fig. 26. The positions of all the hydrogen atoms have been located for the veratridine molecule and the intramolecular donors and acceptors are identified as...

The family Solanaceae is one of the important and interesting plant families. It may be classified into four groups based on their usefulness and chemical composition of alkaloids contained (1) Nicotiana spp. such as N. tabacum and N. rustica, which provide tobacco and contain nicotiana alkaloids such as nicotine and nomicotine (2) Hyoscyamus, Scopolia, Atropa, and Datura species, which are pharmacologically important and contain tropane alkaloids such as hyocyamine, scopolamine, and tropine (3) Solanum spp., which are sometimes the starting material for production of synthetic steroids for medical uses and which contain solanum alkaloids and (4) Capsicum, Solanum, and Lycoper-sicum species, which serve as foods and are alkaloid-free. 

The most famous of the many alkaloids isolated so far is without any doubt batrachotoxin and its derivatives. Batrachotoxin has a LD50 of 2 ug per kg body weight (mouse, i.m.), thus being the most toxic nonprotein substance at all. Because of its special pharmacologic activity to keep open irreversably the sodium channels of nerve cells it has become an important tool in the studies of sodium channels. Chemically the batrachotoxins are esters of a 20-hydroxy steroid, batrachotoxinin A, with different pyrrol carboxylic acids. Although the activities of the different batrachotoxins is qualitatively the same, it differs quantitatively according to the acid part of the molecule (refs. 14, 15). 

Amphibian toxins a group of chemically very heterogeneous toxins (biogenic amines, peptics, alkaloids, steroids) produced by toads, salamanders, frogs (see Batrachotoxin) and newts (see Tarichatox-in). Pharmacologically, they include heart, muscle... 

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