Reserpine biological activity

With the exception of raujemidine, the structures of the compounds in Table IV have been obtained by a combination of partial degradation, parallelism of properties with reserpine or deserpidine, and partial synthesis. Thus, the structure of methyl raunescate rests entirely upon those reactions which were authenticated in the case of methyl reserpate and deserpidate. Methyl pseudoreserpate was partially synthesized from reserpine (132), which established its structure except for the attachment of the acyl residue. Apart from the biological activity evinced by the... 

Effectively the observed biological activities were at least partially in accordance with the boiling point selection criteria (Table 13.7). On the reserpine ptosis and the 5-HT potentiation tests, the closest activities result from the replacement of the pyridazine ring (BP = 208°C) by the 1,3,4,-thiadiazole (BP = 204-205 C) or the 1,2,4-triazine... 

In addition to reserpine, ajmaline was isolated from the roots of R. serpentina at almost the same time [6,7]. Its chemical struaure, including absolute stereochemistry, was established in 1962 [8-10]. The biological activity of ajmaline is quite different from that of reserpine. It possesses antiarrhythmia activity and is used clinically for this purpose. 

This brief survey of indole pharmaceuticals and indole candidate drugs is necessarily incomplete. Many more indoles are known that have excellent biological activity, but space does not permit coverage. For example, myriad indole alkaloids have a range of biological activities, and some, like the antihypertensive reserpine, are clinically useful. In addition, the many indohne- and oxindole-based pharmaceuticals could not be included in this chapter. 

L-Tryptophan is an indole ring containing aromatic amino acid derived via the shikimate pathway. The tryptophan-derived alkaloids are found in eight families, of which, Apocynaceae, Loganiaceae, Rubiaceae, and Nyssaceae are the best sources. The alkaloids under discussion are the Catharanthus alkaloids, namely, ajmalicine, tabersonine, catharanthine, vindoline, vinblastine, vincristine and vincamine as well as terpenoid alkaloids derived from other families, namely, yohimbine, reserpine, strychnine, brucine, and ellipticine. The above-mentioned alkaloids are pharmacologically very important and hence extremely valuable. This chapter describes various aspects of the tryptophan-derived alkaloids like occurrence, biological activity, phytochemistry, and commercial and biotechnological aspects. 

The biochemical and histochemical data for Lu 5-003 (22) and nine of its analogs show that these compounds have a selective action on the membrane pump mechanism of the central and peripheral catecholamine neurons and have little or no anticholinergic activity.26 The synthesis and biological activity of 23. a "bridged" amitriptyline, and of several related structures have been reported. These tetracyclic structures did not show significant activity in reversing reserpine-induced hypothermia in mice.27... 

Reserpine, used as a folk medicine in India, was found to have antipsychotic properties at about the same time as CPZ. Both agents affected the dopaminergic system, albeit in different ways, but the functional results were similar (i.e., lowering dopamine activity). This phenomenon has continued to be an important factor in hypotheses about the mechanism of action of these drugs and for biological theories about the pathophysiology of psychotic disorders. 

Rhynchophylline is composed of tryptamine and a Cjo unit with the corynanthe skeleton. Thus, the partial structure of this alkaloid somewhat resembles those of reserpine (Seaion 2.10) and yohimbine (Section 2.11), although its biological aaivities are different. Unlike reserpine, rhynchophyUine does not cause sedative activity, and, unlike yohimbine, no convulsive activity occurred when it was given to frogs and mice. In addition, unlike reserpine. 

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