Monoterpenoid oxindole alkaloids

U. tomentosa is a significant traditional medicinal plant that is an important source of monoterpenoid oxindole alkaloids (MOAs) with bioactivities including immunomodulatory, cytotoxic, anti-HIV, and antileukemic activities [100]. It will be of interest to understand biosynthetic insights of bioactive compounds of this plant as an example here. Studies have reported the regulation of biosynthesis of sterols and triterpenes in U. tomentosa [100]. Administration of pectin to U. tomentosa cell suspension cultures increased the activity of isopentyl diphosphate isomerase of ursolic and oleanolic acid. The treated cells also transformed a higher percentage of labeled mevalonic acid precursors into triterpenes and resulted in the decrease in activity of far-nesyl diphosphatase by a factor of two when compared to the control. The... 

The isolation and synthesis of indole alkaloids containing a non-rearranged monoterpenoid unit have been reviewed <03NPR216>, as has the synthesis of spiro[pyrrolidine-3,3 -oxindoles] as building blocks for oxindole alkaloids <03EJ02209>. 

Oxindole alcaloids. A widely distributed group of monoterpenoid indole alkaloids and other alkaloid groups, all of which have oxindole (l,3-dihydro-2//-indol-2-one) as core structure. 

Arbain and coworkers [35] discovered unusual indole monoterpenoid gluco-alkaloid, characterized by a glucose moiety on the benzenoid ring. Recent studies reported an unusual oxindole alkaloid, macrophylUonium (1.23), pair of new tetracyclic oxindole alkaloids, macrophyllines A and B (1.24 and 1.25) with significant vasodilating activity [36]. 

Monoterpenoid Alkaloids.—Corynantheine-Heteroyohimbine- Yohimbine Group, and Related Oxindoles. The leaves of Strychnos decussata (Pappe) Gil. contain a new glycosidic alkaloid for which the gross structure (78) has been proposed 52 so far, nothing is known about its stereochemistry. Nevertheless it seems distinctly possible that this alkaloid is a close biosynthetic relative of vallesiachotamine. 

Monoterpenoid Alkaloids.—Corynantheine-Heteroyohimbine-Yohimbine Group, and Related Oxindoles. The first recorded extraction of the leaves and twigs of Peschiera laeta Mart, has yielded geissoschizol, a base not previously found in the Peschiera genus. Antirhine and, to a lesser extent, its quaternary Nb-metho-derivative, occur in the bark of Strychnos camptoneura Gilg. et Busse and in Amsonia elliptica, which also contains tetrahydrosecamine, pleiocarpamine,... 

Monoterpenoid Alkaloids.— Yohimbine-Corynantheine-Heteroyohimbine and Related Oxindoles) Group. Holeinine ° from Bleekeria vitiensis ° (and Ochrosia sandwicensis) is isoreserpiline metho-salt the former source contains, inter alia, 10,11 -dimethoxyalstonine. ... 

Monoterpenoid Alkaloids. — Corynantheine - Heteroyohimbine - Yohimbine Group, and Related Oxindoles. Details of the AT-ray crystal structure determination of borreline (92) have now been published,and the species from which it was isolated has been identified as Borreria capitata R. et P. A second alkaloid from this species, borrecapine (93), has a similar structure but, in place of the second methyl group in borreline, borrecapine contains an isobutenyl group which completes the monoterpenoid unit of the non-tryptamine part of the molecule. 

---