Amsonia elliptica, alkaloids

Among plumeran alkaloids isolated from the leaves of T. coffeoides (Hazunta modesta), two minor compounds were not previously discussed (70). One was recognized as 3-oxotabersonine (68, C21H22N203, MP 151.5-153°C, [a]D -11.4°) identical to the product isolated by Sakai from the seeds of Amsonia elliptica (198). Compound 68 was also obtained in 32% yield by KMn04 oxidation of tabersonine (67). 

The Nb-oxide of tabersonine (78) is reported to occur in the seeds of Amsonia elliptica Roem. et Schult. (101), in which it is accompanied by 3-oxotabersonine (107). Four other sources of 3-oxotabersonine have also been recorded (15,93,103,109). The structure of this alkaloid was established (101) by hydrogenation to 3-oxovincadifformine, which was identified by comparison with a (racemic) synthetic sample (1), and by its preparation by oxidation of tabersonine by means of potassium permanganate (101). 

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,... 

The occurrence of ajmalicine and lochnericine in the roots of Catharanthus roseus has again been noted " the same two alkaloids are biosynthesised, together with catharanthine, vindoline, and vinblastine, in the callus tissue culture of the same species. Ervine (rauniticine) occurs in the aerial parts of Vinca major,and tetrahydroalstonine in the seeds of Amsonia elliptica and in the leaves of Hunteria elliottii (Stapf.) Pichon. ... 

The enzyme responsible for the stereospecific condensation of trypt-amine and secologanin 34) was called strictosidine synthase, and its presence was demonstrated by Treimer and Zenk 194) in a number of indole alkaloid-producing plants, including Amsonia salicifolia, Catharanthus roseus, Ochrosia elliptica, Rauwolfia vomitoria, Rhazya orientalis, Stem-madenia tomentosa. Vinca minor, and Voacanga africana. Enzyme activity as high as 1698 pkat/mg protein was observed for O. elliptica. No... 

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