P-21 南タイ産キョウチクトウ科植物より得られる新規インドールアルカロイド類の構造研究(ポスター発表の部)

抄録

For the purpose of contributing to the development of medicinal material, we have continuously studied on the phytochemical investigation of Thai medicinal plants, mainly counting indole alkaloids. In the present study, the alkaloidal constituents of the three Apocynaceae plants, native to the south part of Thailand, were exhaustively investigated. I: Alkaloids from the leaves of Rauwoifia sumatrana Jack. Three new indole alkaloids, rausutrine (1), rausutranine (2), and 11-methoxystrictamine (5), were found from the ethanol extracts of the leaves of this plant, along with ten known bases. Rausutrine and rausutranine are novel bis-indole alkaloids composed of an akuammilane unit and a vincorane unit, the latter of which has a unique iminoquinone function. II: Alkaloids from Hunteria zeylanica (Retz.) Gardn. ex Thw. II-1. Glycosidic alkaloids Two novel glycosidic indole alkaloids, hunterioside (8) and hunterioside B (9), together with strictosidinic acid (6), were isolated from the n-BuOH fraction of the ethanol extracts of the stem bark of this plant, and their structures were respectively found to be 6'-α-glucoside and 3'-α-glucoside of strictosidinic acid. This isolation is the first finding of a biosidic congener of monoterpenoid indole alkaloid glucosides. II-2. A new class of dimeric indole alkaloids and the corymine-related alkaloids Two novel dimeric indole alkaloids, coryzeylamine (14) and deformylcoryzeylamine (15), which are composed of sarpagine-type and echitamine-type monoterpenoid indole alkaloids, were isolated from the leaves of Hunteria zeylanica. Furthermore, the major alkaloidal constituent, corymine (10), and three minor corymine derivatives (11-13), were obtained. III: Alkaloids from Alstonia glaucescens Mona. The first phytochemical investigation of this plant has resulted in the isolation of three new indole alkaloids (17-19) along with five known bases.