Benzylisoquinoline Alkaloids from Gnetum parvifolium
摘要:
The investigation of the chemical constituents from the lianas of Gnetum parvifolium resulted in the isolation of three new benzylisoquinoline alkaloids, (+/-)-N-methylhigenamine (1), (-)-N-methylhigenamine N-oxide (2), and (+/-)-8-(p-hydroxybenzyl)-2,3,10,11-tetrahydroxyprotoberberine (3), together with two known alkaloids, higenamine and trigonelline. The structures of 1-3 were determined by chemical methods and spectral analysis including 2D NMR and NOE studies.
Tetrandrine is a bisbenzytehahydroisoquinoline alkaloid. Its structure is very complex and the preparation of labeled derivatives is difficult. We have prepared 3H-tetrandrine using the tritium gas exposure method.1 This method produces many fragments which make isolation and purification of small quantities difficult. We investigated these fragments of unlabeled d-tetrandrine and found almost all contain one to several hydroxide groups. Using this information, we designed a two-step paper chromatography method for isolation and purification of 3H-Tetrandrine. This method involves the application of a pH 4.7 Na2HPO4-citric acid buffer to the paper to block the migration of hydroxide group fragments of tetrandrine. 3H-tetrandrine was successfully with a radiochemical purity of 90%.