Bioactive aristolactams, furanoditerpenoids, c-metrylribofuranouracil and other metabolites of three Tanzanian plants

This Thesis reports results from phytochemical investigations of three Tanzanian plant species Toussaintia orientalis Verdc. (Annonaceae), Stuhlmania moavi Taub. and Cynometra brachyrrachis Harms (Caesalpiniaceae), and antifungal, antibacterial, antioxidant, anti-inflammatory and cytotoxic activities of the metabolites therefrom. The stem bark of T. orientalisyielded an unreported aristolactam alkaloid aristolactam AN (toussalactam), as well as the known onespiperolactam C, aristolactam. FIligodiopeladine, cepharone B/aristolactam BII, and aristolactam AII, as bioactive principles. The leaves yielded the new indolones toussaindolones A, B and C, and the apparent rearranged derivatives of toussaindolone A, toussabenzofuranoylamide A and B. The stern and root barks alsoyielded the unusual nucleoside 1 -(2- C-methyl-O-D-ri bo furanosyluracil, 3 ,4,5 -tri methox yphenyl-fl-D-glucopyranoside and epicatechin-40,8-epicatechin (procyanidin B-2),2-hydroxy-3,4,6-trimethoxychalcone, 2-hydroxy-3,4,6-trimethoxydihydrochalcone, dependensin, polycarpol and other constituents. Two new diterpenes 18- hydroxyvoucap an- 1 9-al and voucapan- 1 8,1 9-diol, voucapan-6a,7a-diol and voucapane were isolated from the stem and root barks of Stuhlmania moavi. -diol exhibited weak activity in anti-inflammatory bioassay systems, Voucapan-18,19 which was enhanced its p-tolylsulphonyl derivative. The leaves gave 3-hydroxy-2,8-dimethoxy-dibenzo[b,dipyran-6-one, 4,5-dihydroblumenol A, amentoflavone, robustaflavone and 1,2,3,4,6-penta-0-galloy143-D-glucopyranose. C. brackishness gave lupeol and lup-20(29)-en-2a,313-diol, and 12-oleanene2,3-diol as the major constituents. Structures were established based on analysis of spectroscopic data. Most of the isolated compounds and derivatives exhibited in vitro antimicrobial, antiproliferative, anti-inflammatory and cytotoxic activity.