RESUMO
The distribution of iridoids among the tribes of Bignoniaceae is shown. In the present work, 18 species from the tribes Bignonieae and Tecomeae as well as one from Eccremocarpeae have been investigated. These data combined with those obtained through a literature review were analysed and showed that iridoids occur predominantly in the tribe Tecomeae. In this tribe, a chemical distintion between the genera Tabebuia and Tecoma was observed: The iridoids in Tabebuia are decarboxylated whereas in Tecoma they are C-4 formylated. The species from Bignonieae are poorly investigated and only few reports have been published, however, the iridoids found are mainly C-4 carboxylated. The only exception, Dolichandra cynanchoides (=Macfadyena cynanchoides), with decarboxylated iridoids, is also morphologically abnormal in Bignonieae.
RESUMO
Callus and cell suspension cultures of Psychotria carthagenensis have been established in Gamborg's B5 medium supplemented, respectively, with 3% sucrose, 0.2 mg/l kinetin, and 1.0 mg/l 2,4-D and 2% sucrose, 2.0 mg/l 2,4-D, 0.2 mg/l kinetin, and 50 mg/l cysteine. Suspension culture presented a typical growth curve with the complete cycle of ca. 18 days and the maximum specific growth rate (µ) was 0.0099 day. The presence of different secondary metabolite pathways was determined by measuring the enzyme activity of phenylalanine ammonia lyase (PAL), tryptophan decarboxylase (TDC), strictosidine synthase (STR), strictosidine-beta-glucosidase (SG), and geraniol-10-hydroxylase (G10H). Activity could only be measured for SG (14.55 pkatal/mg protein) and G10H (0.3 pkatal/mg protein). Analysis of extracts from leaves, callus and cell suspension cultures demonstrated the presence of two major triterpenes: beta-sitosterol and ursolic acid.(2)
