Growth characteristics and chemical analysis of Psychotria carthagenensis cell suspension cultures

Abstract

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-β-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: β-sitosterol and ursolic acid. 2