The biotransformation of cinobufagin by cell suspension cultures of Catharanthus roseus was investigated. After 6 days incubation, four new glucosylated derivatives, desacetylcinobufagin 16-O-β-D-glucoside, 3-epi-desacetylcinobufagin 16-O-β-D-glucoside, 3-oxo-desacetylcinobufagin 16-O-β-D-glucoside, and cinobufagin 3-O-β-D-glucoside, respectively, were isolated and identified on the basis of their physical and chemical data. This is the first report of bufadienolides with a glucosyl substituent at the C-16 position.

Four major active saponins (ginsenosides Rg1, Rb1, Rd and notoginsenoside R1) in Panax notoginseng were determined in rat urine after oral and intravenous administration of total saponins of P. notoginseng (PNS), and the urine samples were treated with solid-phase extraction (SPE) prior to liquid chromatography. A reversed-phase liquid chromatography system with ultraviolet detection and a Zorbax SB-C18 column was used. The within-day and between-day assay coefficients of variation for the four saponins in urine were less than 7% and the recovery of this method was higher than 85%. Using this method, the excretion profile of the drug in rat urine after administration of PNS was revealed for the first time.

The diterpenoid triepoxides are the major active constituents of Tripterygium wilfordii with potent antitumor and immune activities. But the strong toxicity of these compounds has restricted their application to a great extent. In order to find more effective compounds with less toxicity, structural modifications of triptonide (1) by Aspergillus niger (AS 3.739) were investigated and four biotransformed products were obtained. Based on their chemical and spectral data, their structures were elucidated as 5αhydroxytriptonide (2), triptolide (3), 17-hydroxytriptonide (4), and 16-hydroxytriptonide (5), among which 2, 4 and 5 are new compounds. All the three new transformed products showed cytotoxic activities against the majority of the human tumor cell lines tested, however, they are found to possess less cytotoxic activity when compared with 1. Both compounds 4 and 5 showed similar cytotoxic activity and their IC50 values were 5-15 fold less than 1, while 2 is about 100 times less active than 1.

Microbial transformations of artemisinin 1 by Cunninghamella echinulata (AS 3.3400) and Aspergillus niger (AS 3.795) were carried out. Two products, 10β-hydroxyartemisinin 2 and 3α-hydroxydeoxyartemisinin 3, were obtained. Their structures were identified on the basis of chemical and spectroscopic data. 10β-Hydroxyartemisinin is a new compound.

Ginkgo biloba cell suspension cultures were used to biotransform 2α, 5α, 10β, 14β-tetra-acetoxy-4 (20),11-taxadiene. Two novel compounds were obtained and their structures were identified as 9α-hydroxyl-2α, 5α, 10β, 14β-tetra-acetoxy-4 (20), 11-taxadiene 1 and 9α, 10β-dihydroxyl-2α, 5α, 14β-tri-acetoxy-4 (20), 11-taxadiene 2, respectively, on the basis of their physical and chemical data. Compound 1 was subsequently used as a substrate for the bioconversion by Ginkgo cell cultures, and the product obtained was confirmed to be the same as 2, which suggested that 2 is biosynthesized from 1. Investigation on properties of the related enzymes responsible for the biotransformation reaction through the experimental techniques of cell-free culture and substrate/product concentration analysis revealed that the enzymes were extracellular and constitutive.