Ginkgo biloba cell suspension cultures were used to bioconvert sinenxan A, 2α, 5α, 10β, 14β-tetra-acetoxy-4 (20), 11-taxadiene, a taxoid isolated from callus tissue cultures of Taxus spp. Besides two major products, 9α-hydroxy-2α, 5α, 10β, 14β-tetra-acetoxy-4 (20), 11-taxadiene 1 and 9α, 10β-dihydroxy-2α, 5α, 14β-triacetoxy-4 (20), 11-taxadiene 2, additional six minor products were obtained and five of them identified as new compounds. On the basis of chemical and spectral data, their structures were identified as 9α,14β-dihydroxy2α, 5α, 10β-triacetoxy-4 (20), 11-taxadiene 3, 6α, 10β-dihydroxy-2α, 5α, 14β-triacetoxy-4 (20), 11-taxadiene 4, 6α, 9α, 10β-trihydroxy2α, 5α, 14β-triacetoxy-4 (20), 11-taxadiene 5, 9α, 10β-O-(propane-2, 2-diy1)-2α, 5α, 14β-triacetoxy-4 (20), 11-taxadiene 6, 9α-hydroxy2α, 5α, 10β, 14β-tetra-acetoxy-4 (20), 11-taxadiene formate 7, 10β-hydroxy-2α, 5α, 9α, 14β-tetra-acetoxy-4 (20), 11-taxadiene formate 8, respectively. Investigation of the properties of the enzymes responsible for the biocatalysis process of sinenxan A to 1 and 2 revealed that the enzymes were extracellular and constitutive. Using sinenxan A and the two major products (1 and 2) as indicators, the stage and concentration of sinenxan A added and the kinetics of the biotransformation reaction were investigated. The results showed that: (1) the optimal stage for sinenxan A addition was the logarithmic phase of the cell growth period, in which sinenxan A was almost completely bioconverted, and the biotransformation rates were up to 60 and 20% for 1 and 2, respectively; (2) the optimal concentration of sinenxan A added was 60mg/L; (3) the substrate was mainly converted into 1 and 2 in the first 48h after addition and then into the minor products.

Nine new triterpenoid saponins, conyzasaponins I-Q (1-9), were isolated from the aerial parts of Conyza blinii. Their structures were established on the basis of extensive 1D and 2D NMR spectra as well as by chemical degradations. Among these compounds, conyzasaponins M-O (5-7) share a common pentasaccharide unit attached to C-28 of the aglycon, 28-O-β-D-apiofuranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-[β-D-apiofuranosyl-(1→3)]-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl ester, which contains two apiofuranosyl residues. To the best of our knowledge, they are among the few examples of natural products possessing two apiofuranose units in a single sugar chain.

Biotransformation of triptolide 1 by Cunninghamella blakesleana (AS 3.970) was carried out. Seven biotransformation products were obtained and four of them were characterized as new compounds. On the basis of their NMR and mass spectral data, their structures were characterized as 5α-hydroxytriptolide 2, 1β-hydroxytriptolide 3, triptodiolide 4, 16-hydroxytriptolide 5, triptolidenol 6, 19α-hydroxytriptolide 7 and 19β-hydroxytriptolide 8 All the new transformed products (2, 3, 7 and 8) were found to exhibit potent in vitro cytotoxicity against some human tumor cell lines.

A new HPLC method for the determination of paeoniflorin in rat serum with solid-phase extraction (SPE) for preconcentration is introduced. Paeoniflorin and an internal standard (pentoxifylline) were extracted from serum by means of SPE using cartridges with octadecyl chemically bound phase. The HPLC separation was then performed on a reversed-phase C18 column using acetonitrile-water (18:82, v/v) as eluting solvent system, and UV detection at 230nm to measure the analyte with a limit of quantitation about 10ngml-1. The calibration curve for paeoniflorin was linear (r=0.9938) in the concentration range of 10-1200ngml-1, both intra-and inter-day precision of the paeoniflorin were determined and their coefficience of variation did not exceed 10%. The validated method has been successfully applied for pharmacokinetic studies of paeoniflorin from rat serum after oral administration of Guan-Xin-Er-Hao decoction.

Thirteen compounds were isolated from the anomalous fruits of Gleditsia sinensis on the basis of bioassay-guided fractionation. These saponins together with six analogues or related compounds were tested for their cytotoxicities against six tumor cell lines by the MTT method. The induction of apoptosis in HL60 cells by these compounds was determined through flow cytometric analysis. Some structure-activity relationships in cytotoxicity and induction of apoptosis were identified. The evaluation of the cytotoxicity and the ability to induce apoptosis revealed that some important structural features are required for activity. A valuable model which enables prediction of their activities was established and may be employed for the drug design of new Gleditsia saponin analogues.