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.

Artemisinin (1) was transformed by Mucor polymorphosporus and Aspergillus niger. Five products were identified as 9β-hydroxyartemisinin (2), 3β-hydroxyartemisinin (3), deoxyartemisinin (4), 3β-hydroxydeoxyartemisinin (5), and 1α-hydroxydeoxyartemisinin (6). Products 2, 3, and 6 are new compounds.

Microbial transformation was used to prepare novel cytotoxic bufadienolides. Twelve products (3-14) were obtained from bufalin (1) by the fungus Mucor spinosus. Their structures were elucidated by high-resolution mass spectroscopy (HR-MS) and extensive NMR techniques, including 1H NMR, 13C NMR, DEPT, 1H-1H correlation spectroscopy (COSY), two dimensional nuclear Overhauser effect correlation spectroscopy (NOESY), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond coherence (HMBC). Compounds 3, 4, 9 and 11-14 are new mono-or dihydroxylated derivatives of bufalin with novel oxyfunctionalities at C-1β, C-7β, C-11β, C-12β and C-16α positions. The in vitro cytotoxic activities against human cancer cell lines of 3-14, together with 16 biotransformed products derived from cinobufagin (15-30) were determined by the MTT method, and their structure-activity relationships (SAR) were discussed.

A sensitive and rapid high-performance liquid chromatography (HPLC) method with solid-phase extraction (SPE) to simultaneously determine albiflorin and paeoniflorin in rat serum was described. Serum samples were pretreated with solid-phase extraction using Extract-CleanTM cartridges, and the extracts were analyzed by HPLC on a reversed-phase C18 column and a mobile phase of acetonitrile-0.03% formic acid (17:83 (v/v)) with ultraviolet detection at 230nm. Pentoxifylline was used as the internal standard (IS). The linear ranges of the calibration curves were 29-1450ng/ml for albiflorin and 10-2000ng/ml for paeoniflorin. The intra-and inter-day precisions (R.S.D.) were≤10.49% for albiflorin and≤11.29% for paeoniflorin, respectively. Mean recovery was determined to be 89.75% for albiflorin and 85.82% for paeoniflorin. The limit of quantification was 29ng/ml for albiflorin and 10ng/ml for paeoniflorin, respectively. The validated method was applicable to pharmacokinetic studies of albiflorin and paeoniflorin from rat serum after oral administration of Si-Wu decoction. The pharmacokinetic study indicated that albiflorin and paeoniflorin had poor absorption and rapid elimination. This assay result was necessary for the pharmacokinetic evaluation of Si-Wu decoction.

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.