Two glutathione S-transferase inhibitors from Radix Angelicae sinensis.

Chemotherapy for malignant tumors fails because of multidrug resistance (MDR). The overexpression of glutathione S-transferase (GST) with MDR is considered one of the major obstacles to successful cancer chemotherapy. High-throughput screening was performed to search for inhibitors of GST from natural products. Two compounds isolated from Radix Angelicae sinensis had an inhibitory effect on GST, with 50% inhibitory concentration (IC(50) ) values of 16.80 and 7.30μm. Kinetic analyses showed that the two compounds acted as reversible noncompetitive inhibitors of GST. They also increased apoptosis of B-MD-C1 (ADR+/+) cells induced by adriamycin with low cytotoxic activity. Radix Angelicae sinensis may be a potential source of GST inhibition for pharmaceutical use.