Solanum lyratum, a medicinal plant, has been used to treat cancers, tumors, and warts for many years. Undifferentiated cell cultures were mainly used to study the precursor-feeding strategy for the production of secondary metabolites of a-solanine, solanidine, and solasodine for pharmaceutical usage. In this study, S. lyratum cells were fed with exogenous plant sterols including cholesterol, stigmasterol, and mixed sterols (P-sitosterol, campesterol, and dihydrobrassicasterol). The results showed that none of the plant sterols exhibited an effect on cell growth as compared to that of the control. Cellular concentrations of solanidine and solasodine were relatively higher than a-solanine levels in all the treatments. The maximal solasodine level in cells was 11.19 mg/g dry weight (DW) after 0.05-1 mg/l stigmasterol feeding, which was about 10-fold higher than the control. With regard to solanidine levels, the maximal level in cells was 5.84 mg/g DW after feeding with 20 mg/l cholesterol. This is the first report on the in vitro enhancement of solanidine and solasodine, steroidal alkaloids with medicinal value, from S. lyratum. (C) 2007 Elsevier Ltd. All rights reserved.