(+)-Tiliarine, a selective in vitro inhibitor of human melanoma cells

Five diphenylbisbenzylisoquinoline (DBBI) alkaloids, tiliacorinine, tiliacorine, nor- tiliacorinine A, tiliarine and tiliamosine were isolated from the ethanol extract of the roots of Tiliacora racemosa Colebr. and identified by spectral techniques. Of these (+)-tiliarine is the only one which exhibited a selective inhibitory effect against human melanoma cells (G 361) and had no activity on normal human fibroblasts (CCD 974 SK). The activity of (+)-tiliarine against the human melanoma cell line was not much modified in the presence of calcium chloride.