Cytotoxic activity of flavonoids and extracts from Retama sphaerocarpa Boissier.

Seven flavonoids isolated from chloroform, ethyl acetate and butanol extracts, obtained from the aerial parts of Retama sphaerocarpa, have been assessed for cytotoxic activity against three human cancer cell lines: TK-10 (renal adenocarcinoma), MCF-7 (breast adenocarcinoma) and UACC-62 (melanoma), using the SRB assay. All of them, extracts and flavonoids, were actives in, at least, one of the three cell lines at the recommended National Cancer Institute doses. They produce a dose-dependent inhibition of cell growth at concentrations in the 10(-6)-10(-4) M and 25-250 microg/ml range for the flavonoids and extracts respectively, being the flavonol rhamnazin the most cytotoxic.