An extract from Ricinus communis L. leaves possesses cytotoxic properties and induces apoptosis in SK-MEL-28 human melanoma cells.

Plants are an important source of several clinically useful anti-cancer agents. A volatile extract was obtained from Ricinus communis L. (Euphorbiaceae) leaves by standard hydrodistillation and subsequent extraction of the cohobated water in chloroform. GC-MS identified three monoterpenoids: 1,8-cineole, camphor and alpha-pinene, and a sesquiterpenoid: beta-caryophyllene, as the main constituents. The leaf extract is cytotoxic to several human tumour cell lines in a dose-dependent fashion, with IC(50) values ranging between 10-40 microg mL(-1). Apoptosis was shown to be induced in SK-MEL-28 human melanoma cells at a concentration of 20 microg mL(-1), as identified by means of morphological examination, nuclear staining and flow cytometric analysis of DNA content. Translocation of phosphatidyl serine to the cell membrane's external surface and loss of mitochondrial membrane potential were also detected. This study provides further insight into the potential use of mixtures of terpenoids as they occur in nature, as inducers of apoptosis in cancer cells.