Cytotoxic activity of Rauvolfia tetraphylla L. on human cervical cancer (HeLa) cells

Background: Although the plant Rauvolfia tetraphylla is used for the treatment of cancer in the traditional medicine of some regions of Mexico, its cytotoxic activity has not been subjected to rigorous investigation. Objective: The aim of the present study was to carry out a bioassay-guided fractionation of Rauvolfia tetraphylla leaves to evaluate the activity on cervical cancer (HeLa) and normal cells. Materials and Methods: Of hexane, dichloromethane and methanol extracts, hexane extract showed the most cytotoxic activity. Its most active fraction was characterized by mass spectrometry and assessed for cytotoxicity (by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays and trypan blue staining) on cervical cancer (HeLa) cells, normal human (HaCat) cells, and other cancer cell lines: A549, Caco-2, MDA-MB-231, and MCF7. Cisplatin served as the reference drug. Apoptosis was explored as a possible mechanism of action by examining DNA fragmentation and phosphatidylserine translocation. Results: The active fraction, composed of at least 5 constituents, was cytotoxic to all cancer cell lines, especially HeLa cells (IC30= 20.10 ± 1.1 μg/mL). To a lesser extent, it was also cytotoxic to normal cells (HaCat; IC30= 40.04 ± 12.78 μg/mL), indicating certain selectivity. Its mechanism of action in HeLa cells involved apoptosis. Conclusion: The active fraction of the hexane extract of R. tetraphylla was cytotoxic to cancer cells and did not produce excessive damage to normal cells. Apoptosis was apparently part of the mechanism of cytotoxicity.