INDUCTION OF CELL CYCLE ARREST AND APOPTOSIS BY A PENTACYCLIC TRITERPENES -RICH FRACTION FROM Tabebuia hypoleuca (C. Wright) Urb. LEAVES IN U-251 GLIOBLASTOMA CELLS

Background: Tabebuia genera had been reported several pharmacological activities. Cuba has numerous endemic species in this genera, but only our group reported the anti-inflammatory, in vitro and in vivo antiproliferative properties from the specie Tabebuia hypoleuca (C. Wright) Urb. In vitro studies demonstrated that 786-0 (kidney), MCF-7 (breast) and glioma (U-251) were among the cancer cell lines most sensitive to ethyl acetate extract of leaves treatment.

Purpose: The aim of this study was to research the induction of cell cycle arrest and apoptosis by a pentacyclic triterpenes -rich fraction from Tabebuia hypoleuca leaves in U- 251 glioblastoma cells and identify the triterpene structures in this fraction.

Methods: A rich fraction of pentacyclic triterpenes were proceeded for the cell cycle arrest and apoptosis on glioblastoma cells using Annexin V and flow cytometry. The chemical composition was determinate by chromatography and spectroscopic methods.

Results: Our results showed that a pentacyclic triterpenes –rich fraction had the ability to cause cell arrest in G2/M phase and induce apoptosis. The elucidation of the chemical compounds in this fraction revealed a mixing of oleanolic, ursolic and betulinic acids. This finding about chemical composition in the first report by the genera.

Conclusion: Therefore, this study showed the presence of different pentacyclic triterpenes in T. hypoleuca and it have promising anticancer activity against glioblastoma.