Anti-leishmanial and Anti-cancer Activities of a Pentacyclic Triterpenoid Isolated from the Leaves of Terminalia arjuna Combretaceae

Abstract

Purpose: Terminalia arjuna Roxb (Combretaceae) is commonly known as Arjjhan and Arjun in Bengal, India. The anti-leishmanial and anticancer activities of a pentacyclic triterpenoid isolated from its leaves were evaluated. Methods: Dried and crushed leaves of Terminalia arjuna were de-fatted with petroleum ether (40-60°C) and extracted with methanol. The extract was subjected to column chromatography and column fractions were monitored on TLC plates developed in a suitable solvent system. Structures of the isolated pure compounds were elucidated by infra-red spectroscopy, mass spectrometry and nuclear magnetic resonance spectroscopy. One of the compounds was screened for anti-leishmanial activity against promastigotes of Leishmania donovani, and anti-cancer activity on K562 leukaemic cell line. Results: A pentacyclic triterpenoid, characterized as 3ß-hydroxyurs-12-en-28-oic acid (together with ß- D-glucoside) and designated ursolic acid, was successfully isolated. The structure was determined on the basis of spectroscopic analyses. In vitro anti-leishmanial activity against promastigotes of Leishmania donovani (strain AG 83) and anti-cancer activity on K562 leukaemic cell line were shown by the isolated ursolic acid. Conclusion: The methanol extract of the leaves of Terminalia arjuna led to the isolation of a pentacyclic triterpenoid, ursolic acid. This compound demonstrated in vitro anti-leishmanial and anti-cancer activities Keywords: Terminalia arjuna Roxb, Pentacyclic triterpenoid, Ursolic acid, Spectroscopy, Antileishmanial, Anti-cancer