Cytotoxicity Against Cancer Cell Lines of Selected Plants Used as Anticancer in Thai Traditional Medicine

Abstract

Twenty-five selected plants used as anticancer in Thai traditional medicine were examined for their cytotoxicity and antioxidant activity. Due to its cytotoxicity, this study selects Croton oblongifolius Roxb. Which had interesting anticancer activity for further investigation of its active compounds. By chemical investigation of the stem bark of Croton oblongifolius Roxb. From Petchaboon province, five compounds were isolated from hexane crude extract and one compound from ethyl acetate crude extract. The structures of these compounds were elucidated on the basis of physical properties and spectroscopic data including IR, MS, 1D-NMR techniques. There were two cembrane diterpenoids; crotocembraneic acid (1) and neocrotocembraneic acid (2); three clerodane diterpenoids; a compound which is similar to kofavenol (3), (-)-hardwikiic acid (4) and (-)-20-benzyloxyhardwickiic acid (5) and one flavan: (+)-catechin (6). All of the six compounds were tested for biological activity: cytotoxicity against human cancer cell lines and antioxidant activity. It was found that neocrotocembraneic acid (2), compound which is similar to kolavenol (3), (-)-20- benzyloxyhardwickiic acid (5) have high activity against 5 cancer cell lines; BT474 (breast), Chago (lung), Hep-G2 (hepatoma), Kato-3 (gastric) and SW620 (colon). Antioxidant assay showed that (+)-catechin (6) had high activity with IC50 0.036M while compounds 1-5 had very low activity or inactive.