BIOLOGICAL ACTIVITY AND STANDARDIZATION OF THE ETHANOLIC EXTRACT OF THE AERIAL PARTS OF MENTHA SUAVEOLENS EHRH

Abstract

A biologically guided fractionation of the ethanolic extract of the aerial parts of Mentha suaveolens Ehrh. cultivated in Egypt revealed that the ethyl acetate fraction had the highest hepatoprotective activity as it prevented the increase caused by CCl4 in the levels of aspartate aminotransferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALP) enzymes by 51.6%, 57.0% and 56.7%, respectively. The same fraction also showed the highest antioxidant activity; in vivo (as it restored the glutathione level in diabetic rats by 98.0 %) and in vitro as it had the highest free radical scavenging activity (IC50=31g/ mL). It also had the highest cytotoxic activity against human liver carcinoma cell line (HEPG2) (IC50 = 5.1 μg/ mL). Consequently, this fraction was purified to yield caffeic acid and rosamarinic acid. Rosmarinic acid, the major component possessed cytotoxic activity on HEPG2 (IC50 = 4.5 μg/ mL) comparable to doxorubicin (IC50 = 3.73 μg/mL). A rapid reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed for the standardization of the active ethyl acetate fraction and the method was validated. Rosmarinic acid content in M. suaveolens was estimated by RPHPLC, to be 1.16 and 50.17% w/w for the powdered aerial parts and ethyl acetate fraction, respectively.