Chemical Composition and Cytotoxicity Evaluation of Essential Oil from Leaves of Casearia Sylvestris, Its Main Compound alpha-Zingiberene and Derivatives

Abstract

Casearia sylvestris (Salicaceae), popularly known as guacatonga, is a plant widely used in folk medicine to treat various diseases, including cancer. the present work deals with the chemical composition as well as the cytotoxic evaluation of its essential oil, its main constituent and derivatives. Thus, the crude essential oil from leaves of C. sylvestris was obtained using a Clevenger type apparatus and analyzed by GC/MS. This analysis afforded the identification of 23 substances, 13 of which corresponded to 98.73% of the total oil composition, with sesquiterpene alpha-zingiberene accounting for 50% of the oil. the essential oil was evaluated for cytotoxic activity against several tumor cell lines, giving IC50 values ranging from 12 to 153 mu g/mL. Pure alpha-zingiberene, isolated from essential oil, was also evaluated against the tumor cell lines showing activity for HeLa, U-87, Siha and HL60 cell lines, but with IC50 values higher than those determined for the crude essential oil. Aiming to evaluate the effect of the double bonds of alpha-zingiberene on the cytotoxic activity, partially hydrogenated alpha-zingiberene (PHZ) and fully hydrogenated alpha-zingiberene (THZ) derivatives were obtained. for the partially hydrogenated derivative only cytotoxic activity to the B16F10-Nex2 cell line (IC50 65 mu g/mL) was detected, while totally hydrogenated derivative showed cytotoxic activity for almost all cell lines, with B16F10-Nex2 and MCF-7 as exceptions and with IC50 values ranging from 34 to 65 mu g/mL. These results indicate that cytotoxic activity is related with the state of oxidation of compound.