In Vitro Cytotoxic Activity and Identification of Bioactive Compounds Isolated from Olea europaea and Syzygium aromaticum Plants

Natural products have been conventional in traditional medicine and still used presently to cure many diseases. In the present study, extracts of two plants – Olea europaea and Syzygium aromaticum – were tested for their phytochemical compositions, cytotoxic effect on hepatocellular carcinoma cells, and chemical profile of the most active fractions. Both plants were extracted with 85% methanol and then fractionated with various solvents. Hemolysis and cytotoxicity effects on normal (Vero) and hepatocellular carcinoma (HepG2) cells were examined. Chemical profiles were studied using GC-MS and chromatographic isolation on silica gel. Phytochemical screening revealed that both plants contain carbohydrates, saponins and flavonoids, while steroids were found only in O. europaea and alkaloids were found only in S. aromaticum . Hemolysis assay showed complete safety of O. europaea, while S. aromaticum exhibited low toxicity. Furthermore, the EtOAc fraction of O. europaea and BuOH fraction of S. aromaticum showed the best IC 50 against HepG2. The GC-MS analysis of EtOAc fraction of O. europaea revealed 15 compounds, the major one being α-linoleic acid methyl ester, and the chromatographic separation of BuOH fraction of S. aromaticum resulted in a pure compound of 3-O-methyl-butyrate-6,7,3 ' ,4 ' -tetrahydroxy-5-methoxy-8-methylflavan. Thus, the study proved that the two title plants have components possessing cytotoxic activity against HepG2 cells.