Phytochemical, Antioxidant and Anticancer Properties of Elaeis guineensis and Elaeis oleifera
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Date
June 2016
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Abstract
Oil palm (Elaeis spp) is largely known for its economic values but it has also been used in folklore for the treatment of a wide range of diseases including cancer. This study was aimed at assessing and comparing the antioxidant and anticancer potentials as well as evaluating the phytochemical constituents of aqueous and hydroethanol extracts of leaves from two species of oil palm, Elaeis guineensis and Elaeis oleifera. Aqueous and hydroethanolic extracts were prepared from dried leaves of Elaeis guineensis and Elaeis oleifera and successively fractionated with petroleum ether, chloroform and ethyl acetate. Anti-proliferative activities of the extracts and fractions were determined using the tetrazolium-based colorimetric, 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on Jurkat, MCF-7, and Chang liver cell lines. Antioxidant potential of crude extracts was assessed by 2, 2- diphenyl-1-picryl hydrazyl (DPPH) and reducing power assays. Total phenol and flavonoid contents were determined by the Folin-Ciocalteu and aluminum chloride spectrometric methods, respectively. The presence of tannins, alkaloids, terpenoids and saponins were qualitatively screened for in the crude aqueous and ethanolic extracts. The study revealed that both E. guineensis and E. oleifera contained tannins, flavonoids, alkaloids, terpenoids and saponins. E. oleifera, however, had higher quantities of total phenolic content than E. guineensis. The E. oleifera hydroethanolic extract had total phenolic content of 34.99 ± 3.92 g GAE/100g, whereas that of the aqueous extract gave 21.05 ± 1.21 mg GAE/100g. The total flavonoid content of hydroethanolic extract of E. oleifera was 100.40 ± 1.39 mgQE/100g, while that of the aqueous extract was 82.15 ± 3.03 mgQE/100g. E. guineensis and E. oleifera showed significant antioxidant properties comparable to the standards, butylated hydroxyl toluene (BHT) and ascorbic acid. The aqueous E. oleifera extract showed higher antioxidant activity of 0.072 ± 0.010 mg/mL and 0.045 ± 0.006 mg/mL for the hydroethanol extract, as well as the ferric reducing ability of the aqueous extract being 0.597 ± 0.014 mg/mL and 0.120 ± 0.010 mg/mL for the hydroethanol extract. E. guineensis and E. oleifera both exhibited cytotoxicities against Jurkat, MCF-7 and Chang liver cells. Jurkat cells were the most sensitive and MCF-7, the most resistive. The hydroethanol E. oleifera extracts exerted the most cytotoxicty with the lowest IC50 of 87.54 ± 4.27μg/mL against Jurkat cell lines with selectivity index of 2.87 whilst on the MCF-7 cell lines, it was 476.32 ± 82.74 μg/mL with selective index of 0.77. The cytotoxicity evaluations of the extracts from successive solvent system fractionations of the crude extracts with petroleum ether, chloroform and ethyl acetate revealed the ethyl ether fractions of E oleifera hydroethanol extract to be the most cytotoxic exhibiting IC50 of 18.88 ± 0.12 μg/mL against the jurkat cells with a selective index of 1.87. Ethyl acetate fraction of aqueous E. oleifera showed the most cytotoxicity against MCF-7 of 27.26 ± 1.26 μg/mL with a selective index of 36.15. The study showed that both E. guineensis and E. oleifera leaf extracts possess significant antioxidant and anticancer properties; however, E. oleifera had a better potential for therapeutic applications.
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A thesis submitted to the Department of Biochemistry and Biotechnology,
College of Science, in partial fulfillment of the requirements for the Award of Master of Philosophy in Biochemistry.