Antioxidant And Anticancer Potentials Of Natural Cocoa Extract

Abstract

In spite of several research efforts and therapeutic interventions, cancer remains a major public health burden across the globe. Cancer treatment is still confronted with challenges including drug resistance and many undesirable side effects. Chemotherapy, the standard cancer treatment is seriously challenged with a lot of shortcomings and hence finding an alternative source of potent anticancer agents is critical to combat the menace. Plant and other natural products have proven to be alternative sources of potent agents for many diseases including cancer. Cocoa and its products have increasingly been in used as medicinal agents since ancient days for the management of various kinds of diseases. The project therefore aimed at investigating the in vitro antioxidant and anticancer activities of natural cocoa extracts. Aqueous and hydroethanolic extracts of the natural cocoa were prepared by cold maceration and dried under reduced pressure. Fractions of the selected hydroethanolic crude extracts were also prepared. The antioxidant activity of the extracts was determined using 2, 2-diphenyl-2-picrylhydrazyl (DPPH), Folin-Ciocalteau, flavonoid and glutathione assays. The antiproliferative activity of the extracts was evaluated by tetrazolium-based colorimetric assay, 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) on leukaemia (Jurkat), prostate (PC3 and LNCaP) and normal liver (Chang Liver) cell lines. Results obtained showed that hydroethanolic cocoa roots, leaves, and beans extracts have good total antioxidant activities with EC50 values, 0.4, 0.41 and 0.83 mg/mL, respectively. Hydroethanolic cocoa root extract showed the strongest scavenging effect on DPPH with EC50 = 0.40 mg/ml. It also recorded the highest phenolic content of 8854.55 mg Gallic acid equivalent /100 g of natural cocoa root extract. Phenols were present in all the extracts but higher concentrations were found in hydroethanolic extracts than the aqueous extracts. Glutathione was present in all extracts but total flavonoid was only prominent in hydroethanolic cocoa leaf extract. Hydroethanolic cocoa bean extract had the highest anticancer activity with an IC50 value of 37.34 μg/mL against LNCaP cell line. Also, the ethyl acetate fraction of hydroethanolic cocoa leaf exhibited highest anticancer activity with an IC50 value of 35.31 μg/mL. Susceptibility of the leukaemic (Jurkat) and prostate cancer (PC3) cell lines to the natural cocoa extracts were similar. Data from this study indicate that the hydroethanolic extracts contain more phenols than the aqueous extracts and the concentration of phenols vary from one part of cocoa to the other. The root of cocoa have a high antioxidant capacity than its beans and leaves. The antioxidant activity of cocoa was found to be associated with phenols and glutathione. The study also indicate that the anticancer activity of cocoa is prominent in the leaves and beans. The Jurkat and Leukaemic cell lines were similarly susceptible to the anticancer effect of cocoa and it was also proven that the hydroethanolic extracts of cocoa has high anticancer activity their aqueous extracts.