Anticancer, antioxidant and phytochemical evaluation of Ageratum Conyzoides linn.

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Cancer is still a major public health burden in many countries and despite the research strides made in respect of therapeutic interventions, challenges still abound in cancer treatment. Chemotherapy, the standard treatment method, is fraught with various shortcomings like drug resistance and undesirable side effects. Consequently, natural products present promising alternatives to cancer chemotherapy and hence finding new anticancer agents from natural sources will be critical in improving patient outcomes. Ageratum conyzoides, an annual herb is increasingly been used in folklore for the treatment of a wide range of diseases including cancer. The study was aimed at investigating the antioxidant and anticancer potentials as well as evaluating the phytochemical constituents of the aqueous and 50% hydroethanolic extracts and fractions of Ageratum conyzoides. The plant was subjected to decoction and ethanol extraction (cold maceration) under reduced pressure and further fractionation was carried out on the ethanolic leaf extract using different solvents. Total antioxidant potential of the crude aqueous and ethanolic extracts was investigated for free radical scavenging activity, for the presence of glutathione as well as total phenolic contents. The anticancer study was performed using the tetrazolium-basesd colorimetric, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, on leukemia, prostate and breast cancers, and prostate normal cell lines (Jurkat, LNCap, MCF-7, and PNT2), respectively, using the crude aqueous and ethanolic extracts as well as fractions of the ethanolic leaf extract. Curcumin was used as standard. The selective ability of each extract and fraction was also determined. The presence of tannins, flavonoids, alkaloids, terpenoids and saponins were qualitatively screened for in the crude aqueous and 50% hydroethanolic extracts. The results showed that the crude extracts scavenged 2,2- diphenyl-1-picryl hydrazyl (DPPH) free radical in a dose dependent manner compared to the positive control, butylated hydroxy toluene (BHT). Phenolic compounds were present, but glutathione was not detected in any of the crude extracts. The aqueous leaf extract was the strongest scavenger of DPPH, with 50% effective concentration (EC50) of 0.091 ± 0.024 mg/ml. It also recorded the highest total phenol content, 1678.86 ± 40.67 mg/g equivalent of gallic acid. The anti-cancer results indicated that the ethanolic leaf extract had comparatively lower cytotoxic effects on the cell lines, with IC50 values of 15.08 ± 0.28, 304.22 ± 71.54 and 934.94 ± 105.91 μg/ml on Jurkat, LNCap and MCF-7 cells respectively. On the other hand, the chloroform and ethylacetate fractions exhibited stronger cytotoxic effects with IC50 values of 6.36 ± 1.56, 35.28 ± 6.46 and 74.27 ± 8.15 μg/ml for the former and 4.6 ± 0.12, 37.28 ± 2.09 and 67.38 ± 1.71 μg/ml for the latter in Jurkat, LNCap and MCF-7 cell lines respectively. All extracts and fractions were not cytotoxic to the PNT2 cell lines. The ethanolic leaf extract as well as the chloroform and ethylacetate fractions were strongly selective against Jurkat cell lines, with selectivity indices (SI) values of 66.33, 15.72 and 21.74 respectively. The presence of tannins, saponins and terpenoids were concentrated in the leaf and flower of the plant. The present investigation suggests that Ageratum conyzoides possesses remarkable antioxidant and anticancer properties and the chemical compounds detected could be responsible for these properties.
A thesis s ubmitted to the Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Philosophy (Biochemistry). 2015