RESUMO
Medicinal plants present a plausible source for anticancer agents. Combination of plant extracts and plant-derived compounds with the currently used cancer drugs has shown a marked improvement of the conventional drugs' efficacy and reduced toxicity. This study evaluated; phytochemical screening, antiproliferative activity and drug interaction potentials of Moringa oleifera and Indigofera arrecta leaf extracts with 5-fluoro uracil against selected cancer cell lines. Phytochemical screening was done using standard procedures. The common 3– (4, 5-dimethylthiazol-2-yr) -2, 5-diphenyltetrazolium (MTT) assay was used to determine the growth inhibitory potential of the extracts towards cancer cells. Drug interaction assays were done using constant ratio combination method. Alkaloids, terpenoids, tannins, flavonoids, glycosides, phenols and saponins were found to be present in the plant's extracts. M. oleifera and I. arrecta methanol-dichloromethane extracts had the highest activity compared to water extracts. All the extracts showed antiproliferative activities towards; HCC 1395 (breast), DU145 (prostate) and Hela (cervical) cancer cell lines. The extracts were not cytotoxic towards Vero cells (IC50>1000 µg/ml). I. arrecta and M. oleifera inhibited DU145 the most with IC50 values of 111.110 µg/ml and 66.290 µg/ml respectively. The plant extracts synergistically inhibited the growth of cancer cells (CI<1). Combination of the plant extracts and 5-Fluorouracil depicted that the concentration of the conventional drug could be reduced and yet achieve the same desired effect against cancerous cells (Dose reduction index (DRI) >1). Further studies to isolate the bioactive compounds and deduce the probable mechanisms of action are recommended.
RESUMO
Tragia brevipes and Tetradenia riparia have been widely used in traditional medicine. T. brevipes relief stomach pain and in treatment of rheumatism while T. riparia; heal chest pains, stomach-ache, malaria and act as antioxidant. However, scanty data exist on their potential anticancer activity. The total phenolic content was determined and anti-proliferative activity of the Methanol-Dichloromethane extract from the leaves evaluated against cancerous cell lines. The total phenolic content of the plants extract was determined using an UV visual spectrophotometer at 765 nm. The 3- (4-5-dimethyl-2-thiazoly)-2, 5-diphenyltetrazolium bromide (MTT) cell proliferation bioassay was used to test for anti-proliferative activity on Hela (cervical), DU145 (prostrate) and HCC (breast) cancer cell lines and Vero (normal) cell. T. brevipes and T. riparia had a phenolic concentration of 30.44 and 20.25 µg/ml, respectively. Both plants showed anti-proliferative activity on cancer cells with the most inhibited being DU145 with an IC50 of 29.67 ± 4.60 µg/ml for T. brevipes and 11.45 ± 0.87 µg/ml for T. riparia. The standard 5 Fluorouracil had an IC50 of 5.04 ± 4.12 µg/ml on DU145. T. riparia had the highest antiproliferative activity of 65.54 ± 16.85 µg/ml on Hela cells and 62.84 ± 1.10 µg/ml on HCC. T. brevipes had an IC50 of 661.11 ± 15. 12 µg/ml on Hela cells and 703.09 ± 18.35 µg/ml on HCC. Extracts from both plants were highly selective on DU145 cancer cells with a selectivity index (SI) of 21.62 for T. brevipes and 7.88 for T. riparia. Methanol-Dichloromethane extracts from T. brevipes and T. riparia exert anti-proliferative activity, however, the active compound (s) and the mechanisms of anti-proliferative action need to be investigated further.