Total phenolic contents and antioxidant activity of Senna singueana, Melia azedarach, Moringa oleifera and Lannea discolor herbal plants

Senna singueana, Melia azedarach, Moringa oleifera and Lannea discolor are claimed to be effective in the management of cancer by some traditional herbal practitioners in Malawi. The study evaluated methanol extracts of leaves of S. singueana, M. azedarach, M. oleifera and barks of L. discolor for total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity. TPC was determined using the Folin Ciocalteau assay while TFC was determined by aluminum chloride assay. Antioxidant activity of extracts was analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Barks of L. discolor contained the highest total phenolic content (27.64 ± 0.09 mg GAE g −1 DW) while leaves of S. singueana contained highest total flavonoid content (7.372 ± 0.01 mg QE g −1 DW). DPPH radical scavenging activity of all extracts ranged from 42.72 ± 0.18 to 89.09 ± 1.18% while FRAP values ranged from 68.47 ± 1.72 to 166.3 ± 1.65 mg TEACg−1 DW. A direct positive significant correlation (p<0.05) was observed between TPC and antioxidant activity. Results from the present study are comparable with literature values of well-known medicinal plants. Thus, these four medicinal plants may contain phenolic aglycones with potential anticancer activity. Future studies are needed to characterize extracts for specific phytochemicals related to anticancer activity.