Free Radical Scavenging Activity of some Anticancer Herbs

Dietary and endogenous antioxidants prevent cellular damage by reacting with and eliminating oxidizing free radicals. However, in cancer treatment, a mode of action of certain chemotherapeutic agents involves the generation of free radicals to cause cellular damage and necrosis of malignant cells. This study determined the 1–1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, total phenolics, flavonoids and anthocyanins of 4 methanolic extracts from 2 indigenous wild plant species [Dialium guineense Willd. (Leguminosae) and Spondias mombin L. (Anacardiaceae)], indicated as anticancer plants in Nigerian traditional medicine. Assays were determined spectrophotometrically. Free radical scavenging activity was measured as maximum fading power of DPPH at 517 nm in presence of known concentration of extracts. Vitamin E, a natural antioxidant, was used as a control. The content of total phenolics was according to the Folin-Ciocalteu assay calculated as Gallic acid equivalents (GAE), total flavonoids and anthocyanins were calculated as rutin and catechin respectively.

Table1. Scavenging activity and the extract content of phenolics, flavonids and anthocyanins

Samples	% Scavenging activity (SA)	Phenolics (GAE) (mg100g-1)	Flavonoids (TF) (mg100g-1)	Anthocyanins (TA) (mg100g-1)
Dialium leaves	51.40±0.04	1.42±0.01	15.63±1.22	0.54±0.06
Dialium seeds	88.99±0.50	4.46±0.12	49.18±0.75	3.72±0.00
Spondias leaves	57.87±0.55	14.68±0.03	13.63±0.11	5.31±0.19
Spondias fruits	0.67±0.05	2.75±0.00	0.65±0.01	0.80±0.04

The correlation between scavenging capacities and the content of total flavonoids was high SA/TF (R²=0.8959). But a low R² with total phenolics and anthocyanins respectively. SA/GAE (R²=0.2448); SA/TA (R²=0.5936). These medicinal plants associated with anticancer might be a potential source of potent natural antioxidants and therapeutic chemopreventive agents.