Antioxidant activity and phytochemical screening of two Cucurbitaceae: Citrullus colocynthis fruits and Bryonia dioica roots

Objective: To evaluate antioxidant activity and quantify total content of polyphenols and\udflavonoids in two Cucurbitaceae plant extracts, Citrullus colocynthis (C. colocynthis) fruits and\udBryonia dioica (B. dioica) roots.\udMethods: Qualitative and quantitative analysis of aqueous and butanolic extracts, prepared\udfrom C. colocynthis fruits and B. dioica roots was carried out using standard methods.\udEstimation of their antioxidant activity was determined by free radical scavenging activity\udassay using 2,2-diphenyl-l-picrylhydrazyl and ferric reducing antioxidant power assay.\udResults: Preliminary phytochemical screening of the aqueous and organic extracts showed the\udpresence of tannins, flavanoids, terpenoids, saponins and quinones. The content of phenolic\udcompounds varies among the two species of cucurbits and even in the different extracts of\udthe same species. The most important amount of total polyphenols and flavanoids expressed\udrespectively as gallic acid and catechin equivalent per gram extract, was determined in\udbutanolic extract of B. dioica roots (541.78 mg/g, 120.60 mg/g). The lowest values were noted\udin C. colocynthis fruit aqueous extract (219.58 mg/g, 46.13 mg/g). Butanolic extract of B.\uddioica roots exhibited an interesting free radical scavenging activity with IC50 = 2.25 µg/mL\udcompared to IC50 = 1.5 µg/mL of ascorbic acid, followed by B. dioica roots aqueous extract (IC50\ud= 47.25 µg/mL), butanolic C. colocynthis fruit extract (IC50 = 61 µg/mL) and C. colocynthis\udfruit aqueous extract (IC50 = 241.25 µg/mL). A highest reducing power was observed in B.\uddioica roots butanolic extract compared to other extracts (C. colocynthis fruit aqueous and\udbutanolic extracts and B. dioica roots aqueous extract).\udConclusions: The results indicate that the wealth of B. dioica roots extracts on polyphenols\udand flavonoids is more than C. colocynthis fruit extracts. These phytoconstituents ensure an\udinteresting free radical scavenging activity and reducing power for the B. dioica roots extracts\udespecially butanolic extract