Antioxidant and Toxicity Screenings of extracts obtained from Cyperus esculentus

Abstract

Phytochemicals responsible for toxicity and antioxidant activities of extracts obtained from Cyperus esculentus were investigated. Toxicity test was carried out using Brine shrimp lethality test while in vitro antioxidant activity was determined by three methods; scavenging effect on 2,2-diphenyl-1-picryhydrazyl radical (DPPH), inhibition of hydroxyl radical and peroxide oxidation by ferric thiocynate method. Secondary plant metabolites responsible for observed activities in Cyperus esculentus are alkaloids, flavonoids, phenols and glycosides. Brine shrimp lethality test revealed that hexane extract was toxic while the methanol extract was not toxic with a lethality dose (LC50) greater than 1000 µ/ml. The toxicity results support its local use as an antibiotics/antifungal. Both extracts possessed significant antioxidant activity when compared with antioxidant standards; butylated hydroxyl anisole (BHA), ascorbic acid and a-tocopherol used in the assay. The %inhibition was between 98.24% and 95.30% at 0.00625 mg/ml for the n - hexane and methanol extracts respectively. The high antioxidant activity of the plant extracts at low concentration shows that it could be very useful for the treatment of ailments resulting from oxidative stress.