Phytochemical Screening and In vitro Evaluation of Free Radical Scavenging Activity of Dionysia revoluta L.

Abstract

Dionysia revoluta L., a plant of Primulaceae family is used for treating ulcers and relieving pain in Iranian traditional system of medicine. The present study was aimed at preliminary phytochemical investigation and evaluation of antioxidant characteristics of D. revolute L. ethanol extract and its various fractions. Total phenolic content was determined by Folin–Ciocalteu method. Evaluation of total flavonoid was carried out by the use of an aluminium chloride/sodium carbonate colorimetric procedure. Lipid peroxidation inhibitory effect of ethanol extract was studied and compared with that of butylated hydroxytoluene (BHT). Radical scavenging properties of ethanolic extract and various fractions were determined by 2,2-diphenyl-l-picrylhydrazyl (DPPH) and nitric oxide methods. High phenolic and flavonoid contents and significant radical scavenging properties were detected for the ethyl, acetate and n-butanol fractions. Comparisons were made with known reference antioxidant compounds ascorbic acid, quercetin, and gallic acid. The radical scavenging effect of n-butanol fraction was the highest among all fractions. Acid hydrolysis of n-butanol fraction led to a significant enhancement in its phenolic and flavonoid contents and DPPH scavenging efficacy. The total phenolic content showed a good correlation with radical scavenging activity. The antioxidant activity found in the ethyl acetate and n-butanol fractions of D. revoluta L. may be attributed to the presence of flavonoids and other phenolic compounds. Among various chemical constituents of this plant, the concentration of flavonoids seems to prevail remarkably as indicated by thin layer chromatography of various fractions and diagnostic colour reactions. The results suggest that D. revoluta bears a remarkable radical scavenging and antioxidant activity and is worthy of further detailed phytochemical and antioxidant studies