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

Dionysia revoluta L. a plant of Primulaceae family is used for treatment of 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.revoluta L.ethanol extract and 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. Anti lipid peroxidation effect was studied with ethanol extract.  Radical scavenging properties of ethanolic extract and various fractions was determined by 2,2-diphenyl-l-picrylhydrazyl (DPPH) and Nitric Oxide (NO) methods. High phenolic and flavonoid content and significant radical scavenging properties were detected for the ethyl acetate and mainly n-butanol fraction. Comparisons were made with known reference antioxidant compounds including  ascorbic acid, quercetin, and gallic acid. The radical scavenging effect of n-butanol fraction approached higher degree of effectiveness among all fractions. Acid hydrolysis of this fraction led to a significant enhancement in the phenolic and flavonoid contents and interestingly in DPPH scavenging efficacy of this fraction. As declared by the results, 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 the various chemical constituents of this plant, the concentration of  flavonoids seem to prevail remarkably as indicated by the inspection of thin layer chromatograms of various fractions and their responses to diagnostic colour reactions. Based on the results obtained in the present study, this plant bears a good radical scavenging and antioxidative character and is worth of further detailed phytochemical and antioxidative studies.