Protocatecheuic Acid Underlies the Antioxidant Activity Exhibited by Illicium Verum Fruit

Abstract

Illicium verum Hook. F, (Star anise) belongs to the family Illiciacea. In traditional medicine, it is used for variety of ailments. The current study was aimed at investigating the antioxidant potential of I. verum (IV) constituents. Various extract, fractions and pure compounds of I. verum were explored for their antioxidant activity using DPPH (1, 1-diphenyl-2 picrylhydrazyl) and deoxyribose sugar assays. The structure of pure compound was elucidated through spectral studies (UV, IR, EIMS and 1 H-NMR data). In DPPH assay, the methanolic extract of I. verum displayed antioxidant activity with an IC50 of 61 g/ml. Among its various fractions, the ethyl acetate (IV-EA) appeared to be potent antioxidant with IC50 value of 18g/ml and its sub-fractions, the ethyl acetate soluble subfraction of ethyl acetate fraction (IV-EA-EA-S), was most potent with IC50 of 42g/ml. Further fractionation led to potent sub-fraction i.e. Petroleum etherethyl acetate insoluble sub fraction (IV-EA-PE:EA-I) with an IC50 of 12g/ml. The purified fraction 13 subsequently appeared to be most potent (7g/ml) which led to the isolation of 3, 4-dihydroxy benzoic acid (protocatechuic acid, [1] as active principle. In deoxyribose degradation assay, the IV-E, IV-EA and protocatechuic acid also demonstrated antioxidant activity with IC50 of approximately 2000, 1400 and 600g/ml respectively. In conclusion, the protocatechuic acid [1] residing in I. verum most probably underlies its antioxidant action.