BIOREACTIVE COMPOUNDS AND ANTIOXIDANT PROPERTIES OF METHANOLIC EXTRACT OF FENNEL (FOENICULUM VULGARE MILLER)

Abstract

Methanolic extract of dried Fennel (Foeniculum vulgare Miller) seeds was analyzed for the presence of bioreactive compounds: ascorbate, riboflavin, tocopherol and polyphenols with potential antioxidant properties. The extract had low ascorbate (197.12+1.82µg), riboflavin (11.97+0.35µg) and tocopherol (280.33+5.67µg/g dry seeds) content. However the extract had high polyphenol content (16.506+0.32mg/g dry seeds). Antioxidant activity of the extract was determined by various mechanisms including DPPH free radical scavenging, metal induced protein and lipid oxidation inhibition and protection of DNA against H2O2 induced damage. Fennel had excellent free radical scavenging activity with IC50 2.1mg dry seed weight. IC50 observed for protection of proteins and lipids against metal ion induced oxidation is 2.1 and 2.5mg dry seed weight respectively. Extract equivalent to 0.5µg seeds is enough to protect DNA against H2O2 induced oxidation. The results suggest that polyphenols are the principal components responsible for high antioxidant potential of methanolic extract of fennel.