Abstract

The present study investigated the total content of phenolic compounds, antioxidant activity, reducing power and chelating of ferrous ion in aqueous and alcoholic extracts of Hibiscus sabdariffa L. The total phenolic content was 77.2 mg/g and 87.7 mg/g for the aqueous and alcoholic extracts, respectively. The antioxidant activity was equal in rates for both the roselle alcoholic extract and artificial antioxidant BHT (75.67%), alcoholic extract showed the highest reducing ability with rate 222.60%, the chelating of ferrous ion in both aqueous and alcoholic extracts were 73.97 and 32.29% at 5 mg/ml concentration. The antibacterial activity of roselle extracts against Escherichia coli,Staphylococcus aureus, Streptococcus mutans and Pseudomonas aeruginosa, showed varying degrees of inhibition on the tested organisms.

Key words: Hibiscus sabdariffa, antioxidant, antimicrobial.