Antioxidant and antimicrobial activity of a mangrove plant Avicennia marina (Forsk.)

Abstract

Objective: To evaluate the antioxidant and antimicrobial potential of different parts (leaf, stem and pneumatophore) of a mangrove plant Avicennia marina (Forsk.) Vierh (Avicenniaceae). Methods: The extraction was done by cold percolation method using solvents of hexane, ethyl acetate, acetone, methanol and water. Total phenol and flavonoid content were measured by Folin-Ciocalteu's reagent and aluminium chloride colorimetric method respectively. The antioxidant activity was evaluated using antioxidant assays of 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, superoxide radical scavenging assay, 2,2'-azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid, ferric reducing antioxidant power and reducing capacity assessment. The antibacterial activity was done by agar well diffusion method against four Gram-positive, four Gram-negative bacteria and four fungi. Results: Different antioxidant assays showed different levels of activity in different parts and different solvent extracts. Overall, acetone extract of stem showed the best antioxidant activity. The Gram-positive bacteria were more susceptible than Gram-negative bacteria and fungi. Conclusions: The results indicated extract of Avicennia marina can be used as a promising source of natural antioxidant.