Phenol content, antioxidant and tyrosinase inhibitory activity of mangrove plants in Micronesia

OBJECTIVE: To find out and compare the in vitro antioxidant and tyrosinase inhibitory activities of two species of mangrove plants. METHODS: Mangrove samples were harvested at the shoreline on the island of Weno, Chuuk State in Micronesia. The phenol content, antioxidant activity (based on DPPH-free radical scavenging) and tyrosinase inhibitory activity in different tissues (leaves, barks and roots) of Rhizophora stylosa (R. stylosa) and Sonneratia alba (S. alba), collected from the island of Weno. RESULTS: Total phenol content ranged from 4.87 to 11.96 mg per g of freeze dried samples. The highest antioxidant activity was observed in R. stylosa bark (85.5%). The highest tyrosinase inhibitory activity was found in S. alba bark. Also, total phenol content and antioxidant activity were higher in methanol extracts than in aqueous extracts. CONCLUSIONS: Taken together, the results of this study proved that mangroves can be excellent sources of antioxidant compounds.