TOXICITY AND FREE RADICAL SCAVENGING ACTIVITY OF RHIZOPHORA MUCRONATA LAMK. BARK EXTRACTS FROM KENDARI BAY OF SOUTHEAST SULAWESI PROVINCE INDONESIA

Abstract

The aim of this study was to evaluate the toxicity and free radical scavenging activity of Rhizophora mucronata Lamk. bark extracts from the mangrove forest of Kendari Bay, Southeast Sulawesi Province Indonesia. The extracts were obtained by maceration of R. mucronata Lamk. bark with n-hexane, ethyl acetate, and methanol, respectively. Toxicity test was conducted by using Brine Shrimp Lethal Test (BSLT) method with Artemia salina Leach as the animal test, while free radical scavenging activity test was carried out by using DPPH (1,1-diphenyl 2-picryl-hydrazyl) free radical. The test results showed n-hexane, ethyl acetate and methanol extracts had LC50 values of 136.40 µg/mL, 82.43 µg/mL and 109.38 µg/mL, respectively. The IC50 values for the free radical scavenging activity of the n-hexane, ethyl acetate, and methanol extracts were 122.19 µg/mL, 37.84 µg/mL, 29.32µg/mL, respectively. Result of phytochemical test showed n-hexane extract was dominated by terpenoid and steroid group compounds, while flavonoids, alkaloids, and tannins were predominantly found in both ethyl acetate and methanol extracts. Extracts of R. mucronata bark, especially ethyl acetate extracts had toxic properties for A. salina larvae, therefore it has potential to be developed as an anti-cancer drug. Metahanol extract, on the other hand, indicated strong anti-oxidant activity, then it is potential to develop it as cosmetics agent.