Evaluation of Secondary Metabolites and Antioxidant Activity of Water, Ethyl Acetate and Hexane Fractions from the Mangrove Young Leaves Sonneratia alba

Abstract

The fractions from young leaves of mangrove Sonneratia alba was studied for its associated secondary metabolites and antioxidant activities. The objective of this study was to determine the secondary metabolite components and antioxidant activity of water, ethyl acetate, and hexane fractions of the young leaves of mangrove S. alba. The fraction was obtained from dry powder of young leaf S.alba using continuous fractionation of crude extracts. The crude extract was attained by 2 extraction methods (soxhlet and maceration) and 2 extraction solvents (methanol and ethanol). Secondary metabolites analyses were qualitatively conducted to detect the presence or absence of phenols, flavonoid, tannin, steroid, triterpenoid and alkaloid. Total phenols were measured using Folin Ciocalteau reagents and gallic acid standard curves whereas antioxidant activity were analyzed using DPPH method (1- 1-diphenil-2-picrihydrasil). Results showed that all fractions contained secondary metabolite components tested. The highest rendement was found in the water fraction fromsoxhletation extract with methanol (6.36±0.29%). The total phenol values were found the highest in the ethylacetatefraction from macerated extract with ethanol (352±9.77 mgGAE/g). Stronger antioxidant activity was also found in ethylacetate  fraction as indicated by the small value of IC50 DPPH namely the ethylacetate fraction with soxhletation extract with ethanol  (3.43±0.25 µg / mL). The results of this study indicate that the semipolar fraction (ethylacetate fraction) has more potential as a source of natural antioxidants.