Phytochemical Composition and Antioxidant Activity of Leaf Extracts from Three Rhizophora Species from Bontang Waters, Indonesia doi.org/10.26538/tjnpr/v6i8.2

Abstract

The Rhizophora genus is a prominent mangrove distributed in tropical Bontang waters. However, exploration of antioxidant potential has received very little attention. The present study was, therefore, conducted to investigate the phytochemical properties and antioxidant activity of three Rhizophora species from Bontang waters in Indonesia. Leaves of Rhizophora mucronata, Rhizophora apiculata, and Rhizophora stylosa were extracted with methanol (polar target molecules) and ethyl acetate (semi-polar target molecule) using the successive extraction method. The extractive yields of the two solvents were determined, and the three Rhizophora crude extracts were subjected to standard phytochemical screening. The DPPH (1,1-diphenyl-2- picrylhydrazyl) radical scavenging assay was used to assess the antioxidant activity of the three Rhizophora extracts. The results showed that ethanol extractive yields were higher in all samples than ethyl acetate extractive yields. The phytochemical screening results indicated that the ethyl acetate extract contains a greater variety of metabolites than the methanol extract. Both ethyl acetate and methanol extracts demonstrated significant anti-DPPH radical activity. The R. mucronata extract in methanol had the highest antioxidant activity, with an IC50 value of 0.04±0.00 g/ml, followed by the R. stylosa extract at 0.37±0.09 g/mL, and the R. apiculata extract at 5.06 ± 0.41 g/mL. Meanwhile, the IC50 values of the R. apiculata, R. stylosa, and R. mucronata extracts in ethyl acetate were 0.72±0.07, 1.16±0.04, and 2.34±0.12 g/mL, respectively. The findings of the study suggest that the ethyl acetate and methanol extracts of Rhizophora mucronata, Rhizophora stylosa, and Rhizophora apiculata have the potential to be developed as natural antioxidants.