In vitro antioxidant activities of ethanol extract from Enhalus acoroides (LF) Royle

Objective:. To search for new sources of safe and inexpensive antioxidants, the leaf, root and rhizome of Enhalus acoroides (E. acoroides) were screened for the first time for their antioxidant activities. Methods: Samples of leaf, root and rhizome from E. acoroides were tested for total phenolic content, proanthocyanidins and in vitro antioxidant activity in terms of total antioxidant assay, DPPB assay and ERAP assay. Results: The leaf sample was found to have high levels of phenolic (0.323+/-0.028 mg TAE/g) and proanthocyanidins (0.570 0+/-0.000 3 mg TAE/g) when compared to root and rhizome. The leaf samples exhibited higher total antioxidant activity (11.770+/-0.026 mg Ascorbic acid equivalent/g), higher percentage of DPPH radical scavenging activity (25.76+/-0.04) and higher reducing power (18.060+/-0.073) in terms of mg GAE/g. In addition, there was a significant correlation between total phenolic content and total antioxidant activity (R-2=0.923), DPPH assay (R-2=0.509), FRAP assay (R-2=0.994). Similarly, significant correlation was found between the proanthocyanidin and total antioxidant activity (R-2=0.977), DPPH assay (R-2=0.464) and the FRAP assay (R-2=0.998). Conclusions: These results suggested that E. acoroides have strong antioxidant potential. Further study is necessary for isolation and characterization of the active antioxidant agents, which can be used to treat various oxidative stress related diseases.