Publication: A comparative study on the antioxidant activity of leaf, flower, stem and root extracts of peperomia pellucida (l.) hbk (piperaceae).
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Date
2016
Authors
Fang, Mok Siew
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Abstract
Peperomia pellucida is an underexploited annual herb abundantly available in Malaysia. It is widely used as ethnomedicines in treating various ailments throughout the tropical and subtropical regions of the world. Previous studies evidenced that P. pellucida possessed antioxidant properties. However, there is no antioxidant study on different parts of the plant was reported. The aim of this study is to determine and compare the antioxidant properties of leaf, flower, stem, and root of P. pellucida, hence providing additional scientific evidence of its potential. Each part of the plant collected was washed, freeze-dried, and ground into fine powder before extracted using 70% ethanol, 70% methanol and distilled water (1:10 w/v). DPPH (2,2-diphenyl-lpicrylhydrazyl) radical scavenging assay was used to determine the antioxidant capacity. Only moderate [half maximal inhibitory concentration (IC50) >0.05 mg/ml] antioxidant activities were detected in all P. pellucida extracts with mean IC50 ranging from 2.14 mg/ml (ethanol flower extract) to 10.06 mg/ml (methanol stem extract). The mean IC50 of all P. pellucida extracts is significantly different from that of standard reference, gallic acid (0.03 mg/ml) (p<0.05). Generally, P. pellucida leaf extracts showed the highest antioxidant activity, followed by flower, root, and stem extracts. However, ethanolic flower extract (IC50 2.14 mg/ml) showed significantly higher antioxidant activity than ethanolic leaf extract (IC50 2.79 mg/ml) (p<0.05). In terms of extraction solvent, ethanolic extracts of P. pellucida generally showed higher antioxidant activity than that of methanolic and aqueous extracts. However, methanolic root extract (IC50 4.35 mg/ml) showed significantly higher antioxidant activity than ethanolic root extract (IC50 6.15 mg/ml) (p<0.05). The results revealed that ethanol is a better extraction solvent than methanol and distilled water for leaf, flower and stem of P. pellucida to show their highest antioxidant activity while methanol is a better extraction solvent for P. pellucida root to show its highest antioxidant activity on DPPH assay.