ASSESSMENT OF IN VITRO ANTIOXIDANT POTENTIAL AND QUANTIFICATION OF TOTAL PHENOLS AND FLAVONOIDS OF AQUEOUS EXTRACT OF PHYLLANTHUS AMARUS

Objective: The modern research is directed towards finding naturally occurring antioxidants of plant origin. To search for new sources of safe and inexpensive antioxidants, present study was undertaken to quantify total phenols and flavonoids and, evaluation and correlation of antioxidant potential of aqueous extract of Phyllanthus amarus Schum & Thonn, (PAAEt) belongs to Euphorbiace family under in vitro condition. Methods: Determination of total phenolic and flavonoid contents was performed by UV-visible spectrophotometer. The antioxidant potential of P. amarus was tested with different antioxidant test systems; inhibition of lipid peroxidation (LPO), scavenging of 1,1-Diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, superoxide and nitric oxide radicals with reducing power. Results : The plant extract has appreciable amounts of total phenolic compounds (120±2.0 mg GA eq. g -1 ) and flavonoids (3.02±0.13 mg Q eq. g -1 ) of the extract. PAAEt exhibited effective and strong antioxidant activity in dose-dependent manners in inhibiting LPO (IC 50 623.4 μg/ml) and scavenging of free radicals such as DPPH (IC 50 200.2 μg/ml), hydroxyl (IC 50 280.6 μg/ml), superoxide (IC 50 201.5 μg/ml), nitric oxide (IC 50 408.5 μg/ml) with reducing power (IC 50 500.0 μg/ml). PAAEt showed effective and strong positive correlation with reducing power (r 2 = 0.972) and LPO inhibition (r 2 = 0.964) and free-radicals (P<0.05). Conclusion : Presence of high amount of phenolic and flavonoid compounds and appreciable amounts of IC 50 for various free radicals and inhibition of LPO and reducing power with significant strong positive correlation for scavenging of free radicals, LPO inhibition and reducing power indicated that PAAEt has strong antioxidant potential.