phytochemical analysis and in vitro antioxidant acitivity of hydroalcoholic seed extract of Nymphaea nouchali Burm.f.

Objective:To evaluate the phytochemical constituents and the antioxidant activity of hydroalcoholic extract of Nymphaea nouchali seed locally prescribed as a diet for diabetes mellitus.Methods:The antioxidant and free radical scavenging activity of hydroalcoholic extract of the plant was assessed against 1,1 diphenyl-2-picryl hydrazyl（DPPH）,nitric oxide and lipid peroxidation using standard protocols.Total phenolics,flavonoids and tannins were also determined.Results:Phytochemical analysis revealed the presence of phenols,flavones,tannins,protein,reducing sugars,glycosides,saponins,alkaloids and steroids.The activities of plant extract against DPPH,nitric oxide and lipid peroxidation was concentration dependent with IG;value of42.82,23.58 and 54.65μg/mL respectively.The total antioxidant capacity was high with 577.73 mg vitamin E/g of the extract and showed a moderately high vitamin C content of 197.22 mg/g.The total tannin content of hydroalcoholic seed extract was high（195.84 GE/g）,followed by phenolics（179.56 GE/g）and flavonoids（23.55 QE/g）.Conclusion:Our findings provide evidence that the crude extract of Nymphaea nouchali is a potential source of natural antioxidants and this justifies its use in folkloric medicine.