Season, Solvent Type and Concentration Modulate in Vitro Antioxidant and Nitric Oxide Radical Scavenging Capabilities of Fignut (Jatropha Gossypfolia) Extract
Olabinri BM, Oladele AP; Olaleye MT

Abstract
The influence of season , solvent type and concentration on the phenolic and flavonoid contents including in vitro antioxidant and nitric oxide radical scavenging activities of stem bark and leaf extracts of fignut (Jatropha gossypfolia) were investigated. Season , extraction solvent type and concentration were critical determinants of the total phenolic and flavonoid contents including in vitro antioxidant and nitric oxide radical scavenging activities of the plant parts. The stem bark extract expressed potent in vitro nitric oxide radical scavenging capabilities in dry season than wet season , which was significant (P< 0.05) , with water, 70% acetone , and absolute(100%) acetone as extraction solvents. The order of the in vitro nitric oxide radical scavenging activities of the stem bark extracts in dry season was: aqueous(76.59%) > 70% acetone( 62.96%)> absolute acetone(59.20%).Water was the most promising solvent for in vitro nitric oxide radical scavenging capability for the stem bark in dry season . The aqueous stem bark could be exploited for the treatment of inflammatory disorder because of its potent in vitro nitric oxide scavenging activity. The total phenolic contents in aqueous extracts were 24.400.11(leaf, dry season), 14.200.45(stem bark , dry season), 5.760.09 (Leaf, wet season ) and 1.70  0.05 mg/ml(stem bark , wet season).In addition,70% acetone was the best candidate extraction solvent for total phenolics extraction of the leaf in dry season(39.600.53mg/ml).Also, 70% acetone was the most promising extraction solvent for in vitro antioxidant activity assay and displayed the most remarkable in vitro antioxidant potential in leaf extract of the plant in wet season(123.901.52% activity)The in vitro antioxidant activity of the leaf extracts in 70% acetone and absolute acetone were slightly higher in wet season than dry season , but the difference was not significant(P>0.05).The leaf extracts was a dull scavenger of nitric oxide in vitro during the dry , but expressed potent antioxidant activity in the same season. In conclusion, there was a clear evidence that the in vitro antioxidant and nitric oxide radical scavenging activities of the stem bark extracts of J.gossypifolia were significantly higher in all the three solvents in dry season (P

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