IN VITRO ANTIOXIDANT, TOTAL PHENOLIC CONTENT AND BRINE SHRIMP LETHALITY STUDIES OF SYNEDRELLA NODIFLORA

The antioxidant activity of methanol extract of whole plant of Synedrella nodiflora  as well as its petroleum ether, carbon tetrachloride, dichloro-methane and aqueous soluble partitionates were evaluated by DPPH of (1, 1-diphenyl-2-picrylhydrazyl) and phosphomolybdenum total antioxidant assay and compared with standard antioxidants butylated hydroxytoluene (BHT) and ascorbic acid (ASA).  The total phenolic content was also determined and expressed in gallic acid equivalent (mg of GAE/g of sample). A great variance was observed for polyphenol content as well as antioxidant activity (1.574-9.4136 mg GAE/g and DPPH IC₅₀ 10.52-31.25 μg/ml) depending on the nature of solvent used to fractionate the crude extract. The result demonstrated that dichloromethane soluble fraction revealed the highest amount of phenolic compounds (9.4136 mg GAE/g) and also had significant free radical scavenging activity (IC₅₀ 10.52 μg/ml).   A positive correlation was observed between total phenolic content and total antioxidant activity of S. nodiflora having correlation coefficient (R²) of 0.9270. The general toxicity of the extractive was studied by brine shrimp lethality bioassay and from the results (LC₅₀ 0.023-0.122 μg/ml), it can be well predicted that the crude extract and the partitionate fractions contain cytotoxic principles and have considerable toxic potencies which supported the insecticidal uses of plant by the indigenous people.