Vesicular Arbuscular Mycorrhiza Association Augments Antioxidant Activity of Vitex negundo Leaves

The study was conducted to evaluate the effect of Vesicular Arbuscular Mycorrhiza treatment on antioxidant activity of leaves of Vitex negundo. Mycorrhiza spores were added to the plants at different time intervals the plants were catergoried as T1, T2, T3 and T4 according to treatments. T1 plants are control while T2, T3 and T4 plants received treatment of spores for one time, twice at intervals of 30 days and every day for 15 days till harvesting. After harvesting and processing of the leaves, methanolic extracts were prepared by maceration and designated as MEVNT1, MEVNT2, MEVNT3 and MEVNT4. The extracts were studied for quantitative analysis of antioxidant phytoconstituents (total phenolic, flavonoid and ascorbic acid contents) and in vitro antioxidant property in 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, hydrogen peroxide scavenging assay, reducing power assay, anti-lipid peroxidation assay. Methanol extract of V. negundo leaves and ascorbic acid showed significant scavenging of (p < 0.05) DPPH free radicals, reducing potential, hydroxyl radical scavenging and anti-lipid peroxidation effect. Among these parameters, IC50 value of MEVNT4 was lowest among all extracts in almost all parameters studied besides its high content of antioxidant phytochemicals. The results indicated that Mycorrhiza treatment caused marked elevation on antioxidant status of the plant. It further states that single treatment or treatment of long intermittent duration may have lesser potential to affect the antioxidant profile that the continuous treatment period. This suggested that the treatment have tendency to augment the concentration or effect of antioxidant present in the leaves.