Stress Induced Alteration in the Antioxidant Activity of In Vitro Adventitious Roots of Withania Somnifera (Genotype Jawahar 20)

The present study was aimed to characterize the enzymatic and non-enzymatic antioxidants in in vitro grown adventitious roots of Withania somnifera (genotype Jawahar 20) under PEG induced drought. Due to the illimitable therapeutic values of roots and the fact that “enhanced activity of antioxidants is directly correlated with oxidative injury promoted by drought”, five major antioxidants (phenol, flavonoids, SOD, CAT and ascorbate) were evaluated. The roots of Withania somnifera were not able to enhance enzymatic antioxidants like SOD and CAT infact 19.28 to 28.54% and 63.89 to 89.48% reduction in SOD and CAT activity were measured with increasing stress duration. In contrast roots were efficient to enhance the phenols and flavonoids under drought with maximum i.e. 52.11% and 231.18% enhancement in phenol and flavonoid content respectively after 45 days of stress treatment. A sudden decrease in ascorbate content from 89.51 to 11.11 mg/g fresh weight and 123.46 to 12.35 mg/g fresh weight was also recorded with increasing concentration of stress after 30 and 45 days respectively, however not such reduction were observed after 60 days. The findings of study indicated that roots of Withania somnifera are rich source of phenolic compounds and their enhancement under drought make them capable to survive in stressful environment..