EFFECTS OF SECONDARY METABOLITE PRODUCTION AND ANTIOXIDANT ENZYME RESPONSE OF SELECTED MEDICINAL PLANTS LEAF CELL CULTURES

Abstract

Leaf explants of three medicinally important plants viz., Convolvulus microphyllus Seib., Peltophorum pterocarpum (DC.) Baker ex. K. Heyne and Pergularia daemia (Forsk.) Chiov. were cultured in Murashige and Skoog’s medium with different concentrations of auxins and cytokinins. Callus of each of the plant species was dried, extracted in alcohol and estimated for total levels of phenolics and flavonoids. Antioxidative enzymes such as catalase (CAT) and ascorbate peroxidase (APX), which play important role in plant defense systems, also calculated. The data reveled that with age of the callus, total levels of phenolics and flavonoids increased. Among the test extracts, 8 weeks-old callus of C. microphyllus demonstrated higher levels of total phenolics (20.36 ± 6.67 mg GAE g-1 dw), while flavonoids were higher in 8 weeks-old callus of P. daemia (23.80 ± 0.05 mg QE g-1 dw). However, ascorbate peroxidase and catalase activities decreased with the age of the callus levels of phenolics and flavonoids were found to be higher. The results indicate that, with the age of cultures generated stress leading to the production of secondary metabolites. It is known that, production of phenolics and flavonoids suppresses CAT and APX activities, critical factor for the damage of oxidative stress.