In this study, 5 lM ABA and GA3 concentration were used to study the effect of these growth regulators
on the andrographolide content and antioxidant potentials of Andrographis paniculata. The growth regulators
were applied by means of foliar spray during morning hours. A significant enhancement in nonenzymatic
antioxidant contents was observed in all sampling days in A. paniculata plants under ABA
and GA3 treatments. Ascorbic acid and a-tocopherol content was increased significantly under the
growth regulator treatments in leaves, stem and roots of A. paniculata. The activities of antioxidant
enzymes such as ascorbate peroxidase, superoxide dismutase and catalase were increased by ABA and
GA3 treatments in the leaves, stem and roots of A. paniculata plants. The HPLC analysis was used to quantify
the andrographolide content in control and growth regulator treated plants. The growth regulators
ABA and GA3 treated plants showed increased contents of andrographolide when compared to control.