Variations in Yield, Quality, and Antioxidant Potential of Kalmegh ( Andrographis paniculata Nees) with Soil Alkalinity and Season

The edaphoclimatic conditions that affect the yield and qualities of Andrographis paniculata Nees, (Kalmegh) were studied. Under seasonal and soil pH variations, andrographolide content ranged between 2.25–3.85% in aerial parts of the plant. Total phenolic content, antioxidant activity and reducing power were 20.3 mg g−1 GAE, 66.8% and 2.8 ASE mL−1. FRSA measured by DPPH showed an IC50 of 0.34 mg mL−1, EC50 of 14.7 mg mg−1 DPPH, and anti-radical power of 6.76. AOA in different assays expressed as IC50 ranged from 0.31 to 1.29 mg mL−1. The extract showed significant protective effect against Fenton's reaction on supercoiled pUC18 DNA.