Drought stress enhanced andrographolides contents in Andrographis paniculata

Abstract Andrographis paniculata (AP) is an important medicinal plant in South China, but it is often exposed to drought and flooding stress. Here three drought stresses and two flooding stresses with three treated time were imposed on potted AP to explore the water stress effects. The growth physiology characteristics and major effective ingredients (andrographolide (AG), 14-deoxy-11,12-didehydroandrographolide (DDAG), and total andrographolides (AGs)) accumulations were studied. Results showed that water stress treated time was statistically effective while its interactions with treatment were not, except for a few parameters. Leaf area and stem diameter of water stressed plants were not statistically differentiated from control all the time, but the plant height, root length, dry weight, and root-shoot ratio were significantly affected by severe drought/flooding stress in prolonged treated time. Significant bioactive component changes were only occurred in the longest treated time under severe stresses, especially those of DDAG and AGs. Results also showed that the plant dry weight were relatively well correlated with andrographolides contents when expressed on ‘per plant’ basis. The underlying mechanisms behind these responses were discussed.