Copper-Induced Modulation of Biomass Growth, Physiological Parameters, Bioactive Centellosides, and Expression of Biosynthetic Pathway Genes in an Important Medicinal Herb, Centella asiatica

Abstract

Hydroponically established Centella asiatica plants were studied under different concentrations of copper (0, 0.32,1.6, and 3.2 µM) for their morphological, physiological, and biochemical characteristics. The plants grown in the medium without any exogenous supply of copper showed improved biomass accumulation with maximum fresh weight (FW = 24.7 g plant−1) and dry weight (DW = 2.35 g plant−1). The total chlorophyll content, leaf number, and the leaf area were higher (0.27 mg g−1 DW, 20 and 100.54 cm2) in the plants grown under copper-deficient conditions. The toxic effects of increased levels of copper were evident by significant inhibition in growth and other morphological parameters. Copper treatment showed an increase in malondialdehyde (MDA) content and SOD activity. Bioactive phytochemical profiling using HPLC analysis revealed that higher levels of copper (1.6 and 3.2 µM) inhibit the accumulation of total centelloside content. The differential accumulation of centelloside content was further validated by the consistent pattern of expression of key pathway genes related to centelloside production in copper-treated C. asiatica plants. The study unveiled some of the important facts associated with the mechanism of copper tolerance in this important medicinal herb C. asiatica. The findings of the present study can be further used to provide better production of high value, in demand centellosides.