Heavy metal stress influence the andrographolide content, phytochemicals and antioxidant activity of Andrographis paniculata

Anna Antony,Praveen Nagella

doi:10.14719/pst.2021.8.2.1034

Abstract

Heavy metals (HM) are toxic components present in the earth’s crust that can have a negative impact on plants as well as animals. Andrographis paniculata or ‘King of bitters’ belonging to the family Acanthaceae, is a medicinal herb traditionally used in the treatment of fever, common cold etc. In the present study, the effect of heavy metals (copper, tin and cobalt) on the andrographolide content, biochemical parameters like chlorophyll, carotenoid, protein, Total phenolic content (TPC), Total flavonoid content (TFC) and antioxidant activity in A. paniculata were analysed. Saplings of A. paniculata were treated at 50 and 100 mM concentrations, three different times at a time interval of 7 days. Andrographolide production was found to increase in copper and cobalt treated saplings when compared with the control. From the results, maximum andrographolide concentration was found in the saplings treated with 50 mM copper (8.51 mg/g of DW) and 50 mM tin (8.10 mg/g of DW) respectively. 50 mM cobalt treated plants have shown the highest concentration of TPC (17.21 mg/g of extract) and TFC (6.97 mg/g of extract). Notable variations in other biochemical parameters like total chlorophyll, carotenoid content and antioxidant activities were observed in all treatments compared with the control.

Highlights

Soil contamination is a serious threat to agriculture where heavy metals (HM) are one of the major environmental pollutants that can cause toxicity within plants
Maximum andrographolide concentration was found in the saplings treated with 50 mM copper (8.51 mg/gm of DW) and 50 mM tin (8.10 mg/gm of DW) respectively. 50 mM cobalt treated plants have shown the highest concentration of Total phenolic content (TPC) (17.21 mg/g of extract) and Total flavonoid content (TFC) (6.97 mg/gm of extract)
A decline in the total chlorophyll concentration was seen in all heavy metal treated samples and the lowest concentration was observed in 100 mM Sn treatment (2.03 mg/gm of the fresh leaf)

Summary

Introduction

Soil contamination is a serious threat to agriculture where heavy metals (HM) are one of the major environmental pollutants that can cause toxicity within plants. The major contributors to soil contamination are Cadmium, Copper, Lead, Chromium, Manganese and Zinc. Essential HM like Copper, Zinc, Iron, Manganese and Molybdenum are an integral parts of many enzymes that have biochemical and physiological functions within plants and animals. Some HM are highly poisonous to metalsensitive enzymes while some are considered essential micronutrients and their uptake in higher concentration can be toxic to plants [1, 2]. Copper is an essential micronutrient and a transition metal involved in the normal growth of the plant. Copper at high concentration can inhibit plant growth, biomass, photosynthesis and respiration. It can reduce the chlorophyll content, root growth and shows symptoms like chlorosis and necrosis [3]. In a study conducted with 81 samples of seven herbs in the United Arab Emirates for the detection of HM metals, it was found that 29% of the samples contained high cadmium content and 64% had lead content exceeding the permissible limit set by FAO/WHO [7]

Methods

Results

Conclusion