Interactive effects of toxic metals on the total phenolic and flavonoid in Hydrocotyle umbellata L.

Abstract

Phenolic and flavonoid content in plants are important abiotic stress biomarkers. The individual and combined impacts of toxiferous metals Arsenic (As), Cadmium (Cd) and (Copper) Cu were employed in recent studies to investigate their effect on Total flavonoids content (TFC) and total phenolic content (TPC) in various parts of Hydrocotyle umbellata L., to explore the role of plant in abating metal contamination. Folin-Ciocalteu and AlCl₃ methods were used to study TPC and TFC, respectively. Two-way analysis of variance (ANOVA) and a classification and regression tree (CART) model was employed for statistical analysis. Highest TPC was observed in decreasing order as leaf > stem > root for all the metals stress. Whereas, highest TFC was found in all plant parts when subjected to As toxicity, and the lowest TFC was found in stem of the plant under Cu toxicity. There was significant effect on TPC when subjected to Cu and As stress; in addition, significant effects of Cd and combined metal stress were also evident. Treatment concentration had non-significant effect on TPC under single metal but had significant effect in case of combined metal stress. Similarly, in case of TFC no significant effect was recorded under all the stress types. Metal type had significant effect on TPC and TFC. Whereas plant part had significant impact on TPC but non-significant values were observed on TFC. This study epitomized TPC and TFC in H. umbellata L. as effective and viable tool to pertain its role in phytoremediation against contamination of Cd, Cu and As.