National Center of Excellence in Molecular Biology (CEMB)
Abstract
Background: Lead is most commonly released environmental contaminant making its way to air, soils and water. It causes hormonal imbalance and over production of reactive oxygen in plants when absorbed through leaves and roots. It contaminates the ground water depending on the type of soils and characteristics of lead. Plants ability to tolerate lead is linked with cell wall potential, activation of antioxidants defense mechanism and synthesis of osmolytes.Methods: The study was designed to evaluate the effects of Pb(NO3)2 induced stress on biological activity and bioactive compounds in maize. The plants were subjected under two different lead concentrations (T1- 0.35mg/ml and T2- 0.45mg/ml). Phytochemical screening revealed the presence of alkaloids, coumarins, saponins, tannins and terpenoids in maize. Total Phenolic Content (TPC) was increased (T1- 45%, T2- 58.42%) under lead stress when compared with control (36.29%). The cytotoxicity was checked using hemolytic activity against human red blood cells.Results: The scavenging rate was highest (T1- 33.5%, T2- 52%) when compared with control (18.6%). Zone of inhibition of Aspergillus niger was highest amongst other fungal strains. The HPLC results showed that maize has some phyto-ingredients which may be accountable for cell reinforcement and anti-microbial activity. The extracts were further analyzed for the biochemical profile like superoxide dismutase, peroxidase, catalase, amylase and protease. Escherichia colishowed maximum activity with control (25±3.46mm) and maximum under stress (T1- 17±1.633 mm, T2- 20±4.08 mm).Conclusion: Lead stress altered all the activities when compared to control plants. In conclusion, Maize can be used as a potential indicator for lead and other compounds to play a vital role in phytoremediation. The results would further lead to find the new compounds and plant mechanism to cope with stress.
