Salicylic acid elicitation improves antioxidant activity of spinach leaves by increasing phenolic content and enzyme levels

Abstract

Elicitation is used in agriculture as a method of crop protection or a means to enhance nutraceutically or pharmaceutically important metabolites with the help of chemical stimuli known as elicitors. In the present experiment elicitor potential of Salicylic acid has been exploited to induce metabolic changes in spinach plant. Salicylic acid of various concentrations (1–0.01 mg/ml) were applied on spinach leaves through foliar spray and observed for biochemical changes. A multifold increase in the amount of total phenolic and total flavonoid as well as enzyme activity of peroxidase, catalase and superoxide dismutase was observed in a dose dependent manner. An increase in the antioxidant activity was observed and was shown to be correlated with the phenolic compounds. Growth parameters measured in the form of total biomass and total chlorophyll were decreased by high concentrations. Metabolite profile of the control and treated leaves was generated through ESI-MS in the positive and negative ion modes. The results showed an increase in the ion intensity peak of phenolic acids, such as gentisic acid, hydroxycinnamic acid, coumaric acid, ferulic acid and caffeic acid as well as major flavonoids of spinach plant, like kaempferol, quercetin, isorhamnetin and patulitin glycosides. Ferulic and caeffic acids were quantified by HPLC and showed an increase in their amount after elicitor treatment.