Analysis of antioxidant capacity, total phenolic and total flavonoid contents in boric acid applied Camellia sinensis L.

Abstract

Consumption of Camellia sinensis L. (tea), a popular beverage, is very common today. In addition to its consumption as a beverage, it is suggested that adding tea to other foods can increase their antioxidant activities. It is known that boric acid used as an insecticide, herbicide, and fungicide, has antioxidant and anti-inflammatory effects. This study aimed to determine the antioxidant capacity (AC), total phenolic content (TPC), and total flavonoid content (TFC) of extracts prepared in different solvents of tea grown in soil treated with boric acid. The area in Rize/Türkiye was divided into 4 groups. No application was made to the control group (B0 group). Boric acid prepared in sodium tetraborate buffer was applied to the other three areas as a single dose at concentrations of 100 (group B1), 300 (group B3), and 500 (group B5) mg m-2. The obtained tea leaves were ground and infused in water, 20% ethanol, and 50% ethanol by the classical infusion method. The extracts obtained after infusion were analyzed for TPC, TFC, and AC. It was determined that ethanol (20% and 50%) was better solvent than water in terms of TPC, TFC, and AC. Although the TPC of extracts prepared in water of tea leaves grown in soils where different doses of boric acid were applied did not change, differences were observed in their flavonoid contents and antioxidant capacities. These results indicated that boric acid should be at a certain dose to improve the quality of the tea plant. In addition, different solvents can be used to reveal more of the tea content.