Effect of selenium on increasing the antioxidant activity of tea leaves harvested during the early spring tea producing season

This research was to determine the effect of foliar application of selenium on increasing the antioxidant ctivity of tea harvested during the early spring tea producing season using a alpha,alpha-diphenyl-picrylhydrazyl (DPPH) radical scavenging method and the linoleic acid system. The results showed that the radical scavenging ability of the tea extracts followed this order during the first 60 min: selenium-enriched tea obtained by fertilization with selenate > BHT > selenium-enriched tea obatined by fertilization with selenite > alpha-tocopherol > regular tea. Se-enriched tea obtained by fertilization with selenate exhibited the highest inhibition percentage of 84.29% at 30 min. Se-enriched tea extracts provided higher hydrogen-donating capabilities than regular tea and contrasts with BHT and cc-tocopherol at the concentration of 100 mug of solids/mL of ethanol. There was a little change in the sequence of radical scavenging ability during the later 60 min: Se-enriched tea obtained by fertilization with selenate > Se-enriched tea obtained by fertilization with selenite > BHT > regular tea > alpha-tocopherol. The individual activity of tea extracts and references measured by the linoleic acid system showed that the tea extracts, BHT, and alpha-tocopherol manifested almost the same patterns of activity as the DPPH method. Tea enriched in selenium by fertilization with selenate still exhibited the highest inhibition activity of lipid oxidation, whereas alpha-tocopherol showed the lowest inhibition. The antioxidant activity of Se-enriched green tea harvested during the early spring tea producing season is enhanced compared to regular tea.