Antioxidant and Antibacterial Activity of Aqueous Extracts from Four Kinds of Tea in Hainan

In order to compare the antioxidant activity and antibacterial activity of four kinds of tea extracts from Ilex kudingcha C. J. Tseng,Baisha green tea,C. sinensis var. assamica cv. Hainan-dayezhong and Mallotus oblongifolius Muell. Arg. in Hainan,water-extract of four kinds of tea was obtained by water-immersion extraction,and antioxidant activity in vitro was determinated by spectrophotometry. The antioxidant and antibacterial activities of four kinds of tea extracts were determined respectively to choose five strains of Saccharomyces cerevisiae and five kinds of pathogenic bacteria as targets. The results showed that the extraction rates of Ilex kudingcha,Baisha green tea,C.sinensis and Mallotus oblongifolius were(251.48±12.3),(315.05±10.98),(395.05±27.70),(420.05±25.65) mg GAE/g DW,respectively. The total flavonoids contents were(691.60±19.47),(292.60±18.36),(524.93±1.53),(217.60±7.00) mg RE/g DW,respectively. The total antioxidant activity of the four kinds of tea changed from strong to weak as:C. sinensis > Mallotus oblongifolius > Baisha green tea > Ilex kudingcha,especially Mallotus oblongifolius and C. sinensis on DPPH free radicals,ABTS free radicals and superoxide anion clearance were higher than that of the standard rutin and TBHQ. At the same time,the survival rate of five strains S. cerevisiae under H₂O₂ oxidative stress was increased. The survival rate of Ilex kudingcha was significantly increased to 30.21% against gsh1Δ. The four kinds of tea had a good inhibitory effect on pathogenic bacteria,of which C. sinensis best inhibitory effect on Staphylococcus aureus,its MIC value of 1.56 mg/mL. It showed that the four tea extracts had different antioxidant and bacteriostatic activities,and there was a good correlation between the polyphenol content and the activity.