In vitro antioxidant and antibacterial activities of green tea leaves (Camella sinensis l.) liquid extracts

Abstract

Introduction. Nowadays, there is high demand of phytochemical extracts with antioxidant and antibacterial properties due to increasing growth of drug-resistant pathogenies. Therefore, study antibacterial and antioxidant activities of green tea extracts is a topical and perspective topic for today. The aim of the work was determined the antioxidant and antibacterial activities of green tea leaves ethanolic and aqueous liquid extracts. Materials & methods. The object of the study was dry green tea leaves of spices Chun Myn were the object of the study, the raw material was collected in Anhui province (China) from March to May. The spectrophotometry was used for the quantitative determination of phenolic compounds, catechins, flavonoids and hydroxycinnamic acids; antioxidant activity was determined by potentiometric method. Results & discussion. Total content of phenolic compounds was 86.70±1.73 and 47.40±0.95 mg/mL, catechins – 84.00±1.68 and 52.50±1.05 mg/mL, flavonoids – 5.14±0.10 and 5.08±0.10 mg/mL and hydroxycinnamic acids – 7.75±0.16 and 4.79±0.10 mg/mL for ethanolic and aqueous extract, respectively. The antioxidant activity was 617.29 and 226.60 mmol-equiv./m_{res dry} for ethanolic and aqueous extracts, respectively. Staphylococcus aureus bacteria was the most sensitive to the ethanolic and aqueous extracts (26.33 and 26 mm) whereas Proteus vulgaris was the most resistant to the ethanolic and aqueous extracts (21.33 and 19.67 mm). Obtained results showed that ethanolic extract had higher antioxidant and antibacterial activities than aqueous extract. Conclusions. In this study, we found that green tea leaves possess the high antioxidant and antibacterial activities. The results showed that ethanol is more appropriate solvent for obtaining the extract. Thus, green tea leaves extracts can prove beneficial in food and pharmaceutical industry as today, there is high demand of antioxidant and antimicrobial drugs. Key words: green tea leaves, antioxidant activity, antibacterial activity, analysis, liquid extracts

DOI: 10.5281/zenodo.6634846