Tannins inhibition of tea leaves (Camellia sinensis) against Escherichia coli diarrhea-causing bacteria

Abstract

Abstract. Cahyani RK, Susilowati A, Sari SLA. 2019. Tannins inhibition of tea leaves (Camellia sinensis) against Escherichia coli diarrhea-causing bacteria. Bioteknologi 16: 48-52. Diarrhea is often suffered by people and has become the biggest cause of death in developing countries. Diarrhea can be caused by Escherichia coli infection. Treatment with antibiotics can lead to resistance, so herbs like tea leaves can be used as an alternative to overcome diarrhea. This research aims to determine the effect of tannins in ethanol extract of tea leaves from Kemuning Estate against diarrhea-causing bacteria. Tea leaves powder was macerated using ethanol 70% to obtain a paste extract for an antibacterial test. The antibacterial test was conducted using contact bioautography methods, which combine thin-layer chromatography with the response of the bacteria test by antibacterial activity. The test results showed that the antibacterial activity of tannins in ethanol extract of tea leaves with a concentration of 30% and 50% could inhibit the growth of E. coli. The strongest concentration to inhibit the E. coli bacteria is 50% which contains 13.8% of tannins and has a 14 mm inhibition zone diameter. In comparison, a concentration of 30%, which contains 8.28% of tannins and an inhibition zone diameter of 10 mm, is included in moderate categorized inhibition. Tannins analysis by Thin Layer Chromatography (TLC) using FeCl₃ reagent formed blue ink or black colors, which means tannins in tea leaves are classified as the hydrolyzed tannins. Analysis of quality tannins with the Folin-Ciocalteu method showed that the tannins content in ethanol extract of tea leaves from Kemuning Estate was 27.6%.