One of problem from anti acne cream formula containing Epigallocatechin gallate (EGCG) from green tea leaves is EGCG stability. The EGCG is unstable to heat and easily oxidated. However, EGCG is the main marker substance related to antibacterial activity. This study aimed to determine the EGCG stability and its antibacterial activity. The EGCG stability testing was obtained during extraction process by adding phosphoric acid buffer, pH 4 buffer solution and control. The stability of these groups then tested at 2, 25 and 40°C temperature. Evaluation for absorbance changing by UV-VIS spectrophotometry was obtained during 15 days. After that, EGCG concentration from the three groups were compared using HPLC. Antibacterial activity testing for acne causing bacteria Staphylococcus epidermidis ATCC 35984 was conducted from phosphoric acid and pH 4 buffer solution groups. The result showed that extreme cold temperature decreasing treatment against green tea leaves extract after infundation, pH 4 buffer solution adding and storage at temperature of 2°C produced the highest EGCG concentration namely 60.98% w/w. Besides that, antibacterial activity from the ethyl acetate fraction of green tea leaves extract by using this method produced a good inhibition against P. acnes and S. epidermidis. Moreover, the antibacterial activity against P. acnes was higher than S. epidermis. The adding of pH 4 buffer solution in extraction process produced the highest EGCG concentration than phosphoric acid adding and no buffer adding. The EGCG was stable at the storage temperature of 2°C and 6% ethyl acetate fraction of green tea leaves extract can be used as an anti acne dosage.

Key words: Camellia sinensis, EGCG stability, antibacterial, S. epidermidis ATCC 35984, Propionibacterium acnes ATCC 6919