Antibacterial tests against acne in vitro, the physical stability and patch test using cream containing ethyl p-methoxycinnamate extracted from Kaempferia galanga L., Rhizoma

Background and Objective: An activity of certain bacterias is one of the causes of acne. Rimpang kencur (Kaempferia galanga L.) has an antibacterial agent from compound ethyl p-methoxycinnamate (EPMC). The purpose of this study is to find out the antibacterial activity using EPMC against P. acne, S. aureus and S. epidermidis with the physical stability of the cream and its safety use as an antiacne cream. Materials and Methods: The antibacterial activity and minimum inhibitory concentration of EPMC are 0.3, 0.6, 1.2 and 2.4% was done using disc diffusion method and broth dilution test. Data obtained from in vitro test of bacterial activity was analyzed using descriptive analysis and Complete Randomized Design (CRD) with 99% (p<0.01) level of confidence. Results: The result shows that all EPMC concentration has significant antibanterial activity (p<0,01) respectively gaining clear zone against P. acne (9.00, 11.50, 14.50 and 16.00 mm), S. aureus (9.00, 11.50, 16.50 and 22.00 mm) and S. epidermidis (10.50, 12.50, 20.50 and 27.00 mm). Conclusion: The EPMC compound with the 0.6, 1.2 and 2.4% concentration is proven to have MIC against P acne bacterias, while on the S. aureus and S. epidermidis reaches up to 1.2 and 2.4% concentration. From the results of safety use (pacth test) on 12 subjects there were no evidence of allergic irritation, therefore cream EPMC 1.2% is safe to be used in topical preparation.