Antibacterial Activity of Melastoma malabathricum L. Leaves and Efficacy in Liquid Spray Formulation against Acne-Causing Bacteria (Staphylococcus epidermidis)

Melastoma malabathricum L. (M. malabathricum L) is traditionally used by the Anak Dalam tribes in Jambi Province to treat diarrhea and is empirically recognized for antibacterial properties, particularly as an anti-acne agent. Therefore, this study aimed to evaluate the antibacterial activity of crude extracts, fractions, and the physical stability of the liquid spray formulation derived from M. malabathricum L. leaves. For the experiment, leaves were extracted using the maceration method, and the crude extract was fractionated with liquid-liquid extraction. Antibacterial activity of crude extracts and fractions of M. malabathricum L. was tested using the disc diffusion method at concentrations of 5%, 10%, and 20% against Staphylococcus epidermidis (S. epidermidis) ATCC 12228. The results showed that all samples had antibacterial activity, namely crude extract (10.4 mm, 16.2 mm, 20.4 mm), n-hexane fraction (10.2 mm, 15 mm, 17.5 mm), ethyl acetate fraction (10.5 mm, 16.4 mm, 18.3 mm), and aqueous residue (10.3 mm, 12 mm, 16.8 mm). Ethyl acetate fraction (10%) showed the highest antibacterial effect (16.4 mm ± 0.20), while liquid spray formulation of the fraction produced a 15.7 mm ± 0.88 inhibition zone. F1 comprising ethyl acetate fraction (10%) was successfully incorporated into liquid spray formulation that showed good stability and was non-irritating. In conclusion, ethyl acetate fraction of M. malabathricum L. leaves showed the most potent antibacterial activity against S. epidermidis and remained effective after being formulated into a stable liquid spray.