The Effect of Solvent Type and Extract Concentration of Binahong Leaves (Anredera cordifolia (Ten.) Steenis) on the In Vitro Antibacterial Activity against Cutibacterium acnes

Abstract

Acne is an inflammatory disorder of the pilosebaceous unit in which Cutibacterium acnes may contribute to disease-associated inflammation. Increasing antimicrobial resistance has encouraged the exploration of medicinal plants as potential sources of antibacterial agents, including binahong leaves (Anredera cordifolia (Ten.) Steenis). This study compared the in vitro antibacterial activity of 96% ethanol and ethyl acetate extracts of binahong leaves against C. acnes. A laboratory experimental study was conducted using 96% ethanol and ethyl acetate extracts at concentrations of 2%, 4%, and 6% w/v, with three replicates for each treatment. Antibacterial activity was assessed using a disk diffusion assay, with 1% Na-CMC and clindamycin 30 ppm as negative and positive controls, respectively. Inhibition zones were measured after incubation at 37 °C for 24 h. Data from the six extract groups were analyzed using two-way ANOVA followed by Tukey’s post hoc test. Both solvent type (p = 0.0002) and extract concentration (p < 0.001) significantly affected inhibition-zone diameter, whereas their interaction was not significant (p = 0.0878). Ethyl acetate extract produced larger inhibition zones than 96% ethanol extract at 4% and 6% concentrations (p = 0.017 for each comparison), whereas no significant difference was observed at 2% (p = 0.909). The largest inhibition zone among the extracts was observed with 6% ethyl acetate extract (18.33 ± 1.53 mm), although this remained lower than that of clindamycin (31.67 ± 0.58 mm). These findings indicate that ethyl acetate extract of binahong leaves has greater in vitro inhibitory activity against C. acnes than the 96% ethanol extract at higher concentrations tested. However, the findings should be considered preliminary and require confirmation using standardized anaerobic conditions, MIC/MBC determination, and chemical standardization of the extract.