Antimicrobial activity of potassium aluminium sulfate and phyllanthus emblica l. leaves extract against common skin pathogens, in vitro study

Abstract

As the use of antibiotics grows worldwide, the expansion of antibiotic-resistant bacteria becomes increasingly threatening to medical treatment. Many natural substances have been reported to have antimicrobial properties. The objectives of the study were to evaluate the antimicrobial property and the synergistic interaction between alum and Phyllanthus emblica leaves against common skin pathogens, including antibiotic-resistant Cutibacterium acnes, antibiotic-susceptible Cutibacterium acnes, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Pseudomonas aeruginosa and Candida albicans. Alum was diluted into four concentrations (2.5, 5, 10, 20%w/v). The P. emblica leaves were extracted with 95% ethanol by maceration method. The crude extracts were then collected and mixed into two concentrations (5, 25 mg/ml). The microorganisms were tested using the agar well diffusion method and the broth microdilution method to determine the minimum inhibitory zone (MIZ) and minimum inhibitory concentration (MIC) respectively. Finally, the synergistic interaction was evaluated by checkerboard assay to determine the fractional inhibitory concentration index (FIC index). The highest inhibition zone (21mm) was observed on P. aeruginosa with the alum concentration of 20%w/v. The lowest inhibition zone (6 mm) was noticed on S. aureus with 2.5% concentration of alum. P. emblica extract at a concentration of 5 mg/ml and 25 mg/ml demonstrated antimicrobial activity against S. aureus, S. epidermidis, M. luteus and C. acnes. The lowest MIC of alum solution (0.0195% w/v) was seen on S. epidermidis. The lowest MIC of P. emblica extract (0.097 mg/ml) was spotted on C. acnes. The highest FIC index (0.421) was observed on M. luteus and the lowest FIC index (0.046) was seen on S. aureus. In summary, both alum and P. emblica leaves exhibited substantial antimicrobial activity and can be combined for enhanced efficacy.

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