Antimicrobial activities of some local plants of Thailand against acne-producing bacteria

Abstract

Natural antimicrobial agents have been recently in focus due to the emerging of drug-resistant bacteria. In this study, Thai local plants (Curcuma longa Linn., Zingiber montanum (Koenig) Link ex Dietr., Andrographis paniculata (Burm.f.) Wall. ex Nees., Orthosiphon aristatus (Blume) Miq., and Boesenbergia rotunda (L.) Mansf.) were examined for antimicrobial activities against acne-producing bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, and Propionibacterium acnes) using broth dilution technique. This study also explored the effects of using different solvents for extraction (distilled water (DW), ethanol (EtOH), dicholoromethane (DCM), and hexane (HEX)) and 1 month-storage of plant samples at 4°C. The results showed that ethanol was the most suitable extraction solvent for almost all the investigated plants to obtain the effective antimicrobial agents with more than 80% inhibitory activities against all four bacteria, especially Streptococcus pyogenes and Staphylococcus aureus. Moreover, DCM extract of Boesenbergia rotunda (L.) Mansf., HEX extracts of Curcuma longa Linn. and Orthosiphon aristatus (Blume) Miq. were also found to have strong antibacterial activities. Nonetheless, when the plant samples were stored at 4°C for 1 month, their antibacterial activities were shown to be moderately decreased. The ethanolic extracts were found to have lower than 60% inhibition and only against Staphylococcus epidermidis and Streptococcus pyogenes. Therefore, this study showed that Thai local plants possessed effective anti-acne properties, which however might be lost during the storage. The findings in this study can be useful for the future development of Thai local plants to be used in the products for acne treatment.