Stability evaluation and screening of the extract from Thai herbal formulations for antimicrobial activity against pathogens causing skin diseases

Abstract

The objective of this study was to study on stability and the antifungal and antibacterial activity against pathogens causing skin diseases of the extract from Thai herbal formulations for treating skin diseases. The preparation of herbal formulas was based on the method of preparation of medicinal formulas according to Thai Traditional Medicine. The medicinal formulas consist of direct drug, auxiliary drug, supporting drug, and flavored drug. There were active compounds that act on the effect of treating skin diseases in Thai herbal formulation.When the herbal formula was obtained, the active compounds were then extracted by using Microwave-assisted extraction (MAE) method and using organic coconut oil as a green solvent, which is an environmentally friendly solvent. In addition, the coconut oil nourish the skin and treat the skin diseases as well. The extracts from the herbal formulas were then evaluated for stability on different conditions and studied for the antimicrobial activity against pathogens causing skin diseases with agar dilution method at concentrations of 0.0025 to 5 mg/ml. The results showed that the extract was stable when it was kept in a well-closed container, protected from light, and stored at 30±2°C. Furthermore, it was active against Staphylococcus aureus ATCC 6538, Propionibacterium acnes DMST 14916, Trichophyton mentagrophytes DMST 19735, and Candida albicans ATCC 10231, at minimum inhibitory concentrations (MIC) of 5, 0.5, 0.5 and 5 mg/ml, respectively. The results of this study can be used as a preliminary information for the development of this herbal formula to a Thai herbal product that was good stability for treating skin infections caused by fungi and bacteria. Moreover, it may be extended to study the effectiveness of herbal products in patients with skin disease caused by fungi and bacteria in the future.