α-Mangostin-Rich Extract: A Potential Oral Antibacterial Agent Prepared by Green Extraction

Abstract

The purpose of this study was to prepare α-mangostin-rich extract (AME) using a green microwave extraction together with a simple one-step green fractionation method on a hydrophobic resin column. Based on the established method, AME containing 95% w/w α-mangostin content was obtained with an extract yield of 0.46% w/w dry plant powder. In addition, investigation of its antibacterial activity against oral pathogenic bacteria, including Streptococcus mitis, S. mutans, S. pyogenes and Bacillus subtilis, compared with the standard marker, α-mangostin found that AME exhibited strong antibacterial activities, which were equivalent to those of α-mangostin (MICs and MBCs of 0.5-2 and 4-16 µg/mL, respectively). Moreover, AME exhibited equivalent antibacterial activity against Propionibacterium acnes when compared to the pure α-mangostin (MIC and MBC of 2 and 8 µg/mL, respectively). A chemical stability evaluation found that AME was stable through a period of 16 weeks, when kept in a well-closed container protected from light and stored either at 4 ± 2 or 30 ± 2°C. On the other hand, AME was instable when exposed to light after 3 weeks of storage. The stability evaluation under accelerated conditions (75% relative humidity, at 45°C) implied that AME has a shelf-life of at least two years.