1. Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
2. Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Sukumvit 23, Bangkok 10110, Thailand
3. Natural Product Research Center of Excellence, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand