Phytochemical analysis of Palauan traditional medicinal plant Phaleria nisidai to determine therapeutic dosing of Mangiferin, A C-glucosyl xanthone

Obesity and ensuing diabetes mellitus type II are among the most prevalent NCDs in Palau and the Pacific as a whole. Local cultures have been utilizing plants for centuries performing clinical trials on themselves for centuries to find cures for common ailments. Prior phytochemical analysis of Phaleria nisidai (Kanehira) has revealed the presence of benzophenones, xanthones, acylglucosylsterols. Of these chemicals benzophenones and xanthones, specifically mangiferin, a C-glucosyl xanthone, has shown activity for metabolic disorder. To compare traditional preparations of Palauan medicinal to laboratory extraction techniques, we have quantified and compared a marker compound, mangiferin, in traditional, aqueous and whole methanol extracts of Phaleria nisidai, a plant used traditionally as an energy tonic and more currently as a treatment for diabetes.

Xanthones previously isolated and indentified from Phaleria nisidai Kanehira were used as standards to perform quantitative analysis. Mangiferin standards were verified by NMR and HPLC-MS. Modifications of previously reported HPLC-PDA-ESIMS methods were used to quantify mangiferin. Mangiferin is isolated in higher percentage in traditional and whole aqueous extract than whole methanolic extracts. Understanding exact therapeutic dosing of mangiferin consumed by traditional usage will allow for future validation studies of Phaleria nisidai.