Date of Degree


Document Type


Degree Name





Michael J. Balick

Subject Categories

Agricultural Science | Agriculture | Plant Sciences


Ethnopharmacology, Palau, Phaleria nisidai, Phytomedicine


There has been a serious deterioration of Palauan culture, language and traditional practices over the last century. To promote health and avoid this deterioration of tradition, ecological, ethnobotanical and phytochemical studies have been carried out on the plant Phaleria nisidai Kaneh. (Thymelaeaceae), "Delal a Kar", Palauan for "Mother of Medicine". This study is the first study that sets the foundations for the development of natural Palauan therapeutics, through validation of ethnomedically significant plants. Validations of these plants is done through documenting Palauan plant ethnomedical data; mapping the distribution of Palauan plants on limestone Rock Islands; and analyzing ethnopharmacological and phytochemical properties of a Palauan panacea, Phaleria nisidai.

Ethnographical data was collected through interviews with Palauan traditional leaders and elders concerning the general uses of Palauan plant flora. From this pool of interviews, the two most frequently described medicinal plants were Premna obtusfolia L. (Verbenaceae) and Phaleria nisidai (Thymelaeaceae). Then ecological studies on plant diversity and distribution were done on the limestone islands in the southern lagoon of Palau, which have the most intact anthropogenic sites in Palau. The Rock Islands of Palau had a relatively homogenous plant distribution with high percent of indigenous plant species. Ethnomedically significant plant species, Phaleria nisidai and Premna serratifolia, were only found on islands with human activity. Furthermore, Phaleria nisidai was only found in close proximity to former habitation/anthropogenic sites. Phaleria nisidai was important and useful to past inhabitants and may have even been brought by original immigrants to Palau.

Obesity and ensuing diabetes mellitus type II are among the most prevalent NCDs in Palau and throughout the Pacific. In order to validate an ethnomedically significant plant species, Phaleria nisidai, and its major phytochemical component, mangiferin, a blood glucose lowering compound, were analyzed. Mangiferin from different populations of Phaleria nisidai used in Palau was quantified from different extraction methods. Aqueous extraction proved to be the most effective method for extracting the highest percentage of the mangiferin, from Phaleria nisidai leaves. These studies on Phaleria nisidai, have set the foundation for future clinical testing for treatment of diabetes mellitus type II.