Bioassay Guided Isolation of Hypoglycemic Compounds from Philippine Medicinal Pla

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Program Director/Principal Investigator (Last, First, Middle): Tolosa, Leah Project Description The Philippines is one of the planet's biodiversity hot spots. Of 6,000 endemic plants, it is believed that traditional doctors and herbalists use about 1,500 as medicinal plants of which only 1% has been characterized for their active components. Despite this paucity of information, in developing countries such as the Philippines where drugs imported from the developing world are beyond the purchasing power of the majority, herbal medicines remain as the main source of remedies for many ailments. Thus, the long-term objectives of this study is to definitively identify plants that are anti-diabetic based on bioassays for metabolite levels, as well as provide a novel method of quantifying efficacy of herbal medicines based on bioassay guided responses of experimental animals. The former will have an immediate impact in the availability of effective and affordable remedies for diabetes in the Philippines. The latter will provide a means of fact-based quality control of herbal medicines that at present is not always available even in the US. In order to arrive at these objectives, we propose to screen 10+ indigenous plants that have been reported to possess anti-diabetic properties. Screening will be executed at the University of the Philippines Diliman. The screening of crude extracts, fractions and isolates will be bioassay directed using a set of biosensors for glucose, glutamine and fatty acids. These biosensors are currently being developed in the Tolosa lab under project grant R01DK072465 for a device for continuous metabolite monitoring. Although the final device is not yet ready, the individual protein- based sensors can be used in an assay format to test for metabolites in blood. Thus, we propose to develop the protocols for measuring metabolite levels in Male Swiss Webster mice in response to a high glucose load. Using this bioassay protocol, we will screen and identify two plants with the most potent hypoglycemic activity from identified Philippine medicinal plants that have been folklorically reported for the treatment of diabetes. Crude extracts will be successively fractionated until the hypoglycemic constituents(s) are isolated from the two most potent Philippine medicinal plants. The chemical structures of these pure compounds will be determined by standard spectroscopic techniques. The novelty of this project is that rather than measuring a single metabolite (glucose), we will multiplex glucose, glutamine and fatty acids to see ratios and trends of these metabolites in response to a high glucose load, and then to the anti-diabetic principle(s). It should be interesting to see if patterns can be gleaned from these trends to further classify anti-diabetic compounds into groups based on their activity. PHS 398/2590 (Rev. 11/07) Page Continuation Format Page