Thesis (M.Sc. In Pharm)--Chulalongkorn University, 2007

Rauvolfia is a medicinal genus belonging to family Apocynaceae. There are five Rauvolfia species reported in Thailand: Rauvolfia serpentina, R. cambodiana, R. micrantha, R. sumatrana, and R. verticillata. Chemical constitution and biological activity in Rauvolfia species were studied and found that there are differences among them. Root of R. serpentina and R. cambodiana were reported as medicinal herbs in Thai herbal medicine. Root of R. serpentina has been used as antihypertensive, antipyretic, anthelmintic, sedative and palliative for insanity. Root of R. cambodiana has been used similar to R. serpentina, but it lacks of antihypertensive activity. Since R. cambodiana was reported as an adulterant for R. serpentina, the precise of authentication of R. serpentina is necessary for quality control of the use for antihypertensive purpose. The accurate identification and quality control of the plant material is, therefore, an essential prerequisite for ensuring the quality, safety, and efficacy. The goal of this study was fingerprinting the internal transcribed spacer (ITS) of rDNA of Rauvolfia species existing in Thailand. Phylogenetic relationship of them were analyzed. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method was applied as a molecular marker to discriminate Rauvolfia species in Thailand. Five crude drugs purchased from crude drug markets were identified in this study. Combination of ITS sequence and PCR-RFLP technique provide an effective and accurate identification of Rauvolfia species in Thailand.