Phytochemical Constituents of Caralluma fimbriata

Caralluma (Fam. Asclepiadaceae) is a genus containing 50 variable species of succulent plants. It is a widespread dwarf stem succulent that occurs throughout western Africa, southwest Asia, and the Indian subcontinent. Caralluma fimbriata, also known as C. adscendens, is mostly found in the southern parts of India, where it has been a part of the regular diet of the locals. Recently, C. fimbriata has found use in western system of traditional medicines, as an appetite suppressant. It is claimed to act on the hypothalamus by modulating the ATP contents in neurons, and this activity is claimed to be due to the presence of steroidal components. Although several other species of Caralluma have shown the presence of wide a range of steroid derivatives, there has not been any phytochemical study on C. fimbriata. Considering the recent launch of C. fimbriata products in the US dietary supplements' market, it is important to study phytochemical constitution of C. fimbriata. Here, we report isolation and structure elucidation of ten pregnane derivates from the methanolic extracts of the aerial parts of C. fimbriata. The isolation of these compounds was carried out by repeated fractionation and reversed phase column chromatography. Acid hydrolysis and X-ray crystallography were used along with 1D/2D NMR as well as LCMS techniques to establish the structures and absolute configurations. These compounds will serve as essential chemical markers to establish the authenticity of the raw plant materials and commercial products. Acknowledgements: Part of the research was funded by “Botanical Dietary Supplements: Science-Base for Authentication” of US FDA Grant FD-U-002071. Thanks to Vaishali Joshi for plant collection and Bharathi Avula for her help in acquiring mass data. Y.J.S. is thankful to NCNPR for graduate research assistantship, and to COBRE-NPN Neuroscience fellowship program for financial support.