Pregnane derivatives from Hoodia gordonii

Hoodia gordonii (Fam. Asclepiadaceae) is a succulent plant indigenous to South Africa, Botswana and Namibia. Hoodia has gained wide popularity as one of the most sought after dietary supplements for its appetite suppressant activity. P57AS3, the reported active constituent from H. gordonii, is claimed to induce increased ATP synthesis in the hypothalamic neurons, thereby reducing appetite by giving out false satiety signals to the appetite center. In our previous phytochemical studies, we had reported the isolation of several oxypregnane glycosides and calogenin bisdesmosides, including P57AS3. Here, we report the isolation and characterization of nine pregnane glycosides, including two novel abeo-sterol aldehyde glycosides, 20-O-β-D-glucopyranosyl-B-nor-pregnan-3β,5β,14β-trihydroxy-6β-aldehyde (1), and, 20-O-β-D-glucopyranosyl-B-nor-pregnan-3β,14β-dihydroxy-5-en-6β-aldehyde (2). This is a first report of abeo-steroid derivatives from Hoodia spp. The chemical structures of the glycosides were established by chemical degradation studies and extensive spectroscopic techniques that included one-dimensional and two-dimensional NMR. Acknowledgements: Part of the research was funded by “Botanical Dietary Supplements: Science-Base for Authentication” of US food and Drug Administration Grant No 2 U01 FD 002071–07. The authors would like to thank the Missouri Botanical Garden, USA for authentic plant material and Dr. Vaishali Joshi for plant identification. Authors also thank Dr. Bharathi Avula for her kind help in acquiring the mass data. Y.J.S. is thankful to NCNPR for graduate research assistantship.