Chemical characterisation of Hoodia gordonii extract.

The chemical composition of a solvent extract of Hoodia gordonii termed 'H.gordonii extract' has been characterised by hyphenated chromatographic methods and traditional analytical techniques. The extract consists of a mixture of steroid glycosides, fatty acids, plant sterols and polar organic material. High performance liquid chromatography (HPLC) with ultra violet (UV) and mass spectrometric (MS) detection was used to quantify and confirm the identity of a number of steroid glycosides (73.7% w/w) present in the extract. Gas chromatography (GC) with MS and flame ionisation detection (FID) was applied to determine the fatty acid (3.12% w/w) sterol (0.39% w/w) and alcohol (0.03% w/w) content of a saponified sample of the extract. Polar organic material was quantified by gravimetric methodology using C(18) SPE separation and was determined to be a minimum of 3% w/w. Moisture content was measured by Karl Fischer coulometric titration (0.81% w/w). The protein content was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) with SYPRO Ruby staining and a negative result was determined with a limit of detection of <0.001%w/w of protein per band. The chemical composition of the extract remained stable for 19 months when stored in re-sealable plastic bags at ambient (21-24°C) temperature and <60% relative humidity.