Profiling the natural products from the cancer-plant Sutherlandia frutescens reveal disrupted sterol homeostasis

From the non-saponifiable fraction of the “cancer bush”- Sutherlandia frutescens was isolated 12 sterols and a pentacyclice triterpenoid mixture of a- and b-amyrin. These natural products derived from the isoprenoid biosynthesis pathway were characterized by a combination of chromatographic and spectral methods. The major sterols of physiological significance to accumulate in stems and leaves at 1% dry weight of original sample were cycloartenol and sitosterol in a ratio of approximately 1 to 1. The notably high accumulation of cycloartenol in this plant is very uncommon but nonetheless is at a level which coincides with the high level of the cancer preventing cycloartane glycosides known as sutherlandiosides. We surmise that developmental of regulation of phytosterol biosynthesis has occurred to block cycloartenol conversion to sitosterol affording redirection of cycloartenol into the glycoside derivatives.