Synthesis, isolation and characterisation of β-sitosterol and β-sitosterol oxide derivatives

β-Sitosterol is the most prevalent plant cholesterol derivative (phytosterol) and can undergo similar oxidation to cholesterol, leading to β-sitosterol oxides. The biological impact of phytosterol oxides has only been evaluated in a phytosterol blend (usually of β-sitosterol, campesterol, stigmasterol and dihydrobrassicasterol). The lack of pure phytosterols, including β-sitosterol, hinders the collection of significant toxicity data on the individual β-sitosterol oxides. An efficient synthetic route to multi-gram quantities of pure β-sitosterol is described here, together with the first syntheses and characterisation of pure β-sitosterol oxides.