Baking Rhubarb Increases Polyphenols

SHEFFIELD, EnglandResearchers from  Sheffield Hallam University, together with the Scottish Crop Research Institute, found that baking British garden rhubarb for 20 minutes dramatically increased its polyphenol levels. These polyphenolic components, such as anthraquinones and stilbenes, have been shown to have a range of anti-cancer bioactivities.

Using liquid chromatographymass spectrometric (LCMS) analysis, the researchers identified over 40 polyphenol components in raw rhubarb, including anthraquinone, stilbene, anthocyanin and flavonol derivatives. Compared to the raw material, fast stewing, baking and slow stewing increased total polyphenol content by facilitating release of the polyphenol compounds and causing a breakdown of the released compounds.

Baking for 20 minutes provided well-cooked rhubarb with the highest antioxidant capacity and the highest anthocyanin content. Initially, the yield of all components increased, but there was a drastic decline in the relative stability of anthraquinone aglycones with increasing cooking time and initial evidence for the turnover of other anthraquinone derivatives was obtained.

Next, the researchers will use the results to study the effect of rhubarb's polyphenols on leukaemia. They aim to discover the best combination of polyphenols and chemotherapy agents to kill leukaemia cells, even those previously resistant to treatment.

Dr Nikki Jordan-Mahy, from Sheffield Hallam University's Biomedical Research Centre, said: "Our research has shown that British rhubarb is a potential source of pharmacological agents that may be used to develop new anti-cancerous drugs."