Screening of effective components for inhibition of tyrosinase activity in rhubarb based on spectrum-efficiency-structure-activity relationship Histochemical localization of anthraquinones in rhizome of Rheum officinale Bail Mechanism study of Rheum officinale on chronic renal failure based on metabolomics Quality control for extracts from aerial parts of Rheum officinale based on multi-assay depending on one determination Mechanism study of Rheum officinale on chronic renal failure based on metabolomics