Water extracts of Polygonum Multiflorum Thunb. and its active component emodin relieves osteoarthritis by regulating cholesterol metabolism and suppressing chondrocyte inflammation

Objective: Polygonum multiflorum Thunb. (PMT) is a widely used traditional Chinese herbal medicine with a variety of pharmacological effects. This study investigates the chemical composition of a water extract of PMT and its potential as a therapy for osteoarthritis (OA). Methods: The components of the aqueous extract of PMT were determined using high-performance liquid chromatography (HPLC). Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses of a gene expression dataset downloaded from the Gene Expression Omnibus (GEO) were performed using Limma in R language. Differential chondrocyte metabolites were determined using gas chromatography-mass spectrometry (GC-MS) before and after treatment. Results: The water extract of PMT showed good ability in improving OA, and the content of the active ingredient emodin increased significantly after processing. Analysis of the GEO database further demonstrated a strong association between OA and metabolic pathways. Emodin promotes chondrocyte proliferation and significantly reduces the number of inflammatory factors. The metabolomic results showed that emodin affected five metabolic pathways related mainly to primary bile acid biosynthesis, steroid biosynthesis, and biosynthesis of unsaturated fatty acids. Conclusions: This study revealed the pharmacological effects of PMT and emodin as the main active components, thereby providing a scientific basis for the treatment of OA. Graphical abstract: http://links.lww.com/AHM/A51