Antiarthritic Effects of a Root Extract from Harpagophytum procumbens DC: Novel Insights into the Molecular Mechanisms and Possible Bioactive Phytochemicals.

Harpagophytum procumbens (Burch.) DC. ex Meisn. is a traditional remedy for osteoarticular diseases, including osteoarthritis (OA), although the bioactive constituents and mechanisms involved are yet to be clarified. In the present study, an aqueous H. procumbens root extract (HPE; containing 1.2% harpagoside) was characterized for its effects on synoviocytes from OA patients and phytochemical composition in polyphenols, and volatile compounds were detected. HPE powder was dissolved in different solvents, including deionized water (HPEH2O), DMSO (HPEDMSO), 100% v/v ethanol (HPEEtOH100), and 50% v/v ethanol (HPEEtOH50). The highest polyphenol levels were found in HPEDMSO and HPEEtOH50, whereas different volatile compounds, mainly ß-caryophyllene and eugenol, were detected in all the extracts except for HPEH2O. HPEH2O and HPEDMSO were able to enhance CB2 receptor expression and to downregulate PI-PLC ß2 in synovial membranes; moreover, all the extracts inhibited FAAH activity. The present results highlight for the first time a multitarget modulation of the endocannabinoid system by HPE, likely ascribable to its hydrosoluble compounds, along with the presence of volatile compounds in H. procumbens root. Although hydrosoluble compounds seem to be mainly responsible for endocannabinoid modulation by HPE, a possible contribution of volatile compounds can be suggested, strengthening the hypothesis that the entire phytocomplex can contribute to the H. procumbens healing properties.

L-carnitine enhances extracellular matrix synthesis in human primary chondrocytes.

Osteoarthritis (OA) is one of the most common degenerative joint disease for which there is no cure. It is treated mainly with non-steroidal anti-inflammatory drugs to control the symptoms and some supplements, such as glucosamine and chondroitin sulphate in order to obtain structure-modifying effects. Aim of this study is to investigate the effects of L-carnitine, a molecule with a role in cellular energy metabolism, on extracellular matrix synthesis in human primary chondrocytes (HPCs). Dose-dependent effect of L-carnitine on cartilage matrix production, cell proliferation and ATP synthesis was examined by incubating HPCs with various amounts of molecule in monolayer (2D) and in hydromatrix scaffold (3D). L-Carnitine affected extracellular matrix synthesis in 3D in a dose-dependent manner; moreover, L-carnitine was very effective to stimulate cell proliferation and to induce ATP synthesis, mainly in 3D culture condition. In conclusion, L-carnitine enhances cartilage matrix glycosaminoglycan component production and cell proliferation, suggesting that this molecule could be useful in the treatment of pathologies where extracellular matrix is degraded, such as OA. To our knowledge, this is the first study where the effects of L-carnitine are evaluated in HPCs.