As the global population ages, the number of people affected by bone and joint diseases is increasing. Nearly half of people over the age of 60 suffer from knee osteoarthritis; More than 80% of people over the age of 75 have knee osteoarthritis. The disability rate of knee osteoarthritis is as high as 53%, which seriously affects the quality of life of patients and also brings heavy economic burden to society. Traditional medicinal plants and nutraceuticals are often applicable in the therapeutic management of bone and joint diseases, and the secondary metabolites are the main effective agents responsible for their pharmacological activities. These metabolites can be flavonoids, alkaloids, coumarins, saponins, etc. Hopefully, the metabolites provide a great resource to develop new potential drugs. For example, salicylic acid, an inhibitor of COX-2, is the first natural compound used in the treatment of osteoarthritis. Also, the estrogen-like activity of some prenylated flavonoids has triggered interest in exploring their potential for the therapeutic management of osteoarthritis and osteoporosis. However, it is essential to explore how the metabolites interact with bone and join in disease states.

The pathological mechanisms of bone and join diseases are orchestrated by dysregulated signaling pathways, which disrupt the homeostasis by the induction of catabolic factors as well as down regulation of anabolic factors. A large number of studies reveal that many signaling pathways, such as the NF-κB pathway, MAPK pathway, TLR pathway, as well as Wnt/β-catenin, TGFβ, and Notch pathways, have been involved in regulating the development of bone and join diseases, and the key factors in these signaling pathways might be potential targets for new drugs. Thus, understanding the molecular mechanisms offers an avenue for scientists to explore the potential interaction between plant secondary metabolites and the bone and join diseases.

In this Research Topic, we welcome Original Research, Reviews, Mini Reviews, Opinion, and Perspective. The subtopics are as follows, but not limited to:

-Evaluation of the pharmacological activity of natural products against bone and joint diseases in vivo and in vitro.

-Extraction and analysis of medicinal ingredients of various plant-based products with pharmacological activity against bone and joint diseases.

-Clinical research of secondary metabolites or traditional medicines with pharmacological activity against bone and joint diseases.

-The toxicological effects of secondary metabolites on bone and joint diseases.

-Evidence-based studies of natural products and herbal medicines are also preferred.