ABSTRACT
Osteoarthritis affects about 10–15% of the world population as the main cause of chronic pain. Its drug treatment involves the use of analgesics, steroidal and nonsteroidal anti-inflammatory drugs, opioids and disease-modifying drugs. These medicines have limitations due to side effects, inefficiency or cost that make natural products (NPs) a promising alternative. Substances obtained from natural products have great anti-inflammatory potential in various processes, including the reduction of pro-inflammatory cytokines (particularly IL-6, which is closely related to the inflammatory process that occurs in arthritis), differentiation, cell proliferation and pain generation. Therefore, the objective of this systematic review was to summarize the preclinical research of the treatment of osteoarthritis with natural products (or substances obtained from them) in arthritis models, which include the evaluation of IL-6 levels. The search was performed using in the databases Pubmed, Scopus, Web of Science and Embase, and resulted in the identification of 42 included studies. The main models used were induction of arthritis by CFA or collagen, and some surgical induction models of osteoarthritis. Among the evaluated outcomes are the levels of pain, functionality, oedema and histological analysis. The levels of IL-6 were measured systematically or locally, mainly by ELISA, with the treatment using NPs showing significant results. Thus, the review demonstrates that NPs are a possible future alternative in the treatment of arthritis, but it is still necessary to standardize these studies.
