In vivo efficacy of turmeric (Curcuma longa L.) in the treatment of peripheral neuropathy: A systematic review of animal models

We report on a systematic review of the efficacy of turmeric derivatives for the in vivo treatment of peripheral neuropathies. Our review protocol followed the PRISMA Statement. The Medline (PubMed), Web of Science, Scopus, and Scielo databases were used. The search strategy was ("neuropathy" OR "neuropathies" OR "nerve injury" OR "nerve injuries") AND ("curcumin" OR "turmeric yellow" OR "yellow, turmeric" OR "diferuloylmethane"). Eligibility criteria were in vivo animal models, published in English, Portuguese, Spanish, or French, evaluating the efficacy of turmeric derivatives in the treatment of peripheral neuropathies. We have included 30 papers, and all consisted of pre-clinical trials with good methodological quality. Animals treated with turmeric derivatives (i.e., curcumin, curcumin by-products and curcumin loaded delivery systems) demonstrated remarkable amelioration in the injuries caused by diabetic and sciatic neuropathy, as well as for vincristine, cisplatin, and alcohol-induced neuropathy, especially with regards to the functional recovery of the affected nerve. Turmeric has great potential for the treatment of peripheral neuropathies, including those associated with diabetes mellitus. Clinical trials still need to be performed to assess the feasibility of human treatment as an alternative or adjuvant to existing pharmacological therapy.