Beneficial Effects of Nigella sativa for Osteoporosis and Bone Healing

Osteoporosis is the most common cause of bone fracture in the elderly. Several experimental studies have reported that Nigella sativa (NS) and/or its main constituent thymoquinone (TQ) have good effects on osteoporosis and bone healing. We conducted this systematic review to evaluate these relevant studies and prove whether NS and/or TQ have a potential effect on osteoporosis and can halt the pathogenesis of this disease or whether this is just a fiction. A search for published studies was conducted in databases such as Scopus, PubMed, Google Scholar, Web of Science and CINAHIL. The search terms included "Nigella sativa, black seed, TQ, osteoporosis, bone healing". Initially, 213 articles were extracted. After reviewing the titles and abstracts, 124 articles (Medline, 43; Scopus, 67; EBSCO, 14) were selected for further analysis. After excluding clinical trial studies, reviews, abstract removal and unrelated studies, seven studies were finally considered suitable for our review. Finally, seven studies were considered suitable for our review. The total number of animals used was 220 (150 rats and 70 rabbits) from different experimental studies. Based on the results of this systematic review, we conclude that NS or therapy with TQ extracts cannot yet be recommended for osteoporosis and that these data are not sufficient to reliably rule out the beneficial effects of NS on bone turnover. The
-form of the oestrogen receptor appears to be most important in regulating bone turnover. Therefore, further studies are needed to investigate the specific cellular and molecular targets of NS or TQ using osteoporosis animal models.