Benefits and mechanisms of polysaccharides from Chinese medicinal herbs for anti-osteoporosis therapy: A review

Osteoporosis is a systemic metabolic bone disease with an increasing incidence rate. Chinese medicinal herbs have a long history of treating bone diseases. Polysaccharides are an important category of phytochemicals in Chinese medicinal herbs, and their health benefits have increased the interest of the public. Numerous studies have indicated that polysaccharides exhibit anti-osteoporosis effects by balancing bone resorption and bone formation, but the detailed effects and mechanism have not been systematically summarized. We performed a comprehensive review of the literature to consolidate studies for the period 2000-2021 by conducting electronic searches on the PubMed, CNKI, VIP, and Wanfang databases. In total, polysaccharides from 19 kinds of Chinese medicinal herbs in 54 studies have shown bone homeostasis protective properties. In vivo and in vitro experiments have demonstrated that polysaccharides present properties in the treatment of postmenopausal osteoporosis, senile osteoporosis, and glucocorticoid-induced secondary osteoporosis, especially postmenopausal osteoporosis. Moreover, a number of signalling pathways, such as the Wnt/β-catenin signalling pathway, BMP/SMAD/RUNX2 signalling pathway, OPG/RANKL/RANK signalling pathway, apoptosis pathway, and transcription factors, are regulated by polysaccharides and participate in improving bone homeostasis. This review will provide a better understanding of the anti-osteoporotic effects of polysaccharides and the concomitant modulations of signalling pathways.