Exploration the mechanism underlying protocatechuic acid in treating osteoporosis by HIF-1 pathway based on network pharmacology, molecular docking, molecular dynamics simulation and experimental verification

• To study the mechanism of protocatechuic acid on osteoporosis in antioxidant stress environment. • Combined with network pharmacology, virtual and experimental verification, the core target of protocatechuic acid was determined. • According to GO and KEGG pathways, protocatechuic acid may play a role through HIF-1 signaling pathway. • The mechanism of protocatechuic acid in treating osteoporosis was expounded from two aspects: MC3T3-E1 cells cultured in vitro and zebrafish model in vivo. Protocatechuic acid (PCA), a naturally occurring polyphenol abundant in fruits, vegetables, and various plants, exhibits diverse biological activities. However, the mechanism of action of PCA in osteoporosis (OP) is unclear. This study aims to elucidate the anti-OP mechanisms of PCA through an integrated approach involving network pharmacology, virtual screening, and experimental validation. In this study, we found that PCA improved zebrafish skeletal development and promoted MC3T3-E1 cell proliferation, increasing ALP activity. In addition, PCA decreased the level of ROS and MDA, increased the level of SOD, GSH and NO, and mitigated the degree of oxidative stress. Concurrently, network pharmacological analysis indicated that PCA upregulated core target levels, activated the HIF-1 signaling pathway, ameliorated oxidative stress, and exerted an anti-OP effect by promoting bone formation. In conclusion, PCA may provide a new strategy in the prevention and treatment of OP.