Coptidis Rhizoma Water Extract Attenuates RANKL-Induced Osteoclast Differentiation via MAPK, Akt, and NF-κB Pathways and Prevents Ovariectomy (OVX)-Mediated Bone Loss.

Excessive osteoclast activity in bone remodeling can lead to an imbalance between bone resorption and formation, a common occurrence in abnormal bone metabolic diseases. This research investigates the effect of Coptidis rhizoma water extract (CRW) on osteoclastogenesis provoked by RANKL in vitro and bone destruction mediated by ovariectomy (OVX) in vivo. CRW, prepared from dried Coptidis rhizoma (CR), was analyzed for its active compounds-coptisine and berberine-using HPLC analysis. CRW markedly decreased the size and number of TRAP-positive multinucleated cells (TRAP+ MNCs), suppressed F-actin ring formation, and diminished bone resorption in RANKL-treated cultures. In the early phase of differentiation, CRW suppressed the phosphorylation of MAPKs p38, JNK, and ERK, as well as NF-κB p65, Iκ-Bα, and Akt. CRW also down-regulated RANKL-mediated induction of c-Fos and NFATc1 and attenuated the activation of NFATc1- dependent genes, such as OSCAR, ATP6V0D2, ACP5 (TRAP), OC-STAMP, DC-STAMP, CTSK (cathepsin K), CALCR (calcitonin receptor), and MMP-9. In ovariectomized rats, micro-CT and histological analyses showed that CRW alleviated femoral bone destruction. These findings indicate that CRW restrains osteoclast differentiation and function and may have therapeutic potential for disorders driven by excessive osteoclast activity.