Cerasus humilis proanthocyanidins alleviate osteoporosis by regulating renal calcium metabolism

BACKGROUND: Postmenopausal osteoporosis is associated with disturbed calcium homeostasis and renal calcium handling. Although Cerasus humilis proanthocyanidins (PA) show anti-osteoporotic activity, their effects on renal calcium metabolism remain unclear. We hypothesized that C. humilis PA could alleviate ovariectomy (OVX)-induced bone loss by improving renal calcium reabsorption. RESULTS: Compared with untreated OVX rats, 12 weeks of PA treatment increased bone mineral density from 125.5 to 232.8 mg cm⁻³ and improved trabecular microarchitecture (P < 0.05). PA reduced β-C-terminal telopeptide and tartrate-resistant acid phosphatase-5b levels, increased bone-specific alkaline phosphatase levels, decreased 24 h urinary calcium excretion, and increased apparent calcium absorption from 50.4% to 87.8% (all P < 0.05). Renal histopathological alterations were attenuated, with increased renal bone morphogenetic protein-7 and urinary Klotho levels and decreased serum fibroblast growth factor 23 levels. Renal protein expression of transient receptor potential vanilloid 5 (TRPV5) and Calbindin-D28k increased by 53.0% and 45.6%, respectively (P < 0.05), with corresponding mRNA upregulation. CONCLUSION: C. humilis PA alleviated OVX-induced bone loss and calcium metabolic disturbances. The effects were associated with reduced urinary calcium loss and increased renal TRPV5 and Calbindin-D28k expression. Renal calcium handling may therefore contribute to the anti-osteoporotic effect of C. humilis PA in OVX rats, and the potential as a dietary ingredient for bone health warrants further investigation. © 2026 Society of Chemical Industry.