Poly(lactic-co-glycolic acid) nanoparticles potentiate the protective effect of curcumin against bone loss in ovariectomized rats

Osteoporosis increases fragility fractures and is a major health issue in the elderly. Curcumin, an active constituent of Curcuma longa, was reported to exert a beneficial effect on osteoporotic bone loss. However, poor aqueous solubility has limited its pharmacological efficacy. Although application of poly(lactic-co-glycolic acid) (PLGA) nanoparticles as carriers for curcumin was demonstrated to improve the bioavailability of curcumin, the effect of curcumin-loaded PLGA (C-P) nanoparticles on bone health has not been investigated. To examine the therapeutic potential of C-P, we prepared C-P nanoparticles and confirmed curcumin was successfully encapsulated within the PLGA polymer. Ovariectomy (OVX)-induced bone loss was found to be ameliorated in rats fed with curcumin or C-P. The in vitro release study showed a typical biphasic pattern with an initial burst and following sustained release. Measurement of bone mineral density and observation of trabecular microarchitecture showed that C-P was more effective than free curcumin against osteoporosis. A qRT-PCR analysis demonstrated that C-P significantly improved bone remodeling. These results suggest that encapsulation with PLGA enhances the protective effect of curcumin against OVX-induced bone loss. This approach could be a promising strategy to improve the therapeutic index of phytochemicals against osteoporosis.