Naringin Suppresses Osteoclast Formation and Enhances Bone Mass in Mice

Abstract

Naringin is a flavonoid commonly found in citrus fruits. Previous studies have supported a positive association between fruit consumption and health including bone quality. To clarify the role of naringin in bone turnover, we examined the effect of naringin on bone mass in mice, and on osteoclast formation induced by bone-resorbing cytokine. When mice were orally administered naringin for 2 weeks, femoral bone mineral density (BMD) was clearly elevated compared with control mice. BMD in distal and middle portion was significantly enhanced, but proximal BMD was not changed by naringin administration. In soft-X-ray analysis, a marked accumulation of cancellous bone could be detected in distal femoral metasphysis in mice treated with naringin. In cocultures of bone marrow cells and osteoblasts, naringin dose-dependently suppressed the number of osteoclasts formed by treatment with interleukin-1 (IL-1). The size of osteoclasts formed in the presence of naringin was smaller than that induced by IL-1. Naringin enhances bone mass possibly by suppression of osteoclast formation in mice, suggesting the role of the citrus flavonoid on bone health and to prevent bone diseases such as osteoporosis.