Isoflavone-enriched soybean leaves attenuate ovariectomy-induced osteoporosis in rats by anti-inflammatory activity

Abstract

BACKGROUND With an increasing aging population, postmenopausal osteoporosis has become a global public health problem. Previous evidence has shown that postmenopausal osteoporosis is a skeletal disease mainly caused by estrogen deficiency, generally accompanied by inflammation, and dietary isoflavones may ameliorate postmenopausal osteoporosis by anti-inflammatory activity. We have generated isoflavone-enriched soybean leaves (IESLs), but their anti-inflammatory activity and effect on attenuating osteoporosis are still obscure. Here, we determined the isoflavone profiles of IESLs and evaluated their anti-inflammatory activity in lipopolysaccharide-stimulated RAW 264.7 cells and anti-osteoporotic effects on ovariectomy-induced osteoporosis in rats. RESULTS IESLs had a high content of total isoflavone. Hydrolysate of IESLs (HIESLs) was rich with the aglycones daidzein and genistein, and HIESLs can significantly inhibit lipopolysaccharide-induced inflammation by reducing messenger RNA expression ofiNOS,COX-2,IL6, andIL1 beta. Moreover, ovariectomized rats receiving aqueous extracts of IESLs (HIESLs) orally maintained more bone mass than control rats did, which was attributed to inhibition of osteoclastogenesis by downregulating the messenger RNA expression of the bone-specific genesRANKL/OPG,OC, andcathepsin K, and the inflammation-related genesIL6,NF kappa B, andCOX-2. CONCLUSION IESLs may attenuate postmenopausal osteoporosis by suppressing osteoclastogenesis with anti-inflammatory activity and be a potential source of functional food ingredients for the prevention of osteoporosis. (c) 2020 Society of Chemical Industry