Protective effects of bitter acids from Humulus lupulus L. against senile osteoporosis via activating Nrf2/HO-1/NQO1 pathway in D-galactose induced aging mice

Abstract

Bitter acids (BA) from Humulus lupulus L. (hops) are known for beer brewing and have been proved to have activities on reliving oxidative stress and osteoporosis. This study firstly determined the effects of BA on senile osteoporosis (SOP) in D-galactose induced aging mice. BA significantly increased femoral bone mineral density, serum levels of alkaline phosphatase, osteocalcin as well as decreased serum tartrate-resistant acid phosphatase contents in D-galactose induced mice. BA also promoted proliferation, differentiation, mineralization and inhibited cell senescence, apoptosis in D-galactose treated osteoblasts. Furthermore, BA attenuated D-galactose induced oxidative stress through the activation of nuclear translocation of Nrf2 and the increase of intracellular HO-1, NQO1 expressions. In conclusion, BA might attenuate osteoporosis in aged mice through activating Nrf2/HO-1/NQO1 signaling pathway. As important components in beer, BA have potential in the development of drugs for SOP treatment.

Keywords

• Bitter acids
• Hops
• Senescence
• Osteoporosis
• D-galactose
• Nrf2