English

Abstract

Introduction Bone homeostasis is maintained through a balance between osteoblastic bone formation and osteoclastic bone resorption. Ageing induces bone loss due to decreased osteoblastic bone formation and increased osteoclastic bone resorption. Osteoporosis with its accompanying decrease in bone mass is widely recognised as a major public health problem. Pharmacological and nutritional factors may play a role in prevention and treatment of bone loss with ageing. Flavonoid p-hydroxycinnamic acid has been found to be a bioactive compound that stimulates bone mineralisation. Among cinnamic acid, p-hydroxycinnamic acid, ferulic acid, caffeic acid or 3, 4-dimethoxycinnamic acid, p-hydroxycinnamic acid was uniquely found to have stimulatory effects on bone mineralisation and suppressive effects on bone resorption using femoral bone tissues in vitro, thereby increasing bone mass. p-Hydroxycinnamic acid stimulates osteoblastogenesis and suppresses osteoclastogenesis in bone marrow culture in vitro. Oral administration of p-hydroxycinnamic acid was found to have preventive effects on bone loss induced with ovariectomy and diabetic state. In this mini-review, the effect of p-hydroxycinnamic acid in the prevention and treatment of osteoporosis is discussed. Conclusion p-Hydroxycinnamic acid had potentstimulatory effects on osteogenesis as compared with that of other phenolic acids, indicating a relationship with chemical structure and osteogenic activity. p-Hydroxycinnamic acid may be useful as a pharmacologic tool to treat osteoporosis. Introduction Bone homeostasis is maintained through a delicate balance between osteoblastic bone formation and osteoclastic bone resorption. Numerous pathological processes have the capacity to disrupt this equilibrium leading to conditions where the rate of bone resorption outpaces the rate of bone formation leading to osteoporosis, a devastating bone disease that is widely recognised as a major public health threat1. Postmenopausal osteoporosis, a consequence of ovarian hormone deficiency, is the archetypal osteoporotic condition in women after menopause and leads to bone destruction through complex and diverse metabolic and biochemical changes1. The most dramatic expression of osteoporosis is represented by fractures of the proximal femur for which the number increases as the population ages2. Diets and nutritional factors may have potential effects in delaying degenerative bone disorders such as osteoporosis. There is growing evidence that supplementation of nutritional and functional food factors may have preventive effects on bone loss that is induced in animal models of osteoporosis and in human subjects4–6. Chemical compounds in food and plants, which regulate bone homeostasis, have been worthy of notice in maintaining bone health and in prevention and treatment of bone loss with increasing age. It appears increasingly probable that as-yetunidentified factors found in daily consumption of fruits or vegetables may play a role in building of optimal peak bone mass and in preservation of decreased bone mass with ageing. Cinnamic acid and its related-compounds are present in many plants and fruits. Among cinnamic acid, phydroxycinnamic acid (HCA), ferulic acid, caffeic acid or 3, 4-dimethoxycinnamic acid, HCA was found to have unique potent-anabolic effects on bone mineralisation, using femoral bone tissues in vitro7. HCA is an intermediate-metabolic substance in plants and fruits and is synthesised from tyrosine (Figure 1). HCA has been shown to have stimulatory effects on osteoblastic bone formation and suppressive effects on osteoclastic bone resorption in vitro. In addition, HCA has been found to have preventive and treatment effects on bone loss with pathophysiological states including ovariectomy and diabetes state. The objective of this mini-review is to outline the recent advances that have been made concerning the role of HCA in the regulation of bone homeostasis and the effect of HCA in preventing and treating osteoporosis. Discussion Bone homeostasis and osteoporosis Bone metabolism plays a physiological role in maintaining the skeletal structure and regulating mineral homeostasis. Bone homeostasis is * Corresponding author Email: yamamasa1155@yahoo.co.jp Department of Haematology and Biomedical Oncology, Emory University School of Medicine, Atlanta, GA, USA