Dietary isoflavones act on bone marrow osteoprogenitor cells and stimulate ovary development before influencing bone mass in pre-pubertal piglets.

Food containing soybeans provide isoflavone phytoestrogens that can preserve bone mass in postmenopausal women, and prevent bone loss in ovariectomized rats. But their effects on bone remain unclear, particularly on bone formation during growth. Two groups of eight pre-pubertal piglets were fed a basal or an isoflavone-enriched (S800) diet for 6 weeks.

Modulation of osteoclastogenesis in porcine bone marrow cultures by quercetin and rutin.

Flavonols, in contrast to soybean isoflavones, are the most abundant phytoestrogens in western diets, being present in onions, beans, fruits, red wine, and tea. They may protect against atherosclerosis, inhibit certain cancer cell types, and reduce bone resorption. The most widely distributed flavonol is quercetin, which occurs mainly as its glycoside, rutin, but data are very scarce regarding the precise mechanism of action of these compounds on bone-resorbing cells at concentrations similar to those detected in human plasma.

Direct visualization of intracellular calcium in rat osteoblasts by energy-filtering transmission electron microscopy.

Osteoblasts are the highly specialized bone cells responsible for matrix mineralization. Mineralization is a complex, incompletely understood, process involving intracellular calcium homeostasis. Rapid changes in ionized calcium concentration ([Ca(2+)](i)) occur in these cells, but the intracellular distribution of total calcium, which may be involved in matrix mineralization, remains unknown.

Guidelines for using in vitro methods to study the effects of phyto-oestrogens on bone.

These guidelines review the relevant literature on the way plant phyto-oestrogens act on bone and the responsiveness of different bone cell systems to phyto-oestrogenic compounds. The primary emphasis is on the experimental conditions used, the markers available for assessing osteoblast and osteoclast function, and their expected sensitivity. Finally, we assess the published results to derive some general recommendations for in vitro experiments in this area of research.

Down-regulation of osteoclast differentiation by daidzein via caspase 3.

Phytoestrogens are plant-derived compounds with estrogen-like activity. Phytoestrogen-rich diets may prevent postmenopausal osteoporosis and these molecules maintain bone mass in ovariectomized animals. We compared the effects of the isoflavone daidzein, which has no action on tyrosine kinases, and 17beta-estradiol on the development and activity of osteoclasts in vitro.