Ultrastructural changes in otoconia of osteoporotic rats.

The etiology of benign paroxysmal positional vertigo (BPPV) remains obscure in many cases and women are affected more often than men. A recent prospective study, performed in women >50 years of age suffering from recurrent BPPV, showed associated osteopenia or osteoporosis in a large percentage of these patients. These results suggested the possible relationship between recurrent BPPV and a decreased fixation of calcium in bone in women >50 years.

Onion decreases the ovariectomy-induced osteopenia in young adult rats.

It has been suggested that fruit and vegetable consumption are associated with good bone health. Onion, in particular, has been verified in its efficacy in bone resorption activity. In this study, we further investigated the effects of an onion-containing diet on ovariectomy-induced bone loss using methods of serum marker assay, histomorphometric analysis and biomechanical tests.

The inhibition of bone resorption in rats treated with (-)-menthol is due to its metabolites.

(-)-Menthol, a monoterpene from Mentha species (Lamiaceae), has been shown to inhibit bone resorption in vivo by an unknown mechanism. In the present study, plasma and urine profiling in rats determined by GC/MS demonstrate that (-)-menthol is extensively metabolized, mainly by hydroxylation and carboxylation, and excreted in the urine, in part as glucuronides. In plasma, very low concentrations of (-)-menthol metabolites were detected after a single dose of (-)-menthol, whereas after repeated treatment, several times higher concentrations and long residence times were measured.

Effect of monoterpenes on the formation and activation of osteoclasts in vitro.

Unlabelled: Monoterpenes, present in aromatic plants, are known to inhibit bone resorption in vivo. In this in vitro study, they inhibited the activation of osteoclasts only at high concentrations but inhibited the formation at much lower concentrations. Therefore, monoterpenes may act in vivo directly on osteoclastogenesis.

A gamma-glutamyl peptide isolated from onion (Allium cepa L.) by bioassay-guided fractionation inhibits resorption activity of osteoclasts.

One gram of onion added to the food of rats inhibits significantly (p < 0.05) bone resorption as assessed by the urinary excretion of tritium released from bone of 9-week-old rats prelabeled with tritiated tetracycline from weeks 1 to 6. To isolate and identify the bone resorption inhibiting compound from onion, onion powder was extracted and the extract fractionated by column chromatography and medium-pressure liquid chromatography.

Determination of menthol in plasma and urine of rats and humans by headspace solid phase microextraction and gas chromatography--mass spectrometry.

A method for the determination of menthol and menthol glucuronide (M-G) after enzymatic hydrolysis in plasma and urine of rats and humans was developed using headspace solid phase microextraction and gas chromatography-mass spectrometry in the selected ion monitoring mode (HS-SPME/GC-MS). The assay linearity for plasma ranged from 5 to 1000 ng/ml. The limit of quantification (LOQ) in plasma was 5 ng/ml.

Various selected vegetables, fruits, mushrooms and red wine residue inhibit bone resorption in rats.

To make a broad survey of the effect of components of the human diet on bone resorption, a few items from the following categories were added to rat diets: vegetables, fruits, beans, nuts and seeds, mushrooms, carbohydrate sources and beverages. The effect on bone resorption was measured by the urinary excretion of tritium released from bones of 9-wk-old rats prelabeled with tritiated tetracycline from weeks 1 to 6. The number of rats per experiment was 26--6, 5, 5, 5 and 5 in the untreated control group fed the plain semipurified diet, the positive control group fed onions and three groups fed one of the newly investigated items, respectively.

Onion and a mixture of vegetables, salads, and herbs affect bone resorption in the rat by a mechanism independent of their base excess.

Prevention of low bone mass is important to reduce the incidence of osteoporotic fractures. In man, the consumption of fruits and vegetables is associated with greater bone mineral density (BMD), an effect that is claimed to be caused by their base excess buffering metabolic acid, thought to dissolve bone. We showed previously that in the rat the consumption of several vegetables, salads, and herbs inhibits bone resorption and that onion increases bone mass.