Effect of quercetin on bone formation.

Quercetin is a flavonol, also a phytoestrogen, available commonly in onions and apples. Our laboratory compared the amount of new bone produced by quercetin in a collagen matrix to that produced by bone grafts and a collagen matrix. Eighteen bone defects, 5 x 10 mm were created in the parietal bone of nine New Zealand White rabbits. In the experimental group, six defects were grafted with quercetin solution mixed with a collagen matrix. In the control groups, six defects were grafted with a collagen matrix alone (active control) and six were left empty (passive control). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Serial sections were cut across each defect. Quantitative analysis of new bone formation was made on 100 sections (50 sections for each group) using image analysis. A total of 556% more new bone was present in defects grafted with quercetin in a collagen matrix than those grafted with a collagen matrix alone. No bone was formed in the passive control group. In conclusion, quercetin in a collagen matrix has the effect of increasing new bone formation locally, and can be used as a bone graft material.