The protective effects of Ginkgo biloba extract (EGb 761) against free radical damage to osteoblast-like bone cells (MC3T3-E1) and the proliferative effects of EGb 761 on these cells

Abstract

An extract of Ginkgo biloba which contains several antioxidative polyphenolics may prevent bone loss and osteoporosis-related bone fractures. The effects of this Ginkgo biloba extract (EGb 761) on the proliferation of the MC3T3-E1 cells, an osteoblast-like cell line, have been examined. Cells were cultured for 24 hr and then incubated with 1000 μg/mL or 2000 μg/mL of EGb 761 extract for another 6 hr. To test the antioxidative effects of EGb 761, cells were exposed to the free radicals H 2O 2 and FeSO 4. The MC3T3-E1 cell proliferation was measured with the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) cell proliferation assay, in which metabolically active cells reduce tetrazolium MTT. Cell morphology was visualized using BrdU (bromodeoxyuridine) labeling in order to establish necrosis as the mechanism of cell death. A significant increase by 3.72-fold in MC3T3-E1 cell proliferation was found with treatment of EGb 761 at 1000 μg/mL as compared to the control (vehicle) group and 3.86-fold with treatment of EGb 761 at 2000 μg/mL as compared to the control group. EGb 761 may act by facilitating glucose uptake and pyruvate concentrations by these bone cells which leads to increased cellular energy and, hence, proliferation. In summary, a dose-response of MC3T3-E1 cell proliferation was very positive for EGb 761. However, the antioxidative effects of EGb 761 against free radical damage showed a small but inconsistent protective effect. This study is the first to examine the antioxidative effects of Ginkgo biloba extract on osteoblast-like cells. These findings in cells in vitro may prove relevant to protecting against the loss of bone mass and the development of osteoporosis in human subjects.