The effects of Ginkgo biloba extract on lipopolysaccharide-induced inflammation in vitro and in vivo.
OBJECTIVE
Ginkgo biloba extract (GBE) contains many different flavone glycosides and terpenoides. Several previous studies have demonstrated that GBE exhibits a wide variety of biological activities, including an antioxidant action, on which we focused our attention. The aim of the present study was to investigate the efficacy of GBE on endotoxin induced uveitis in rats. The anti-inflammatory potency of GBE in vivo was compared with that of prednisolone. In addition, we also investigated nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-alpha (TNF-alpha) and the expression of iNOS in a mouse macrophage cell line (RAW 264.7) treated with GBE in vitro to clarify the anti-inflammatory effect.


METHODS
EIU was induced in male Lewis rats by a footpad injection of lipopolysaccharide (LPS). Immediately after the LPS inoculation, either 1, 10 or 100 microg of GBE were injected intravenously. 24hr later, the aqueous humor was collected from both eyes, and the number of infiltrating cells, protein concentration and NO level in the aqueous humor was determined. The RAW 264.7 cells were pretreated with various concentrations of GBE for 24hr and subsequently incubated with LPS for 24hr. Levels of NO, PGE2 and TNF-alpha were determined by enzyme-linked immunosorbent assay. The expression of iNOS protein was analyzed by Western blotting method.


RESULTS
GBE treatment in vivo decreased the concentrations of protein and NO in the aqueous humor of EIU rats. The anti-inflammatory effect of 1 mg GBE was as strong as that of same dose prednisolone. It also significantly reduced the concentration of PGE2, TNF-alpha and NO production in the medium of RAW 264.7 cells compared to that of the LPS group in vitro. The expression of iNOS protein in the 1000 microg ml(-1) of GBE treated cells decreased significantly.


CONCLUSIONS
The present results indicate GBE suppresses the inflammation of EIU by blocking the iNOS protein expression and its anti-inflammatory effect on eye is comparable with the effect of prednisolone used in similar doses.
Department of Ophthalmology and Visual Sciences, Hokkaido University Graduate School of Medicine, North 15, West 7, Kita-ku, Sapporo 060-8638, Japan.
Iliyana
I
Ilieva
Kazuhiro
K
Ohgami
Kenji
K
Shiratori
Yoshikazu
Y
Koyama
Kazuhiko
K
Yoshida
Satoru
S
Kase
Hirokuni
H
Kitamei
Yuko
Y
Takemoto
Kazunaga
K
Yazawa
Shigeaki
S
Ohno
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001082:Aqueous Humor / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D020441:Ginkgo biloba; D008070:Lipopolysaccharides; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D008517:Phytotherapy / Q000379:methods*; D010936:Plant Extracts / Q000627:therapeutic use; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014605:Uveitis / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology
D000894:Anti-Inflammatory Agents, Non-Steroidal; D018932:Chemokine CCL2; D005136:Eye Proteins; D008070:Lipopolysaccharides; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D015232:Dinoprostone