Gingko Biloba shown to protect optic nerve cells from injury

Oral consumption of Ginkgo biloba led to a higher survival rate of optic nerve cells (retinal ganglion cells). The effect was dosage-dependent - the higher concentrations of Ginkgo resulted in higher optic nerve cell survival rates. The dosages of Ginkgo were comparable to those an average person could safely consume.

Dosage dependence of the effect of Ginkgo biloba on the rat retinal ganglion cell survival after optic nerve crush - Abstract 

Purpose To investigate the dosage dependence of the Ginkgo biloba effect on retinal ganglion cell survival in the rat optic  nerve crush model.

Methods The study included 56 Sprague- Dawley rats, the right optic nerve of which was crushed in a standardized manner. Two  hours after the crush and once daily during the follow-up, the animals received intragastral applications of saline (saline group; n 1/4 13), of a G. biloba extract of 0.25% concentration (n 1/4 14; low-dosage group), 1% concentration (n 1/4 15; medium-dosage group), or 4%  concentration (n 1/4 14; high-dosage group). At 23 days after the optic nerve crush, the retinal  ganglion cells were retrogradely labelled by injecting 3% fluorogold into the superior colliculi of the brain. At 4 weeks after baseline, the animals were killed. Retinal flat mount photographs were assessed for number and density of the retinal ganglion cells.

Results The mean survival rate defined as the ratio of retinal ganglion cell density in the right eye with optic nerve crash divided by the  retinal ganglion cell density in left eye without optic nerve intervention increased  significantly (Po0.001) from 58.4±9.0% in the  saline group to 68.5±5.7% in the low-dosage group, to 73.7±6.4% in the medium-dosage group, and to 74.2±6.8% in the high-dosage group.

Conclusions Intragastral applications of a G. biloba extract applied after an experimental  and standardized optic nerve crush in rats were associated with a higher survival rate of retinal ganglion cells in a dosage-dependent  manner. end end end end end end.

G. biloba was also
effective against ischaemia-reperfusion disorders
because of the occlusion of the central retinal artery or by
intraocular hypertony. Like other antioxidants, G. biloba
significantly attenuated, according to a dose-response
effect, the free radical injury.

   In conclusion, intragastral applications of G. biloba
given from then and 2 h after an experimental and
standardized optic nerve crush daily in rats were
associated with a dosage-dependent higher survival rate
of retinal ganglion cells. It may suggest a positive effect
of G. biloba on the survival of the retinal ganglion cells. It
remains unclear whether and how far these results from
an animal experimental study can be transferred into the
clinical situation. 

Eye. 2009 Jul;23(7):1598-604. Epub 2008 Sep 26.

Ma K, Xu L, Zhan H, Zhang S, Pu M, Jonas JB.
Department of Ophthalmology, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital University of Medical Science, Beijing, China.

PMID: 18820658 [PubMed - in process]