Ginseng for an eye: effects of ginseng on ocular diseases

Abstract

The sense of vision is the primary means by which we gather information from our surroundings, and vision loss, therefore, severely compromises the life of the affected individuals, their families, and society. Loss of vision becomes more frequent with age, and diabetic retinopathy, age-related macular degeneration, cataracts, and glaucoma are the major causes of vision impairment. To find active pharmacological compounds that might prevent or ameliorate the vision-threatening eye diseases, numerous studies have been performed, and some botanical compounds, including those extracted from ginseng, have been shown to possess beneficial effects in the treatment or prevention of common ocular diseases. In this review, we summarize the recent reports investigating the therapeutic effects of ginseng and ginsenosides on diverse ocular diseases and discuss their therapeutic potential.

Keywords: Age-related macular degeneration; Cataract; Diabetic retinopathy; Ginseng; Glaucoma.

Fig. 1

Structure of ginsenosides. (A) Protopanaxadiol- and protopanaxatriol-type saponins, (B) ginsenoside Rg5, (C) ginsenoside Rk1, and (D) compound K. Glc, β-D-glucose; Ara(p), arabinose (pyranose); Ara(f), arabinose (furanose); Rha, α-L-rhamnose; NR1, notoginsenoside R1; Xyl, β-D-xylose.

Fig. 2

Basic anatomy of the eye. Cross section of the eye showing major structures (“Three internal chambers of the eye” by Holly Fischer is licensed under CC BY 3.0).

Fig. 3

Bruch's membrane (BM). BM is placed between the retinal pigment epithelium (RPE) and choroidal capillaries and consists of an RPE basement membrane, inner collagenous zone, central elastic fiber bands, outer collagenous zone, and choroid basement membrane (“Illustration of Bruch's membrane” by Evan Mason is licensed under CC BY-SA 4.0).

Fig. 4

Therapeutic effect of ginseng on VEGF signaling pathway in diabetic retinopathy ginsenoside Rg3 inhibits the expression of VEGF by suppressing TNF-α production. Ginsenoside Rb1, cFXT, and P. quinquefolius ethanol extracts repress the expression of VEGF. Dammarenediol-II inhibits the VEGF-induced ROS production. Ginsenoside Rk1 increases the stability of tight junction proteins and reduces retinal endothelial permeability. cFXT, constituents of Fufang Xueshuantong; ROS, reactive oxygen species; TNF-α, tumor necrosis factor-alpha; VEGF, vascular endothelial growth factor.