Anti-glaucoma potential of hesperidin in experimental glaucoma induced rats

Ocular topical application of alpha-glucosyl hesperidin as an active pharmaceutical excipient: in vitro and in vivo experimental evaluation

Alpha-glucosyl hesperidin (GH) is an aqueous soluble, amphipathic hesperidin derivative with several pharmacological effects, and it is postulated in this manuscript that GH could potentially be utilized as an active pharmaceutical excipient in eyedrops. The ocular safety of GH was evaluated according to in vitro cytotoxicity and in vivo ocular tolerance. The in vivo corneal permeation of coumarin-6 (Cou-6) with or without GH was characterized, and the in vivo inducing corneal wound healing using bisdemethoxycurcumin (BDMC) with or without GH was also evaluated to determine whether GH is an active pharmaceutical excipient in eyedrops. The results demonstrated that as high as 30 mg/ml of GH exhibits high-level in vitro and in vivo safety profiles according to four in vitro and in vivo evaluations. GH improved the corneal permeation of Cou-6 in mice, as well as demonstrated in vitro antioxidant activity. Concerning in vivo activity, a BDMC-GH suspension was shown to be synergistic in promoting corneal wound healing in mice, as well as restoring corneal sensitivity, promoting corneal epithelial wound healing, and restoring the corneal tissue structure without inflammatory cell infiltration. Overall, GH could be a novel and promising active excipient in eyedrops.

Treatment of Glaucoma with Natural Products and Their Mechanism of Action: An Update

Glaucoma is one of the leading causes of irreversible blindness. It is generally caused by increased intraocular pressure, which results in damage of the optic nerve and retinal ganglion cells, ultimately leading to visual field dysfunction. However, even with the use of intraocular pressure-lowering eye drops, the disease still progresses in some patients. In addition to mechanical and vascular dysfunctions of the eye, oxidative stress, neuroinflammation and excitotoxicity have also been implicated in the pathogenesis of glaucoma. Hence, the use of natural products with antioxidant and anti-inflammatory properties may represent an alternative approach for glaucoma treatment. The present review highlights recent preclinical and clinical studies on various natural products shown to possess neuroprotective properties for retinal ganglion cells, which thereby may be effective in the treatment of glaucoma. Intraocular pressure can be reduced by baicalein, forskolin, marijuana, ginsenoside, resveratrol and hesperidin. Alternatively, Ginkgo biloba, Lycium barbarum, Diospyros kaki, Tripterygium wilfordii, saffron, curcumin, caffeine, anthocyanin, coenzyme Q10 and vitamins B3 and D have shown neuroprotective effects on retinal ganglion cells via various mechanisms, especially antioxidant, anti-inflammatory and anti-apoptosis mechanisms. Extensive studies are still required in the future to ensure natural products' efficacy and safety to serve as an alternative therapy for glaucoma.

Current situation and progress of drugs for reducing intraocular pressure

Glaucoma, the most common cause of irreversible blindness worldwide, usually causes characteristic optic nerve damage. Pathological intraocular pressure (IOP) elevation is a major risk factor. Drug reduction of IOP is the preferred treatment for clinicians because it can delay the progression of disease. However, the traditional IOP-lowering drugs currently used by patients may be poorly tolerated. Therefore, in recent years, some new drugs have been put into clinical application or in clinical phase I–III studies. They have a better IOP-lowering effect and fewer adverse reactions. Because glaucoma is a chronic disease, drugs need to be administered continuously for a long time. For patients, good compliance and high drug bioavailability have a positive effect on the prognosis of the disease. Therefore, clinicians and scientists have developed drug delivery systems to solve this complex problem. In addition, natural compounds and dietary supplements have a good effect of reducing IOP, and they can also protect the optic nerve through antioxidant action. We summarize the current traditional drugs, new drugs, sustained-release drug delivery systems, and complementary drugs and outline the mechanism of action and clinical effects of these drugs on glaucoma and their recent advances.