Protective Effects Of Phenolic Acid Derivatives Of Coffee And Indian Gooseberry Extracts On Retinal Degeneration

Jang, Holim

Protective Effects Of Phenolic Acid Derivatives Of Coffee And Indian Gooseberry Extracts On Retinal Degeneration

Abstract

The human retina is a thin layer of tissue on the inner back wall of the eye, containing millions of photoreceptor cells that receive and combine visual information. The retina sends visual information to the superior colliculus of the brain through the optic nerve. Because the retina ranks as one of the highest energy-consuming systems in the body, it requires a constant and abundant oxygen supply from the blood. Therefore, the retina is relatively susceptible to damage induced by oxidative stressors. Excessive oxidative stress is a key contributing factor in the pathophysiology of retinal disorders such as age-related macular degeneration, glaucoma, and retinopathy, which can lead to visual loss or complete blindness. Clinical studies have shown that the progression of retinal diseases can be slowed down by dietary treatment with antioxidant compounds such as vitamins, carotenoids, zinc, and phenolic phytochemicals. Coffee is one of the most frequently consumed beverages worldwide and its popularity continues to increase. Although coffee is rich in phenolic compounds and is the main contributor of dietary antioxidant intake in the diet, its protective effect against retinal degeneration has never been studied. In these studies, we employed several approaches to examine the protective effect of phenolic compounds in coffee on the retina. Specifically, the studies presented here investigated (i) the effects of coffee extracts and chlorogenic acid, a major phenolic compound in coffee, on retinal degeneration and (ii) the effects of phenolic acid metabolites formed after coffee consumption on retinal degeneration. The results showed that chlorogenic acid and coffee extracts could significantly reduce the apoptosis induced by hypoxia or optic nerve crush stress in the retina. In addition, coffee metabolites, especially chlorogenic acid, caffeic acid, and dihydrocaffeic acid, could reach the eye and protect the retina against hypoxia and optic nerve crush in vivo. Moreover, we show that extracts of Indian gooseberry, which is widely consumed in Asia as an ingredient in traditional medicine, juice, and cosmetics, has a retinal protective effect against amyloid beta-induced neuronal degeneration. Collectively, these findings suggest that coffee and Indian gooseberry consumption may help to prevent retinal degeneration.

Date Issued

2015-05-24

Keywords

Coffee; indian gooseberry; retinal degeneration

Committee Chair

Lee,Chang Yong

Committee Member

Novakovic,Andrew Milovan
Padilla-Zakour,Olga I.

Degree Discipline

Food Science and Technology

Degree Name

Ph. D., Food Science and Technology

Degree Level

Doctor of Philosophy

Types

dissertation or thesis