Synergistic cytoprotective effect of Crocin (CRN) and Resveratrol (RSV) on Primary Human Retinal Pigmentepithelium (RPE) cells

CRN and RSV have shown potent cytoprotective effects against damage caused by intense light, a known risk factor for age-related macular degeneration (AMD). This study for the first time showed a synergistic effect on primary human RPE cells against light-induced oxidative damage when cells were pre-treated with a combination of CRN and RSV. Primary human RPE cell cultures were pre-treated for 48 hours with either CRN (100µM), RSV (1µM), or a combination of these two compounds. The pre-treated cell culture medium was then replaced with PBS and cells were illuminated (300 mW/cm2) for 60min. Cells were re-incubated in serum-free cell culture medium for 24 hours, and cell viability was measured by methylthiotetrazole (MTT) assay. Each compound protected cells against phototoxic death (cell viability: CRN, 72%; RSV, 69%; control, 31%). The combination of CRN with RSV showed synergistic cytoprotective effect (78% cell viability), compared to individual treatments. Results also showed that each compound and their combination had no cell toxicity when tested at wide range of concentrations (CRN: 10µM to 500µM, RSV: 0.1µM to 25µM, CRN: 40–150µM+RSV: 0.5–2.5µM). This data in consideration with prior clinical observations supports a nutritional role for combination of CRN and RSV in protecting RPE cells from photooxidative damage. Experimental data on cell protection and safety will be presented.