Purple Rice Extract and Anthocyanidins of the Constituents Protect against Light-Induced Retinal Damage in Vitro and in Vivo

Abstract

This study evaluated the protective effects of purple rice ( Oryza sativa L.) bran extract (PRE) and its major anthocyanidins (cyanidin and peonidin) against light-induced retinal damage. In an in vitro experiment, cultured murine photoreceptor cells (661W) were damaged by a 24 h exposure to light. Viability of 661W after light treatment, assessed by the tetrazolium salt (WST-8) assay and Hoechst 33342 nuclear staining, was improved by the addition of PRE, cyanidin, and peonidin. Intracellular radical activation in 661W, evaluated using the reactive oxygen species (ROS) sensitive probe 5-(and 6)-chloromethyl-2,7-dichlorodihydrofluorescein diacetate acetyl ester (CM-H(2)DCFDA), was reduced by PRE and its anthocyanidins. Electron spin resonance (ESR) measurements showed that PRE, peonidin, and cyanidin all exhibited radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide anion radical ((•)O(2)(-)), and hydroxyl radical ((•)OH). In an in vivo mouse experiment, intravitreous injection of PRE significantly suppressed photoreceptor degeneration induced by exposure to light as revealed by histological analysis using hematoxylin-eosin staining. These findings suggest that PRE and its anthocyanidins possess protective effects with antioxidation mechanism in both in vitro and in vivo models of retinal diseases.

Anti-hyperglycaemic and anti-hyperlipidaemic effects of black and red rice in streptozotocin-induced diabetic rats

“…compounds and lipophilic compounds in BRE and RRE are the major compounds having biological activities on the free radical scavenging capacities and is consistent with other findings 7,8,16 . In our study, the in vivo testing of the protective effect of BRE and RRE on diabetes rat models was performed.…”

“…In the present study, we determine the simplest diabetes prevention method of using local food sources, particularly coloured rice. Red rice and black rice are gaining popularity as carbohydrate food sources which provide additional benefits from their nutritional enrichment and potent sources of antioxidant phytochemicals such as γ-oryzanol, tocopherols, tocotrienols, anthocyanins, and proanthocyanidins [5][6][7] . In addition to being sources of antioxidants, many studies, particularly of black rice, have shown a number of beneficial properties including antiglycation capacity 5 , antiinflammation 8 , as well as an ability to attenuate blood lipid profile 9,10 .…”

Dietary anthocyanin‐rich plants: Biochemical basis and recent progress in health benefits studies

“…Nevertheless, in recent studies using cellular and animal models by Hara and colleagues, blueberry anthocyanins were found to exhibit neuroprotective effects by reducing oxidative stress in eye tissue and preventing symptoms of diabetic retinopathy [87][88][89]. In addition, they also reported that purple rice-derived anthocyanins exhibited similar effects [90,91]. For comparative analysis on in vivo absorption of blueberry anthocyanins and BA, experiments in rats have demonstrated that BA was more efficiently absorbed into blood circulation compared with blueberry anthocyanins.…”

Visualization of anthocyanin species in rabbiteye blueberry Vaccinium ashei by matrix-assisted laser desorption/ionization imaging mass spectrometry

“…Recently, much interest in anthocyanins has emerged not only because of their functions in plants but also other properties, including potential applications as anti-diabetics [2], anti-cancer drugs [3] and antinociceptives [4]. Anthocyanins may also protect against cardiovascular damage [5], amyloid β-peptide-induced degeneration [6], and light-induced retinal damage [7] because of their antioxidant and anti-inflammatory properties [8]. Despite these potential benefits of anthocyanins, little is known about their potential harmful effects, although no evidence of toxicity has yet been reported, despite widespread consumption of food products that contain anthocyanins [9].…”