Indena SpA, Milan, Italy.
Eur Rev Med Pharmacol Sci. 2017 May;21(10):2518-2525.
Dry eye, a chronic disease of lachrymal fluid and corneo-conjunctival epithelium, could significantly impact visual function, affects quality of life and work productivity. Beside several conventional treatments, nutritional supplements based on bilberry extract have been identified as effective contributors to eye health. Here, we aim at investigating the bioavailability of a standardized bilberry extract, its ability to alleviate dry eye symptoms and its antioxidant potential.
Either bilberry dried standardized extract derived from Vaccinium myrtillus L. fresh frozen fruits (Mirtoselect®) or a highly purified anthocyanin-rich extract, devoid of the non anthocyanin component and supported on maltodextrins, were each orally administrated to 5 male rats. Blood samples were collected at 5, 10, 15, 20, 30, 45, 60, 90, 120 minutes after treatment, processed and analyzed by UV spectrophotometric method. In a parallel analysis, 22 otherwise healthy subjects suffering from dry eye symptoms were enrolled randomly assigned to receive the more bioavailable bilberry extract or placebo. Ophthalmological and clinical examinations including Schirmer's test, pupil constriction, diacron-reactive oxygen metabolites (d-ROMs) test and biological antioxidant potential (BAP) test were performed at inclusion and after the 4-week study period.
The area under the curve of plasmatic levels of anthocyanosides in rats resulted 202.34±24.23 µg·min/ml for Mirtoselect® and 130.93±4.93 µg·min/ml for the highly purified anthocyanin-rich bilberry extract, notwithstanding the fact that the highly purified anthocyanin-rich extract group received an anthocyanins dosage much higher than the Mirtoselect® group (354 mg/Kg in anthocyanosides vs. 136 mg/Kg in anthocyanosides). 21 subjects, 11 subjects in the bilberry extract (Mirtoselect®) group and 10 subjects in the placebo group completed the clinical study. Schirmer's test values indicating the volume of tear secretion were significantly improved in the bilberry extract group (p=0.019), whereas no significant changes were observed in the placebo group. A subset analysis revealed that Mirtoselect® could be more effective in subjects with higher tendency of dry eye. In terms of antioxidant potential, the bilberry extract produced significant improvement of BAP (p=0.003) and an increase of modified BAP/d-ROMs ratio, an indicator of overall balance between antioxidant potential and oxidative stress.
Our results suggested that natural, standardized bilberry extract (Mirtoselect®) is a natural more bioavailable delivery form anthocyanins, suggesting a strong matrix effect exerted by the non-anthocyanin component. Furthermore, it can improve tear secretion and plasmatic antioxidant potential in subjects suffering from DED symptoms.
干眼症是一种泪液和角结膜上皮的慢性疾病，会显著影响视觉功能，降低生活质量和工作效率。除了几种常规治疗方法外，基于越橘提取物的营养补充剂已被确定为对眼睛健康有效的贡献者。在这里，我们旨在研究标准化越橘提取物的生物利用度、其缓解干眼症症状的能力及其抗氧化潜力。
分别将越橘干标准化提取物（源自 Vaccinium myrtillus L. 新鲜冷冻水果）或高度纯化的富含花青素提取物（不含非花青素成分，支持麦芽糊精）口服给予 5 只雄性大鼠。在治疗后 5、10、15、20、30、45、60、90、120 分钟采集血样，经处理后用紫外分光光度法进行分析。在平行分析中，22 名患有干眼症症状的其他健康受试者随机分为接受更具生物利用度的越橘提取物或安慰剂的两组。在纳入和 4 周研究期后进行眼科和临床检查，包括 Schirmer 测试、瞳孔收缩、二羟反应性氧代谢物 (d-ROMs) 测试和生物抗氧化潜力 (BAP) 测试。
大鼠血浆花青素苷水平的曲线下面积分别为 Mirtoselect® 组 202.34±24.23µg·min/ml 和高度纯化富含花青素的越橘提取物组 130.93±4.93µg·min/ml，尽管高度纯化富含花青素的越橘提取物组的花青素苷剂量远高于 Mirtoselect®组（354mg/kg 花青素苷与 136mg/kg 花青素苷）。21 名受试者，11 名在越橘提取物（Mirtoselect®）组和 10 名在安慰剂组完成了临床研究。泪液分泌量的 Schirmer 测试值表明，越橘提取物组的泪液分泌量显著改善（p=0.019），而安慰剂组无明显变化。亚组分析显示，Mirtoselect® 可能对干眼症倾向较高的患者更有效。就抗氧化潜力而言，越橘提取物可显著提高 BAP（p=0.003）和改良 BAP/d-ROMs 比值，这是抗氧化潜力和氧化应激之间整体平衡的指标。
我们的结果表明，天然标准化越橘提取物（Mirtoselect®）是一种天然更具生物利用度的花青素苷给药形式，提示非花青素成分发挥了强大的基质效应。此外，它可以改善 DED 症状患者的泪液分泌和血浆抗氧化潜力。
