北极海洋红球菌B7740（Rhodococcus sp.）产类胡萝卜素和类异戊二烯醌的抗氧化、抗增殖活性

本实验旨在研究来自北极海洋红球菌B7740类胡萝卜素和类异戊二烯醌提取物（B7CIQE）的体外抗氧 化活性（通过β-胡萝卜素漂白测定、脂质和蛋白质氧化抑制实验、DNA氧化断裂抑制实验）、抗增殖活性（通过 抗人肝癌细胞HepG2和人口腔癌细胞KB增殖实验）和细胞内抗氧化效果。实验中使用日常饮食常见高等植物来 源类胡萝卜素（β-胡萝卜素、叶黄素、番茄红素）作为对照组，评价B7CIQE的生物活性：β-胡萝卜素氧化抑制 率为B7CIQE（70.20%）＞2,6-二叔丁基-4-甲基苯酚（66.70%）＞表没食子儿茶素没食子酸酯（17.80%）＞番茄 红素（1.90%）；油脂开始氧化的温度顺序为B7CIQE（175 ℃）＞β-胡萝卜素（165 ℃）＞叶黄素（162 ℃）＞ 番茄红素（160 ℃）；蛋白质氧化抑制率为B7CIQE（25.75%）＞β-胡萝卜素（24.97%）＞叶黄素（17.94%）＞ 番茄红素（10.40%）；HepG2细胞抗增殖实验半最大效应浓度为叶黄素（20.86 μg/mL）＜β-胡萝卜素 （124.88 μg/mL）＜B7CIQE（126.34 μg/mL）＜番茄红素（139.24 μg/mL）；KB细胞抗增殖实验半最大效应浓度为 B7CIQE（25.14 μg/mL）＜叶黄素（64.29 μg/mL）＜番茄红素（69.87 μg/mL）＜β-胡萝卜素（149.16 μg/mL）。结 果表明，与植物源类胡萝卜素相比，B7CIQE具有相对更优异的抗氧化和抗增殖活性。

Antioxidant and Antiproliferative Activity of Carotenoids and Isoprenoid Quinones from Rhodococcus sp. B7740

In this paper, the antioxidant and antiproliferative activity of a carotenoid and isoprenoid quinone-rich extract (B7CIQE) from Rhodococcus sp. B7740 were determined. The in vitro antioxidant activity was evaluated by β-carotene bleaching, lipid peroxidation inhibition, protein oxidation inhibition and oxidative DNA cleavage inhibition assays, and the antiproliferative activity against HepG2 human liver cancer and KB human oral cancer cells and the cellular antioxidant activity were investigated as well. Three common carotenoids from higher plants, β-carotene, lutein and lycoypene, were used as controls. The inhibition rate of β-carotene oxidation by different antioxidants was in the decreasing order of B7CIQE (70.20%) > butylated hydroxytoluene (66.70%) > epigallocatechin gallate (17.80%) > lycopene (1.90%). Peanut oil with the addition of B7CIQE had the lowest initial oxidation temperature (175 ℃) followed by β-carotene (165 ℃), lutein (162 ℃) and lycopene (160 ℃). The inhibition rate of protein oxidation was in the decreasing order of B7CIQE (25.75%) > β-carotene (24.97%) > lutein (17.94%) > lycopene (10.40%). The median effective concentration (EC50) against HepG2 cells was in the decreasing order of lutein (20.86 μg/mL) < β-carotene (124.88 μg/mL) < B7CIQE (126.34 μg/mL) < lycopene (139.24 μg/mL), whereas the EC50 against KB cells decreased in the following order: B7CIQE (25.14 μg/mL) < lutein (64.29 μg/mL) < lycopene (69.87 μg/mL) < β -carotene (149.16 μg/mL). These results demonstrated that B7CIQE had superior antioxidant activity and antiproliferative effect when compared with plant-derived carotenoids.