Elisia Ingrid, Kitts David D
Food, Nutrition and Health, Faculty of Land and Food Systems, University of British Columbia, 2205 East Mall, Vancouver, BC, Canada V6T-1Z4.
Mol Cell Biochem. 2008 May;312(1-2):139-45. doi: 10.1007/s11010-008-9729-1. Epub 2008 Mar 10.
The antioxidant activity of anthocyanins has been well characterized in vitro; many cases has been postulated to provide an important exogenous mediator of oxidative stress in the gastrointestinal tract. The objective of this study was to evaluate the efficacy of anthocyanin protection against peroxyl radical (AAPH)-induced oxidative damage and associated cytotoxicity in Caco-2 colon cancer cells. Crude blackberry extracts were purified by gel filtration column to yield purified anthocyanin extracts that were composed of 371 mg/g total anthocyanin, 90.1% cyanidin-3-glucoside, and 4.9 mmol Trolox equivalent/g (ORAC) value. There were no other detectable phenolic compounds in the purified anthocyanin extract. The anthocyanin extract suppressed AAPH-initiated Caco-2 intracellular oxidation in a concentration-dependent manner, with an IC50 value of 6.5+/-0.3 microg/ml. Anthocyanins were not toxic to Caco-2 cells, but provided significant (P<0.05) protection against AAPH-induced cytotoxicity, when assessed using the CellTiter-Glo assay. AAPH-induced cytoxicity in Caco-2 cells was attributed to a significant (P<0.05) reduction in the G1 phase and increased proportion of cells in the sub G1 phase, indicating apoptosis. Prior exposure of Caco-2 cells to anthocyanins suppressed (P<0.05) the AAPH-induced apoptosis by decreasing the proportion of cells in the sub-G1 phase, normalized the proportion of cells in other cell cycle phases. Our results show that the antioxidant activity of anthocyanins principally attributed to cyanidin-3-O-glucoside and common to blackberry, are effective at inhibiting peroxyl radical induced apoptosis in cultured Caco-2 cells.
花青素的抗氧化活性在体外已得到充分表征；在许多情况下，它被认为是胃肠道氧化应激的一种重要外源性介质。本研究的目的是评估花青素对过氧自由基（AAPH）诱导的Caco-2结肠癌细胞氧化损伤及相关细胞毒性的保护效果。通过凝胶过滤柱对黑莓粗提物进行纯化，得到纯化的花青素提取物，其总花青素含量为371 mg/g，矢车菊素-3-葡萄糖苷含量为90.1%，Trolox当量为4.9 mmol/g（ORAC值）。纯化的花青素提取物中未检测到其他酚类化合物。花青素提取物以浓度依赖的方式抑制AAPH引发的Caco-2细胞内氧化，IC50值为6.5±0.3 μg/ml。当使用CellTiter-Glo检测法评估时，花青素对Caco-2细胞无毒，但能显著（P<0.05）保护细胞免受AAPH诱导的细胞毒性。AAPH诱导的Caco-2细胞毒性归因于G1期细胞比例显著（P<0.05）降低以及亚G1期细胞比例增加，表明发生了凋亡。预先将Caco-2细胞暴露于花青素可通过降低亚G1期细胞比例来抑制（P<0.05）AAPH诱导的凋亡，并使其他细胞周期阶段的细胞比例恢复正常。我们的结果表明，主要归因于矢车菊素-3-O-葡萄糖苷且黑莓中常见的花青素抗氧化活性，在抑制培养的Caco-2细胞中过氧自由基诱导的凋亡方面是有效的。
