Hunan Provincial Key Laboratory of the Traditional Chinese Medicine Agricultural Biogenomics, Changsha Medical University, Changsha 410219, China.
College of Food Science and Technology, Hunan Agricultural University, Changsha 410128, China.
Nutrients. 2024 Aug 23;16(17):2820. doi: 10.3390/nu16172820.
α-tocopherol (α-T), β-sitosterol (β-S), canolol (CA), and sinapic acid (SA) are the four main endogenous lipid phytochemicals (LP) found in L. seed oil, which possess the bioactivity to prevent the risk of several chronic diseases via antioxidant-associated mechanisms. Discovering the enhancer effects or synergies between LP is valuable for resisting oxidative stress and improving health benefits. The objectives of this study were to identify a potentially efficacious LP combination by central composite design (CCD) and cellular antioxidant activity (CAA) and to investigate its protective effect and potential mechanisms against HO-induced oxidative damage in HepG2 cells. Our results indicated that the optimal concentration of LP combination was α-T 10 μM, β-S 20 μM, SA 125 μM, and CA 125 μM, respectively, and its CAA value at the optimal condition was 10.782 μmol QE/100 g. At this concentration, LP combination exerted a greater amelioration effect on HO-induced HepG2 cell injury than either antioxidant (tea polyphenols or magnolol) alone. LP combination could reduce the cell apoptosis rate induced by HO, lowered to 10.06%, and could alleviate the degree of oxidative damage to cells (ROS↓), lipids (MDA↓), proteins (PC↓), and DNA (8-OHdG↓). Additionally, LP combination enhanced the antioxidant enzyme activities (SOD, CAT, GPX, and HO-1), as well as the T-AOC, and increased the GSH level in HepG2 cells. Furthermore, LP combination markedly upregulated the expression of Nrf2 and its associated antioxidant proteins. It also increased the expression levels of Nrf2 downstream antioxidant target gene (, , , , , and ) and downregulated the mRNA expression levels of Keap1. The oxidative-stress-induced formation of the Keap1/Nrf2 complex in the cytoplasm was significantly blocked by LP treatment. These results indicate that LP combination protected HepG2 cells from oxidative stress through a mechanism involving the activation of the Keap1/Nrf2/ARE signaling pathways.
α-生育酚（α-T）、β-谷甾醇（β-S）、丁香脂醇（CA）和咖啡酸（SA）是菜籽油中发现的四种主要内源性脂类植物化学物质（LP），它们具有通过抗氧化相关机制预防多种慢性疾病风险的生物活性。发现 LP 之间的增强效应或协同作用对于抵抗氧化应激和提高健康益处是有价值的。本研究的目的是通过中心复合设计（CCD）和细胞抗氧化活性（CAA）来确定一种潜在有效的 LP 组合，并研究其对 HepG2 细胞中 HO 诱导的氧化损伤的保护作用及其潜在机制。我们的结果表明，LP 组合的最佳浓度分别为α-T 10 μM、β-S 20 μM、SA 125 μM 和 CA 125 μM，在最佳条件下的 CAA 值为 10.782 μmol QE/100 g。在该浓度下，LP 组合对 HO 诱导的 HepG2 细胞损伤的改善作用大于单独使用任何一种抗氧化剂（茶多酚或厚朴酚）。LP 组合可以降低 HO 诱导的 HepG2 细胞凋亡率，降至 10.06%，并可以减轻细胞氧化损伤的程度（ROS↓）、脂质（MDA↓）、蛋白质（PC↓）和 DNA（8-OHdG↓）。此外，LP 组合增强了抗氧化酶活性（SOD、CAT、GPX 和 HO-1）以及 T-AOC，并增加了 HepG2 细胞中的 GSH 水平。此外，LP 组合显著上调了 Nrf2 及其相关抗氧化蛋白的表达。它还增加了 Nrf2 下游抗氧化靶基因（、、、、和）的表达水平，并下调了 Keap1 的 mRNA 表达水平。LP 处理显著阻断了 Keap1/Nrf2 复合物在细胞质中形成，从而导致氧化应激。这些结果表明，LP 组合通过激活 Keap1/Nrf2/ARE 信号通路，保护 HepG2 细胞免受氧化应激。
