Background/Aims: Ximenynic acid is a rare conjugated enyne fatty acid found primarily in plants in the Santalaceae family. It has been reported that sandalwood seed oil (SWSO) affects fatty acid metabolism in animal studies; however, the effects of pure ximenynic acid remain unclear. The present study aimed to study the impact of SWSO and ximenynic acid on n-3 fatty acid metabolism in the liver and brain. Methods: Thirty C57BL/6 male mice aged 4 weeks were fed SWSO (1.0 mL/20 g bodyweight), olive oil (OO), or a combination of SWSO and OO (n = 10/group) for 8 weeks. Liver and brain fatty acid compositions were determined using gas chromatography. HepG2 cells were treated with up to 150 μM ximenynic acid and oleic acid for 48–72 h. The expression and abundance of genes and proteins relevant to n-3 fatty acid metabolism pathways were investigated. Results: The intake of SWSO in mice elevated the levels of total n-3 fatty acids and decreased total n-9 fatty acids in the liver (p < 0.05) compared with the OO group. In contrast, total n-3 fatty acids were significantly decreased in the brain (p < 0.05). HepG2 cells treated with ximenynic acid for 48 h showed significant reductions in n-9 fatty acids and docosahexaenoic acid (C22:6n-3) (p < 0.05) compared with HepG2 cells treated with oleic acid. In HepG2 cells, stearoyl-CoA desaturase (SCD) and fatty acid desaturase 2 (FADS2) gene expression, as well as FADS2 protein expression, were significantly down-regulated after a 72-h incubation with 150 μM of ximenynic acid compared with the vehicle (p < 0.05). Conclusion: Ximenynic acid may regulate fatty acid metabolism by suppressing the expression of key enzymes of lipid metabolism. In contrast, SWSO, which has a high level of C18:3n-3, positively affected n-3 fatty acid synthesis in mouse liver compared to pure ximenynic acid. We hypothesize that a high level of precursor C18:3n-3 in SWSO promotes the endogenous synthesis of C22:6n-3 despite the presence of ximenynic acid.

中文翻译：

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西门宁酸对肝脏和大脑中 n-3 PUFA 含量的调节

背景/目的：西门炔酸是一种稀有的共轭烯炔脂肪酸，主要存在于檀香科植物中。据报道，檀香籽油 (SWSO) 在动物研究中影响脂肪酸代谢；然而，纯西门炔酸的作用仍不清楚。本研究旨在研究 SWSO 和 ximenynic acid 对肝脏和大脑中 n-3 脂肪酸代谢的影响。方法：30 只 4 周龄的 C57BL/6 雄性小鼠被喂食 SWSO（1.0 mL/20 g 体重）、橄榄油（OO）或 SWSO 和 OO 的组合（n = 10/组）8 周。使用气相色谱法测定肝和脑脂肪酸组成。HepG2 细胞用高达 150 μM 的西门炔酸和油酸处理 48-72 小时。研究了与 n-3 脂肪酸代谢途径相关的基因和蛋白质的表达和丰度。结果：与OO组相比，小鼠摄入SWSO提高了肝脏中总n-3脂肪酸水平并降低了总n-9脂肪酸水平（p < 0.05）。相比之下，大脑中的总 n-3 脂肪酸显着减少（p < 0.05）。与用油酸处理的 HepG2 细胞相比，用西门炔酸处理 48 小时的 HepG2 细胞显示 n-9 脂肪酸和二十二碳六烯酸 (C22:6n-3) 显着减少（p < 0.05）。在 HepG2 细胞中，与载体相比，在与 150 μM 昔曼宁酸孵育 72 小时后，硬脂酰辅酶 A 去饱和酶 (SCD) 和脂肪酸去饱和酶 2 (FADS2) 基因表达以及 FADS2 蛋白表达显着下调(p < 0.05)。结论：西门炔酸可能通过抑制脂质代谢关键酶的表达来调节脂肪酸代谢。相比之下，与纯西门炔酸相比，具有高水平 C18:3n-3 的 SWSO 对小鼠肝脏中的 n-3 脂肪酸合成产生积极影响。我们假设 SWSO 中高水平的前体 C18:3n-3 促进了 C22:6n-3 的内源性合成，尽管存在西门宁酸。