Antihyperlipidaemic effect of triterpenic acid-enriched fraction from <i>Cyclocarya paliurus</i> leaves in hyperlipidaemic rats

Context:Cyclocarya paliurus (Batal) Iljinskaja (Juglandaceae) is an edible and medicinal plant; the leaves are used in Chinese folkloric medicine to treat dyslipidaemia and diabetes. Objective: This study evaluates the antihyperlipidaemic potential of the triterpenic acid-enriched fraction (TAE) from C. paliurus and the underlying mechanism. Materials and methods: The hyperlipidaemic rats were induced by high fat diet for 6 weeks. After oral administration of TAE (200 and 400 mg/kg), the neutral fraction (150 and 300 mg/kg) and statin (4 mg/kg) to the hyperlipidaemic rats for 4 weeks, lipid profile and apolipoprotein (apoB48) level in plasma, and the expression levels of apoB48, microsomal triglyceride transfer protein (MTP), phosphorylation of mitogen-activated protein kinase (MAPK) and tumour necrosis factor α (TNF-α) in intestine were examined. The main constituents in the TAE were identified by HPLC-MS. Results: TAE administration (400 mg/kg) decreased the levels of atherogenic lipids in serum and liver (p < 0.05) and increased serum high-density lipoprotein cholesterol by 19.7%. Furthermore, TAE treatment (200 and 400 mg/kg) decreased plasma apoB48 level by 15.3 and 19.5%, downregulated intestinal apoB48 and MTP expression levels (p < 0.05), and inhibited TNF-α expression by 36.2 and 56.2% and the phosphorylation level of MAPK by 8.8 and 13.2%, respectively. HPLC analysis revealed the presence of pentacyclic- and tetracyclic-triterpene acids in TAE. Conclusion and discussion: These findings suggested that TAE possessed antihyperlipidaemic activity partially involved in the inhibitory effect on apoB48 overproduction, which may provide evidence about its potential role in ameliorating dyslipidaemia.Context: 青钱柳（Cyclocarya paliurus (Batal) Iljinskaja，隶属于胡桃科（Juglandaceae），是一种药食同源植物，其叶片在我国民间医药中被用于治疗血脂异常与糖尿病。 Objective: 本研究旨在评估青钱柳中富含三萜酸的组分（TAE）的抗高脂血症活性及其潜在作用机制。 Materials and methods: 采用高脂饲料诱导构建高脂血症大鼠模型，造模周期为6周。随后对高脂血症大鼠经口给予TAE（200、400 mg/kg）、中性组分（150、300 mg/kg）以及他汀类药物（4 mg/kg），连续干预4周后，检测各组大鼠血浆中的血脂谱与载脂蛋白B48（apoB48）水平，同时检测肠道组织中apoB48、微粒体甘油三酯转运蛋白（microsomal triglyceride transfer protein, MTP）、丝裂原活化蛋白激酶（mitogen-activated protein kinase, MAPK）的磷酸化水平以及肿瘤坏死因子α（tumour necrosis factor α, TNF-α）的表达水平。采用高效液相色谱-质谱联用技术（HPLC-MS）对TAE中的主要成分进行定性鉴定。 Results: 400 mg/kg剂量的TAE干预可显著降低血清与肝脏中的致动脉粥样硬化脂质水平（p < 0.05），并使血清高密度脂蛋白胆固醇水平升高19.7%。此外，200 mg/kg与400 mg/kg剂量的TAE干预可分别使血浆apoB48水平降低15.3%与19.5%，下调肠道组织中apoB48与MTP的表达水平（p < 0.05），同时分别使TNF-α表达水平降低36.2%与56.2%，MAPK磷酸化水平降低8.8%与13.2%。高效液相色谱分析结果显示，TAE中含有五环三萜酸与四环三萜酸类成分。 Conclusion and discussion: 本研究结果表明，TAE具备抗高脂血症活性，其作用机制可能部分通过抑制apoB48过度生成，该发现可为青钱柳改善血脂异常的潜在应用价值提供实验依据。