Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing 210014, China.
Biomed Pharmacother. 2018 Jan;97:1125-1130. doi: 10.1016/j.biopha.2017.11.043. Epub 2017 Nov 10.
Loquat (Eriobotrya japonica) leaf has displayed beneficial effect on metabolic syndrome. In our previously study, total sesquiterpene glycosides (TSG) isolated from Loquat leaf exhibited therapeutic effect on Non-alcoholic fatty liver disease (NAFLD) in vivo, but the accurate active compound remains unknown. Sesquiterpene glycoside 1 (SG1) is a novel compound, which is exclusively isolated from Loquat leaf, but its biological activity has been rarely reported. The present study was designed to evaluate the pharmacological effect of SG1, the main component of TSG, in oleic acid (OA)-induced HepG2 cell model of NAFLD with its related mechanisms of action. In this study, both SG1 and TSG were found to significantly reduce the lipid deposition in the cell model. They could also decrease total cholesterol (TC), triglyceride (TG) and intracellular free fatty acid (FFA) contents. Compared with OA-treated cells, the superoxide dismutase (SOD) level increased, and the malondialdehyde (MDA) and 4-hydroxynonenal levels respectively decreased after the administration of SG1 or TSG. The high dose of SG1 (140 μg/mL) displayed a similar therapeutic effect as TSG at 200 μg/mL. Both SG1 and TSG were found to suppress the expression of cytochrome P450 2E1 (CYP2E1) and the phosphorylation of c-jun terminal kinase (JNK) and its downstream target c-Jun in OA-treated cell. These results demonstrate again that TSG are probably the main responsible chemical profiles of Loquat leaf for the treatment of NAFLD, for which it can effectively improve OA-induced steatosis and reduce oxidative stress, probably by downregulating of CYP2E1 expression and JNK/c-Jun phosphorylation, while SG1 may be the principle compound.
枇杷叶对代谢综合征有有益的影响。在我们之前的研究中，从枇杷叶中分离得到的总三萜糖苷（TSG）在体内对非酒精性脂肪性肝病（NAFLD）有治疗作用，但确切的活性化合物尚不清楚。三萜糖苷 1（SG1）是一种新型化合物，仅从枇杷叶中分离得到，但它的生物活性很少被报道。本研究旨在评价 SG1（TSG 的主要成分）在油酸（OA）诱导的 HepG2 细胞 NAFLD 模型中的药理作用及其相关作用机制。在这项研究中，SG1 和 TSG 都被发现能显著减少细胞模型中的脂质沉积。它们还可以降低总胆固醇（TC）、甘油三酯（TG）和细胞内游离脂肪酸（FFA）的含量。与 OA 处理的细胞相比，SG1 或 TSG 给药后超氧化物歧化酶（SOD）水平升高，丙二醛（MDA）和 4-羟基壬烯醛水平分别降低。高剂量的 SG1（140μg/ml）与 TSG 在 200μg/ml 时表现出相似的治疗效果。SG1 和 TSG 均能抑制 CYP2E1 和 c-Jun 末端激酶（JNK）及其下游靶标 c-Jun 在 OA 处理细胞中的表达。这些结果再次表明，TSG 可能是枇杷叶治疗 NAFLD 的主要活性成分，它能有效改善 OA 诱导的脂肪变性，减轻氧化应激，可能是通过下调 CYP2E1 表达和 JNK/c-Jun 磷酸化，而 SG1 可能是主要化合物。
