Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, 300072, P. R. China.
Tianjin Agricultural University, Tianjin 300384, P.R. China; State Key Laboratory of Nutrition and Safety, Tianjin University of Science & Technology, Tianjin 300457, P.R. China.
Phytomedicine. 2021 Nov;92:153714. doi: 10.1016/j.phymed.2021.153714. Epub 2021 Aug 25.
As one of traditional Chinese medicine, mulberry leaf is abundant in diverse active ingredients and widely used for the treatment of metabolic disease and its complications. However, there are a few of reports on its application in the prevention and treatment of obesity. And the molecular mechanism on the anti-obesity of mulberry leaf are unknown till now.
The present study aimed to evaluate the potential ingredients and targets of mulberry leaf and uncover the anti-obesity mechanisms by using the network pharmacology tactics and verify its effect by biological experiments.
Active ingredients and key targets of mulberry leaf, genes related to obesity were screened through public database. Based on the results of network pharmacology, the flavonoids-enriched fraction of mulberry leaf (MLF) was extracted and composition of this fraction was identified. After that, HepG2 cells model of lipid accumulation was established for verifying the effect of MLF and related mechanisms.
A total of 37 active ingredients in mulberry leaf, 192 predicted biological targets and 8813 obesity-related targets were determined, of which 180 overlapping targets might have obvious curative effects on obesity. The networks showed that mulberry leaf might play a role through key targets, such as AKT, MAPK and IL-6, and regulated PI3K-Akt signaling pathway. Based on HPLC-ESI-QQQ-MS analysis, 13 constituents of MLF were identified, including 9 flavonoids. Furthermore, HepG2 cells model of lipid accumulation was established. The results indicated that MLF treatment could down-regulate the secretion of inflammatory cytokines, as well as clearly inhibited lipid droplets formation and alleviated TC, TG, HDL-C and LDL-C levels. Positive effect was observed on hypolipidemic efficacy due to the regulation of PI3K/Akt/Bcl-xl pathway, as indicated by the amelioration of PI3K, Akt and Bcl-xl gene and protein expression.
This study firstly systematically disclose the multi-ingredients, multi-targets mechanisms of mulberry leaf on obesity by using network pharmacology approach, and validate in HepG2 cells that the protective effect of MLF against obesity involved both inflammation response and lipid metabolism involving PI3K/Akt/Bcl-xl signaling pathway. It provides indications for further mechanistic research of mulberry leaf and also for the development as a potential candidate for the therapy for obese patients.
作为中药的一种，桑叶富含多种活性成分，广泛用于治疗代谢性疾病及其并发症。然而，关于桑叶在肥胖预防和治疗中的应用的报道较少。目前尚不清楚桑叶的抗肥胖作用的分子机制。
本研究旨在利用网络药理学策略评估桑叶的潜在成分和靶点，并通过生物实验验证其抗肥胖机制。
通过公共数据库筛选桑叶的活性成分和关键靶点、与肥胖相关的基因。基于网络药理学的结果，提取桑叶的黄酮类富集部分（MLF），并鉴定该部分的成分。然后，建立 HepG2 细胞脂肪积累模型，验证 MLF 的作用及其相关机制。
共确定了桑叶中的 37 种活性成分、192 个预测生物靶点和 8813 个肥胖相关靶点，其中 180 个重叠靶点可能对肥胖有明显的治疗作用。网络显示，桑叶可能通过关键靶点，如 AKT、MAPK 和 IL-6 发挥作用，并调节 PI3K-Akt 信号通路。基于 HPLC-ESI-QQQ-MS 分析，鉴定出 MLF 的 13 种成分，包括 9 种黄酮类化合物。此外，还建立了 HepG2 细胞脂肪积累模型。结果表明，MLF 处理可下调炎症细胞因子的分泌，明显抑制脂滴形成，改善 TC、TG、HDL-C 和 LDL-C 水平。通过调节 PI3K/Akt/Bcl-xl 通路，观察到降脂疗效的阳性作用，表现为 PI3K、Akt 和 Bcl-xl 基因和蛋白表达的改善。
本研究首次通过网络药理学方法系统揭示了桑叶对肥胖的多成分、多靶点作用机制，并在 HepG2 细胞中验证了 MLF 对肥胖的保护作用，涉及炎症反应和脂质代谢，涉及 PI3K/Akt/Bcl-xl 信号通路。这为进一步研究桑叶的机制提供了依据，也为开发治疗肥胖患者的潜在候选药物提供了依据。
