Quercetin and crocin are the main active constituents of Eucommia and Gardenia species, respectively. This study was conducted to explore the effects of quercetin and crocin on fat reduction and renal fibrosis and the relationship of these compounds with autophagy. First, a model of high-fat diet- and streptozotocin-induced type 2 diabetes was established and then subjected model animals to 8 weeks of metformin, quercetin and crocin gavage. Then, a high glucose-induced rat mesangial cells (RMCs) model was established, and these cells were cocultured with quercetin and crocin. The results showed that quercetin and crocin can decrease fasting blood glucose levels, reduce fat accumulation in the liver, alleviate renal fibrosis, and reduce blood lipid levels. Quercetin and crocin increased autophagy-related protein (LC3, Atg5, Beclin-1 and p-AMPK) levels in the liver and decreased autophagy-related protein (LC3, Atg5, Beclin-1 and p-AMPK) levels in the kidneys. Moreover, quercetin and crocin inhibited the excessive proliferation of RMCs induced by high-glucose (HG) conditions, decreased autophagy-related protein (LC3, Atg5, Beclin-1 and p-AMPK) levels, and decreased TGF-β1 expression. Importantly, cotreatment with quercetin and crocin had a more significant effect than treatment with either compound alone. These results suggest that combined administration of quercetin and crocin can more significantly reduce blood glucose/lipid levels and improve renal fibrosis than administration of either compound alone and that AMPK-dependent autophagy might be involved in this process. Eucommia ulmoides Oliv. and Gardenia could be developed as drugs for Type 2 diabetes treatment.

槲皮素和藏红花素分别是杜仲和栀子的主要活性成分。本研究旨在探讨槲皮素和藏红花素对减脂和肾纤维化的影响以及这些化合物与自噬的关系。首先，建立高脂饮食和链脲佐菌素诱导的2型糖尿病模型，然后对模型动物进行8周的二甲双胍、槲皮素和藏红花素灌胃。然后，建立高糖诱导的大鼠系膜细胞（RMC）模型，并将这些细胞与槲皮素和藏红花素共培养。结果表明，槲皮素和藏红花素可以降低空腹血糖水平，减少肝脏脂肪堆积，减轻肾脏纤维化，降低血脂水平。槲皮素和藏红花素可增加肝脏中自噬相关蛋白（LC3、Atg5、Beclin-1 和 p-AMPK）的水平，并降低肾脏中自噬​​相关蛋白（LC3、Atg5、Beclin-1 和 p-AMPK）的水平。此外，槲皮素和藏红花素可抑制高糖（HG）条件下诱导的RMCs过度增殖，降低自噬相关蛋白（LC3、Atg5、Beclin-1和p-AMPK）水平，并降低TGF-β1表达。重要的是，槲皮素和藏红花素的共同治疗比单独使用任一化合物的治疗具有更显着的效果。这些结果表明，与单独使用任一化合物相比，槲皮素和藏红花素的联合给药可以更显着地降低血糖/脂质水平并改善肾纤维化，并且AMPK依赖性自噬可能参与该过程。杜仲 (Eucommia ulmoides Oliv)。栀子花可以开发为治疗2型糖尿病的药物。