Natural products are one of the main sources for discovering new lead compounds. We previously reported that cinnamon extract has a promising effect in regulating lipid tissue volume and insulin sensitivity in vivo. However, its effective component and the underlying mechanism are not known. In the present study, we analyzed the effect of different components of cinnamon on regulating insulin sensitivity in 3T3-L1 adipocytes. Functional assay revealed that, of the six major components of cinnamon extracts, the B-type procyanidin, procyanidin C1, improves the differentiation of 3T3-L1 cells (TG content: 1.10 ± 0.09 mM at a dosage of 25 μM vs 0.67 ± 0.02 mM in vehicle group, p < 0.001) and promotes insulin-induced glucose uptake (8.58 ± 1.43 at a dosage of 25 μM vs 3.05 ± 1.24 in vehicle group, p < 0.001). Mechanism studies further suggested that procyanidin C1 activates the AKT-eNOS pathway, thus up-regulating glucose uptake and enhancing insulin sensitivity in mature adipocytes. Taken together, our study identified B-type procyanidin C1, a component of cinnamon extract, that stimulates preadipocyte differentiation and acts as a potential insulin action enhancer through the AKT-eNOS pathway in mature adipocytes.

中文翻译：

---

原花青素C1，肉桂提取物的一种成分，是一种针对脂肪细胞的潜在胰岛素增敏剂

天然产物是发现新的铅化合物的主要来源之一。我们先前报道肉桂提取物在体内调节脂质组织体积和胰岛素敏感性方面具有良好的作用。但是，其有效成分和潜在机制尚不清楚。在本研究中，我们分析了肉桂不同成分对调节3T3-L1脂肪细胞中胰岛素敏感性的影响。功能测定表明，在肉桂提取物的六个主要成分中，B型原花青素，原花青素C1改善了3T3-L1细胞的分化（TG含量：1.10±0.09 mM，剂量为25μMvs 0.67±0.02 mM在车辆组中，p<0.001）并促进胰岛素诱导的葡萄糖摄取（剂量为25μM时为8.58±1.43，而媒介物组为3.05±1.24，p <0.001）。机制研究进一步表明，原花青素C1激活AKT-eNOS途径，从而上调葡萄糖摄取并增强成熟脂肪细胞中的胰岛素敏感性。两者合计，我们的研究确定B型原花青素C1，肉桂提取物的一个成分，它刺激前脂肪细胞的分化，并通过成熟脂肪细胞中的AKT-eNOS途径充当潜在的胰岛素作用增强剂。