School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, China.
School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, China.
J Ethnopharmacol. 2020 Nov 15;262:113178. doi: 10.1016/j.jep.2020.113178. Epub 2020 Jul 28.
Exocarpium Citri Grandis (ECG; Huajuhong in Chinese) is a precious traditional Chinese medicine with a history of hundreds of years in China. It has been demonstrated to possess numerous pharmacological properties, including antitussive, expectorant, anti-inflammatory, hypoglycemic, and hypolipidemic. However, no in-depth report exists on the hypoglycemic and hypolipidemic properties of ECG.
This study aimed to evaluate the hypoglycemic and hypolipidemic properties of ECG flavonoids extract in vitro and in vivo so as to lay the foundation for further researches in this field.
Total flavonoids (TF) and naringin were separately extracted from ECG, and the components of TF were identified by HPLC-MS. The antioxidant capacities of TF and naringin were determined by 2,2,1-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging tests, and digestive enzymes activity inhibition assays in vitro in order to evaluate their hypoglycemic properties. Furthermore, diabetic mice experiments were performed to assess the hypoglycemic and hypolipidemic properties of TF and naringin in vivo.
Five compounds were identified from TF, including naringin, rhoifolin, poncirin, bergaptol, and naringenin. The half maximal inhibitory concentration (IC) of TF and naringin to DPPH-free radicals were 0.269 and 1.946 mg/mL, respectively. TF and naringin demonstrated a certain inhibitory effect on α-glucosidase and a weaker inhibitory effect on α-amylase. The results of animal experiments showed that TF and naringin had no significant effect on the blood glucose levels, but they could lead to significant (p < 0.05 or p < 0.01) increase in the serum insulin level and high-density lipoprotein cholesterol (HDL-C) levels with concomitant reduction in the total cholesterol (TC), total triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) levels in diabetic mice. In addition, TF and naringin could reduce the liver index of diabetic mice (p < 0.01) and reduce the kidney index at low doses (p < 0.05).
Our study revealed that the hypoglycemic and hypolipidemic activities of TF is mainly derived from naringin, and other active ingredients in TF also have the effects of alleviating oxidative stress, inhibiting digestive enzyme activity and reducing blood lipids. Our results thus provide a scientific basis for the application of ECG in antidiabetic treatment.
ETHNOPHARMACOLOGICAL 相关性：陈皮（ECG；中文名称为化橘红）是一种具有数百年历史的珍贵中药，具有止咳、化痰、抗炎、降血糖和降血脂等多种药理作用。然而，目前尚无关于 ECG 降血糖和降血脂作用的深入报道。
本研究旨在评估 ECG 黄酮提取物的体外和体内降血糖和降血脂作用，为该领域的进一步研究奠定基础。
分别从 ECG 中提取总黄酮（TF）和柚皮苷，并通过高效液相色谱-质谱联用（HPLC-MS）鉴定 TF 的成分。通过 2,2,1-二苯基-1-苦基肼（DPPH）自由基清除试验和体外消化酶活性抑制试验测定 TF 和柚皮苷的抗氧化能力，以评估其降血糖作用。此外，还进行了糖尿病小鼠实验，以评估 TF 和柚皮苷在体内的降血糖和降血脂作用。
从 TF 中鉴定出 5 种化合物，包括柚皮苷、芦丁、新橙皮苷、伯格普醇和柚皮素。TF 和柚皮苷对 DPPH 自由基的半抑制浓度（IC）分别为 0.269 和 1.946mg/mL。TF 和柚皮苷对α-葡萄糖苷酶有一定的抑制作用，对α-淀粉酶的抑制作用较弱。动物实验结果表明，TF 和柚皮苷对血糖水平无显著影响，但可显著（p<0.05 或 p<0.01）提高糖尿病小鼠血清胰岛素水平和高密度脂蛋白胆固醇（HDL-C）水平，并降低总胆固醇（TC）、总甘油三酯（TG）和低密度脂蛋白胆固醇（LDL-C）水平。此外，TF 和柚皮苷可降低糖尿病小鼠的肝指数（p<0.01），并在低剂量时降低肾指数（p<0.05）。
本研究表明，TF 的降血糖和降血脂活性主要来源于柚皮苷，而 TF 中的其他活性成分也具有缓解氧化应激、抑制消化酶活性和降低血脂的作用。本研究结果为 ECG 在糖尿病治疗中的应用提供了科学依据。
