Gothandam Kirubananthan, Ganesan Vijayan Siva, Ayyasamy Thangaraj, Ramalingam Sundaram
1Department of Biotechnology, University of Madras, Guindy Campus, Chennai, 600025 India.
2Department of Plant Biology and Plant Biotechnology, Government Arts College for Men (Autonomous), Nandanam, University of Madras, Chennai, 600035 India.
J Basic Appl Zool. 2019;80(1):43. doi: 10.1186/s41936-019-0115-1. Epub 2019 Jun 21.
Theaflavins are major polyphenols in black tea which is the most widely consumed tea in the world. They possess a broad spectrum of biological activities, such as antioxidant, anti-tumor, anti-inflammatory, and cardio-protective effects. The present study was aimed to evaluate the protective effect of theaflavin on glycoprotein content and tricorboxylic acid cycle enzymes in high-fat diet and streptozotocin-induced diabetic rats as there was no study on this aspect. Diabetes was induced in male albino Wistar rats by feeding them with high-fat diet and injecting them intraperitoneally with streptozotocin (40 mg/kg b.wt).
Different doses of theaflavin (25, 50, and 100 mg/kg b.wt /day) were administered orally to high-fat diet and streptozotocin-induced diabetic rats for 30 days for fixing the glucose lowering dose. However, the dose at 100 mg/kg b.wt showed a significant reduction in the levels of plasma glucose and Homeostatic Model Assessment of Insulin Resistance with concomitant elevation of insulin when compared to the other two doses (25 and 50 mg/kg b.wt). Hence, 100 mg/kg b.wt was fixed as an effective dose and used for further analysis. Theaflavin administration restored the altered glycosylated hemoglobin, hemoglobin and glycoproteins (Hexose, hexosamine, fucose, and sialic acid) and TCA cycle enzymes (isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, and malate dehydrogenase) near the normal levels by correcting hyperglycemia. Improved histological changes were observed in the pancreas of diabetic rats upon treatment with theaflavin which supported the biochemicals investigated.
The effect produced by the theaflavin on various parameters was comparable to that of metformin-a reference antidiabetic drug. These findings suggest that theaflavin can replace the commercial drugs which could lead to reduction in toxicity and side effect caused by the later as well as reduce the secondary completions.
茶黄素是红茶中的主要多酚类物质，红茶是世界上消费最广泛的茶。它们具有广泛的生物活性，如抗氧化、抗肿瘤、抗炎和心脏保护作用。由于目前尚无关于这方面的研究，本研究旨在评估茶黄素对高脂饮食和链脲佐菌素诱导的糖尿病大鼠糖蛋白含量及三羧酸循环酶的保护作用。通过给雄性白化Wistar大鼠喂食高脂饮食并腹腔注射链脲佐菌素（40mg/kg体重）诱导糖尿病。
给高脂饮食和链脲佐菌素诱导的糖尿病大鼠口服不同剂量的茶黄素（25、50和100mg/kg体重/天），持续30天以确定降血糖剂量。然而，与其他两个剂量（25和50mg/kg体重）相比，100mg/kg体重的剂量显示血浆葡萄糖水平和胰岛素抵抗稳态模型评估显著降低，同时胰岛素水平升高。因此，将100mg/kg体重确定为有效剂量并用于进一步分析。茶黄素给药通过纠正高血糖，使糖化血红蛋白、血红蛋白和糖蛋白（己糖、氨基己糖、岩藻糖和唾液酸）以及三羧酸循环酶（异柠檬酸脱氢酶、α-酮戊二酸脱氢酶、琥珀酸脱氢酶和苹果酸脱氢酶）恢复到接近正常水平。在用茶黄素治疗的糖尿病大鼠胰腺中观察到组织学变化改善，这支持了所研究的生化指标。
茶黄素对各种参数产生的作用与二甲双胍（一种参考抗糖尿病药物）相当。这些发现表明茶黄素可以替代商业药物，这可能会降低后者引起的毒性和副作用以及减少继发性并发症。
