Starzec Aneta, Włodarczyk Maciej, Kunachowicz Dominika, Dryś Andrzej, Kepinska Marta, Fecka Izabela
Department of Pharmacognosy and Herbal Medicines, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211a, 50-556 Wroclaw, Poland.
Department of Pharmaceutical Biochemistry, Division of Biomedical and Environmental Sciences, Faculty of Pharmacy, Wroclaw Medical University, Borowska 211a, 50-556 Wroclaw, Poland.
Antioxidants (Basel). 2023 Feb 22;12(3):553. doi: 10.3390/antiox12030553.
The European Food Safety Authority recommends as a natural source of antioxidants. Its activity is essentially determined by polyphenols, although specific compounds are not finally indicated. The available plant material comes from different subspecies and locations, which can lead to differences in chemical composition and potency. For this reason, we conducted a detailed analysis of the polyphenol content and antioxidant activity of 52 different teas from Turkey, Albania, Greece, and unspecified regions. We focused special attention on ellagitannins, which have not been properly determined so far. Besides oxidative stress, hyperglycemia is an essential component of cardiometabolic diseases. Therefore, in subsequent experiments, we evaluated the ability of extracts and individual polyphenols to inhibit α-glucosidase. Using statistical methods, we analyzed how differences in chemical composition affect activity. The results showed that is a rich source of ellagitannins (2.5-19%), which dominate among polyphenols (5.5-23%). Turkish-origin products had higher ellagitannin content and a greater antioxidant effect (FRAP, ABTS) than Albanian and Greek products. In contrast, the flavonoid and phenolic acid contents and DPPH values were at similar levels in all products. An in-depth analysis of their composition indicated that all groups of polyphenols are involved in the antioxidant effect, but a significant contribution can be attributed to ellagitannins and flavonoids. extracts showed a high capacity to inhibit α-glucosidase activity (IC 125-145 μg/mL). Ellagitannins were the most effective inhibitors (IC 0.7-1.1 μM), with a potency exceeding acarbose (3.3 mM). In conclusion, , due to the presence of ellagitannins and flavonoids, exhibits powerful antioxidant and α-glucosidase inhibitory effects.
欧洲食品安全局推荐其作为抗氧化剂的天然来源。其活性主要由多酚决定，不过尚未最终明确具体的化合物。现有的植物材料来自不同的亚种和产地，这可能导致化学成分和效力的差异。因此，我们对来自土耳其、阿尔巴尼亚、希腊以及未明确地区的52种不同茶叶的多酚含量和抗氧化活性进行了详细分析。我们特别关注了鞣花单宁，到目前为止其含量尚未得到准确测定。除了氧化应激外，高血糖是心脏代谢疾病的一个重要组成部分。因此，在后续实验中，我们评估了茶叶提取物和单个多酚抑制α - 葡萄糖苷酶的能力。我们运用统计方法分析了化学成分的差异如何影响活性。结果表明，茶叶是鞣花单宁的丰富来源（2.5 - 19%），在多酚中占主导地位（5.5 - 23%）。土耳其原产的产品比阿尔巴尼亚和希腊的产品含有更高的鞣花单宁含量和更强的抗氧化效果（铁还原抗氧化能力法、2,联氨 - 二(3 - 乙基苯并噻唑啉 - 6 - 磺酸)铵盐法）。相比之下，所有产品中的黄酮类和酚酸含量以及二苯基苦味酰基自由基值处于相似水平。对其成分的深入分析表明，所有多酚类都参与了抗氧化作用，但鞣花单宁和黄酮类的贡献尤为显著。茶叶提取物显示出较高的抑制α - 葡萄糖苷酶活性的能力（半数抑制浓度为125 - 145微克/毫升）。鞣花单宁是最有效的抑制剂（半数抑制浓度为0.7 - 1.1微摩尔），其效力超过阿卡波糖（3.3毫摩尔）。总之，由于含有鞣花单宁和黄酮类，茶叶具有强大的抗氧化和α - 葡萄糖苷酶抑制作用。
