Bljajić Kristina, Petlevski Roberta, Vujić Lovorka, Čačić Ana, Šoštarić Nina, Jablan Jasna, Saraiva de Carvalho Isabel, Zovko Končić Marijana
Faculty of Pharmacy and Biochemistry, University of Zagreb, A. Kovačića 1, 10000 Zagreb, Croatia.
Faculty of Sciences and Technology, University of Algarve, Campus de Gambelas, Bd. 8, 8005-139 Faro, Portugal.
Molecules. 2017 Apr 28;22(5):703. doi: 10.3390/molecules22050703.
(bilberry) leaf is traditionally used in southeastern Europe for the treatment of diabetes. In the present study, the ability of bilberry leaf extracts to inhibit carbohydrate-hydrolyzing enzymes and restore glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress was investigated. A comprehensive analysis of the antioxidant activity of two bilberry leaf extracts was performed. The aqueous extract showed excellent total antioxidant and chelating activity. Its antioxidant activity in the β-carotene-linoleic acid assay was very good, reaching the activity of the antioxidant standard BHA (93.4 ± 2.3% vs. 95.1 ± 2.4%, respectively). The hydroethanolic extract (ethanol/H₂O, 8:2, /), on the other hand, was a better radical scavenger and Fe reducing agent. Furthermore, the aqueous extract was able to efficiently increase glutathione concentration in Hep G2 cells subjected to glucose-induced oxidative stress and restore it to the levels observed in non-hyperglycaemic cells. The hydroethanolic extract strongly inhibited α-glucosidase, with the IC statistically equal to the antidiabetic drug acarbose (0.29 ± 0.02 mg/mL vs. 0.50 ± 0.01 mg/mL, respectively). Phytochemical analysis revealed the presence of quercetin and kaemferol derivatives, as well as chlorogenic and -coumaric acid. The study results indicate that leaf may have promising properties as a supporting therapy for diabetes.
（越橘）叶在欧洲东南部传统上用于治疗糖尿病。在本研究中，研究了越橘叶提取物抑制碳水化合物水解酶以及恢复经受葡萄糖诱导氧化应激的Hep G2细胞中谷胱甘肽浓度的能力。对两种越橘叶提取物的抗氧化活性进行了全面分析。水提取物显示出优异的总抗氧化和螯合活性。其在β-胡萝卜素-亚油酸测定中的抗氧化活性非常好，达到抗氧化标准丁基羟基茴香醚的活性（分别为93.4±2.3%和95.1±2.4%）。另一方面，氢乙醇提取物（乙醇/H₂O，8:2，/）是更好的自由基清除剂和铁还原剂。此外，水提取物能够有效提高经受葡萄糖诱导氧化应激的Hep G2细胞中的谷胱甘肽浓度，并将其恢复到非高血糖细胞中观察到的水平。氢乙醇提取物强烈抑制α-葡萄糖苷酶，其IC在统计学上与抗糖尿病药物阿卡波糖相当（分别为0.29±0.02 mg/mL和0.50±0.01 mg/mL）。植物化学分析表明存在槲皮素和山奈酚衍生物，以及绿原酸和香豆酸。研究结果表明，越橘叶作为糖尿病的辅助治疗可能具有有前景的特性。
