Syabana Mohamad Ana, Yuliana Nancy Dewi, Batubara Irmanida, Fardiaz Dedi
Department of Food Science and Technology, IPB Dramaga Campus, IPB University, Bogor, Indonesia; Department of Food Technology and Center of Excellence for Local Food Innovation, Sultan Ageng Tirtayasa University, Serang, Indonesia.
Department of Food Science and Technology, IPB Dramaga Campus, IPB University, Bogor, Indonesia; Tropical Biopharmaca Research Center, IPB University, Bogor, Indonesia; Halal Science Center, IPB University, Bogor, Indonesia.
J Ethnopharmacol. 2022 Jan 10;282:114618. doi: 10.1016/j.jep.2021.114618. Epub 2021 Sep 9.
Syzygium polyanthum (Wight) Walp leaves are traditionally used to cure diabetes in many regions of Indonesia. Traditional use involves boiling the leaves until the water is reduced to half volume, and then the decoction is taken 1-2 times daily. Despite several studies reporting the antidiabetic activity of this plant, bioactive compounds have not been well identified.
Indonesia is one of the countries with the highest diabetes cases, particularly type 2 diabetes mellitus (T2DM). Few people have access to modern medicinal treatment; thus, the role of antidiabetic traditional medicine has become increasingly important. This research aimed to identify α-glucosidase inhibitors from S. polyathum leaves using a metabolomics approach. When the active compounds of S. polyathum are properly identified, the quality of the herb can be more easily controlled.
The dried leaves of S. polyanthum were extracted by a comprehensive extraction method using a solvent combination of n-hexane, acetone, and water in a gradient, resulting in a total of 42 fractions. All fractions were subjected to an in vitro α-glucosidase inhibition test and chemical profile analysis using Nuclear Magnetic Resonance (NMR) and high performance liquid chromatography (HPLC). Orthogonal projection least square (OPLS) analysis was used to correlate the two data to identify NMR signals, and HPLC chromatogram peaks correlated to the activity. 2D NMR and ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) analyses were also used to give more precise compound identification. The activity of the identified active compounds was confirmed by an in silico technique.
The results of the α-glucosidase activity test showed that the most active fractions were obtained from solvents with medium polarity: Fractions 9 and 10 (F9 and F10), obtained from gradient acetone-water 4:1 and 3:2, respectively. The IC50 values of F9 and F10 were 24.8 and 31.8 μg/mL, respectively. NMR data showed that F9 had more intense and diverse signals in the aromatic region than F10. OPLS analysis results showed that some typical flavonoid signals abundant in F9 positively correlated with α-glucosidase activity. 2D NMR and UHPLC-HRMS analysis of F9 led to the conclusion that these signals could be attributed to myricetin-3-O-rhamnoside (myricitrin) and epigallocatechin-3-gallate (EGCG). In silico analysis confirmed these results, as myricitrin and EGCG had binding energies resembling acarbose as a positive control (-8.47, -8.19, and -10.13, respectively).
NMR and HPLC-metabolomics successfully identified myricitrin and EGCG as α-glucosidase inhibitors from S. polyanthum leaves, and docking analysis validated their inhibitory activity. The results of this study justified the traditional use of S. polyanthum as an antidiabetes herbal.
在印度尼西亚的许多地区，多花蒲桃（Wight）Walp叶传统上用于治疗糖尿病。传统用法是将叶子煮沸至水量减少一半，然后每天服用煎剂1 - 2次。尽管有几项研究报道了这种植物的抗糖尿病活性，但生物活性化合物尚未得到很好的鉴定。
印度尼西亚是糖尿病病例数最高的国家之一，尤其是2型糖尿病（T2DM）。很少有人能获得现代药物治疗；因此，抗糖尿病传统药物的作用变得越来越重要。本研究旨在使用代谢组学方法从多花蒲桃叶中鉴定α - 葡萄糖苷酶抑制剂。当多花蒲桃的活性成分被正确鉴定后，草药的质量就能更容易得到控制。
多花蒲桃的干燥叶采用综合提取方法，使用正己烷、丙酮和水的溶剂组合进行梯度提取，共得到42个馏分。所有馏分均进行体外α - 葡萄糖苷酶抑制试验，并使用核磁共振（NMR）和高效液相色谱（HPLC）进行化学图谱分析。采用正交投影最小二乘法（OPLS）分析将这两个数据相关联，以鉴定NMR信号以及与活性相关的HPLC色谱峰。二维NMR和超高效液相色谱 - 高分辨率质谱联用（UHPLC - HRMS）分析也用于更精确地鉴定化合物。通过计算机模拟技术确认所鉴定活性化合物的活性。
α - 葡萄糖苷酶活性测试结果表明，活性最高的馏分来自中等极性的溶剂：馏分9和10（F9和F10），分别从丙酮 - 水比例为4:1和3:2的梯度溶液中获得。F9和F10的IC50值分别为24.8和31.8μg/mL。NMR数据表明，F9在芳香区的信号比F10更强且更多样化。OPLS分析结果表明，F9中丰富的一些典型黄酮类信号与α - 葡萄糖苷酶活性呈正相关。对F9进行二维NMR和UHPLC - HRMS分析得出结论，这些信号可归因于杨梅素 - 3 - O - 鼠李糖苷（杨梅苷）和表没食子儿茶素 - 3 - 没食子酸酯（EGCG）。计算机模拟分析证实了这些结果，因为杨梅苷和EGCG的结合能与作为阳性对照的阿卡波糖相似（分别为 - 8.47、 - 8.19和 - 10.13）。
NMR和HPLC - 代谢组学成功鉴定出杨梅苷和EGCG为多花蒲桃叶中的α - 葡萄糖苷酶抑制剂，对接分析验证了它们的抑制活性。本研究结果证明了多花蒲桃作为抗糖尿病草药的传统用途是合理的。
