Department of Biology, Khalifa University, Abu Dhabi, United Arab Emirates.
Department of Chemistry, Khalifa University, Abu Dhabi, United Arab Emirates.
PLoS One. 2022 Mar 14;17(3):e0264969. doi: 10.1371/journal.pone.0264969. eCollection 2022.
α-glucosidase inhibitors represent an important class of type 2 antidiabetic drugs and they act by lowering postprandial hyperglycemia. Today, only three synthetic inhibitors exist on the market, and there is a need for novel, natural and more efficient molecules exhibiting this activity. In this study, we investigated the ability of Tamarix nilotica ethanolic and aqueous shoot extracts, as well as methanolic fractions prepared from aqueous crude extracts to inhibit α-glucosidase. Both, 50% ethanol and aqueous extracts inhibited α-glucosidase in a concentration-dependent manner, with IC50 values of 12.5 μg/mL and 24.8 μg/mL, respectively. Importantly, α-glucosidase inhibitory activity observed in the T. nilotica crude extracts was considerably higher than pure acarbose (IC50 = 151.1 μg/mL), the most highly prescribed α-glucosidase inhibitor on the market. When T. nilotica crude extracts were fractionated using methanol, enhanced α-glucosidase inhibitory activity was observed in general, with the highest observed α-glucosidase inhibitory activity in the 30% methanol fraction (IC50 = 5.21 μg/mL). Kinetic studies further revealed a competitive reversible mechanism of inhibition by the plant extract. The phytochemical profiles of 50% ethanol extracts, aqueous extracts, and the methanolic fractions were investigated and compared using a metabolomics approach. Statistical analysis revealed significant differences in the contents of the crude extracts and fractions and potentially identified the molecules that were most responsible for these observed variations. Higher α-glucosidase inhibitory activity was associated with an enrichment of terpenoids, fatty acids, and flavonoids. Among the identified molecules, active compounds with known α-glucosidase inhibitory activity were detected, including unsaturated fatty acids, triterpenoids, and flavonoid glycosides. These results put forward T. nilotica as a therapeutic plant for type 2 diabetes and a source of α-glucosidase inhibitors.
α-葡萄糖苷酶抑制剂是一类重要的 2 型抗糖尿病药物，通过降低餐后高血糖起作用。目前，市场上仅存在三种合成抑制剂，因此需要新型的、天然的、更有效的具有这种活性的分子。在这项研究中，我们研究了柽柳的乙醇和水提物以及从水提粗提取物中制备的甲醇馏分抑制α-葡萄糖苷酶的能力。50%乙醇和水提取物均以浓度依赖的方式抑制α-葡萄糖苷酶，IC50 值分别为 12.5 μg/mL 和 24.8 μg/mL。重要的是，柽柳粗提取物中观察到的α-葡萄糖苷酶抑制活性明显高于市场上最常开的α-葡萄糖苷酶抑制剂阿卡波糖（IC50 = 151.1 μg/mL）。当用甲醇对柽柳粗提取物进行分级时，总体上观察到增强的α-葡萄糖苷酶抑制活性，在 30%甲醇馏分中观察到最高的α-葡萄糖苷酶抑制活性（IC50 = 5.21 μg/mL）。动力学研究进一步揭示了植物提取物的竞争性可逆抑制机制。使用代谢组学方法研究并比较了 50%乙醇提取物、水提取物和甲醇馏分的植物化学特征。统计分析显示粗提取物和馏分的含量存在显著差异，并可能确定了导致这些观察到的变化的主要分子。更高的α-葡萄糖苷酶抑制活性与萜类化合物、脂肪酸和类黄酮的富集有关。在所鉴定的分子中，检测到具有已知α-葡萄糖苷酶抑制活性的活性化合物，包括不饱和脂肪酸、三萜类化合物和黄酮苷类化合物。这些结果表明柽柳是 2 型糖尿病的治疗植物和α-葡萄糖苷酶抑制剂的来源。
