In this study, a novel series of 8‑methoxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid and N-substituted 8‑methoxy-2-oxo-1,2-dihydroquinoline-3-carboxamide derivatives 2–10 were designed, synthesized, and screened for their in vitro α-amylase, α-glucosidase and DPP-4 enzymes resulting in effective anti-diabetic agents. The research results showed that these compounds had significant inhibitory effects on both α-amylase and α-glucosidase enzymes. Specifically, compound 4 demonstrated the most potency with IC₅₀ of 30.50±2.67 and 19.98±3.24µM for α-glucosidase and α-amylase activities respectively, which was significantly more powerful than the drug Acarbose (IC₅₀ = 48.97±3.42µM and 16.59±3.78µM). Also, compound 4 Exhibits strong inhibitory activity against DPP-4 with an IC₅₀ value of 0.035±6.65nM as compared to the positive control sitagliptin (IC₅₀ =0.014±6.91nM).Also, we had performed the kinetic study for the most potent compound 4 on α-amylase and α-glucosidase enzymes to study the type of inhibition of enzymes. The results showed that compound 4 was non-competitive inhibitor that can bind to an enzyme at a site other than the active site, known as the allosteric site. Investigating the potential of compound 4 to treat diabetes, we evaluated its cytotoxic and antioxidant properties. Our results indicated that it had a highly effective scavenging ability for DPPH with an IC₅₀ value of 15.45±3.83µM, outperforming ascorbic acid (IC₅₀ =7.24±8.01µM), the positive control. Exhilarated by these promising findings, we continue to explore the varied possibilities for these compounds.

在这项研究中，一系列新型8-甲氧基-2-氧代-1,2-二氢喹啉-3-羧酸和N-取代的8-甲氧基-2-氧代-1,2-二氢喹啉-3-甲酰胺衍生物2-设计、合成并筛选了 10 种体外α-淀粉酶、α-葡萄糖苷酶和 DPP-4 酶，从而形成有效的抗糖尿病药物。研究结果表明，这些化合物对α-淀粉酶和α-葡萄糖苷酶均具有显着的抑制作用。具体而言，化合物 4 对 α-葡萄糖苷酶和 α-淀粉酶活性的IC _{50分别为 30.50±2.67 和 19.98±3.24μM，表现出最强的效力，明显比药物阿卡波糖（IC 50} = 48.97±3.42μM 和 16.59±3.78μM）。此外，与阳性对照西他列汀相比，化合物 4 对 DPP-4 表现出强抑制活性，IC ₅₀值为 0.035±6.65nM (IC ₅₀ =0.014±6.91nM)。此外，我们还进行了大多数动力学研究。有效的化合物 4 对 α-淀粉酶和 α-葡萄糖苷酶的作用，以研究酶的抑制类型。结果表明，化合物4是非竞争性抑制剂，可以在活性位点以外的位点（称为变构位点）与酶结合。为了研究化合物 4 治疗糖尿病的潜力，我们评估了其细胞毒性和抗氧化特性。我们的结果表明它对 DPPH 具有高效的清除能力，IC 为₅₀值为15.45±3.83μM，优于阳性对照抗坏血酸(IC _{50 =7.24±8.01μM)。}我们对这些有希望的发现感到兴奋，继续探索这些化合物的各种可能性。