Postprandial glucose excursions contribute substantially to overall glycemic burden in type 2 diabetes. Pharmacologic inhibition of digestive glycosidases — specifically α‑amylase and α‑glucosidase — is an established approach to slow carbohydrate digestion and reduce glucose absorption. This study investigated a series of 2,4‑thiazolidinedione (TZD) derivatives as potential dual inhibitors of these enzymes, aiming to identify molecules with strong inhibitory activity, acceptable in silico ADME profiles, and preliminary cellular safety.
The authors synthesized twenty‑one TZD‑based derivatives organized into two series: 5AT (compounds a–g) and 5IT (compounds a–n). The report lists these series as the primary chemical scaffolds evaluated for enzyme inhibition, with specific structural variations that included indole and other substituents. The full synthetic details, including yields, reaction conditions, and structural characterization, were reported in the primary article (not reproduced here in full in the abstract).
Molecular docking was performed to estimate binding affinities of the synthesized compounds toward α‑glucosidase and α‑amylase. Reported docking scores indicated favorable predicted interactions: binding affinities ranged from −7.1 to −9.7 kcal/mol against α‑glucosidase and from −8.5 to −10.7 kcal/mol against α‑amylase. The authors additionally evaluated ADME and drug‑likeness properties and described them as acceptable for the most promising compounds, supporting their suitability for further experimental testing.
Enzyme inhibition assays identified multiple active compounds. Notably, 5IT(b) emerged as the most potent α‑amylase inhibitor with an IC50 value of 6.7 ± 0.2 μM. This activity surpassed that of the clinical reference acarbose, which showed an IC50 of 27.30 ± 0.1 μM in the same assay conditions reported by the authors.
For α‑glucosidase, the methoxy‑substituted indole derivative 5IT(e) was the strongest inhibitor, with an IC50 of 10.89 ± 1.8 μM. Several other 5IT derivatives also showed activity against one or both enzymes.
Based on the in vitro data, the following compounds demonstrated dual inhibitory activity (effective against both enzymes): 5IT(a), 5IT(b), 5IT(e), 5IT(f), 5IT(h), 5IT(i), 5IT(j), 5IT(l), and 5IT(m). The presence of multiple dual‑acting compounds supports the concept that the TZD scaffold can be tuned to simultaneously target α‑amylase and α‑glucosidase.
Kinetic enzyme studies were reported for key lead molecules to characterize the mode of inhibition. The most potent α‑amylase inhibitor, 5IT(b), followed a mixed‑type inhibition pattern, with reported inhibition constants Ki = 50.9 μM and Kis = 26.33 μM. The leading α‑glucosidase inhibitor, 5IT(e), exhibited competitive inhibition with a reported Ki of 18.8 μM. These kinetic profiles provide mechanistic insight into how the compounds interact with each enzyme and can inform structure‑activity relationship (SAR) and optimization strategies.
The most potent compounds were evaluated for cellular toxicity using MTT assays. The abstract reports that the most active derivatives showed favourable cell viability, indicating an absence of overt cytotoxicity in the tested conditions. Details on cell lines, concentrations tested, and exact viability percentages were presented in the full text but are not provided in the abstract summary.
The authors conclude that several synthesized 2,4‑thiazolidinedione derivatives act as promising dual inhibitors of α‑amylase and α‑glucosidase, with lead compounds 5IT(b) and 5IT(e) demonstrating superior in vitro potency relative to the reference drug acarbose for α‑amylase and potent α‑glucosidase inhibition, respectively. Acceptable in silico ADME profiles and favourable cell viability in preliminary assays support further preclinical investigation. These findings position TZD derivatives as candidate scaffolds for the development of antidiabetic agents aimed at reducing postprandial hyperglycaemia via dual enzyme targeting.
Note: The summary above reflects information reported in the PubMed abstract. Specific experimental methods, full kinetic plots, synthetic procedures, and detailed ADME results are available in the full article but were not included in the abstract.