Table 2.
IC50 and Ki values of principal thiosugar sulfoniums (1–6), acarbose, voglibose, miglitol, and 1-deoxynojirimycin against human small intestinal maltase
| IC50 (μM) | Ki (μM) | |
|---|---|---|
| Salacinol (1) | 4.9 | 0.44 |
| Neosalacinol (2) | 9.0 | 1.2 |
| Kotalanol (3) | 3.9 | 0.32 |
| Neokotalanol (4) | 3.9 | 0.33 |
| Ponkoranol (5) | 5.0 | 0.32 |
| Neoponkoranol (6) | 4.0 | 0.70 |
| Acarbose | 15.2 | 2.6 |
| Voglibose | 1.3 | 0.17 |
| Miglitol | 3.7 | 0.57 |
| 1-Deoxynojirimycin | 0.96 | 0.071 |
Maltase inhibitory activity: Human small intestinal microsome (batch MIC318017, purchased from BIOPREDIC International, Rennes, France) in 0.1 M maleate buffer (pH 6.0) was prepared as an enzyme solution. A substrate solution in the maleate buffer (maltose: 74 mM, 50 μL), the test sample solution (25 μL), and the enzyme solution (25 μL) were mixed at 37 °C for 30 min and then immediately heated in boiling water for 2 min to stop the reaction. The glucose concentrations were determined using the glucose-oxidase method. The IC50 value was determined graphically by plotting the percent inhibition vs. log of the test compound. Each value represents the mean of four experiments. Commercial acarbose, voglibose, miglitol, and 1-deoxynojirimycin were purchased from FUJIFILM Wako Pure Chemicals Co. (Osaka, Japan)
Kinetic analysis: The enzyme and test samples (1.0–4.0 μM: acarbose; 1 and 3: 0.5–2.0 μM; 2–6 and miglitol: 0.25–1.0 μM; 0.10–0.40 μM: voglibose) were incubated with increasing concentrations of maltose (3.0–10.6 mM)
Reproduced in part with permission from Nutrients, 7, 1480–1493. Copyright [2015] MDPI