Design, synthesis, in vitro, in vivo and in silico pharmacological characterization of antidiabetic N-Boc-L-tyrosine-based compounds

In this study, we synthesized five N-Boc-L-tyrosine-based analogues to glitazars. The in vitro effects of compounds 1-5 on protein tyrosine phosphatase 1B (PTP-1B), peroxisome proliferator-activated receptor alpha and gamma (PPARα/γ), glucose transporter type-4 (GLUT-4) and fatty acid transport protein-1 (FATP-1) activation are reported in this paper. Compounds 1 and 3 were the most active in the in vitro PTP-1B inhibition assay, showing IC50s of approximately 44 μM. Treatment of adipocytes with compound 1 increased the mRNA expression of PPARγ and GLUT-4 by 8- and 3-fold, respectively. Moreover, both compounds (1 and 3) also increased the relative mRNA expression of PPARα (by 8-fold) and FATP-1 (by 15-fold). Molecular docking studies were performed in order to elucidate the polypharmacological binding mode of the most active compounds on these targets. Finally, a murine model of hyperglycemia was used to evaluate the in vivo effectiveness of compounds 1 and 3. We found that both compounds are orally active using an exploratory dose of 100 mg/kg, decreasing the blood glucose concentration in an oral glucose tolerance test and a non-insulin-dependent diabetes mellitus murine model. In conclusion, we demonstrated that both molecules showed strong in vitro and in vivo effects and can be considered polypharmacological antidiabetic candidates.