Unveiling the Multitarget Potential of a Rare Caffeoyl Ester from Artemisia capillaris for Diabetes Mellitus: An Integrated In Vitro and In Silico Study

As a part of our ongoing search for bioactive constituents of Artemisia capillaris, we isolated 4-O-caffeoyl-2-C-methyl-d-threonic acid (PPT-14). This is a rare caffeic acid ester derivative that is reported here for the first time in the Artemisia species, which is the third occurrence in any plant species worldwide. In this study, we evaluated the anti-diabetic potential of PPT-14 using in vitro and in silico approaches. PPT-14 demonstrated significant inhibitory activity against two crucial enzymes linked to diabetes progression and complications: protein tyrosine phosphatase 1B (PTP1B) and aldose reductase (AR). These had IC₅₀ values of 64.92 and 19.50 µM, respectively. Additionally, PPT-14 exhibited free radical scavenging activity with 2,2-diphenyl-2-picrylhydrazyl (IC₅₀ 14.46 µM). Molecular docking and 200 ns molecular dynamics simulations confirmed that there were stable binding interactions with the key residues of PTP1B and AR, highlighting strong affinity and dynamic stability. Pharmacokinetic analyses revealed favorable water solubility, adherence to Lipinski’s Rule of Five, and minimal interactions with cytochrome P450 enzymes, indicating the drug-like potential of PPT-14. Toxicity studies confirmed its safety profile, showing no genotoxicity, hepatotoxicity, or significant toxicity risks, with an acceptable oral LD₅₀ value of 2.984 mol/kg. These findings suggest that PPT-14 could be a promising multitarget lead compound for ameliorating diabetes and its associated complications.