Integrated in silico molecular docking andin vitro evaluation of phytoconstituentsas aldose reductase inhibitors fordiabetes management

Abstract

Aims: This study aims to evaluate the in vitro antidiabetic potential of selected phytoconstituents belonging to alkaloidal
amide, flavone, saponin, and alkaloid classes, and to investigate their potential role in modulating insulin-related
activity, thereby elucidating their therapeutic relevance in diabetes management. Materials and Methods: Through
in silico and in vitro methods, possible aldose reductase (AR) inhibitors were identified using a phytoconstituent
database collected from plants. To estimate the binding energy and interaction key of the residues, a molecular library
comprising representative phytochemicals of the alkaloidal amide, flavone, saponin, and alkaloid classes was created
and utilized for molecular docking-based virtual screening against human AR. Candidates were chosen based on their
docking results for experimental validation. Candidates were chosen based on their docking results for experimental
validation. A sample cuvette containing 0.3 mL of enzyme extract, 0.5 mL of nicotinamide adenine dinucleotide
phosphate (0.104 mM), 0.75 mL of sodium phosphate buffer (0.1 M, pH 6.2), 0.1 mL of phytoconstituents, and
0.7 mL of deionized water was used to measure the AR inhibitory activity. Using in vitro anti-diabetic models,
assays were conducted. A spectrophotometric enzyme inhibition assay was used to measure the in vitro AR
inhibitory activity. The antidiabetic potential was assessed by calculating the IC50 values and the percentage of
inhibition. Results: Strong binding affinities and advantageous interactions between a number of phytoconstituents
and the AR active site were found by molecular docking studies, indicating the potential for their inhibitory effects.
Subsequent in vitro evaluation confirmed significant, dose-dependent AR inhibition by selected compounds, with
aegelin, quercetin, piperine, apigenin, and chrysin exhibiting the highest inhibitory activities and low IC₅₀ values.
The inhibition of AR enzyme activity was tested at doses ranging from 100 to 700 μg/mL. Aegelin, quercetin,
piperine, apigenin, and chrysin showed the highest levels of inhibition (87.18, 86.67, 86.33, 85.77, and 81.13%,
respectively). The concordance between computational predictions and experimental findings validates the screening
strategy and highlights the relevance of these phytoconstituents as potential modulators of glucose metabolism and
diabetic complications. Conclusion: The present study demonstrates that an integrated molecular docking and in
vitro evaluation approach is effective in identifying promising plant-derived AR inhibitors. The findings highlight
selected phytoconstituents as potential lead candidates for the development of safer, natural antidiabetic therapeutics.