Targeting mTORC1/TGFB1 signaling with a novel Bergapten-Esculetin combination: a computational and experimental approach in idiopathic pulmonary fibrosis.

This study investigates the synergistic antifibrotic potential of coumarin derivatives Bergapten (BER) and Esculetin (ESC) in idiopathic pulmonary fibrosis (IPF), a progressive lung disease characterized by epithelial-mesenchymal transition and fibrotic remodeling. Current therapies have limited effectiveness, often focusing on single pathways and failing to reverse disease progression. Therefore, synergistic and multi-targeted strategies are required to inhibit key profibrotic signals with minimal toxicity. In this research, an in-silico and in-vitro approach was used to evaluate whether ESC enhances the cytotoxic activity of BER in fibroblast models. In-silico Pharmacokinetic profiling using SwissADME and pkCSM confirmed favorable drug-likeness, low toxicity, and good absorption. Target prediction and Network pharmacology identified 104 common targets, with MTOR and TGF-β1 identified as major regulators within the PI3K/Akt/mTOR signaling pathway. Molecular docking studies indicate strong binding affinities of BER and ESC toward these targets, while molecular dynamics simulations indicate stable MTOR-ligand interactions compared to TGF-β1. MM-GBSA analyses further supported their binding stability, and density functional theory calculations indicated favorable HOMO-LUMO energy gaps correlated with redox reactivity. In-vitro studies using L929 fibroblasts showed that ESC significantly enhanced the cytotoxic efficacy of BER, particularly at fixed ratios of 1:2 and 2:1, as validated by the Chou-Talalay method (combination index < 1 and Dose Response Index > 1). The 1:2 ratio exhibited the strongest synergistic effect, and these results support the potential of BER and ESC as antifibrotic agents for further evaluation in IPF.