In silico Pharmacokinetics and In vivo Anti-inflammatory Activity of C-4 Composition

Inflammation remains a key pathological process underlying a wide range of chronic diseases, and natural compounds continue to attract attention as safer therapeutic alternatives. In this study, a novel composition (C-4), containing Cysteine, L-Carnitine, and Quercetin, was evaluated through a combination of in vivo, in silico, and pharmacokinetic approaches. The carrageenan-induced paw edema model in rats was employed to assess acute anti-inflammatory activity. C-4 administration (10 mg/kg, oral) significantly reduced paw swelling compared to the control and was comparable to the reference drug Loxidol (7 mg/kg), with the most pronounced effect observed after 3 hours. To further explain these effects, SwissADME pharmacokinetic predictions were performed. Both Cysteine and L-Carnitine exhibited high solubility but poor gastrointestinal absorption and no blood–brain barrier permeability, suggesting limited systemic bioavailability. Neither compound inhibited major cytochrome P450 isoforms nor acted as P-glycoprotein substrates, indicating a favorable safety profile but reduced distribution potential. Molecular docking studies against key pro-inflammatory proteins (COX-2, TNF-α, NF-κB, IL-6, MAPK) revealed that Quercetin possessed the strongest binding affinities, consistent with its marked in vivo anti-exudative activity. L-Carnitine showed moderate interactions, while Cysteine demonstrated weak direct binding, supporting its indirect role in redox regulation rather than direct enzymatic inhibition. The integration of experimental, pharmacokinetic, and computational data highlights Quercetin as the primary contributor to the anti-inflammatory activity of the C-4 composition, with L-Carnitine and Cysteine playing complementary cytoprotective and antioxidant roles. These findings suggest that combined formulations of natural compounds may provide synergistic benefits and represent promising candidates for the development of safe, multi-targeted anti-inflammatory therapies.