Immunomodulatory Effects of Hyoscine Butylbromide on Mammalian Macrophages

Hyoscine butylbromide (HB), popularly known as Buscopan, is a common anticholinergic antispasmodic used worldwide for gastrointestinal disorders. While the interaction between the cholinergic system and immunity is increasingly recognized, the direct immunomodulatory potential of HB on macrophages remains underexplored. Therefore, this study aimed to investigate whether HB exhibits immunomodulatory properties on a mammalian macrophage cell line, J774.2, in vitro. Proinflammatory cytokine production (TNF-α, IL-6, GM-CSF, and IL-12p40) in LPS-stimulated macrophages was quantified by ELISA. Based on the obtained results, it could be determined that HB did not affect cell viability at the tested concentrations. However, HB revealed a comparatively strong anti-inflammatory effect in LPS-stimulated macrophages. Our findings reveal that HB significantly and dose-dependently reduces IL-12p40, TNF-α, and IL-6 levels, with the most profound inhibition observed in IL-12p40 (p < 0.001). Surprisingly, no significant effect was observed on the levels of GM-CSF. Such selective modulation implies that the effect of HB targets specific inflammatory signaling pathways-most likely by the blockade of nonneuronal muscarinic receptors-rather than causing general suppression of cytokine release. These findings suggest that HB, besides being an effective muscle relaxant, possesses intrinsic anti-inflammatory potential that can modulate immune responses. Identifying the specific cytokine-suppressing effect of HB illuminates its broader clinical profile and lays a sound foundation for its use in inflammatory gastrointestinal conditions such as irritable bowel syndrome (IBS). This study fills a critical gap in the literature on the immunomodulatory effect of hyoscine butylbromide.