Background: The NLRP3 inflammasome is a multiprotein complex of the innate immune system that mediates the maturation and secretion of interleukin-1β (IL-1β) and plays a pivotal role in the pathogenesis of chronic inflammatory diseases, including asthma, metabolic disorders, and autoimmune diseases. However, natural product-derived metabolites that directly modulate NLRP3 activation remain limited. This study aimed to investigate the inhibitory effects of Methods: TMH was prepared by methanol extraction and chemically profiled using UPLC-QTOF/MS analysis. Human monocytic THP-1 cells and murine macrophage J774A.1 cells were used to evaluate inflammasome activation. Following lipopolysaccharide (LPS) priming, cells were stimulated with ATP or nigericin to induce NLRP3 inflammasome activation. IL-1β secretion was quantified by ELISA, and the expression of NLRP3 inflammasome-related proteins was evaluated by Western blot analysis. Cell viability was assessed using the EZ-CYTOX assay. Results: TMH exhibited no cytotoxicity at concentrations up to 100 μg/mL. TMH treatment (10, 50, and 100 μg/mL) significantly reduced LPS/ATP- or LPS/nigericin-induced IL-1β secretion. However, even at the highest concentration tested (100 μg/mL), TMH did not significantly affect pro-IL-1β expression or NF-κB signaling, indicating that the priming step was not altered. Instead, TMH suppressed NLRP3 inflammasome activation during the activation phase. In addition, TMH treatment at 1 μg/mL was associated with reduced NLRP3 ATPase activity, suggesting a potential effect on inflammasome assembly. Conclusion: TMH attenuated NLRP3 inflammasome activation without affecting the priming step. These findings suggest that TMH may act as a natural product-derived modulator of NLRP3-mediated inflammatory responses.