Effects of drying methods on polyphenolic composition and anti‐inflammatory activity of Lilium lancifolium leaves and stems

BACKGROUND: Lilium lancifolium Thunb. (tiger lily) is widely utilized in East Asia for its medicinal and edible bulb, whereas its aerial parts (leaves and stems) are largely discarded despite containing potentially valuable polyphenolic constituents. This study investigated how different drying methods affect the polyphenolic composition and anti-inflammatory activity, and explored associated transcriptional responses related to inflammation. RESULTS: Eight target polyphenols were detected and quantified across leaf and stem samples using high-performance liquid chromatography, with regaloside A and regaloside C as the dominant constituents. Drying methods markedly influenced polyphenol stability: vacuum drying increased the summed concentration of quantified polyphenols in leaves and partially preserved these constituents in stems, whereas hot-air and natural-air drying caused substantial degradation. In a lipopolysaccharide-induced zebrafish inflammation model, stem extracts from fresh and vacuum-dried samples exhibited the strongest inhibition of NO and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β). For leaves, the response varied by inflammatory endpoint: fresh leaf extract showed the greatest reductions in NO and TNF-α, whereas IL-6 and IL-10 did not differ significantly among the extract-treated groups. RT-qPCR analysis demonstrated that fresh stem and leaf extracts downregulated pro-inflammatory gene expression while upregulating il10, with higher concentrations showing transcriptional changes consistent with attenuation of NF-κB/MAPK-associated inflammatory responses. CONCLUSION: Drying methods profoundly influence the chemical composition and bioactivity of L. lancifolium aerial parts. Vacuum drying showed tissue-dependent advantages in polyphenol preservation, while inflammation-related activity varied according to tissue and endpoint. These findings highlight the potential of leaves and stems as sustainable resources for developing natural anti-inflammatory agents and promote their high-value utilization. © 2026 Society of Chemical Industry.