A Novel Polysaccharide from the Flowers of Lilium lancifolium Alleviates Pulmonary Fibrosis In Vivo and In Vitro

Lily flowers are widely used in China for lung nourishment; however, their active ingredients remain unknown. To address this question, we isolated a novel polysaccharide (L005-B) from the flowers of Lilium lancifolium. Its backbone is comprised of Glcp, Galp, and 1,2-linked α-Rhap. The branch is composed of Xyl and T-α-Glcp residues substituted at the C-4 position of Rhap, along with portions of Glcp, Galp, Araf, and GlcpA residues substituted at the C-4 position of glucose or the C-3 position of galactose. Bioactivity study showed that L005-B alleviated fibrosis-associated protein (fibronectin, collagen, α-SMA) expression in TGF-β1-induced human fibroblast cells (MRC-5). Moreover, L005-B significantly inhibited the epithelial-mesenchymal transition of the human alveolar type II epithelial cell. More importantly, L005-B dramatically improved bleomycin-induced histopathological changes and attenuated the pulmonary index and hydroxyproline contents. Taken together, our findings revealed that L005-B may serve as a promising leading compound for the development of novel antipulmonary fibrosis therapeutics.