A Novel Polysaccharide from the Flowers of Liliumlancifolium Alleviates Pulmonary Fibrosis <i>In Vivo</i> and <i>In Vitro</i>

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 Glc<i>p</i>, Gal<i>p</i>, and 1,2-linked α-Rha<i>p</i>. The branch is composed of Xyl and T-α-Glc<i>p</i> residues substituted at the C-4 position of Rha<i>p</i>, along with portions of Glc<i>p</i>, Gal<i>p</i>, Ara<i>f</i>, and Glc<i>p</i>A 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.