Therapeutic potential of rosamultin in UC: modulation of neutrophil activity, lactoferrin release, and ferroptosis via A2A adenosine receptor activation

1. Rosamultin significantly ameliorates DSS-induced colitis symptoms, with efficacy slightly superior to the clinical drug mesalazine. 2. Rosamultin suppresses neutrophil activation, degranulation, and NET formation, thereby reducing lactoferrin release and ultimately inhibiting ferroptosis. 3. The inhibitory effect of rosamultin on neutrophil activation is mediated through the A2A adenosine receptor. Ferroptosis-induced epithelial cell death and intestinal barrier impairment represent one of the pivotal pathogenic mechanisms in Ulcerative colitis (UC). Rosamultin is abundantly present in many edible Rosaceae plants with its remarkable antioxidant and anti-inflammatory activities. However, it remains unclear whether rosamultin has therapeutic effects on UC. In this paper, we report that rosamultin alleviates murine colitis, with efficacy matching or exceeding that of mesalazine. Proteomic analysis revealed that rosamultin primarily modulated proteins involved in neutrophil degranulation and iron ion homeostasis, distinct from mesalazine. Rosamultin suppressed ferroptosis not only in DSS-induced mice but also in erastin-stimulated HIEC cells. However, exogenous lactoferrin partially reversed rosamultin-mediated inhibition of ferroptosis and diminished its protective effects on UC. Additionally, rosamultin suppressed fMLP-induced neutrophil degranulation and PMA-induced NET formation. Furthermore, molecular docking, affinity-responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA) indicated that rosamultin binds to the A2A adenosine receptor (A2AR), and A2AR antagonist ZM241385 attenuated the suppressive effect of rosamultin on NETs. Our study establishes rosamultin as a promising UC therapeutic by defining a novel A2AR-mediated mechanism: the inhibition of neutrophil NETosis, which reduces ferroptosis and enhances barrier repair. These mechanistic insights ultimately validate the potential of rosamultin-containing functional foods.