Bioactive phenolics from the bulbs of Hymenocallis littoralis

Hymenocallis littoralis, commonly known as Coastal Spider lily, is a perennial herbaceous plant in the Amaryllidaceae family. It is native to tropical and subtropical regions of the Americas, celebrated for its remarkably beautiful flowers. In this study, five previously undescribed chromones, one new benzopyran, along with five known chromones and fourteen known flavonoids, were identified. Among these, compounds 6, 9, 12, 18, 19, 20, and 22 were natural products isolated from H. littoralis for the first time. Their structures were determined using spectroscopic techniques (NMR and MS). Anti-inflammatory activities of the isolated chromone and benzopyran were evaluated in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophage cells. Compound 11 exhibited significant inhibitory effects on nitric oxide (NO) production with an IC₅₀ value of 38.24 μM. Further investigations revealed that compound 11 exerted its anti-inflammatory activity by preventing the nuclear translocation of NF-κB and down-regulating the expression of pro-inflammatory factors, including iNOS, COX-2, IL-1β, and IL-6, in a concentration-dependent manner. This study provides evidence that benzopyran from H. littoralis may serve as a potential source of an anti-inflammatory agent.