Anti-inflammatory activity of alkaloids from the leaves of Atalantia buxifolia

A chemical study on the leaves of Atalantia buxifolia afforded ten compounds. Among them, two were characterized as new alkaloids, namely a benzoyltyramine designated hortiamide B ( 1 ) and an acridone alkaloid named acrignine B ( 2 ), while the remaining eight were known analogues ( 3–10 ). Extensive spectroscopic techniques were employed to determine their structures, with the absolute configuration of 1 being unambiguously established by single-crystal X-ray diffraction analysis. In an evaluation of anti-inflammatory potential, all compounds were tested for their ability to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. This assay revealed that compounds 1 , 9 , and 10 possessed notable activity, with IC 50 values of 8.5 ± 0.7, 12.7 ± 1.2, and 23.4 ± 2.1 μM, respectively. The present work enriches the phytochemical profile of A. buxifolia and highlights specific isolates as valuable candidates for future development of anti-inflammatory agents. • Two new alkaloids were isolated from the leaves of Atalantia buxifolia. • The absolute configuration of hortiamide B was defined by X-ray crystallography. • Compounds 1 , 9 , and 10 exhibited significant anti-inflammatory activity.