Anti-inflammatory activities of compounds from twigs of Morus alba

Abstract Five new compounds, 10-oxomornigrol F ( 1 ), (7″ R )-(−)-6-(7″-hydroxy-3″,8″-dimethyl-2″,8″-octadien-1″-yl)apigenin ( 2 ), ramumorin A ( 3 ), ramumorin B ( 4 ), and (4 S ,7 S ,8 R )-trihydroxyoctadeca-5 Z -enoic acid ( 5 ), together with 31 known compounds ( 6–36 ), were isolated from the twigs of Morus alba (Moraceae). The chemical structures of these compounds were established using spectroscopic analyses, 1D and 2D NMR, high-resolution electrospray ionization mass spectrometry (HRESIMS), and Mosher's methods. The anti-inflammatory activities of the compounds were evaluated by investigating their ability to inhibit lipopolysaccharide (LPS)-induced nitric oxide (NO) production in macrophage RAW 264.7 cells. Compounds 1 , 2 , 13 , 17 , 19 , 25 – 28 , and 32 showed inhibitory effects with IC 50 values ranging from 2.2 to 5.3 μg/mL. Compounds 1 , 2 , 17 , 25 , and 32 reduced LPS-induced inducible nitric oxide synthase (iNOS) expression in a concentration-dependent manner. In addition, pretreating the cells with compound 1 , 17 , and 32 significantly suppressed LPS-induced expression of cyclooxygenase-2 (COX-2) protein.