Lanostanes fromPhellinus igniariusand Their iNOS Inhibitory Activities

Four new lanostanol-type triterpenoids, igniarens A - D ( 1- 4), were isolated from the fruit body of Phellinus igniarius together with two known triterpenoids, and two known ergostanes. These four new compounds were identified by spectroscopic analysis as 22 R-hydroxy-24-methylene-29-norlanost-7, 9(11)-dien-3-one (1), 3alpha,22 R-dihydroxy-24-methylene-29-norlanost-7, 9(11)-diene (2), 3alpha,22 R-dihydroxy-24-methylene-29-norlanost-8-ene ( 3), and 3alpha,22 R-dihydroxy-24-methylenelanost-8-ene ( 4). Their effects on NO production in lipopolysaccharide (LPS)-activated macrophages were assessed. Compounds 1- 8 inhibited NO production in activated RAW 264.7 cells to various degrees. The most potent compound 5alpha,8alpha-epidioxy-22 E-ergosta-6,22-dien-3beta-ol ( 7) significantly inhibited LPS-induced NO production in a concentration-dependent manner without affecting the cellular viability, with an IC (50) of 37.57 +/- 1.38 microM.