title: New phenanthrenes and stilbenes from Dendrobium loddigesii.
abstract: New phenanthrenes, loddigesiinols A (1) and B (7), and stilbenes, loddigesiinols C (8) and D (9), were isolated from 80% ethanol extract of Dendrobium loddigesii ROLFE (Orcharedceae) along with known compounds, including five phenanthrenes, three stilbenes, two lignans, and three sterols. Their structures were determined by spectroscopic studies. These compounds were evaluated for their inhibitory activities against nitric oxide (NO) production and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging. Phenanthrenes (1-3, 7) and dihydrophenanthrenes (4-6) showed significant inhibitory activity against NO production. In particular, 2 showed stronger inhibitory activity against NO production than 5 and 6. This suggested that this phenanthrene is a stronger inhibitor of NO production than dihydrophenanthrene. The new phenanthrenes, loddigesiinols A (1) and B (7), significantly inhibited NO production with IC(50) values of 2.6 and 10.9 muM, respectively. One new dihydrostilbene, loddigesiinol D (9), showed weak inhibitory activity against NO production with an IC(50) value of 69.7 microM, but the other new dihydrostilbene, loddigesiinol C (8), did not show this activity at 100 microM.
authors.affiliation: Research Unit of Pharmacognosy, School of Pharmacy, Nihon University, 7-7-1 Narasinodai, Funabashi, Chiba 274-8555, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ito
authors.forename: Keiichi
authors.initials: K
authors.lastname: Matsuzaki
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Akihiro
authors.initials: A
authors.lastname: Daikonya
authors.forename: Nai-Li
authors.initials: NL
authors.lastname: Wang
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Yao
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitanaka
mesh_terms: D000818:Animals; D002460:Cell Line; D031667:Dendrobium / Q000737:chemistry* / Q000145:classification*; D020128:Inhibitory Concentration 50; D008264:Macrophages / Q000187:drug effects; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D010616:Phenanthrenes / Q000737:chemistry* / Q000494:pharmacology; D035261:Plant Components, Aerial / Q000737:chemistry; D013267:Stilbenes / Q000737:chemistry*
chemical_list: D010616:Phenanthrenes; D013267:Stilbenes; C551754:loddigesiinol A; C551753:loddigesiinol B