Volume 9 Issue 3
Inhibitory Effects of Benzaldehyde Derivatives from the Marine Fungus Eurotium sp. SF-5989 on Inflammatory Mediators via the Induction of Heme Oxygenase-1 in Lipopolysaccharide-Stimulated RAW264.7 Macrophages
Kyoung-Su Kim, Xiang Cui, Dong-Sung Lee, Wonmin Ko, Jae Hak Sohn, Joung Han Yim, Ren-Bo An, Youn-Chul Kim and Hyuncheol Oh
1College of Pharmacy, Wonkwang University, Iksan 570-749, Korea
2Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan 570-749, Korea
3Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, Yanbian University College of Pharmacy, 977 Gongyuan Road, Yanji 133002, China
4Inha Research Institute for Medical Sciences, Inha University School of Medicine, Incheon 400-712, Korea
5College of Medical and Life Sciences, Silla University, Busan 617-736, Korea
6Korea Polar Research Institute, KORDI, 7-50 Songdo-dong, Yeonsu-gu, Incheon 406-840, Korea
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Abstract
Two benzaldehyde derivatives, flavoglaucin (1) and isotetrahydro-auroglaucin (2), were isolated from the marine fungus Eurotium sp. SF-5989 through bioassay- and 1H NMR-guided investigation. In this study, we evaluated the anti-inflammatory effects of these compounds in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. We demonstrated that compounds 1 and 2 markedly inhibited LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by suppressing inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression without affecting cell viability. We also demonstrated that the compounds reduced the secretion of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6). Furthermore, compounds 1 and 2 inhibited LPS-induced nuclear factor-κB (NF-κB) activation by suppressing phosphorylation of IkappaB (IκB). These results indicated that the anti-inflammatory effects of these benzaldehyde derivatives in LPS-stimulated RAW264.7 macrophages were due to the inactivation of the NF-κB pathway. In addition, compounds 1 and 2 induced heme oxygenase-1 (HO-1) expression through the nuclear transcription factor-E2–related factor 2 (Nrf2) translocation. The inhibitory effects of compounds 1 and 2 on the production of pro-inflammatory mediators and on NF-κB binding activity were reversed by HO-1 inhibitor tin protoporphyrin (SnPP). Thus, the anti-inflammatory effects of compounds 1 and 2 also correlated with their ability of inducing HO-1 expression.
Keywords:enzaldehyde derivatives; marine fungus; Eurotium rubrum; RAW264.7 macrophages; heme oxygenase-1; anti-inflammatory effect; nuclear factor-κB