Naphthoquinone Derivatives with Anti-Inflammatory Activity from Mangrove-Derived Endophytic Fungus Talaromyces sp. SK-S009

Twelve 1, 4-naphthoquinone derivatives, including two new (1 and 2) and 10 known (3-12), were obtained from endophytic fungus Talaromyces sp. SK-S009 isolated from the fruit of Kandelia obovata. All structures were identified through extensive analysis of the nuclear magnetic resonance (NMR), mass spectrometry (MS) and circular dichroism (CD), as well as by comparison with literature data. These compounds significantly inhibited the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in the murine macrophage cell line (RAW 264.7 cells). The half maximal inhibitory concentration (IC50) values, except for compound 2, were lower than that of indomethacin (26.3 mu M). Compound 9 inhibited the LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions in RAW 264.7 macrophages. Additionally, compound 9 reduced the mRNA levels of pro-inflammatory factors interleukin (IL)1 beta, IL-6, and tumor necrosis factor (TNF)-alpha. The results of this study demonstrated that these 1, 4-naphthoquinone derivatives can inhibit LPS-induced inflammation.