Anti-inflammatory Metabolites from Chaetomium nigricolor

Twelve metabolites were obtained from the culture media of Chaetomium nigricolor, including a new furan derivative, methyl succinyl Sumiki's acid (1), and two new atropisomers of the previously reported bis-naphtho-γ-pyrones, (aS)-asperpyrone A and (aS)-fonsecinone A (2 and 3). The structures were elucidated by spectroscopic, chemical, and chiroptical techniques. Compounds 2 and 3 inhibited nitric oxide production in lipopolysaccharide-stimulated RAW 264.7 macrophages. Compound 2 was found to inhibit nuclear factor-kappa B and c-Jun N-terminal kinase activation, in turn suppressing pro-inflammatory mediators and cytokines including nitric oxide, prostaglandin E₂, interleukin (IL)-1β, tumor necrosis factor-α, IL-6, and IL-12.