Catenulamide A, an acylated tripeptide containing 5-methoxy-L-kynurenine lactam from an actinomycete of the genus Catenuloplanes.

A novel linear acylated tripeptide, catenulamide A (1), was isolated from a culture extract of Catenuloplanes sp. RD061694. Comprehensive spectroscopic analyses coupled with Marfey's analysis established that 1 comprised n-butyric acid, N-methyl-L-isoleucine, L-valine, and a lactamized new amino acid, 5-methoxy-L-kynurenine lactam. Compound 1 exhibited dual PPARα and PPARγ agonist activities in a luciferase reporter gene assay and anti-inflammatory potential by inhibiting nitric oxide production in lipopolysaccharide-stimulated murine macrophages with an IC50 value of 29 µM. Furthermore, 1 at 1 μM promoted radicle elongation of germinated lettuce seeds by 40% compared to vehicle-treated seeds.