Phytochemical investigation and chromatographic separation of extracts from one new actinobacteria strain Amycolatopsis taiwanensis that was isolated from soil of Yilan township, in the north of Taiwan, led to the isolation of nine new compounds, amycolataiwanensins A-I (1-9, resp.), and one new natural product, namely amycolataiwanensin J (10). The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic-data analysis (1D- and 2D-NMR, MS, and UV) and comparison with literature data. The effect of some isolates on the inhibition of NO production in lipopolysaccharide-activated RAW 264.7 murine macrophages was evaluated. Of the isolates, 3, 5, 7 and 8 exhibited potent anti-NO production activity, with IC50 values of 17.52, 12.31, 17.81 and 13.32 μM, respectively, compared to that of quercetin, an iNOS inhibitor with an IC50 value of 35.94 μM. This is the first report on indole metabolite from the genus Amycolatopsis.
Keywords: Amycolatopsis taiwanensis; NO inhibition; Pseudonocardiaceae; actinobacteria; secondary metabolites.