A new thiazole containing pyridoacridine alkaloid, named sagitol D (1), and five known alkaloids kuanoniaminesA (2), C (3), D (4), E (5), and F (6), have been isolated from an unidentified Vietnamese ascidian. The structure of the new compound was established from NMR spectroscopic data. Kuanoniamines C, D, E, and F showed moderate antioxidant activity in the DPPH (IC50 36 μM) and ABTS assays (TE = 0.5), while sagitol D showed weak activity (IC50 92 μM; TE = 0.10), and kuanoniamine A was inactive.
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