Antioxidative acylphloroglucinols from the roots of Lysidice rhodostegia

Four new acylphloroglucinols, lysidicins I and J (1 and 2), and lysidisides V and W (3 and 4), were isolated from the roots of Lysidice rhodostegia. Among them, compound 1 is a novel acylphloroglucinol, and compound 2 is the first naturally occurring acylphloroglucinol derivative with an uncommon spiro(benzofuran-[2H]pyran) skeleton. Their structures were elucidated by spectroscopic and chemical methods. The absolute configuration of 1 was assigned by employing dimolybdenum tetraacetate-induced CD spectrum method, and that of 2 was determined by analysis of their experimental and theoretically calculated CD spectra. Compounds 3 and 4 exhibited potent antioxidative activity with IC50 values of 3.29 and 3.39 μM, respectively.