Phloroglucinols with Antioxidant Activities Isolated from Lysidice rhodostegia

Two new phloroglucinols, lysidisides X and Y (1 and 2), and two known compounds, 2-(2-methylbutyryl)phloroglucinol 1-O-β-d-glucopyranoside (3) and (E)-resveratrol 3-(6″-galloyl)-O-β-d-glucopyranoside (4), have been isolated from the roots of Lysidice rhodostegia. The structures of 1 and 2 were elucidated primarily by NMR experiments. Their absolute configurations were deduced via circular dichroism (CD) data and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 exhibited significant antioxidative activities with IC₅₀ values of 12.0 and 11.8 µM, respectively.