New isocoumarin and stilbenoid derivatives from the tubers of <i>Sparganium stoloniferum</i> (Buch.-Ham.)

<p>A new isocoumarin derivative 8,5′-dihydroxy-6′-methoxy-4-phenyl-5,2′-oxidoisocoumarin (<b>1</b>) and a new stilbenoid derivative methyl 5-hydroxy-2-(2-hydroxyphenyl)benzofuran-4-carboxylate (<b>2</b>) together with nine known compounds (<b>3</b>–<b>11</b>) were isolated from the tubers of <i>Sparganium stoloniferum</i> Buch.-Ham.. Another stilbenoid derivative (<b>3)</b> and a xanthone (<b>4)</b> were identified as new natural products and compounds <b>5</b>–<b>10</b> were obtained for the first time from the genus <i>Sparganium</i>. All their structures were elucidated by comprehensive spectroscopic analysis and comparison with available literature information.