Structures and antioxidant activity of diketopiperazines isolated from the mushroom Sarcodon aspratus = 능이버섯(Sarcodon aspratus)으로부터 분리한 diketopiperazine계 화합물의 화학구조 및 항산화활성

Abstract

Three antioxidants, Sa-1, Sa-2 and Sa-3, were isolated from the MeOH extract of the mushroom Sarcodon aspratus through EtOAc extraction, silica gel and Sephadex LH-20 column chromatography, and C18 HPLC. The structures of the compounds were determined mainly by NMR and mass spectroscopic data analyses. Sa-1, Sa-2 and Sa-3 were identified as diketopiperazines, and their structures were determined to be cyclo(prolylvalyl), cyclo(prolyl-leucyl) and cyclo(prolyl-isoleucyl), respectively. This is the first time that these compounds were isolated from this mushroom. They showed antioxidant activity by scavenging DPPH radical (EC50 0.15~0.18 mM) and superoxide radical (EC50 0.21~0.24 mM).