능이버섯(Sarcodon aspratus) 자실체의 MeOH 추출물을 n-hexane, EtOAc, n-BuOH 및 물로 추출하였다. 이 중 프리라디칼 소거활성을 나타내는 EtOAc 분획을 silica gel 및 Sephadex LH-20 column chromatograpy를 실시한 후 $C_{18}$ HPLC를 통해 프리라디칼 소거활성을 나타내는 3종의 항산화 활성물질 Sa-1, Sa-2 및 Sa-3를 분리하였다. 각 화합물의 구조를 NMR 및 MS 등의 스펙트럼 데이터를 분석하여, diketopiperazine계 화합물들인 cyclo(prolyl-valyl), cyclo(prolyl-leucyl) 및 cyclo(prolyl-isoleucyl)로 동정하였다. 이 화합물들은 능이버섯으로부터 최초로 분리되었으며, 이들의 항산화 활성을 측정한 결과 DPPH radical 소거활성$(EC_{50};0.15{sim}0.18;mM)$ 및 superoxide radical 소거활성$(EC_{50};0.21{sim}0.24;mM)$을 나타내었다.
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 $C_{18}$ 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(prolyl-valyl), 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 $(EC_{50};0.15{sim}0.18;mM)$ and superoxide radical $(EC_{50};0.21{sim}0.24;mM)$.
