New 3,5,4′-Trihydroxystilbene (Resveratrol) Oligomers from <i>Carex fedia</i> Nees var. <i>miyabei</i> (Franchet) T. Koyama (Cyperaceae)

Abstract

The chemical constituents of a Japanese sedge “birodo-suge” [Carex fedia Nees var. miyabei (Franchet) T. Koyama] were investigated, and four 3,5,4′-trihydroxystilbene (resveratrol 1) oligomers, one dimer, one trimer and two tetramers, were isolated. Their structures were determined by spectroscopic evidence and biogenetic consideration. The dimer was identified as ε-viniferin (2) that had already been identified as a phytoalexin of grape vine leaves. The trimer and the tetramers were structurally new compounds, and were named miyabenols C (for the trimer 5), and A and B (for the tetramers 3 and 4 respectively). The antimicrobial test of 3 (the predominant constituent) revealed that 3 was antibiotic only against Gram positive bacteria.