Bioactive Styrylchromones and a Suberin Derivative from the Staminate Flowers of Carex kobomugi.

Carex kobomugi is a dioecious perennial sedge native to coastal sand dunes in temperate northeastern Asia. While previous phytochemical investigations of this species have focused exclusively on its roots and rhizomes, this study represents the first report on the chemical constituents of its flowers. From the methanolic extract of the staminate flowers, two new styrylchromones, kobochromones B (1: ) and C (2: ), and a new suberin derivative, kobosuberin (5: ), were isolated. Their structures were elucidated by spectroscopic analysis (1D/2D NMR and HRESIMS). Their cytotoxic activity was assessed against four human cancer cell lines (HCT15, MCF7, 22Rv1, and PANC1), and the normal human hepatic stellate cell line LX-2 was used as a reference normal cell line. The study revealed a unique chemical profile of the staminate flowers, contributing to the understanding of the specialized metabolites in this dioecious species.