Constituents of the Egyptian Centaurea scoparia. III. Phenolic constituents of the aerial parts.

The ethanolic extract of the aerial parts of Centaurea scoparia Sieb. (Asteraceae) afforded five polyoxygenated flavones apigenin, luteolin, salvigenin, cirsimaritin, and hispidulin, the two lignans (-)-matairesinol and (-)-arctigenin together with omega-hydroxypropioguaiacone and vanillin. The structure elucidations of the isolated compounds are based on spectroscopic methods including 1D- and 2D-NMR spectra. Some proton and carbon signals are revised or newly reported.