(3,3″)-Linked Biflavanones from Ouratea spectabilis and Their Effects on the Release of Proinflammatory Cytokines in THP-1 Cells

Ouratea spectabilis is an arborous species traditionally used in Brazil as an anti-inflammatory agent. Four new (3,3″)-linked biflavanone O-methyl ethers, named ouratein A (1), B (2), C (3), and D (4), were isolated from the bark extract of the species. Ouratein A (1) is an enantiomer of neochamagesmine A, which has never been described before. The structures were elucidated by extensive spectroscopic data analyses, whereas their absolute...