Two pairs of new diastereoisomeric flavonolignans from the seeds of Hovenia acerba

Two pairs of new diastereomeric flavonolignans, hovenins A–D (1–4), were isolated from the seeds of Hovenia acerba. Their structures were established on the basis of spectroscopic methods and circular dichroism experiments. All compounds significantly inhibited NO and IL-6 generation in lipopolysaccharide (LPS)-stimulated macrophages (RAW264.7 cells) in a dose-dependent manner.