Inhibitors from the rhizomes of Alpinia officinarum on production of nitric oxide in lipopolysaccharide-activated macrophages and the structural requirements of diarylheptanoids for the activity Original Research Article

The 80% aqueous acetone extract from the rhizomes of Alpinia officinarum, a Chinese medicinal herb, were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. Through bioassay-guided separation, two diarylheptanoids [7-(4″-hydroxy-3″-methoxyphenyl-1-phenylhept-4-en-3-one and 3,5-dihydroxy-1,7-diphenylheptane] and a flavonol constituent (galangin) substantially inhibited LPS-induced NO production with IC50 values of 33–62 μM. To clarify structure–activity relationships of diarylheptanoids, related diarylheptanoids from Curcuma zedoaria were examined. Results indicate that the double bond or enone moiety at the 1–7 positions is important for the activity.