Structure–activity relationships of 1′S-1′-acetoxychavicol acetate for inhibitory effect on NO production in lipopolysaccharide-activated mouse peritoneal macrophages

1′S-1′-Acetoxychavicol acetate from the rhizomes of Alpinia galanga inhibited nitric oxide (NO) production in lipopolysaccharide-activated mouse peritoneal macrophages with an IC50 value of 2.3 μM. To clarify the structure–activity relationship of 1′S-1′-acetoxychavicol acetate, various natural and synthetic phenylpropanoids and synthetic phenylbutanoids were examined, and the following structural requirements were clarified. (1) The para or ortho substitution of the acetoxyl and 1-acetoxypropenyl groups at the benzene ring was essential. (2) The S configuration of the 1′-acetoxyl group was preferable. (3) The presence of the 3-methoxyl group and disappearance of the 2′–3′ double bond by hydrogenation reduced the activity. (4) The substitution of acetyl groups with propionyl or methyl groups reduced the activity. (5) Lengthening of the carbon chain between the 1′- and 2′-positions reduced the activity.