Triterpene alcohol and sterol ferulates from rice bran and their anti-inflammatory effects

Six novel feruloyl esters of triterpene alcohols and sterols, viz., two tra ns-ferulates, cycloeucalenol and 24-methylenecholesterol trans-ferulates, a nd four cis-ferulates, cycloartenol, 24-methyelene- cycloartanol, 24-methyl cholesterol, and sitosterol cis-ferulates, besides five known trans-ferulat es, cycloartenol (CAR), 24-methylenecycloartanol (24-MCA), 24-methylcholest erol, sitosterol, and stigmastanol trans-ferulates, and one known cis-ferul ate, stigmastanol cis-ferulate, were isolated from the methanol extract of edible rice bran. These and eight other synthetic trans- and cis-ferulates of triterpene alcohols and sterols, along with the corresponding free alcoh ols, were evaluated with respect to their anti-inflammatory activity agains t 12-O-tetradecanoylphorbol-13-acetate (TPA)induced inflammation (1 mu g pe r ear) in mice. All of the ferulates showed marked inhibitory activity, and their 50% inhibitory dose (ID50) was 0.1-0.8 mg per ear. On the other hand , whereas two free triterpene alcohols, CAR and 24-MCA, showed strong inhib ition (ID50 0.2-0.8 mg/ear), eight free sterols examined showed weaker acti vity (ID50 0.7-2.7 mg/ear)than their corresponding ferulates.