Compared with placebo , R@ and R@ significantly decreased the plasma levels of total sphingolipids including those of ceramide ( -@ % and -@ % ) , sphingomyelin ( -@ % and -@ % ) , monohexosylceramide ( -@ % and -@ % ) , dihexosylceramide ( -@ % and -@ % ) , and trihexosylceramide ( -@ % and -@ % ) , and GM@ gangliosides ( -@ % and -@ % ) , lysophosphatidylcholine ( -@ % and -@ % ) , alkylphosphatidylcholine ( -@ % and -@ % ) , phosphatidylcholine ( -@ % and -@ % ) , alkenylphosphatidylcholine ( plasmalogen ) ( -@ % and -@ % ) , alkylphosphatidylethanolamine ( -@ % , P = @ and -@ % , P = @ ) , alkenylphosphatidylethanolamine ( plasmalogen ) ( -@ % , P = @ and -@ % , P = @ ) , phosphatidylglycerol ( -@ % , P = @ , -@ % , P = @ ) , and phosphatidylinositol ( -@ % and -@ % ) .