Malonylated Glycerolipids from the Glandular Trichome Exudate of Ceratotheca triloba

Chemical investigation of the glandular trichome exudate from Ceratotheca triloba (Pedaliaceae) led to the identification of nine 1-O-acetyl-2-O-[(R)-3-acetyloxy-fatty acyl]-3-O-malonylglycerols. Among these, 1-O-acetyl-2-O-[(R)-3-acetyloxyicosanoyl]-3-O-malonylglycerol (7) was the most abundant constituent (41%), followed by 1-O-acetyl-2-O-[(R)-(3-acetyloxyoctadecanoyl)-3-O-malonylglycerol (2; 21%). Compounds having iso- and anteiso-type structures in the 3-acetyloxy-fatty acyl groups in the fatty acyl moiety were also characterized as minor constituents. This is the first report of the isolation of malonylated glycerolipids as natural products.