Two new non-glycosidic iridoids from the leaves of Campsis grandiflora

Two new non-glycosidic iridoids, which were named cachinot (1) and 1-O-methyl cachinol (2), were isolated from the methanol extract of the leaves of Campsis grandiflora together with a known iridoid cachineside 1 (3). The structures of compounds 1 and 2 were determined on the basis of spectroscopic methods including two dimensional NMR and high resolution mass spectrometry. All of the isolated compounds showed mild inhibitory activities on rat platelet aggregation. Compounds 1 and 3 (IC50: 246 and 219 mu M, respectively) showed about 2-fold higher inhibitory effects than acetylsalicylic acid (ASA, IC50: 412 mu M) on collagen-induced aggregation. Compounds 1 and 2 (IC50: 43.2 and 38.4 mu M, respectively) were about 2-fold more inhibitory than ASA (IC50: 75.2 mu M), and about 4-fold more effective than their glycoside 3 (IC50: 189 mu M) on AA-induced aggregation.