A new in vitro tissue factor inhibitory triterpene from the fruits of Chaenomeles sinensis.

Tissue factor (TF, tissue thromboplastin) accelerates the blood clotting, activating both the intrinsic and the extrinsic pathways to serve as a cofactor. In order to isolate TF inhibitors from the fruits of Chaenomeles sinensis, an activity-guided purification was carried out to yield four triterpenoid compounds. One compound was new and its structure was elucidated as 28-O-beta- D-glucopyranosyl-2alpha,3beta-dihydroxyolean-12-ene-24,28-dioic acid (2), named chaenomeloside A by means of spectral analysis and chemical conversion. Other compounds were trachelosperoside A-1 (1), oleanolic acid (3) and ursolic acid (4). Compound 2 and its aglycone 2a, named chaenomelogenin A inhibited by 50 % the TF activity at concentrations of 0.036 and 0.028 mM/unit of TF, respectively. Compound 1 isolated for the first time from this plant as well as 3 and 4 were inactive.