Studies On The Chemical Constituents Of Tetrastigma Planicaule (Hook.) Gagnep

The plant Tetrastigma planicaule (Hook.) Gagnep belongs to the genus Tetrastigma in family vitaceae. It mainly distributes in south China. Tetrastigma planicaule (Hook.) Gagnep, as a medicinal plant, was traditionally used in Yao nationality of China. The rizhome or stem of the plant was frequently used for the therapy of various diseases such as rheumatoid arthritis, strain of lumbar muscles, hemiplegia, cough, asthma and urticaria. So far, the chemical constituents of the plant have never been reported. In order to search active compounds, we had systematically investigated the chemical constituents of the plant.The stems of Tetrastigma planicaule (20 Kg) were extracted with 95% EtOH under room temperature to give a crude extract. By far, seventeen compounds and a cerebroside mixture were isolated, and twenty-one compounds were identified. Their structures were identified as sitostane-3β,5α,6β-triol (1),3β-hydroxysitost-5-en-7-one (2),7α-hydroxysitosterol (3), stigmast-4-en-6β-ol-3-one (4),β-sitosterol (5), daucosterol (6),β-sitosterol-3-O-β-D-xylopyranoside (7), erythro-diol (8), protocatechuic acid (9), salicylic acid (10), vanillic acid (11), syringic acid (12), glycerol-2-(3-methoxy-4-hydroxybenzoic acid) ether (13), palmitic acid (14), (8,11R*,12R*,9E)-trihydroxyoctadec-9-enoic acid (15), glyceryl monopalmitate (16), succinic acid (17), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8E)-2-N-[(2'R)-2'-hydroxy-docosanoyl]-3,4-dihydroxy-8-octadene (18), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8E)-2-N-[(2'R)-2'-hydroxytricosanoyl]-3,4-dihydroxy-8-octadene (19),1-O-β-D-glucopy-ranosyl-(2S,3S,4R,8E)-2-N-[(2'R)-2'-hydroxytetracosanoyl]-3,4-dihydroxy-8-octade-ne(20), 1-O-β-D-glucopyranosyl-(2S,3S,4R,8E)-2-N-[(2'R)-2'-hydroxypentacosan-oyl]-3,4-dihydroxy-8-octadene (21). All these compounds were isolated from this plant for the first time, and compounds 1～4,7～9,11～13,15,16,18～21 were firstly isolated from the genus Tetrastigma. Compound 13 was isolated from natural products for the first time.Phenolic acids isolated from stems of Tetrastigma planicaule are the major constituents, and the bioactivity of such compounds is relative to the indications or functions of Tetrastigma planicaule, so we could presume that phenolic acids are parts of the active compositions of Tetrastigma planicaule. The cytotoxic activities of parts of the compounds against CNE cell were also carried out. The IC50 value of compounds 2,3,9 are 44.20μg/ml,65.63μg/ml,76.75μg/ml, respectively.