Miyazawa Mitsuo, Okuno Yoshiharu, Imanishi Koji
Department of Applied Chemistry, Faculty of Science and Engineering, Kinki University Kowakae, Higashiosaka-shi, Osaka 577-8502, Japan.
J Agric Food Chem. 2005 Mar 23;53(6):2312-5. doi: 10.1021/jf035430y.
The methanol extract from Uncaria sinensis showed a suppressive effect on umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK1002 against the mutagen 3-amino-1,4-dimethyl-5H-pyrido[4,3b]indole (Trp-P-1), which requires liver metabolizing enzymes. The methanol extract from U. sinensis was re-extracted with hexane, CH2Cl2, BuOH, and water, respectively. CH2Cl2 extract showed a suppressive effect. A suppressive compound 1 in CH2Cl2 extract was isolated by SiO2 column chromatography. Compound 1 was identified as ursolic acid by IR, electron ionization EI-MS, and NMR spectroscopy. Suppressive effects of ursolic acid (1) and its derivatives, methyl ursolate (1M), acetylursolic acid (1A), and methyl acetylursolate (1MA), were determined in the umu test. These compounds suppressed 61.3, 37.7, 71.5, and 37.8% of the Trp-P-1-induced SOS response at a concentration of 0.4 micromol/mL, respectively. The ID50 values of compounds 1 and 1A were 0.17 and 0.20 micromol/mL. In addition, these compounds were assayed with the activated Trp-P-1. Suppressive effects on activated Trp-P-1 were decreased as compared with those of Trp-P-1.
中华钩藤的甲醇提取物对鼠伤寒沙门氏菌TA1535/pSK1002中针对诱变剂3-氨基-1,4-二甲基-5H-吡啶并[4,3b]吲哚（Trp-P-1）的SOS反应的umu基因表达具有抑制作用，该诱变剂需要肝脏代谢酶。分别用己烷、二氯甲烷、正丁醇和水对中华钩藤的甲醇提取物进行再提取。二氯甲烷提取物显示出抑制作用。通过硅胶柱色谱法从二氯甲烷提取物中分离出一种抑制性化合物1。通过红外光谱、电子电离EI-MS和核磁共振光谱鉴定化合物1为熊果酸。在umu试验中测定了熊果酸（1）及其衍生物熊果酸甲酯（1M）、乙酰熊果酸（1A）和乙酰熊果酸甲酯（1MA）的抑制作用。这些化合物在浓度为0.4微摩尔/毫升时分别抑制了Trp-P-1诱导的SOS反应的61.3%、37.7%、71.5%和37.8%。化合物1和1A的半数抑制浓度（ID50）值分别为0.17和0.20微摩尔/毫升。此外，用活化的Trp-P-1对这些化合物进行了测定。与Trp-P-1相比对活化的Trp-P-1的抑制作用有所降低。
