Hybrid antioxidants cinnamoyldopamine（2a）, p-coumaroyldopamine（2b）, caffeoyldopamine（2c）, feruloyldopamine（2d） and sinapoyldopamine（2e） were synthesized by conjugation of dopamine（DA） and hydroxycinnamic acids（HCAs）. The stabilities were studied in buffers at p H 1.3, p H 5.0, and p H 7.4 including the human plasma. All the compounds were found highly stable at acidic p H, but underwent hydrolysis at neutral p H. Furthermore, the hydrolysis proceeded much faster in plasma in the following order as indicated by half-life values（t1/2）, 2c（1.21 h）〈2e（1.52 h）〈2d（1.85 h）〈2b（3.38 h）〈2a（3.88 h）, correlating with the number of electron-donating groups. It has been proven by UV spectrum that 2c, 2d, and 2e displayed red shift of more than 50 nm as compared to 2a and 2b, because of the presence of OH and OCH3 groups. In addition, the compounds（2b–e） showed no cytotoxicity on normal HUVEC cells as DA, although 2a displayed a 16% inhibition of proliferation at 40 μM following 48 h incubation. Their free radical-scavenging activities were evaluated using ABTS^＊＋ and superoxide anion assays and the mechanisms were proposed. It was found that they all exhibited higher activities than trolox, a recognized antioxidant. Amazingly, in the case of the hybrids（2a–e）, their activity was higher than that of HCAs while lower or comparable to that of DA, suggesting that there may be a ＂saturation effect＂ with the hybrid molecules in the antioxidant activities.
在BIIB021的基础上合成了一系列硝基还原酶(NTR)前药,作为潜在的抗癌剂,并在体外测试了其细胞毒性作用。结果表明:化合物1c和2c具有良好的抗肿瘤活性,IC50分别为0.72和1.12μM。此外,与阳性母体化合物BIIB021相比,这两种化合物对正常细胞WI-38的毒性也较低(IC50=495.51和570.27μM vs 261μM)。细胞周期测试分析表明:两种化合物都对HeLa细胞周期阻滞在G2/M期,同时G0/G1期的细胞数量减少,并诱导其凋亡。综上所述:化合物1c和2c具有潜在的抗肿瘤活性,有潜力作为先导化合物,用于进一步结构优化和体内验证研究。
