A new series of sixteen N4-aryl substituted 5-chloroisatin-3-thiosemicarbazones 2a-2p has been synthesized,
characterized and tested for selected biological activities i.e. cytotoxicity, phytotoxicity and urease inhibition. In the brine
shrimp bioassay, all the synthesized compounds gave LD50 values 2.30 X 10-4 M - 2.79 X 10-4 M and were, therefore,
found to be almost inactive, whereas in phytotoxicity assay, regardless of the nature of aryl substituents, they displayed
weak to moderate (5-40%) phytotoxic activity at the highest tested concentrations (500 or 1000 μg/mL). In urease inhibition
bioassay, compounds 2a, 2c, 2e, 2f, 2k and 2m exhibited relatively a higher degree of urease inhibition with IC50 values
ranging from 38.91 μM to 76.65 μM and thus proved to be potent inhibitors of the enzyme. Of these, 2f and 2m displayed
pronounced inhibition with IC50 values 38.91 μM and 39.50 μM, respectively, and may act as lead compounds for
further studies. Structure-activity relationship (SAR) studies revealed that electronic effects of the substituents about the
phenyl ring at N4 of the thiosemicarbazone moiety played an important role in enhancing the urease inhibitory potential of
some of the synthesized compounds.
合成了一系列16种N4-芳基取代的
5-氯靛红-3-缩
氨基
硫脲2a-2p,并对它们进行了表征和选择性
生物活性测试,包括细胞毒性、植物毒性和
脲酶抑制活性。在卤虫
生物测定中,所有合成化合物的L
D50值为2.30 X 10-4 M至2.79 X 10-4 M,因此被发现几乎无活性;而在植物毒性测定中,无论芳基取代基的性质如何,它们在最高测试浓度(500或1000 μg/mL)下表现出微弱至中等的(5-40%)植物毒性活性。在
脲酶抑制
生物测定中,化合物2a、2c、2e、2f、2k和2m表现出较高的
脲酶抑制程度,IC50值范围为38.91 μM至76.65 μM,证明了它们是该酶的有效
抑制剂。其中,2f和2m表现出显著的抑制作用,IC50值分别为38.91 μM和39.50 μM,可能作为进一步研究的先导化合物。结构-活性关系(
SAR)研究表明,缩
氨基
硫脲部分N4位
苯环上的取代基的电子效应对某些合成化合物的
脲酶抑制潜力起着重要作用。