Design, synthesis and anticancer activities evaluation of novel pyrazole modified catalpol derivatives

Catalpol, a natural product mainly existed in plenty of Chinese traditional medicines, is an iridoid compound with the comprehensive effects on neuroprotective, anti-inflammatory, choleretic, hypoglycemic and anticancer. However, there are some disadvantages for catalpol such as a short half-life in vivo, low druggability, stingy binding efficiency to target proteins and so on. It is necessary to make structural modification and optimization which enhance its performance on disease treatments and clinic applications. Pyrazole compounds have been reported to have excellent anticancer activities. Based on the previous research foundation of our research group on iridoids and the anticancer activities of catalpol and pyrazole, a series of pyrazole modified catalpol compounds were synthesized by principle of drug combination for serving as potential cancer inhibitors. These derivatives are characterized by ¹H NMR, ¹³C NMR and HRMS. The efficacy of anti-esophageal cancer and anti-pancreatic cancer activities were evaluated by the MTT assay on two esophageal cancer cells Eca-109 and EC-9706, and two pancreatic cancer cells PANC-1, BxPC-3 and normal pancreatic cell line HPDE6-C7, which showed that the compound 3e had strong inhibitory activity against esophageal cancer cells, this providing a theoretical basis for the discovery of catalpol-containing drugs.