Synthesis and Biological Activity of Aldehyde Derivatives of Isopimaric Acid

Four series of acylhydrazone derivatives, including halogenated aryl modified acylhydrazone, thiophene, pyrrole and quinoline, were synthesized and characterized. The minimum inhibitory concentrations of the compounds against five bacteria were determined and most of the compounds displayed some degree of antibacterial activity. Isopimaric acid (pyrrole-3-carboxaldehyde) acylhydrazone (3j) exhibited the most potent activity against Streptococcus pneumonia and Klebsiella Pneumonia, with the minimum inhibitory concentration being 3.91 μg/mL. The antimicrobial activity against S. pneumoniae was improved when the pyrrole structure was introduced into isopimaric acid. All heterocyclic acylhydrazone derivatives of isopimaric acid exhibited a good in vitro antitumorial activity at 100 μM. It is concluded that the inhibitory effect of isopimaric acid (2-fluoro-6-methoxybenzaldehyde) acylhydrazone (3d) on Hep G2 and isopimaric acid (3-bromothiophene-2-carbaldehyde) acylhydrazone (3g) on Hep G2 and MDAMB 231 is better than that of the positive control 5-fluorouracil (5-FU) (76.51%), which is a widely used clinical anticancer agent, at 100 μM.