Synthesis, theoretical study of aryl-lactones and evaluation of their inhibitory activity on the formation of β-hematin and the enzyme β-lactamase

Abstract

Infectious diseases have become a problem of public health due to the resurgence of microbial resistance. More than five millions of people from Colombia live in endemic regions of malaria whose parasite is resistant to chloroquine. Microorganisms like S. aureus y Enterococcus spp., have developed β-lactamase enzyme which converts them resistant to antibiotics. Four α,γ-aryllactones was synthetized which were evaluated as inhibitors of β-hematin formation at 2 mg/mL . The reaction was performed at 60 °C for 1 h at pH 4.0 and the complex was determined by measuring the absorbance at 386 nm . The lactones were evaluated too as inhibitors of β-lactamase enzyme at 5.4 µmol/L and amoxicillin as substrate at 36-108 µmol/L . The enzymatic activity of the compounds was carried out at 37 ºC for 10 h at pH 7.3 and the enzymatic kinetic was determined by measuring the absorbance at 250 nm . The modeling of the lactone-Fe porphyrin complexes shows the interaction was stablished through furan ring oxygen, but when the lactone had an α-pyridinyl group the interaction was improved through the nitrogen with loss of the inhibitory activity. The molecular modeling of the enzyme-complexes shown the active site residues responsible for the interaction with the lactones were Ser64 and Tyr150 through hydrogen bounds between the hydroxyls of this residues and carbonyl oxygen of the lactone.