Selective Targeting of Human and Animal Pathogens of the Helicobacter Genus by Flavodoxin Inhibitors: Efficacy, Synergy, Resistance and Mechanistic Studies

Antimicrobial combinations against Helicobacter pylori including benzoxadiazol-based flavodoxin inhibitors: in vitro characterization

IMPORTANCE

The antimicrobial resistance of Helicobacter pylori (Hp) currently poses a threat to available treatment regimens. Developing antimicrobial drugs targeting new bacterial targets is crucial, and one such class of drugs includes Hp-flavodoxin (Hp-fld) inhibitors that target an essential metabolic pathway in Hp. Our study demonstrated that combining these new drugs with conventional antibiotics used for Hp infection treatment prevented the regrowth observed with drugs used alone. Hp-fld inhibitors show promise as new drugs to be incorporated into the treatment of Hp infection, potentially reducing the development of resistance and shortening the treatment duration.

Design, Synthesis, and Biological Investigations of Novel Carbamoylguanidinyl Nitrobenzoxadiazoles against Chitinolytic Enzymes

Chitinase has been identified as an important target for insecticides. In this study, a series of novel chitinase inhibitors was designed and synthesized with nitrobenzoxadiazoles. Compound 8d, which contains the N-methylcarbamoylguanidinyl, exhibited high enzyme inhibitory activity and achieved nanomolar inhibition against OfChtI (IC50 = 12.3 nM). Delightfully, it was also found to possess significant inhibitory activity against OfHex1 (IC50 = 1.76 μM). The computational simulation results indicated that compound 8d interacted with OfChtI and OfHex1 in similar modes through hydrogen bonds and hydrophobic and π-π interactions. Insecticidal activity studies revealed that compound 8d showed high mortality against the Lepidoptera Plutella xylostella (mortality rate = 81%) at 200 mg/L. Toxicity studies indicated that compound 8d exhibited negligible toxicity to the natural enemy Trichogramma ostriniae. These results indicate that compound 8d may be a promising candidate for the development of environmentally friendly chitinase inhibitors. Moreover, this study provides a new angle for the design of innovative inhibitors of chitinolytic enzymes.

Forces Driving a Magic Bullet to Its Target: Revisiting the Role of Thermodynamics in Drug Design, Development, and Optimization

Drug discovery strategies have advanced significantly towards prioritizing target selectivity to achieve the longstanding goal of identifying “magic bullets” amongst thousands of chemical molecules screened for therapeutic efficacy. A myriad of emerging and existing health threats, including the SARS-CoV-2 pandemic, alarming increase in bacterial resistance, and potentially fatal chronic ailments, such as cancer, cardiovascular disease, and neurodegeneration, have incentivized the discovery of novel therapeutics in treatment regimens. The design, development, and optimization of lead compounds represent an arduous and time-consuming process that necessitates the assessment of specific criteria and metrics derived via multidisciplinary approaches incorporating functional, structural, and energetic properties. The present review focuses on specific methodologies and technologies aimed at advancing drug development with particular emphasis on the role of thermodynamics in elucidating the underlying forces governing ligand–target interaction selectivity and specificity. In the pursuit of novel therapeutics, isothermal titration calorimetry (ITC) has been utilized extensively over the past two decades to bolster drug discovery efforts, yielding information-rich thermodynamic binding signatures. A wealth of studies recognizes the need for mining thermodynamic databases to critically examine and evaluate prospective drug candidates on the basis of available metrics. The ultimate power and utility of thermodynamics within drug discovery strategies reside in the characterization and comparison of intrinsic binding signatures that facilitate the elucidation of structural–energetic correlations which assist in lead compound identification and optimization to improve overall therapeutic efficacy.