Research progress in pharmacological activities and structure-activity relationships of tetralone scaffolds as pharmacophore and fluorescent skeleton

Antibiotic Potentiation Through Phytochemical-Based Efflux Pump Inhibitors to Combat Multidrug Resistance Bacteria

BACKGROUND

Antimicrobial resistance development poses a significant danger to the efficacy of antibiotics, which were once believed to be the most efficient method for treating infections caused by bacteria. Antimicrobial resistance typically involves various mechanisms, such as drug inactivation or modification, drug target modification, drug uptake restriction, and drug efflux, resulting in decreased antibiotic concentrations within the cell. Antimicrobial resistance has been associated with efflux Pumps, known for their capacity to expel different antibiotics from the cell non-specifically. This makes EPs fascinating targets for creating drugs to combat antimicrobial resistance (AMR). The varied structures of secondary metabolites (phytomolecules) found in plants have positioned them as a promising reservoir of efflux pump inhibitors. These inhibitors act as modifiers of bacterial resistance and facilitate the reintroduction of antibiotics that have lost clinical effectiveness. Additionally, they may play a role in preventing the emergence of multidrug resistant strains.

OBJECTIVE

The objective of this review article is to discuss the latest studies on plant-based efflux pump inhibitors such as terpenoids, alkaloids, flavonoids, glycosides, and tetralones. It highlighted their potential in enhancing the effectiveness of antibiotics and combating the development of multidrug resistance.

RESULTS

Efflux pump inhibitors (EPIs) derived from botanical sources, including compounds like lysergol, chanaoclavine, niazrin, 4-hydroxy-α-tetralone, ursolic acid, phytol, etc., as well as their partially synthesized forms, have shown significant potential as practical therapeutic approaches in addressing antimicrobial resistance caused by efflux pumps. Further, several phyto-molecules and their analogs demonstrated superior potential for reversing drug resistance, surpassing established agents like reserpine, niaziridin, etc. Conclusion: This review found that while the phyto-molecules and their derivatives did not possess notable antimicrobial activity, their combination with established antibiotics significantly reduced their minimum inhibitory concentration (MIC). Specific molecules, such as chanaoclavine and niaziridin, exhibited noteworthy potential in reversing the effectiveness of drugs, resulting in a reduction of the MIC of tetracycline by up to 16 times against the tested strain of bacteria. These molecules inhibited the efflux pumps responsible for drug resistance and displayed a stronger affinity for membrane proteins. By employing powerful EPIs, these molecules can selectively target and obstruct drug efflux pumps. This targeted approach can significantly augment the strength and efficacy of older antibiotics against various drug resistant bacteria, given that active drug efflux poses a susceptibility for nearly all antibiotics.

Screening of natural product libraries in MCF7 cell line reveals the pro-apoptotic properties of β tetralone

Despite the exponential increase in research toward better treatment options for breast cancer patients, developing an effective drug with fewer side effects continues to remain a challenge. Natural compounds have emerged as a viable option and several drugs have been derived or inspired from them. In this study, we screened a library of natural compounds with diverse chemical structures against selected kinase proteins using in silico methods such as molecular docking and dynamics simulation. The best results were obtained between β tetralone and MDM2 E3 ubiquitin ligase protein. In vitro experiments such as cytotoxicity, scratch assays and flow cytometry analysis using an MCF7 cell line were performed to determine the anti-cancer potential of the compound. As the treatment resulted in cell death and apoptosis, β tetralone was screened in silico against anti-apoptotic targets where the best results were obtained between Bcl-w and β tetralone. This comprehensive study suggests that the anti-cancer activity of β tetralone is probably through the dual targeting of MDM2 E3 ubiquitin kinase and Bcl-w anti-apoptotic protein.Communicated by Ramaswamy H. Sarma.