Antimicrobial peptides: structure, function, mechanism of action and therapeutic applications in human diseases

Microbial pathogens with antibiotic resistance have become challenging to manage in the last few decades. The situation is alarming and a threat to humankind. Despite emerging new drug candidates, there are numerous strategies for efficient antibiotic delivery for treating such infections; antibiotic-resistant bacteria are still not eradicated adequately from the infected hosts. Recently, antimicrobial peptides (AMPs) have emerged as saviors in overcoming antibiotic resistance against bacteria. AMPs are being produced naturally as well as synthetically. Irrespective of the source of production, AMPs have shown higher specificity and lower toxicity to the host. Such functions have been attributed to distinct structures, functions, and varied mechanisms of action. This review highlights sources, structural and physiological characteristics, action mechanisms, and biological potency towards clinical applications. Most recently, AMPs have also been explored in treating cancers and tumors. Despite the entry of a few AMPs into clinical trials, there are limitations associated with their usage, like shorter half-life, protease cleavage, and toxicity. There is an urgent need to produce AMPs with intensified activity, biocompatibility, and lesser toxicity. This review sheds light on these aspects and the future of AMPs for the betterment of the human race.