Improving Anti-Microbial Activity of Allicin and Carvacrol through Stabilized Analogs and Nanotechnology

Allicin and carvacrol have been appreciated as broad-spectrum antimicrobial agents since the early 20th century and used in both Ayurvedic and traditional Chinese medicines for at least five thousand years. Although research since the 1980s identified several important mechanisms of action for allicin and carvacrol, neither has become part of a classical pharmaceutical regimen. Allicin and carvacrol, like other natural phytochemicals, have been hard to purify and stabilize, which has been a major barrier in their entry into a drug discovery process. During the past two decades, two distinct strategies have changed this position. Bioengineering has allowed allicin and carvacrol to be bound to nanoparticles and immobilized onto coated surfaces or into gels; all these methods maximize the retention of activity coupled with a more targeted release. The fields of synthetic and computational chemistry have long been used to create semi-synthetic and synthetic variants of natural molecules or predict binding strengths of molecules that have improved activity and or bioavailability when compared with the parent compounds. Stabilization using one, or both, of these strategies, has been successful for both allicin (garlic) and carvacrol (oregano). This chapter will review the antimicrobial spectrum of these agents and document the methods that have currently been used to stabilize or generate semi-synthetic forms of each of them. Finally, potential and currently available delivery systems will be explored.

Keywords: Allicin, Carvacrol, Nanoparticles, Natural molecules, Semi-synthetic analogs, Nanotechnology.