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.