Pharmacists and chemists have found another use for the multipurpose cannabis as a source of antibacterial chemicals for multidrug resistant bacteria. Ironically, inhaling cannabis is known to damage the lung's ability to fend off invading pathogens, but the ingredients in cannabis, particularly the cannabinoids, have antiseptic properties. Although scattered research has been conducted since the 1950s, no comprehensive study existed that relates the structure of cannabinoids with antibacterial activity. Giovanni Appendino, Simon Gibbons, and coworkers attempted to remedy that problem by examining the activity of five common cannabinoids and their synthetic derivatives.



Five of the most common cannabinoids.

All five cannabinoids (THC, CBD, CBG, CBC, and CBN) were potent against bacteria. Notably, they performed well against bacteria that were known to be multidrug resistant, like the strains of MRSA that plagued U.K. hospitals. CBD and CBG have the most potential for consumer use because they are nonpsychotropic.

Besides identifying antibacterial capability, the researchers wanted to figure out why these cannabinoids are so good at killing bacteria. They obviously are very effective at specifically targeting some vital process in the bacteria. Unfortunately, even after extensive work at modifying the cannabinoids and comparing their activities, that targeting mechanism remains a mystery. The scientists were able to figure out that the position of the n-pentyl chain (orange) relative to the terpenoid moiety (blue) serves to control lipid affinity.

These cannabinoids are promising enough to warrant rigorous clinical trials. They are applicable as topical antiseptics, biodegradable antibacterial compounds for cosmetics, and systematic antibacterial agents.

J. Nat. Prod., 2008. DOI: 10.1021/np8002673