Science News Archive

Minty fresh magnolia

Researchers have found that the key to fresh breath might lie in an extract of magnolia bark.

Michael Greenberg and his colleagues found that, in the test tube, two key chemicals in the bark, magnolol and honokiol, could kill more than 99.9% of the mouth bacteria that cause bad breath in just 5 minutes.  To find out whether the extracts could also work in the mouth the researchers collected saliva samples from 9 volunteers 1 hour after lunch and then at 30 and 60 minutes after eating a mint laced with the chemicals or at 40 minutes after chewing a piece of chewing gum containing the same chemicals.  In separate trials the subjects also chewed control gum and mints that did not contain any magnolia extracts.  The saliva was then incubated on bacterial growth media and the numbers of bacterial colonies that grew were counted.

The results were impressive.  The mints reduced salivary bacteria by 62% at 30 minutes and 33.8% at 60 minutes, whilst the chewing gum cut bacteria by 43% at 40 minutes.  By comparison, the placebo mint cut bacterial levels by 3.5% at 30 minutes and increased bacteria by 50% at 60 minutes.  The placebo chewing gum cut bacteria by 18%. The researchers point out that this could represent an effective way to cut oral bacteria without the risks of side effects and "rebound halotosis" (subsequently worse oral malodour!) associated with other breath-freshening strategies.  For instance, triclosan has been found to react with chlorine in drinking water to form toxic substances, chlorhexidine-based solutions have been found to stain teeth, whilst alcohol-based rememdies can dry the mouth and make the problem worse.  The team behind the results are based at Wrigleys, so it shouldn't be too long before magnolia gum hits the shelves; but whether it will stick's another matter.

2nd Dec 2007