A compound in saliva, along with common proteins in blood and muscle, may protect human cells from powerful toxins in tea, coffee and liquid smoke flavoring, according to results of a new study led by investigators at the Johns Hopkins Kimmel Cancer Center.
The findings, reported online May 19 in Food and Chemical Toxicology, suggest that people naturally launch multiple defenses against plant chemicals called pyrogallol-like polyphenols or PLPs found in teas, coffees and liquid smoke flavoring. The presence of these defenses could help explain why PLPs are not crippling cells and causing illness as would be expected from their toxic punch and widespread use, the researchers say.
Last year, Johns Hopkins investigator Scott Kern, M.D., and his colleagues demonstrated that PLPs found in everyday foods and flavorings could do significant damage by breaking strands of DNA, the carrier of all genetic information. The impact of the toxins was so strong--in some cases producing 20 times the damage of chemotherapy drugs delivered to cancer patients--that the researchers immediately thought to find out why there wasn't more damage, and to look for ways that cells might be fighting back.
"If these chemicals are so widespread--they're in flavorings, tea, coffee--and they damage DNA to such a high degree," Kern said, "we thought there must be defense mechanisms that protect us on a daily basis from plants we choose to eat."
Kern and colleagues found that an enzyme in saliva called alpha-amylase, the blood protein albumin, and the muscle protein myoglobin all protected cells from DNA breakage by tea, coffee and isolated PLPs. The researchers identified the amount of DNA damage in the cells by looking for high activity levels of a gene called p53. The gene helps repair DNA damage.
"It was quite easy to uncover a few of these protective substances against the tested cancer therapeutic drugs, which suggests there may be
|Contact: Vanessa Wasta|
Johns Hopkins Medicine