Pharmacology
Caffeic acid has a variety of potential pharmacological effects in in vitro studies and in animal models, but no clinical effects have been demonstrated in humans.
Caffeic acid is an antioxidant in vitro and also in vivo. Caffeic acid also shows immunomodulatory and antiinflammtory activity. Caffeic acid outperformed the other antioxidants, reducing aflatoxin production by more than 95 percent. The studies are the first to show that oxidative stress that would otherwise trigger or enhance Aspergillus flavus aflatoxin production can be stymied by caffeic acid. This opens the door to using natural fungicide methods by supplementing trees with antioxidants.
Studies of the carcinogenicity of caffeic acid have mixed results. Some studies have shown that it inhibits carcinogenesis, and other experiments show carcinogenic effects. Oral administration of high doses of caffeic acid in rats has caused stomach papillomas. In the same study, high doses of combined antioxidants, including caffeic acid, showed a significant decrease in growth of colon tumors in those same rats. No significant effect was noted otherwise. Caffeic acid is listed under some Hazard Data sheets as a potential carcinogen, as has been listed by the International Agency for Research on Cancer as a Group 2B carcinogen ("possibly carcinogenic to humans"). More recent data show that bacteria in the rats' guts may alter the formation of metabolites of caffeic acid. There have been no known ill-effects of caffeic acid in humans.
Read more about this topic: Caffeic Acid