DR. Don's Research Updates
October 14, 2002: Fungicides reduce beneficial compounds in grapes.

Editor's NOTE

Don Lotter is a post-doctoral researcher here at the Rodale Institute. In addition to analyzing data from our research trials and developing new domestic and international research initiatives, Don reviews dozens of research studies each week. He'll present the most interesting of his findings every Monday on the web site.

Resverotrol, a compound found in red grapes, has been shown to be beneficial to health by lowering cholesterol and preventing cell oxidation, an important process in the prevention of cancer. Researchers have found that grapes sprayed with fungicides commonly used on conventional vineyards had 80% less resverotrol. Resverotrol occurs in grapes as a defense compound produced in a process known as systemic acquired resistance, or SAR. SAR in plants produces many types of defense compounds and is induced by low to medium levels of pathogen and insect attack. It goes without saying that organically grown crops would have SAR induction occurring on a regular basis, since organic farmers do not, for the most part, use eradication as an approach to pest management and commonly have low levels of pests as part of their overall equilibrium. There is evidence for this increased SAR, such as the recent finding that soup made from organic ingredients contain higher levels of salicylic acid than the same soup made from conventionally grown vegetables (Baxter 2001)*. Salicylic acid is an important component of the SAR process, and in fact of the two major SAR pathways in a plant, one is called the salicylic acid pathway.

* Baxter, G. J. et. al. 2001. Salicylic acid in soups prepared from organically and non-organically grown vegetables. European Journal of Nutrition, 40:289-292.

Source: Magee, J.B. and B. J. Smith. 2002. Resveratrol content of muscadine berries is affected by disease control spray program. HortScience, 37 (2):358-361