There is a growing vocal subculture who contend chemical additives are bad (mmmkay). Anything that isn’t “natural” isn’t “good.” Vitanet (I won’t bother linking) tells us that “in the past century, modern organic chemistry has synthesized and released into the world an estimated 300,000 xenobiotic (foreign to our normal biology) chemicals. The food processing and food growing industries put an approximate 10,000 xenobiotic chemicals into our food supply alone.” And the only way to stop this is to buy their detoxification products. Only naturally grown foods with no chemical additives can save us now. Unfortunately, toxicologists disagree.
But an ASAP in The Journal of Agriculture and Food Chemistry (doi: 10.1021/jf9013313) provides some new information. Dean Kopsell from the University of Tennessee shows that mesotrione (a naturally-derived herbicide), used alone or in combination with atrazine (a herbicide banned in the EU), does more than just suppress weed growth. It also upregulates the formation of nutritionally important carotenoids, specifically zeaxanthin. Corn is one of the few vegetable sources of zeaxanthin, and the carotenoid is believed to be protective against age-induced macular degeneration.
Basically, mesotrione inhibits the carotenoid biosynthetic pathway resulting in a buildup of phytoene. Mesotrione is also completely metabolized by the plant to nonherbicidal byproducts. Once the mesotrione is metabolized, carotenoid biosynthesis begins anew, and the surplus of starting materials pushes the biosynthesis to produce more carotenoids. The authors conclude the mechanistic data is still unclear, but “data from this study suggest the possibility to increase concentrations of nutritionally important kernel carotenoid in sweet corn genotypes through applications of HPPD-inhibiting herbicides such as mesotrione.”