Mesotrione

Mesotrione is an herbicide sold under the brand names Callisto and Tenacity that was brought to market by Syngenta in 2001. It is a synthetic analog of leptospermone developed to mimic the effects of this natural herbicide. Mesotrione is a member of the class of HPPD inhibitors, which all work by inhibiting the plant enzyme 4-hydroxyphenylpyruvate dioxygenase. In plants, HPPD is necessary for carotenoid biosynthesis; carotenoids in turn protect chlorophyll from being degraded by sunlight. When an HPPD inhibitor is sprayed on a plant, it prevents carotenoid from being made, chlorophyll degrades and the plant dies. Mesotrione is an herbicide sold under the brand names Callisto and Tenacity that was brought to market by Syngenta in 2001. It is a synthetic analog of leptospermone developed to mimic the effects of this natural herbicide. Mesotrione is a member of the class of HPPD inhibitors, which all work by inhibiting the plant enzyme 4-hydroxyphenylpyruvate dioxygenase. In plants, HPPD is necessary for carotenoid biosynthesis; carotenoids in turn protect chlorophyll from being degraded by sunlight. When an HPPD inhibitor is sprayed on a plant, it prevents carotenoid from being made, chlorophyll degrades and the plant dies. Sales by Syngenta were more than $400 million per year in 2011 but worldwide patent rights started to expire in 2012, opening the market to generic competition.