Dicamba (CAS 1918-00-9)

Dicamba is a polar phenoxy herbicide employed for post-emergence control of broad-leaf weeds in grasslands and cereals. It possesses water emulsifiable properties. Its primary concern lies in its potential environmental impact, warranting immediate measures to restrict its spread. As a liquid, it has the capacity to permeate soil and contaminate groundwater and nearby streams. Inhalation, skin absorption, or ingestion of dicamba can lead to illness. Notably, dicamba functions as a herbicide. Chemically, dicamba is characterized as a methoxybenzoic acid, specifically O-methylsalicylic acid with chloro groups substituted at positions 3 and 6. It assumes multiple roles as a xenobiotic, environmental contaminant, herbicide, synthetic auxin, and agrochemical. Dicamba is classified as a methoxybenzoic acid and a dichlorobenzene. It acts as a conjugate acid of 3,6-dichloro-2-methoxybenzoate. In plants, dicamba operates as a chlorinated organic herbicide that imitates auxin plant growth hormones, leading to uncontrolled growth. However, this hormonal mode of action exclusively affects plants and does not impact animals. Studies indicate that dicamba can induce hepatic peroxisomal enzymes and activate the peroxisomal proliferator activator receptor (PPAR) in rats, suggesting potential liver tumor-promoting activity akin to other peroxisomal proliferators. However, investigations employing a two-stage hepatocarcinogenesis model in rats have not supported this hypothesis, revealing dicamba′s inactivity as a tumor promoter.