Pesticides plant-growth inhibitors

Rotenone is an alkaloid botanical pesticide isolated from plants (Denis sp. or Lonchocarpus sp.). It blocks mitochondrial electron transport. It is associated with dermatitis and mucous membrane irritation in humans and is very potent in fish. In humans, intoxication is rare but when present is directed toward the respiratory system. Rotenone is used as a topical ectoparasiticide. As mentioned in the text, it has been implicated as possibly having a role in Parkinson s disease. The newest and by far safest class of insecticides available today are the insect growth inhibitors, such as methoprene (PreCor ), and chitin synthesis inhibitors, such as lufenuron (Program ). 

Several pesticides and other xenobiotics are metabolized in plants by mixed-function oxidases which are cytochrome P-450-dependent [28]. Inhibitors of such enzymes might therefore serve as synergists of herbicides or other crop protection compounds which are oxidatively degraded. Therefore, it has been logical to test whether the growth retardants believed to be oxygenase inhibitors would interfere with xenobiotic metabolism. Under in vitro conditions it has indeed been observed that tetcyclacis at relatively low concentrations inhibits the metabolism of the herbicide chlortoluron [10]. Similarly, the herbicidal activity of bentazon could be enhanced by tetcyclacis which, most likely, reduced its oxidative inactivation [18]. Further studies will, however, be required to find out whether such effects can be used under practical conditions. 

---