rotenone

Rotenone is a botanical insecticide/pesticide derived from the roots of certain plants (e.g., Derris and Lonchocarpus species). Mechanistically, it binds to and inhibits Complex I of the electron transport chain, blocking electron transfer from NADH to ubiquinone (coenzyme Q). This inhibition prevents the pumping of protons at Complex I, decreasing the proton gradient and ultimately reducing ATP synthesis via oxidative phosphorylation.

In biochemistry courses, rotenone is a classic example used alongside other ETC inhibitors/uncouplers (e.g., cyanide inhibits Complex IV, oligomycin inhibits ATP synthase, 2,4-DNP is an uncoupler) to teach the electron transport chain and oxidative phosphorylation. Because Complex I inhibition backs up electrons, it leads to increased reactive oxygen species (ROS) production, contributing to oxidative stress.

Clinically and in research, rotenone exposure has been implicated in the pathogenesis of Parkinson's disease. It selectively damages dopaminergic neurons in the substantia nigra pars compacta due to their high metabolic rate and vulnerability to oxidative stress, and it is used to create animal models of Parkinsonism. Epidemiologically, chronic pesticide exposure (including rotenone) has been associated with increased Parkinson's disease risk in some studies, supporting the mitochondrial dysfunction/oxidative stress hypothesis of neurodegeneration.

High-yield associations for boards: - Complex I inhibitor (like amytal/barbiturates) - Used as insecticide/pesticide - Linked to Parkinson's disease pathogenesis (mitochondrial dysfunction model) - Causes decreased ATP production, increased ROS - Contrast with cyanide (Complex IV), CO (Complex IV), oligomycin (ATP synthase), and uncouplers like 2,4-DNP or aspirin overdose (which increase O2 consumption but uncouple ATP production)