Absorption of rotenone from the gastrointestinal (GI)
tract is low and incomplete. In animals, rotenone has been
found to be hundreds of times more toxic by IV route than
by oral route. Fats and oils increase the absorption of
rotenone from the GI tract. Rotenone is metabolized in
the liver by nicotinamide adenine dinucleotide phosphate
(NADP)-linked hepatic microsomal enzymes. Several
metabolites have been identified as rotenoids, such as
rotenolone I and II, hydroxyl and dihydroxyrotenones, etc.
(Hayes, 1982; Gosselin et al., 1984). It has been reported
from the studies conducted on rats and mice that approximately
20% of a dose is excreted in urine within 24 h of oral
administration (Hayes, 1982). Unabsorbed rotenone from
the GI tract excretes in feces.