Circulating naphthionic acid in nonpregnant and pregnant rats after feeding amaranth

Abstract

Naphthionic acid (NA) [1-naphthylamine-4-sulfonic acid], is one of the azoreduction products absorbed from the rat's gut after oral ingestion of amaranth [FD&C Red No. 2, C.I. 16185; CAS [915-67-3]]. This report describes the blood levels of NA in male and nonpregnant female rats as well as the level of NA in fetal blood, amniotic fluid, and maternal blood of rats fed various doses of amaranth. Three groups of five male and eight female rats were fed diets for 9 days to provide estimated daily doses of 20, 200, and 2000 mg amaranth/kg body wt. Five male and six female rats were fed a control diet. Blood samples were collected twice daily after 1, 2, 3, 4, 5, and 8 days of feeding and analyzed for NA. After the ninth day, the male rats were fasted and blood was collected at specific intervals over the next 96 hr. The female rats were mated with untreated males and received the same dosages of amaranth throughout mating and gestation. The amniotic fluids and blood from each fetus as well as the maternal blood were collected between the 19th and 21st day of gestation for the NA determination. A significant elevation in plasma NA concentrations occurred in male and female rats receiving estimated doses of 200 or 2000 mg amaranth/kg body wt. Plasma NA concentrations were slightly but not significantly increased at 20 mg amaranth/kg body wt. The NA concentrations in fetal plasma and amniotic fluid from the 2000 mg amaranth/kg body wt dose group were significantly less than ( p < 0.05) 10-fold higher than those from the 200 mg amaranth/kg body wt dose group. The NA concentrations in maternal blood from the 2000 mg amaranth/kg body wt dose group were less than (although not significant statistically) 10-fold higher than from the 200 mg amaranth/kg body wt dose group. The NA concentrations in maternal plasma were about five times higher than in plasma of their fetuses. There was a significant increase in the NA concentrations in amniotic fluid between the 20th and 21st day of gestation.