Safety evaluation studies on argemone oil through dietary exposure for 90 days in rats

Abstract

Epidemic dropsy is a disease caused by the consumption of mustard oil contaminated with argemone oil (AO). During 1998 dropsy in New Delhi, which is so far the largest with more than 3000 victims and over 60 deaths, it was enquired at various scientific and regulatory meetings about the maximum tolerated dose of AO. Hence, the present study was aimed to investigate the safety levels of AO in rats. Animals were given AO in diet at a dose of 0.001%, 0.01%, 0.1%, 0.5% and 1% daily for 90 days and the two control groups received the standard diet with and without 1% mustard oil. A decrease in body weight gain (28–31%) was observed in 0.5% and 1% AO groups; while significant increases in relative lungs and liver weight was noticed in respective doses of 0.01% and 0.1% AO groups as well as in higher dosage animals. Reduction in RBC count and hemoglobin content ( p < 0.05) was noticed in 0.01% and 0.1% AO exposed animals. This effect was more pronounced in higher AO doses. Serum marker enzymes including alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) were found to be significantly elevated in 0.01–1% AO groups. Further, a decrease in albumin/globulin ratio (42–78%) was observed in the serum of 0.01% to higher AO dose groups. The levels of serum triglycerides and VLDL cholesterol were found to be enhanced ( p < 0.05) in AO treated (0.01–1.0%) animals. Histopathological changes in lung were observed at 0.01% dose of AO while liver, kidney and heart produced changes at 0.1% AO and above doses. None of the parameters were found to be affected in 0.001% AO treated animals. These results suggest that the no observed adverse effect level (NOAEL) dose of AO is 0.001% in rats and considering a factor of 100 for humans for highly toxic compound, the safe limit of 0.00001% (100 ppb or 100 ng AO/g oil) AO can be implicated which shall contain only 0.55% of sanguinarine equivalent to 0.6 ng sanguinarine per gram oil. However, the minimum detectable limit of AO is 5 ppm (equivalent to 5 μg sanguinarine per gram oil) with the present existing HPLC method, thereby suggesting that mustard oil should be absolutely free from AO contamination.