Safety Evaluation of Amaranth Extract by Acute, Sub-Chronic and Chronic Exposure in Rats

Abstract

Amaranth is one of the popularly grown leafy vegetables in tropical regions globally and contains a large amount of nitrate. The present study's objective was evaluation of acute and repeated dose toxicity of amaranth extract as per the OECD guidelines. The acute oral toxicity was conducted in 6 female rats (150-170 g; 8-10 Weeks old) as per OECD 423 guidelines. The amaranth extract had no adverse/toxic effects and no mortality was noted at the dose of 2000mg/kg. The oral LD50, therefore, was considered greater than 2000mg/kg. The sub-chronic (28-day repeated dose) toxicity was studied in 40 rats (150-170 g; 8-10 Weeks old) as per OECD 407 guidelines whereas chronic (365-days repeated dose) toxicity study was conducted in 200 rats (150-170 g; 8-10 Weeks old) as per OECD 452 guidelines. Sub-chronic study confirmed the safety of amaranth extract at the highest dose of 1000 mg/kg/day. The 1000 mg/kg in rats was considered as NOEL (No Observed Adverse Effect Level). The chronic toxicity study established a NOEL of 180 mg/kg in rats. In the repeated dose toxicity studies, body weight, food consumption, blood profile, biochemistry parameters and histopathology of major organs were similar in test and control groups. The current study results indicated that amaranth extract was safe upon acute, sub-chronic and chronic administration in rats, under testing conditions and at dose levels employed.