Safety Assessment of a Hemp Extract using Genotoxicity and Oral Repeat-Dose Toxicity Studies in Sprague-Dawley Rats

Dziwenka, Margitta; Coppock, Robert; Alexander, McCorkle; Palumbo, Eddie; Ramirez, Carlos; Lermer, Stephen

There was no concentration related or substantial test article related increases in the number of revertant colonies for each of the strains tested in the presence or absence of metabolic activation (S9 mix), in either the plate incorporation or the pre-incubation methods (data not shown). Precipitation which interfered with lawn evaluation was noted for all strains at doses ≥7,633.5 μg/plate but did not obscure counts in the test with the diluted test article. Precipitation which obscured lawn evaluation was seen in all strains with the supercritical CO 2 extract at doses ≥ 1580 μg/plate with and without S9 in both the plate incorporation and pre-incubation methods. Toxicity was evident for strains TA 98, TA 1535, TA 1537 and E. coli WP2 uvrA at ≥50 μg/plate, with and without S9, in the plate incorporation and/or pre-incubation tests. Precipitation which obscured lawn evaluation was seen in all strains with the isopropanol extract at doses ≥ 1580 μg/plate with and without S9 in both the plate incorporation and pre-incubation methods. Toxicity was noted for strains TA 1537 and TA 100 at 500 and/or 1580 μg/plate without S9 in the pre-incubation method. The studies were considered valid as the mean revertant colony counts for vehicle controls were close to or within the expected range based on the laboratory historical controls and/or published values and the positive control substances resulted in the expected substantial increases in revertant colony counts.