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

The hemp extract in these studies was shown to be non-mutagenic in a bacterial test system used to evaluate mutagenicity. Marx et al. [4] reported on a GLP-compliant study that concentrations of 5,000 μg/ plate of a CO 2 supercritical extract of C. sativa were not mutagenic in a bacterial test system. Our GLP-compliant mutagenicity testing on the diluted extract showed that concentrations of 76,355 μg/plate were not mutagenic with and without the S9 metabolic activation. The extracts produced by isopropanol extraction and supercritical CO 2 extraction were not mutagenic with and without S9 metabolic activation at concentrations up to 5000 μg/plate. The bacterial test system with the S9 mix did cause mutagenicity providing evidence that mutagenic metabolites were not produced with any of the extracts. The two additional Ames tests conducted on the undiluted extracts produced by two different extraction methods, were conducted to determine if the method of production or the olive oil diluent impacted the results of the Ames assay. No mutagenicity was noted in any of the tests conducted. Other botanical extracts have been evaluated for mutagenicity. Mutagenic studies on extracts from the plant Euphorbia triaculeata showed that it is not mutagenic and provides protection from the mutagenic effects of cyclophosphamide [31] . A study on a novel taste modulating powder derived from Cordyceps sinensis showed this product was not mutagenic in the Ames test and these results were supported in the micronucleus assay [32] . In a study on the genotoxicity of CBD in Caco-2 cells, 10 μM of CBD did not significantly cause DNA damage after 24 hours of incubation, and CBD was also shown in the comet assay to protect Caco-2 cells from hydrogen peroxide-induced DNA damage [33] . CBD at an oral dose of 1 mg/kg was shown to significantly (P < 0.05) reduce azoxymethane-induced colonic aberrant crypt foci, colonic polyps and tumors [33] .