An evaluation of the genotoxicity and 90-day repeated-dose toxicity of a CBD-rich hemp oil.

Currently, there is much interest in the sales and study of consumable Cannabis sativa L. products that contain relatively high levels of cannabidiol (CBD) and low levels of Δ-9-tetrahydrocannabinol. While there are published safety evaluations for extracts containing low concentrations of CBD, toxicological assessments for those with higher concentrations are still scant in the public domain. In this paper, genotoxicity tests and a 90-day repeated-dose toxicity study of an ethanolic extract of C. sativa containing ~85% CBD were performed following relevant OECD guidelines. No increased gene mutations were observed in a bacterial reverse mutation assay compared to controls up to the maximum recommended concentration of the guideline. An in vitro chromosomal aberration assay showed no positive findings in the short-term (3 h) treatment assays. Long-term treatment (20 h) showed an increased number of cells containing aberrations at the highest dose of 2 µg/mL, which was outside of historical control levels, but not statistically significantly different from the controls. An in vivo micronucleus study showed no genotoxic potential of the test item in mice. A 90-day repeated-dose gavage study using 0, 75, 125, and 175 mg/kg bw/day showed several slight findings that were considered likely to be related to an adaptive response to consumption of the extract by the animals but were not considered toxicologically relevant. These included increases in liver and adrenal weights compared to controls. The NOAEL was determined as 175 mg/kg bw/day, the highest dose tested (equivalent to approximately 150 mg/kg bw/day of CBD).

Safety evaluation of Veillonella atypica FB0054 with genotoxicity and subchronic toxicological studies.

Veillonella atypica is a nonmotile, nonsporulating anaerobic bacteria commonly found in various human biofilms. V. atypica FB0054 was isolated from the gastrointestinal tract of marathon runners, who have increased amounts of this species after athletic events. Interestingly, the consumption of this strain by rodents has been shown to increase their treadmill endurance, leading to the hypothesis that consumption of this species may improve athletic performance in humans as well. Further evaluation, in humans, of the usefulness of this strain should be preceded by safety studies. Therefore, the genotoxic and subchronic toxicological potential was evaluated as a contribution to this effort. Genotoxicity investigation was performed using the in vivo comet assay and in vivo mammalian micronucleus assay due to the anaerobic characteristic of the strain. A 90-day, repeated-dose oral toxicity study was performed in rats up to 2200 mg/kg bw/d to investigate general toxicity and identify any target organs. Mitsuoka buffer, a solution shown to preserve the viability of anaerobic bacteria, was used as the vehicle. All three studies revealed no toxicological effects from exposure to FB0054 was isolated from the gastrointestinal tract of marathon runners, who have increased amounts of this species after athletic events. Interestingly, the consumption of this strain by rodents has been shown to increase their treadmill endurance, leading to the hypothesis that consumption of this species may improve athletic performance in humans as well. Further evaluation, in humans, of the usefulness of this strain should be preceded by safety studies. Therefore, the genotoxic and subchronic toxicological potential was evaluated as a contribution to this effort. Genotoxicity investigation was performed using the in vivo comet assay and in vivo mammalian micronucleus assay due to the anaerobic characteristic of the strain. A 90-day, repeated-dose oral toxicity study was performed in rats up to 2200 mg/kg bw/d to investigate general toxicity and identify any target organs. Mitsuoka buffer, a solution shown to preserve the viability of anaerobic bacteria, was used as the vehicle. All three studies revealed no toxicological effects from exposure to FB0054 at the highest doses tested.

A toxicological evaluation of 8-28 nm gold nanocrystals.

Gold nanocrystals (AuNC) are gold nanoparticles (AuNP) relatively homogenous in size at 8-28 nm with clean surfaces and crystalline structures. There are concerns and a lack of consensus in the scientific literature and major regulatory bodies regarding not only the safety of nanoparticles when consumed by humans, but exactly how to determine their safety and whether evidence from a nanoparticle with one set of physiochemical properties extends to one with a different set. Additionally, there are few general long-term toxicity data on AuNP. To our knowledge, the potential toxicity of AuNC specifically, with the above characteristics, or otherwise, has not been investigated in preclinical studies; thus, we conducted a battery of genetic toxicity tests and an oral repeated-dose toxicity test to further explore their safety. AuNC were not mutagenic or clastogenic in bacterial reverse mutation and in vitro mammalian chromosomal aberration tests, respectively, and did not exhibit in vivo genotoxicity in a micronucleus test in mice. In a 60-day, repeated-dose oral toxicity study, rats were administered 0, 2.5, 5, or 10 mg/kg bw/day of AuNC by gavage. No toxicity was identified. Therefore, a no observed adverse effect level was determined as 10 mg/kg body weight/day.

A toxicological evaluation of lithium orotate.

Lithium orotate, the salt of lithium and orotic acid, has been marketed for decades as a supplemental source of lithium with few recorded adverse events. Nonetheless, there have been some concerns in the scientific literature regarding orotic acid, and pharmaceutical lithium salts are known to have a narrow therapeutic window, albeit, at lithium equivalent therapeutic doses 5.5-67 times greater than typically recommended for supplemental lithium orotate. To our knowledge, the potential toxicity of lithium orotate has not been investigated in preclinical studies; thus, we conducted a battery of genetic toxicity tests and an oral repeated-dose toxicity test in order to further explore its safety. Lithium orotate was not mutagenic or clastogenic in bacterial reverse mutation and in vitro mammalian chromosomal aberration tests, respectively, and did not exhibit in vivo genotoxicity in a micronucleus test in mice. In a 28-day, repeated-dose oral toxicity study, rats were administered 0, 100, 200, or 400 mg/kg body weight/day of lithium orotate by gavage. No toxicity or target organs were identified; therefore, a no observed adverse effect level was determined as 400 mg/kg body weight/day. These results are supportive of the lack of a postmarket safety signal from several decades of human consumption.

A toxicological evaluation of geranylgeraniol.

Geranylgeraniol (GGOH) is an isoprenoid compound found in annatto seeds and an intermediate of the mevalonate pathway found within organisms serving various functions. Toxicological studies on its safety profile are not readily available. To assess the safety of GGOH, a molecularly distilled, food grade annatto oil, consisting of approximately 80% trans-GGOH, was subjected to a bacterial reverse mutation test, an in vitro mammalian chromosomal aberration test, and an in vivo mammalian micronucleus test in order to investigate its genotoxic potential and a 90-day repeated-dose oral toxicity study in rats in order to investigate its potential subchronic toxicity and identify any target organs. No evidence of mutagenicity or genotoxic activity was observed under the applied test systems. In the 90-day study, male and female Hsd. Han Wistar rats were administered daily doses of 0, 725, 1450, and 2900 mg/kg bw/day by gavage. Treatment-related adverse effects were observed in the forestomach at all dose levels and in the liver at the intermediate- and high-dose levels. Based on these results, the lowest observed adverse effect level (LOAEL) for local effects and the no observed adverse effect level (NOAEL) for systemic effects were determined as 725 mg/kg bw/day.

Assessment of toxicological potential of sodium carboxymethyl beta-glucan, a novel beta-glucan.

In this experimental work, sodium carboxymethyl beta-glucan (CMBG), a chemically altered beta-glucan, is evaluated for mutagenicity and sub-acute oral toxicity. Specifically, the tested material was CM-Glucan Nu, a food grade powder ≥90% CMBG derived from Saccharomyces cerevisiae. A bacterial reverse mutation test was performed and resulted in no mutagenicity. A 28-day, repeated-dose, oral (gavage) toxicity test on rats was performed at dose levels of 0, 500, 1000, and 2000 mg/kg bw/day. No mortality, target organs or other treatment related effects were observed. The no observed adverse effect level (NOAEL) was 2000 mg/kg bw/day, the highest dose tested, for both male and female Han:WIST rats.

Development and Validation of an LC-MS-MS Method for the Quantification of Cyanate in Rat Plasma and Its Application to Toxicokinetic Bioanalysis.

Cyanate has been recognized as a uremic toxin that can adversely affect the clinical status of patients with chronic kidney disease. Besides, its toxicity has been under investigation in mammalian toxicology. If such studies are supplemented with toxicokinetic sampling and bioanalysis, additional information can be acquired about the systemic exposure. In order to serve this need, a liquid chromatography with tandem mass spectrometry (LC-MS-MS) method was elaborated and validated for the quantification of cyanate in rat plasma using its isotope-labeled analog for internal standard. Cyanate was converted to a product compatible with reverse-phase LC-MS-MS via a two-step derivatization reaction with the reagent-anthranilic acid. It was observed that this reagent solution contains the reaction products even if prepared freshly in ultrapure water. The phenomenon was interpreted as the presence of urea and its reactivity with anthranilic acid. Contrary to previous research results where fresh anthranilic acid solution was recommended to use, we have found that the aging of the reagent solution is a crucial factor to eliminate the interference. Thereafter, the optimal pH was selected for the plasma sample and processing conditions. Bioanalytical validation and incurred sample reanalysis confirmed the reliability of the method when the intermediate reaction product was used for detection. Only one freeze-thaw cycle stability could be proven, which highlighted the need to collect two sample aliquots whenever possible. Real samples were analyzed in a toxicity study to evaluate systemic exposure of potassium cyanate at three dose levels. Further on, this method might be adapted to provide additional information about the pathophysiological concentration of cyanate in patients with chronic kidney disease for therapeutic support.

A toxicological evaluation of monomethylsilanetriol (MMST) stabilized in acacia gum, a novel silicon preparation.

Monomethylsilanetriol (MMST), a silicon-containing compound, has been sold in dietary supplements. However, toxicological studies on its safety profile are not readily available. To assess the safety of MMST stabilized in acacia gum, a novel delivery form of MMST, in accordance with internationally accepted standards, the genotoxic potential and repeated-dose oral toxicity of Living Silica® Acacia Gum Stabilized Monomethylsilanetriol (formerly known as Orgono Acacia Gum Powder®), a food grade product consisting of 80 ± 10% acacia gum and 2.8% (SD ± 10%) elemental silicon from MMST, was investigated. A bacterial reverse mutation test, an in vitro mammalian chromosomal aberration test, an in vivo mammalian micronucleus test, and a 90-day repeated-dose oral toxicity study in rats were performed. No evidence of mutagenicity or genotoxic activity was observed under the applied test systems. In the 90-day study, male and female Hsd.Han Wistar rats were administered daily doses of 0, 500, 1000, and 2000 mg/kg bw/day by gavage. No mortality or treatment-related adverse effects were observed, and no target organs were identified. Therefore, the no observed adverse effects level (NOAEL) was determined as 2000 mg/kg bw/day (201 mg MMST/kg bw/day), the highest dose tested.

A Toxicological Evaluation of Germanium Sesquioxide (Organic Germanium).

A battery of OECD- and GLP-compliant toxicological studies was performed to assess the safety of a highly purified germanium sesquioxide, an organic form of the naturally occurring, nonessential trace element germanium. Germanium dioxide and germanium lactate citrate (inorganic germaniums) have been shown to induce renal toxicity, whereas germanium sesquioxide (an organic germanium) has been shown to have a more favorable safety profile. However, past toxicity studies on germanium sesquioxide compounds have not clearly stated the purity of the tested compounds. In the studies reported herein, there was no evidence of mutagenicity in a bacterial reverse mutation test or an in vitro mammalian chromosomal aberration test. There was no genotoxic activity observed in an in vivo mammalian micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/day. In a 90-day repeated-dose oral toxicity study in Han:WIST rats conducted at doses of 0, 500, 1000, and 2000 mg/kg bw/day by gavage, there were no mortalities, treatment-related adverse effects, or target organs identified. The no-observed-adverse-effect-level (NOAEL) was determined to be 2000 mg/kg bw/day.

A Toxicological Evaluation of Mango Leaf Extract (Mangifera indica) Containing 60% Mangiferin.

A battery of OECD- and GLP-compliant toxicological studies was performed on mango leaf extract (Mangifera indica) containing 60% mangiferin (MLE). No evidence of genotoxicity was found in a bacterial reverse mutation test (Ames). While evidence of clastogenic activity was noted in an in vitro chromosomal aberration test, an in vivo mammalian micronucleus test showed no findings up to the limit dose (2000 mg/kg bw). A 90-day repeated dose oral toxicity study was conducted in rats using doses of 0 (vehicle control), 500, 1000, and 2000 mg/kg bw/day. Based on the lack of mortality or toxic effects in the 90-day study, the NOAEL for MLE in Han:Wist male and female rats was determined to be 2000 mg/kg bw/day, the highest dose tested.

Toxicological Evaluation of a Mixture of Astragalus membranaceus and Panax notoginseng Root Extracts (InnoSlim®).

Astragalus spp. and Panax spp. have a long history of traditional human use. A blend, InnoSlim®, of highly purified and fractionated root extracts from Astragalus membranaceus and Panax notoginseng has now been developed for human consumption; however, the unique constituent content of this blend has not been specifically evaluated with respect to safety. Therefore, the toxicological potential of the blend was formally investigated in a series of studies-genetic toxicity was evaluated in a bacterial reverse mutation test followed by an in vivo mammalian micronucleus test, and general toxicity was evaluated in a 28-day repeated-dose oral toxicity study in rats. No evidence of mutagenicity was observed in the bacterial tester strains used, and no evidence of in vivo chromosomal damage resulting in increased frequency of micronucleated cells was observed in male Crl:NMRI BR mice. No mortality or toxic effects were observed, and no target organs were identified, in male and female Han:WIST rats exposed to 0, 400, 800, or 1200 mg/kg bw/day of the blend by gavage for 28 consecutive days. The highest dose-1200 mg/kg bw/day-was determined to be the NOAEL. Based on these results, extrapolation towards a safe human consumption level can be explored.

Toxicological evaluations of colostrum ultrafiltrate.

Colostrum has been consumed safely for many years as a food collected directly from cows. More recently, an ultrafiltrated bovine colostrum product has been developed; however, its safety in toxicology studies has not been extensively evaluated. To assess the safety of bovine colostrum ultrafiltrate, in accordance with internationally accepted standards, the genotoxic potential was investigated in a bacterial reverse mutation test, an in vitro chromosomal aberration test, and an in vivo mammalian micronucleus test. No mutagenicity or genotoxic activity was observed in these three tests. A 90-day repeated-dose oral toxicity study in Hsd.Han Wistar rats was conducted at doses of 0, 1050, 2100, and 4200 mg/kg bw/day by gavage. After 90 days of continuous exposure, no mortality or treatment-related adverse effects were observed, and no target organs were identified. The no-observed-adverse-effect level (NOAEL) was determined to be 4200 mg/kg bw/day, the highest dose tested.

A comprehensive toxicological safety assessment of an extract of Ageratum conyzoides.

A battery of toxicological studies was conducted to aid in the safety assessment of an ethanolic extract of Ageratum conyzoides for use as an ingredient in food. In accordance with internationally accepted standards, a bacterial reverse mutation test, an in vitro mammalian chromosomal aberration test, an in vivo mammalian micronucleus test, and a 90-day repeated-dose oral toxicity study in rats were performed. In the first three applied test systems, no evidence of mutagenicity, clastogenicity or genotoxicity was revealed. Ageratum conyzoides did not cause mortality or toxic changes in Hsd.Han Wistar rats in the 90-day repeated dose oral (gavage) toxicity study at doses of 500, 1000 and 2000 mg/kg bw/d. The NOAEL was determined to be 2000 mg/kg bw/d for both male and female rats, the highest dose tested.

A Toxicological Evaluation of Methylliberine (Dynamine®).

Methylliberine (CAS 51168-26-4), a methoxiuric acid, is a caffeine metabolite present at low levels in various Coffea plants; however, very little has been published regarding this compound and we could find no toxicological data in the public domain. Therefore, we undertook the toxicological investigation of a pure, synthetic form of methylliberine in order to evaluate its potential health hazards as a food ingredient. A (1) bacterial reverse mutation test, (2) in vitro mammalian chromosomal aberration test, (3) in vivo mammalian micronucleus test, and (4) 90-day repeated-dose oral toxicity study in rats with a 28-day recovery period were conducted. No in vitro mutagenic or clastogenic activity was observed in the presence or absence of metabolic activation up to the maximum OECD recommended test concentrations. No genotoxicity was observed in the mammalian micronucleus study up to the highest dose tested of 700 mg/kg bw. In the 90-day study, methylliberine was administered to Han:WIST rats at doses of 0, 75, 112, 150, 187, and 225 mg/kg bw/day. No mortality or morbidity was observed and no toxicologically relevant clinical effects or effects on clinical pathology parameters were observed. In male animals, test item-related effects on body weight and sexual organs, which were not reversible after a 28-day recovery period without treatment, were observed in the high-dose group. Body weight development was also slightly and reversibly depressed in the 187 mg/kg bw/day male group. No toxicological effects were observed in females. The NOAEL for females was determined to be 225 mg/kg bw/day, the highest dose tested, while the NOAEL for males was determined to be 150 mg/kg bw/day. Future studies are encouraged to corroborate the safety, and assess efficacy, of methylliberine in humans.

An Assessment of the Genotoxicity and Subchronic Toxicity of a Supercritical Fluid Extract of the Aerial Parts of Hemp.

A battery of toxicological studies was conducted on a supercritical CO2 extract of the aerial parts of the Cannabis sativa plant, containing approximately 25% cannabinoids. No evidence of genotoxicity was found in a bacterial reverse mutation test (Ames), in an in vitro mammalian chromosomal aberration test, or in an in vivo mouse micronucleus study. A 14-day repeated oral dose-range finding study conducted in Wistar rats at 1000, 2000, and 4000 mg/kg bw/day resulted in effects where a NOAEL could not be concluded. Based on those results, a 90-day repeated dose oral toxicity study was performed in rats using doses of 100, 360, and 720 mg/kg bw/day, followed by a 28-day recovery period for two satellite groups. Significant decreases in body weight, body weight gain, and differences in various organ weights compared to controls were observed. At the end of the recovery period, many of the findings were trending toward normal; thus, the changes appeared to be reversible. The NOAEL for the hemp extract in Hsd.Han Wistar rats was considered to be 100 mg/kg bw/day for males and 360 mg/kg bw/day for females.

A Toxicological Evaluation of Chlamydomonas reinhardtii, a Green Algae.

There is a current worldwide interest in developing novel sustainable nonanimal nutritional sources, and one such source is the green algae Chlamydomonas reinhardtii, the only green algae that has been studied as a model organism for many biological processes ranging from photosynthesis to flagellar movement. However, its potential as a safe nutritional source for use in various foods has not been thoroughly investigated. To assess the safety of C reinhardtii for use as a nutritional human food ingredient, in accordance with internationally accepted standards, the genotoxic potential and repeated-dose oral toxicity of the dried C reinhardtii (THN 6) algal biomass was investigated. The following studies were conducted: (1) a bacterial reverse mutation test, (2) an in vitro mammalian chromosomal aberration test, (3) an in vivo mammalian micronucleus test, and (4) a 28-day repeated-dose oral toxicity study in rats. No evidence of mutagenicity or genotoxic activity was observed in the first 3 tests under the applied test systems. In the 28-day study, male and female Hsd.Han Wistar rats were exposed to daily doses of 0, 1,000, 2,000, and 4,000 mg/kg bw by gavage. Following 28 days of continuous exposure, no mortality or treatment-related adverse effects were observed and no target organs were identified. Therefore, a no observed adverse effect level was concluded as 4,000 mg/kg bw/day, the highest dose tested.

A Toxicological Assessment of Creatyl-l-Leucine.

A battery of toxicological studies was conducted to investigate the genotoxicity and repeated-dose oral toxicity of creatyl-l-leucine, a synthetic compound, in rats in accordance with internationally accepted guidelines. There was no evidence of mutagenicity in a bacterial reverse mutation test and in an in vitro mammalian chromosomal aberration test. There was no genotoxic activity observed in an in vivo mammalian micronucleus test at concentrations up to the limit dose of 2,000 mg/kg bw/d. Creatyl-l-leucine did not cause mortality or toxic effects in Hsd.Han Wistar rats in a 90-day repeated-dose oral (gavage) toxicity study at doses of 1,250, 2,500, and 5,000 mg/kg bw/d. The no observed adverse effect level from the 90-day study was determined to be 5,000 mg/kg bw/d, the highest dose tested, for both male and female rats.

A 28-day oral toxicology study of an aqueous extract of Polypodium leucotomos (Fernblock®).

Fernblock® is a standardized commercial aqueous extraction of the leaves of the tropical fern Polypodium leucotomos promoted as an orally active photoprotective substance. In a previous battery of toxicological tests on Fernblock®, no genotoxicy was observed and no oral toxicity was observed up to 1200 mg/kg bw/day. The current study was conducted in Hsd.Han Wistar rats using doses of 0, 2000, 3500, and 5000 mg/kg bw/day Fernblock® by gavage for 28 consecutive days. No mortality or toxic effects were observed and no target organs were identified. The no observed adverse effect level was determined to be 5000 mg/kg bw/day, the highest dose tested.

A Comprehensive Toxicological Safety Assessment of an Extract of Olea Europaea L. Leaves (Bonolive™).

A battery of toxicological studies was conducted to investigate the genotoxicity and repeated-dose oral toxicity of Bonolive™, a proprietary water-soluble extract of the leaves of the olive tree (Olea europaea L.), in accordance with internationally accepted protocols. There was no evidence of mutagenicity in a bacterial reverse mutation test and in an vitro mammalian chromosomal aberration test nor was any genotoxic activity observed in an in vivo mouse micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/d. Bonolive™ did not cause mortality or toxic effects in Crl:(WI)BR Wistar rats in a 90-day repeated-dose oral toxicity study at doses of 360, 600, and 1000 mg/kg bw/d. The no observed adverse effect level in the 90-day study was 1000 mg/kg bw/d for both male and female rats, the highest dose tested.

A comprehensive toxicological safety assessment of an aqueous extract of Polypodium leucotomos (Fernblock(®)).

A battery of toxicological studies was conducted in accordance with internationally accepted standards to investigate the genotoxicity and repeated-dose oral toxicity of Fernblock(®), a commercial aqueous extraction of the leaves of the tropical fern Polypodium leucotomos used for its oral and topical photoprotective properties. No evidence of mutagenicity was observed in a bacterial reverse mutation test or in vitro mammalian chromosomal aberration test nor was any genotoxic activity observed in an in vivo mouse micronucleus test. Two repeated-dose oral toxicity studies were conducted in male and female Wistar rats. In the first study, no mortality or toxic effects were observed and no target organs were identified at doses administered for 14 days by gavage up to the maximum dose of 5000 mg/kg bw/day. Based on these results, a 90-day study was conducted at 0, 300, 600, and 1200 mg/kg bw/day. No mortality or treatment-related adverse effects were observed and no target organs were identified. The NOAEL from the 90-day study was determined to be 1200 mg/kg bw/day, the highest dose tested.