Pharmacokinetic, pharmacological, and genotoxic evaluation of deuterated caffeine.

Altering caffeine's negative physiological effects and extending its duration of activity is an active area of research; however, deuteration as a means of achieving these goals is unexplored. Deuteration substitutes one or more of the hydrogen atoms of a substance with deuterium, a stable isotope of hydrogen that contains an extra neutron. Deuteration can potentially alter the metabolic profile of a substance, while maintaining its pharmacodynamic properties. d9-Caffeine is a deuterated isotopologue of caffeine with the nine hydrogens contained in the 1, 3, and 7 methyl groups of caffeine substituted with deuterium. d9-Caffeine may prove to be an alternative to caffeine that may be consumed with less frequency, at lower doses, and with less exposure to downstream active metabolites of caffeine. Characterization of d9-caffeine's genotoxic potential, pharmacodynamic, and pharmacokinetic behavior is critical in establishing how it may differ from caffeine. d9-Caffeine was non-genotoxic with and without metabolic activation in both a bacterial reverse mutation assay and a human mammalian cell micronucleus assay at concentrations up to the ICH concentration limits. d9-Caffeine exhibited a prolonged systemic and brain exposure time in rats as compared to caffeine following oral administration. The adenosine receptor antagonist potency of d9-caffeine was similar to caffeine.

Safety studies conducted on a proprietary high-purity aloe vera inner leaf fillet preparation, Qmatrix.

The aloe vera plant has a long history of safe use for oral and topical applications. This publication describes safety studies conducted on a proprietary high-purity aloe vera inner leaf fillet preparation, Qmatrix. In a 13-week study in rats, Qmatrix was administered via gavage at 0, 500, 1000 and 2000 mg/kg body weight (bw)/day. There were no significant changes in food or water consumption, body weight, serum biochemistry or hematology at any of the doses tested. Sporadic, significant increases were observed in some of the measured urinalysis parameters; however, these variations were not treatment-related, as most were observed only in one sex, not dose-dependent and within historical control values. Organ weights were unaffected, except for a statistically significant, though not dose-dependent, increase in absolute and relative weights of the right kidney in males at 500 and 2000 mg/kg bw/day, respectively. Histopathological analysis revealed no abnormal signs. Qmatrix was non-mutagenic in an Ames test and a chromosomal aberration test at concentrations up to 10,000 microg/plate, and in an in vivo bone marrow micronucleus test at doses up to 5000 mg/kg bw/day. Based on these results, Qmatrix is not genotoxic in vitro or in vivo and; has an oral NOAEL greater than 2000 mg/kg bw/day following 90 days of oral exposure.

Safety studies conducted on high-purity trans-resveratrol in experimental animals.

trans-Resveratrol is a naturally occurring polyphenolic compound found in a variety of foods, but predominantly in grapes. Safety studies were conducted on high-purity trans-resveratrol (Resvida), including skin and eye irritation, dermal sensitization, subchronic and reproductive toxicity, genotoxicity, and absorption, metabolism and excretion. Resvida was non-irritating to skin and eyes and non-sensitizing. It was non-mutagenic in a bacterial reverse mutation assay in Salmonella typhimurium and Escherichia coli, but exhibited clastogenic activity in a chromosomal aberration test in human lymphocytes. However, in an in vivo bone marrow micronucleus test in rats, Resvida was non-genotoxic. In a 28-day study, Resvida caused no adverse effects in rats at 50, 150 and 500 mg/kg bw/day. Similarly, in a 90-day study, Resvida did not cause any adverse effects in rats at up to 700 mg/kg bw/day; the highest dose tested. Resvida did not induce any adverse reproductive effects in an embryo-fetal toxicity study in rats at a dose of 750 mg/kg bw/day. Also, in vitro and in vivo absorption, metabolism, and excretion studies in Caco-2 cells, rat primary hepatocytes and male and female rats (in vivo) show that Resvida is readily absorbed, metabolized and excreted. These studies provide evidence that Resvida is well tolerated and non-toxic.

Genotoxicity studies on a high-purity rebaudioside A preparation.

Rebaudioside A (Reb A) is a steviol glycoside isolated from the leaves of the Stevia rebaudiana plant. This non-nutritive, natural sweetener is reported to be 250-450 times sweeter than sucrose and has potential for wide use in the US diet, and is used in Japan and South America today. The safety of Reb A has been investigated in several recently published studies and information on genotoxicity is described herein. Reb A was investigated for its potential to induce genotoxicity in three in vitro and two in vivo assays (conducted according to OECD guidelines). Reb A was non-mutagenic in an Ames test using Salmonella typhimurium and Escherichia coli, in a chromosomal aberration test using Chinese Hamster V79 cells and in a mouse lymphoma assay using L5178Y+/- cells, all studies were conducted at concentrations up to 5000 microg/ml, with and without metabolic activation. Also, Reb A was non-genotoxic in a bone marrow micronucleus test in mice at doses up 750 mg/kg bw and in an unscheduled DNA synthesis test in rats at 2000 mg/kg bw. These studies provide additional evidence that Reb A is not genotoxic at the doses tested and further support the generally recognized as safe determination of Reb A.

Safety assessment of coriander (Coriandrum sativum L.) essential oil as a food ingredient.

Coriander essential oil is used as a flavor ingredient, but it also has a long history as a traditional medicine. It is obtained by steam distillation of the dried fully ripe fruits (seeds) of Coriandrum sativum L. The oil is a colorless or pale yellow liquid with a characteristic odor and mild, sweet, warm and aromatic flavor; linalool is the major constituent (approximately 70%). Based on the results of a 28 day oral gavage study in rats, a NOEL for coriander oil is approximately 160 mg/kg/day. In a developmental toxicity study, the maternal NOAEL of coriander oil was 250 mg/kg/day and the developmental NOAEL was 500 mg/kg/day. Coriander oil is not clastogenic, but results of mutagenicity studies for the spice and some extracts are mixed; linalool is non-mutagenic. Coriander oil has broad-spectrum, antimicrobial activity. Coriander oil is irritating to rabbits, but not humans; it is not a sensitizer, although the whole spice may be. Based on the history of consumption of coriander oil without reported adverse effects, lack of its toxicity in limited studies and lack of toxicity of its major constituent, linalool, the use of coriander oil as an added food ingredient is considered safe at present levels of use.

In vitro and in vivo safety studies of a proprietary whey extract.

A proprietary whey growth factor extract (WGFE) or Lactermin (Lact milk; ermin growth factors) is a whey fraction of milk containing the major proteins lactoperoxidase and lactoferrin, together with a variety of minor proteins and peptides such as the growth factors IGF-I, IGF-II, PDGF, FGF, TGF-ss and betacellulin. This growth factor component of milk has been suggested to possess biological properties such as the promotion of tissue repair and anti-inflammatory activity. In this study the safety of Lactermin has been evaluated using genotoxicity assays (Ames, mouse lymphoma and micronucleus assay) and in a subchronic (13 week) rat oral toxicity study. In vitro Lactermin did not show any mutagenic properties in the Ames or mouse lymphoma assay and in vivo did not show any adverse clinical effects or in the bone marrow of male or female mice. In the subchronic oral toxicity study in which 10 rats per sex were fed Lactermin mixed with rat diet to deliver doses of 300, 1000 and 3000 mg/kg/day for 13 weeks, male and female rats did not show any test article-related clinical observations or effects on body weight, food consumption, ophthalmic effects, functional observational battery, organ weights, locomotor activity, hematology, serum chemistry, urinalysis or macroscopic or microscopic pathology. The results from the genotoxicity studies and the subchronic oral toxicity study suggest Lactermin is safe for consumption with a no-observed-adverse-effect level (NOAEL) of 3000 mg/kg/day.

Safety assessment of 2-ethyl-3,(5 or 6) dimethylpyrazine as a food ingredient.

2-Ethyl-3,(5 or 6)-dimethylpyrazine (CAS No. 27043-05-6), a heterocyclic, nitrogen-containing compound, is used in the food industry as a flavor ingredient for its characteristic roasted odor and flavor, reminiscent of roasted cocoa or nuts. Pyrazines, including 2-ethyl-3,(5 or 6)-dimethylpyrazine, are widely distributed in foods and because of their natural unavoidable occurrence in cooked food; therefore, pyrazine compounds, including 2-ethyl-3,(5 or 6)-dimethylpyrazine, are commonly consumed in the daily diet. 2-Ethyl-3,(5 or 6)-dimethylpyrazine is oxidized in rats almost exclusively via its aliphatic side-chain to carboxylic acid derivatives. The LD(50) of 2-ethyl-3,(5 or 6)-dimethylpyrazine in rats was reported as 460 mg/kg and it is reported to be irritating to the skin, eyes and the upper respiratory tract. Two 90-day rat feeding studies have been conducted on 2-ethyl-3,(5 or 6)-dimethylpyrazine, with the one reporting a no effect level of 12.5mg/kg/day (both sexes) and a second study reporting a NOAEL of 2-ethyl-3,(5 or 6)-dimethylpyrazine 17 and 18 mg/kg/day for male and female rats, respectively. Although no genotoxicity studies were found on 2-ethyl-3,(5 or 6)-dimethylpyrazine, structurally similar pyrazine derivatives were reported as clastogenic in mammalian cells and non-mutagenic in bacterial assays. The relevance of the positive results in assays with Saccharomyces cerevisiae and Chinese hamster ovary cells in vitro is unclear. The data and information available, including a prolonged history of safe use, indicate that at the current level of intake, the food flavoring use of 2-ethyl-3,(5 or 6)-dimethylpyrazine is safe.

Safety assessment of sandalwood oil (Santalum album L.).

Sandalwood (Santalum album L.) is a fragrant wood from which oil is derived for use in food and cosmetics. Sandalwood oil is used in the food industry as a flavor ingredient with a daily consumption of 0.0074 mg/kg. Over 100 constituents have been identified in sandalwood oil with the major constituent being alpha-santalol. Sandalwood oil and its major constituent have low acute oral and dermal toxicity in laboratory animals. Sandalwood oil was not mutagenic in spore Rec assay and was found to have anticarcinogenic, antiviral and bactericidal activity. Occasional cases of irritation or sensitization reactions to sandalwood oil in humans are reported in the literature. Although the available information on toxicity of sandalwood oil is limited, it has a long history of oral use without any reported adverse effects and is considered safe at present use levels.