An evaluation of the genotoxicity and subchronic toxicity of the peel extract of Ponkan cultivar 'Ohta ponkan' (Citrus reticulata Blanco) that is rich in nobiletin and tangeretin with anti-dementia activity.

Nobiletin and tangeretin are major components of polymethoxylated flavones in the peels of citrus fruits such as Citrus reticulata. Because nobiletin and tangeretin have attracted attention due to their beneficial health properties, citrus peel extracts, in which they are concentrated, have the potential to serve as a functional food ingredient to prevent diseases. In this study, a series of toxicological studies on the peel extract of Ponkan cultivar 'Ohta ponkan' (Citrus reticulata Blanco), was conducted. No mutagenic activity was observed in a bacterial reverse mutation test, whereas chromosomal aberrations were induced in an in vitro mammalian chromosomal aberration test. No genotoxicity was observed in an in vivo mammalian micronucleus test. In a 90-day study at daily doses of 54, 180, or 540 mg/kg body weight (bw)/day, hyaline droplet nephropathy, which specifically occurs in adult male rats, was observed in males of 540 mg/kg bw/day group. No other adverse effects were observed in the 90-day study. The no adverse effect level in the 90-day study was considered to be 540 mg/kg bw/day for female rats and less than 540 mg/kg bw/day for male rats.

Genotoxicity and subchronic toxicity evaluation of dried Euglena gracilis ATCC PTA-123017.

Euglena gracilis is a microalga capable of synthesizing various nutrients of interest in human and animal nutrition. When cultivated aerobically in the dark, Euglena synthesize paramylon, a storage polysaccharide comprised of high molecular weight beta-1,3-D-glucose polymers organized in cytoplasmic granules. Beta-glucans have been shown to have immune modulation effects, including anti-microbial, anti-tumor, and anti-oxidant properties, and metabolic effects, such as regulation of cholesterol and blood sugar levels. Preparations of E. gracilis and paramylon may therefore have potential utility as functional food ingredients for human and animal nutrition. A battery of toxicological studies was conducted on a dried preparation of E. gracilis and paramylon to support their safe food use. The dried alga was not genotoxic in a bacterial reverse mutation test and mammalian micronucleus test. In the subchronic toxicity study, rats were provided E. gracilis in the diet at levels of 0, 12,500, 25,000 or 50,000 ppm. Paramylon was provided at a concentration of 50,000 ppm. No effects that could be attributable to treatment were observed in clinical observations, body weight, food consumption, ophthalmology, hematology and clinical chemistry, urinalysis, and macroscopic and microscopic findings. A NOAEL of 50,000 ppm in the diet was determined for both ingredients.

Development of the dietary fiber functional food and studies on its toxicological and physiologic properties.

Dietary fiber (DF) obtained from wheat bran by microbial fermentation was used as a food additive to cookies. The cookies were evaluated sensorally through an orthogonal test to gain the optimized production conditions as follows: the suitable DF content 8%, leavening agent 1.5%, standing time 5 min, and baking time of the cookies is 8 min. A series of toxicological and physiological functions of the cookies were studied using KM mice as the experimental animal in this paper. No deaths or abnormal behaviors of mice occurred either in acute toxicity tests or in short-term feeding tests. Besides, the weight gains, food utilization ratios, blood and serum biochemical parameters, organ coefficients and the results of organ histopathology tests of all doses groups exhibited no significant differences with the control group. This reveals that the dietary fiber functional cookies made by this formula have no acute or sub-chronic toxicity. In terms of physiological function, compared with the control group, the total cholesterol (TC) and triglycerides (TG) were 17.0-21.7% and 18.7-35.0% lower in mice serum of all DF cookie doses groups, respectively, but this difference was not significant (P>0.05). Compared with positive control group, the Cd(2+) and Pb(2+) excretion ratios of DF group were 27.4% and 25.2% higher, respectively. Thus, a conclusion has been drawn that dietary fiber functional cookies made by this formula have no toxic or harmful actions on animals or humans, and the DF food was able to decrease TC and TG concentrations to some extent in serum and increase excretion of Cd(2+) and Pb(2+) in Feces.

Yeast thioredoxin-enriched extracts for mitigating the allergenicity of foods.

Thioredoxin (TRX) catalyzes the reduction of disulfide bonds in proteins via the NADPH-dependent thioredoxin reductase system. Reducing the disulfide bonds of allergenic proteins in food by TRX lowers the allergenicity. We established in this study a method to prepare TRX-enriched extracts from the edible yeast, Saccharomyces cerevisiae, on a large and practical scale, with the objective of developing TRX-containing functional foods to mitigate food allergy. Treating with the yeast TRX-enriched extracts together with NADPH and yeast thioredoxin reductase enhanced the pepsin cleavage of ß-lactoglobulin and ovomucoid (OM). We also examined whether yeast TRX can mitigate the allergenicity of OM by conducting immediate allergy tests on guinea pigs. The treatment with TRX reduced the anaphylactic symptoms induced by OM in these tests. These results indicate that yeast TRX was beneficial against food allergy, raising the possibility that yeast TRX-enriched extracts can be applied to food materials for mitigating food allergy.