Toxicologic evaluation of DHA-rich algal oil: Genotoxicity,acute and subchronic toxicity in rats

DHA-rich algal oil ONC-T18, tested in a battery of in vitro and in vivo genotoxicity tests, did not show mutagenic or genotoxic potential. The acute oral LD50 in rats has been estimated to be greater than 5000 mg/kg of body weight. In a 90-day subchronic dietary study, administration of DHA-rich algal oil at concentrations of 0, 10,000, 25,000, and 50,000 ppm in the diet for 13 weeks did not produce any significant toxicologic manifestations. The algal oil test article was well tolerated as evidenced by the absence of major treatment-related changes in the general condition and appearance of the rats, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, routine hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The no observed adverse effect level (NOAEL) was the highest level fed of 50,000 ppm which is equivalent to 3,305 and 3,679 mg/kg bw/day, for male and female rats, respectively. The studies were conducted as part of an investigation to examine the safety of DHA-rich algal oil. The results confirm that it possesses a toxicity profile similar to other currently marketed algal oils and support the safety of DHA-rich algal oil for its proposed use in food.     

A chronic toxicity study of cyadox in Wistar rats

To investigate the chronic toxicity of cyadox, a growth promoting agent, five groups of Wistar rats (30 rats/group/sex) were fed with the diets containing cyadox (0, 100, 400 and 2000 mg/kg) or olaquindox (400 mg/kg) for 78weeks. There were significant decreases in body weights in both genders during most of the study period in 2000 mg/kg cyadox and 400 mg/kg olaquindox rats. Significant decreases in serum alkaline aminotransferase in the 2000 mg/kg cyadox rats at weeks 26, 52 and 78 were observed. Relative weights of liver and kidney were significantly increased in 2000 mg/kg cyadox and 400 mg/kg olaquindox rats at weeks 26, 52 and 78. A significant increase in relative brain and heart weights in 2000 mg/kg cyadox males was observed. The histopathological examinations revealed that 2000 mg/kg cyadox diet or 400 mg/kg olaquindox diet could induce proliferation of bile canaliculi in the portal area of liver and swelling and fatty degeneration of the proximal renal tubular epithelial cells in kidneys. In conclusion, the target organs of cyadox for rats were liver and kidney. The no-observed-adverse-effect level of cyadox in this study was estimated to be 400 mg/kg diet.     

13-Week oral toxicity study of oil derived from squid (Todarodes pacificus) in Sprague-Dawley rats

Recommendations to increase the consumption of the long-chain omega-3 fatty acids are challenged by the global problem of declining fish stocks. Non-traditional and more sustainable sources of the long-chain omega-3 fatty acids are needed. Squid (Todarodes pacificus) represents a uniquely sustainable source of these fatty acids. A 13-week oral toxicity study was conducted in male and female Sprague-Dawley rats administered either 0, 250, 500, or 1000 μl/kg body weight (bw)/day of a refined squid oil. All of the rats survived through to the end of the study. All of the rats grew normally and had normal clinical and ophthalmic observations. No signs of toxicity were evident from clinical chemistry, hematology, and urinalysis data measured. No abnormal findings attributable to exposure to purified squid oil were observed following the necropsy of male and female rats and the histopathological examination of the organs. The no-observed-adverse-effect level for refined squid oil was determined to be 1000 μl/kg bw/day, the highest dose tested.     

Evaluation of the toxicity of mastic gum with 13 weeks dietary administration to F344 rats.

Dietary toxicity of mastic gum, a natural food additive, was studied in male and female F344 rats fed 0%, 0.22%, 0.67% and 2% levels mixed into powdered basal diet for 13 weeks. No mortality or obvious clinical signs were observed in any of the animals throughout the experimental period. Body weights were significantly reduced in the high dose-treated group from week 2 to the end of the experiment in males, and at weeks 8 and 13 in females. There were increased absolute and relative liver weights in a dose-related manner or limited to the high dose group males or females, along with changes in hematological parameters, including increased WBC and platelet in high dose males. Altered serum biochemistry parameters included increases of total proteins, albumin, and total cholesterol in both sexes, and gamma-GTP in females only. However, macroscopic examination at necropsy revealed no gross lesions, and microscopic examination also revealed no treatment-related findings in any organs examined. As dietary treatment of mastic gum for 13 weeks in the present study caused decreased body weights at the high dose, especially in males, and increased liver weights in a dose-related manner in both genders without any morphological findings, it is concluded that the administration of it has a no observed adverse effect level (NOAEL) of 0.67% in the diet.     

Toxicological effects of arsenate exposure on hematological,biochemical and liver transaminases activity in an Indian major carp, Catla catla

The impact of acute and sublethal toxicity of arsenate on hematological, biochemical and enzymological parameters of an Indian major carp Catla catla were estimated. The median lethal concentration of sodium arsenate to the fish Catla catla for 96 h was found to be 43.78 mg/L. During acute treatment (43.78 mg/L), hemoglobin (Hb), hematocrit (Ht), red blood cell count (RBC), white blood cell count (WBC), plasma glucose, plasma protein, liver aspartate and alanine aminotransferase (AST and ALT) levels decreased, whereas corpuscular indices like mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC) increased in arsenate treated fish. In sublethal treatment (4.378 mg/L), Hb, Ht, RBC, plasma protein levels decreased while MCHC and plasma glucose levels increased throughout the exposure period. A biphasic trend was noticed in WBC, MCV, MCH, liver AST and ALT levels. The alterations of these parameters can be effectively used as a rapid method to assess health of fish exposed to arsenate in the aquatic environment.     

Twenty-eight days repeated oral dose toxicity study of gemifloxacin in Wistar albino rats

The purpose of this study was to investigate the potential toxicity of gemifloxacin by 28-day repeated oral dose in Wistar albino rats. The test article, was administered daily by gavage to male and female rats at dose levels of 0, 50, 100, 200 mg/kg/day. At the end of treatment period, 12 rats/sex/group was sacrificed, while six extra rats/sex in the vehicle control and highest dose groups sacrificed after 14 days recovery period. During the treatment and recovery periods, clinical signs, mortality, body weights, food and water consumption, ophthalmoscopy, urinalysis, phototoxicity, hematology, serum biochemistry, synovial fluid biochemistry, electrocardiogram (ECG), gross findings, organ weights, microscopic examination of synovial fluid, and histopathology were examined. Hematological and serum biochemical investigations revealed a dose-dependent increase in the total white blood cell (WBC), total bilirubin (T-BIL), glucose (GLU), alanine aminotransferase (ALT) and significant decreases in total protein (TP) were observed in both sexes at the same dose, at the end of treatment period, but the levels returned toward normal during the recovery period. Histopathology of talar joint showed that erosion of the articular surface of that joint in both sexes at the end of treatment period at the dose level of 200 mg/kg/day. Degenerative changes in tendinocytes were observed in Achilles tendon of both sexes at the high dose level at the end of treatment period. In histopathological study shows partial effacement of liver architecture and focal ulceration in gastric mucosa at the high dose level at the end of treatment period. Based on these results, it was concluded that 28 days repeated oral dose of gemifloxacin caused increases in the liver weight, WBC count, T-BIL, glucose level, ALT, decreasing the TP, cause chronic hepatitis and acute gastritis, erosion of the articular surface of joint and histopathologic changes in Achilles tendon in rats at the dose level of 200 mg/kg/day.     

Lack of chronic toxicity or carcinogenicity of dietary N-acetylglucosamine in F344 rats

Chronic toxicity and carcinogenicity of N-acetylglucosamine (GlcNAc) were examined in male and female F344 rats. GlcNAc was given in the diet at levels of 0%, 1.25%, 2.5% or 5% to groups of 10 rats of each sex for 52 weeks in the chronic toxicity study and 0%, 2.5% or 5% to groups of 50 rats of each sex for 104 weeks in the carcinogenicity study. GlcNAc exerted no toxic effects with regard to clinical signs, mortality, hematology, serum biochemistry and histopathological assessment. Slight suppression of body weight gain was observed at more than 2.5%, but this appeared to be due to slight reduction of caloric intake with the high concentration of test compound, rather than any toxicity. Thus, it was concluded that GlcNAc has neither toxic nor carcinogenic effects in F344 rats, the no observed adverse effect levels (NOAEL) estimated from the chronic toxicity study being 5% in both sexes, equivalent to 2323 and 2545 mg/kg/day in males and females, respectively.     

A 90-day oral (dietary) toxicity study of the 2R,4R-isomer of monatin salt in Sprague–Dawley rats

The root bark of Sclerochitin ilicifolius contains an intensely sweet substance analytically identified as isomers of 2-hydroxy-2-(indol-3-ylmethyl)-4-aminoglutaric acid and generically coined “monatin.” Groups of male and female Crl:CD(SD) rats were fed 0 (control), 5000, 10,000, 20,000 or 35,000 ppm R,R-monatin salt in the diet for 90 days. There were no toxicologically relevant clinical or histopathological findings in any of the test article-treated groups. Significantly lower cumulative body weight gains were noted in the 35,000 ppm group. Mean body weights in the 35,000 ppm group males and females were 7% and 12% lower, respectively, than the control group at study week 13. In the absence of other observations associated with systemic toxicity and lower food consumption, the magnitude of the body weight difference in the 35,000 ppm group females relative to the control group exceeded 10%, which indicated attainment of a maximum tolerated dose (MTD) level. Based on the results of this study, and conservatively assuming the body weight observations at the MTD to be indicative of an adverse effect, the dietary no-observed-adverse-effect level (NOAEL) of R,R-monatin salt for 90 days was 20,000 ppm in female rats (approximately 1544 mg/kg bw/day) and 35,000 ppm in male rats (approximately 2368 mg/kg bw/day).     

A 90-day ad libitum administration toxicity study of oligoglucosamine in F344 rats.

A 90-day ad libitum administration toxicity study of oligoglucosamine (OG) was carried out using F344 rats of both sexes. The animals were divided into four groups of 20 animals each, 10 of each sex, and fed a diet containing 0, 0.04, 0.2 or 1.0 (w/w)% OG. During the administration period, no animals of either sex died or exhibited abnormal signs in the 0.04% OG and 0.2% OG groups. In the 1% OG group, in both sexes, erythema and swelling of the snout and forelimbs and loss of fur in the forelimbs were observed. On macroscopic observation, emaciation, swelling of the snout, auricles and forelimbs and alopecia of the forelimbs were also observed in 2-3 males of the 1% OG group. It was suggested that these topical abnormalities might be due to dermal responses to OG adhering to the skin and fur, which are easily soiled with saliva during grooming. In the animals of the 1% OG group, food consumption decreased, resulting in body weight gain being suppressed. This was found concomitantly with the abnormal findings mentioned above. Thus, feeding difficulties due to the topical lesions on the snout and forelimbs were thought to affect body weight. In hematology, platelet count, lymphocyte count and differential neutrophil count increased in males of the 1% OG group. These changes might be related to the dermal inflammation. Abnormalities in urinalysis and blood chemistry, as well as a small thymus, small spleen, dark spots or areas on the glandular stomach mucosa, pale Harderian glands and small testes in histopathology, were also observed in males in the 1% OG group. Whether or not all these changes were related only to the malnutrition remains to be elucidated. From these results, OG gave rise to no adverse effects in rats up to the dose level of 0.2 (w/w)%. Thus, the no observed adverse effect level was determined to be 0.2 (w/w)% for rats of either sex (124.0mg/kg/day in males, 142.0mg/kg/day in females).     

Results of a 90-day safety assessment study in mice fed a glucan produced by Agrobacterium sp. ZX09

Salecan is a novel water-soluble glucan produced by Agrobacterium sp. ZX09. It has potential application as a food additive with a unique chemical composition and excellent physicochemical properties. The objective of this study was to investigate the acute and subchronic toxicity of Salecan. The oral LD50 of Salecan in ICR mice was greater than 3000 mg/kg body weight. In the subchronic study, ICR mice (10/sex/group) were fed diets containing 0%, 1.0%, 2.5% and 5.0% of Salecan (weight/weight) for 13 weeks. Based on the results from the subchronic study, the overall health, body weight gain, food consumption and clinical pathology parameters were comparable between the groups feed Salecan and the control. No dose-related effects were observed in the treated animals. The only exception was the observation that blood glucose in female mice fed Salecan was lower than in the control group. In addition, the fecal matter from Salecan fed mice exhibited increased water content versus the control animals. The no observed adverse effect level (NOAEL) of 14478 mg/kg body weight/day was determined. The results from this study support the conclusion that Salecan is non-toxic at the levels tested and does not pose a risk to human health when used in food.     

Safety assessment of ellagic acid, a food additive, in a subchronic toxicity study using F344 rats.

Ellagic acid is a phenolic acid compound, used as a food additive for its antioxidative properties. Because of its chemical characteristics, use is also to be expected in cosmetics. The present 90-day subchronic toxicity study was performed in F344 rats at dose levels of 0, 1.25, 2.5 and 5% in powdered basal diet, with actual doses of 9.4, 19.1, 39.1 g/kg b.w., respectively, in males, and 10.1, 20.1, 42.3 g/kg b.w. in females. No mortality or treatment-related clinical signs were observed throughout the experimental period. Body weight gain was significantly reduced from weeks 3 (5% group), 6 (2.5% group) and 7 (1.25% group) to the end of the experiment (except week 8 in the lowest group) in the treated females, the final body weights being decreased in the 5% (92.5%), 2.5% (94.2%) and 1.25% (94.8%) treated groups as compared to the control. Changes in MCV and serum AST, ALP, Ca, Cl and P were sporadically observed, but these were not considered to be treatment-related alterations. There were no obvious histopathological changes in any of the groups. The no-observed-effect level (NOEL) was estimated to be 5% (3011 mg/kg b.w./day) for males and the no-observed-adverse-effect level (NOAEL) and NOEL in females were estimated to be 5% (3254 mg/kg b.w./day) and <1.25% (778 mg/kg b.w./day), respectively.     

Safety assessment of yerba mate (Ilex paraguariensis) dried extract: results of acute and 90 days subchronic toxicity studies in rats and rabbits

Acute toxicity of yerba mate dried extract (YMDE) was investigated in Wistar rats (6/sex/group) from single dose of 2g/kg body weight by intragastric administration and 14days monitoring. Subchronic toxicity was investigated in Wistar rats, by intragastric administration (10/sex/group), and in New Zealand rabbits by oral administration (3/sex/group) of 2g/kg body weight for 12weeks. Toxicological parameters included clinical signs, body weight, water, and food consumption, hematological and serum parameters, and histopathological assessment. Acute YMDE administration showed no effects on survival, clinical observations, macroscopic examination of organs, body weight or food, and water consumption. Sub-chronic administration of YMDE did not change behavior, body weight, and histopatological assessment of stomach, kidney, liver, and small gut. Moreover, most of biochemical and hematological parameters remained unchanged. In summary, the results of our preclinical toxicological investigation are indicative that the YMDE is well tolerated for both single and chronic administration.     

A subacute toxicity evaluation of green tea (Camellia sinensis) extract in mice

Green tea is believed to be beneficial to health because it possesses antioxidant, antiviral and anticancer properties. The potential toxicity of green tea when administered at high doses via concentrated extracts, however, has not been completely investigated. The objective of the present study was to evaluate the safety of green tea extract in ICR mice using a subacute exposure paradigm. In this study, mice were orally administered (gavage) green tea extract at doses of 0 (as normal group), 625, 1250 and 2500 mg/kg body weight/day for 28 days. The results showed that oral administration of green tea extract did not cause adverse effects on body weight, organ weights, hematology, serum biochemistry, urinalysis or histopathology. Additionally, administering green tea extract via gavage significantly reduced triglyceride and cholesterol levels. These observed effects could be attributed to the high levels of catechins present in green tea as these compounds have been reported to have beneficial health effects. The no-observed-adverse-effect level for green tea extract derived from the results of the present study was 2500 mg/kg body weight/day.     

Oral 28-day and developmental toxicity studies of (R)-3-hydroxybutyl (R)-3-hydroxybutyrate

(R)-3-Hydroxybutyl (R)-3-hydroxybutyrate (ketone monoester) has been developed as an oral source of ketones, which may be utilized for energy. In a 28-day toxicity study, Crl:WI (Wistar) rats received diets containing, as 30% of the calories, ketone monoester (12 and 15 g/kg body weight/day for male and female rats, respectively). Control groups received either carbohydrate- or fat-based diets. Rats in the test group consumed less feed and gained less weight than control animals; similar findings have been documented in studies of ketogenic diets. Between-group differences were noted in selected hematology, coagulation, and serum chemistry parameters; however, values were within normal physiological ranges and/or were not accompanied by other changes indicative of toxicity. Upon gross and microscopic evaluation, there were no findings associated with the ketone monoester. In a developmental toxicity study, pregnant Crl:WI (Han) rats were administered 2 g/kg body weight/day ketone monoester or water (control) via gavage on days 6 through 20 of gestation. No Caesarean-sectioning or litter parameters were affected by the test article. The overall incidence of fetal alterations was higher in the test group; however, there were no specific alterations attributable to the test substance. The results of these studies support the safety of ketone monoester.     

A one-year oral toxicity study of sodium stearoyl lactylate (SSL) in rats

The toxicity of sodium stearoyl lactylate (SSL) was examined in Wistar rats fed diets containing 0, 1.25, 2.5, and 5% SSL for one year, equivalent to mean daily intakes of 558, 1115, and 2214 mg/kg/day in males and 670, 1339, and 2641 mg/kg/day in females, respectively. SSL was well tolerated at these dietary levels as evidenced by the absence of toxicologically significant changes in the general condition and appearance of the rats, survival, neurobehavioral endpoints, growth, feed and water intake, ophthalmoscopic examinations, hematology and clinical chemistry parameters, urinalysis, or necropsy findings. The occurrence of uterine endometrial stromal polyps was the only finding of potential significance. Given the frequent occurrence of these benign tumors in rats, wide variability in the reported incidence of this type of polyps in rats, the lack of statistical significance and lack of biological evidence to suggest a mechanism for the slightly greater incidence in the groups fed 2.5 and 5% SSL, it was concluded that the endometrial stromal polyps observed in females fed SSL were not related to treatment. The no observed adverse effect level (NOAEL) of SSL was placed at 5%, the highest dietary level tested (equivalent to 2214 mg/kg/day for males and 2641 mg/kg/day for females).     

Toxicity evaluation of the aqueous extract of the rhizome of Elephantorrhiza elephantina (Burch.) Skeels. (Fabaceae), in rats

Elephantorrhiza elephantina root extract has been used as a traditional remedy for a wide range of ailments both in humans and livestock. As part of the safety assessment of the extract, acute, sub-acute and chronic toxicity tests were conducted by the oral route in rats. Male and female rats were divided into four groups consisting of five rats each and given doses of 200–1600 mg/kg bwt, 200–800 mg/kg bwt and 50–400 mg/kg bwt in acute (1 day), sub-acute (14 days) and chronic toxicity (35 days), respectively. During the experiment, no deaths were observed in any groups and there were no remarkable changes in general appearance, as well as in food and water consumption. Significant (P < 0.05) changes were however noted in body weights, haematological and serum biochemical parameters between the control and treated groups. Histopathological changes were also noted in kidneys, lungs, liver and spleen of rats receiving high doses. Based on these findings, it can be inferred that the plant has some potential toxicity at certain dose levels; therefore caution has to be taken when using E. elephantina for medicinal purposes.     

A 90-day subchronic toxicity study of nivalenol, a trichothecene mycotoxin, in F344 rats.

A subchronic toxicity study of nivalenol (NIV), a trichothecene mycotoxin, was conducted in male and female F344 rats fed diet containing 0, 6.25, 25 or 100 ppm concentration for 90 days. Decrease of body weight and loose stools were observed at 100 ppm in both sexes from the start of the experiment, and body weight reduction was also observed at 25 ppm in males from week 6. At necropsy, many organs demonstrated reduced absolute weights at 100 ppm in both sexes, mostly due to the reduction in the body growth, with reduction of relative thymus weight also being evident in females. Hematologically, decrease of the white blood cell count was found at 100 ppm in males and from 6.25 ppm in females. In addition, decreased platelet counts in both sexes, red blood cell counts in males, and the hemoglobin concentration in females were detected at 100 ppm. Histopathologically, treatment-related changes were predominantly observed in the hematopoietic and immune organs and the anterior pituitary in both sexes and female reproductive organs at 100 ppm, such as thymic atrophy, hypocellularity in the bone marrow, diffuse hypertrophy of basophilic cells with increase of castration cells in the anterior pituitary, and increase of ovarian atretic follicles. Based on the hematological data, the no-observed-adverse-effect level of NIV was determined to be less than 6.25 ppm (0.4 mg/kg body weight/day for both males and females).     

Toxicologic evaluation of modified gum acacia: mutagenicity, acute and subchronic toxicity.

Modified gum acacia, produced from acacia gum by a process analogous to the production of modified food starch, was tested for mutagenicity in the microbial reverse mutation assay. The assay employed a wide range of dose levels, both with and without metabolic activation. Test results gave no indication that modified gum acacia possessed any mutagenic potential. The acute oral toxicity of modified gum acacia was determined in two studies employing Sprague-Dawley rats, and the LD50 values were found to be >2000 mg/kg. The primary dermal irritation potential of modified gum acacia was evaluated in rabbits by the Draize method. Test results indicated that modified gum acacia was slightly irritating by the Environmental Protection Agency (EPA) classification but not a primary irritant by Consumer Product Safety Commission (CPSC) guidelines. The subchronic toxicity of modified gum acacia was examined in Sprague-Dawley rats fed diets containing 0%, 1%, 2.5%, and 5% modified gum acacia for 13 weeks. No dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed. Results of these studies indicate that modified gum acacia does not possess mutagenic potential and that animals are not adversely affected by acute or subchronic exposure to modified gum acacia.     

Effect of diallyl trisulfide-rich garlic oil on blood coagulation and plasma activity of anticoagulation factors in rats.

Diallyl trisulfide (DAT)-rich garlic oil was fed to Sprague-Dawley rats and the effects of this DAT-rich garlic oil on bleeding time, clotting time and anticoagulation factors were examined. Garlic oil supplement at 5 or 50mg garlic oil/kg bodyweight significantly prolonged bleeding time and thrombin time, and enhanced anticoagulation factor activity, such as antithrombin III and protein C (P<0.05). These results suggested that the anticoagulant action of DAT-rich garlic oil was due to inhibition and/or inactivation of thrombin. In addition, DAT-rich garlic oil benefits blood anticoagulation factors, which might further prevent the development of thrombus formation. However, the intake of garlic oil at high dose significantly increased plasma fibrinogen concentration (P<0.05), and affected the levels of several hematological parameters such as erythrocyte count, hemoglobin and platelets (P<0.05). The adverse effect of high doses of garlic oil might further influence the hemostatic balance. Therefore, the concentration of DAT-rich garlic oil should be carefully considered in its application. Supplementation of garlic oil at 5mg/kg bodyweight has anticoagulation effect in this animal study.     

A 13-week subchronic toxicity study of madder color in F344 rats.

A 13-week repeated oral dose toxicity study of madder color (MC), a natural food colorant extracted from the roots of Rubia tinctorum L., was performed using F344 rats. Five groups of animals, each consisting of 10 males and 10 females, were fed diet containing 0, 0.6, 1.2, 2.5 or 5.0% MC for 13 weeks. During the experiment, lower body weight was evident from the 2.5% dose. Hematologically, fluctuation in red blood cell (RBC) parameters suggestive of weak anemia (females), and slight increases of platelet counts (both sexes) and white blood cell (WBC) counts (males) were observed at higher doses. Serum biochemically, slight fluctuations were observed in many parameters, including increased total protein (TP), conjugated bilirubin, Ca, and inorganic phosphate, and decrease of the albumin/globulin (A/G) ratio in both sexes, with dose-dependence for TP and A/G from 0.6% in females. Histopathological changes were mainly observed in the renal proximal tubules, such as microvesicular vacuolar degeneration in the cortex and karyomegaly in the outer medulla involving both sexes, lesions being evident even with 0.6%. In the outer medulla, elevation of cell proliferation activity as assessed with proliferating cell nuclear antigen was observed in males from 2.5%. Severity of focal necrosis of hepatocytes was increased only in females at 5.0%, while the increased relative liver weight as with the increased conjugated bilirubin was evident in both sexes from 1.2%. The results thus suggest that MC exerts mild toxicity, targeting liver, kidneys, and possibly RBCs and WBCs, some renal changes being evident from 0.6% in diet, that is attributable to be the lowest-observed adverse effect level (305.8-309.2mg/kg body weight/day).