90-day subchronic toxicity study in rats and mice fed N-methylpyrrolidone (NMP) including neurotoxicity evaluation in rats.

In mice, there were no effects on body weight or food consumption. As observed in rats, mice fed 2,500 or 7,500 ppm exhibited a change in urine coloration which was not associated with morphological changes in cholesterol, triglycerides, calcium, and alkaline phosphatase occurred at 28 days but not 90 days. These changes are thus assessed as being of minor toxicological relevance. Liver weights were elevated in males fed 2,500 or 7,500 ppm and centrilobular hypertrophy was seen in both sexes fed 7,500 ppm. These changes may be regarded as an adaptation process but are clearly related to NMP exposure. Other toxicological endpoints examined were unaffected by NMP. The NOAEL was 3,000 ppm for both sexes of rats based on body weight effects and changes in 3 neurobehavioral parameters (males only) at higher feeding levels. In mice, the NOAEL was 1,000 ppm based on liver responses to higher concentrations.     

A 28-day oral (dietary) toxicity study of sucromalt in Sprague--Dawley rats.

A new sweetener, sucromalt, was produced via enzymatic conversion of sucrose and maltose to a mixture of fructose, leucrose and gluco-oligosaccharides. The present study evaluated the safety of this sweetener when administered as a dietary admix at concentrations of 50, 100 and 200 g/kg to Sprague-Dawley rats for 28 days. There were no treatment-related effects on the general condition and behavior as determined by clinical observations, functional observational battery and locomotor activity assessments. Evaluation of clinical pathology parameters revealed no toxicologically-relevant treatment-related effects on hematology, serum chemistry or urinalysis. Macroscopic and microscopic findings revealed no treatment-related effects on any organ evaluated. A treatment-related increase in mean food consumption was observed resulting in slightly higher body weight gains (2-4%) for both the male and female rats, which was not toxicologically relevant. Results of this study clearly demonstrate that consumption of high concentrations of sucromalt for 28 days is not associated with obvious signs of toxicity.     

A 28-day oral toxicity study of echimidine and lasiocarpine in Wistar rats

Pyrrolizidine alkaloids (PAs) are a class of naturally-occurring plant toxins. Echimidine is one of the predominant PAs found in honeys produced in Australia and New Zealand. There is a lack of information on the oral toxicity of echimidine on which to base regulatory decisions concerning the risk to humans of these honeys. This GLP study was conducted to assess the subchronic dietary toxicity of echimidine to rats compared to that of lasiocarpine as a positive control. Wistar rats, 10/sex, were fed diets containing 0, 0.6, 1.2 or 2.5 mg/kg bw echimidine. Positive control groups, 10/sex, were fed diets containing 0.6, 1.2 or 2.5 mg/kg bw lasiocarpine.Neither PA had any effect on survival, food consumption, clinical signs, gross lesions, or histopathology. Consumption of lasiocarpine, but not echimidine, decreased bodyweight gain in males at ≥ 1.2 mg/kg bw, and in females at 2.5 mg/kg bw. Slight alterations in white cell counts and serum ALT concentrations at 2.5 mg/kg bw of both PAs were not clinically significant, had no histological correlates, and were considered to be of equivocal relevance.In conclusion, the subchronic No Observed Adverse Effect Level (NOAEL) for echimidine is 2.5 mg/kg bw/day, whereas, on the basis of a treatment-related decrease in bodyweight gain in males at 1.2 mg/kg bodyweight, the NOAEL for lasiocarpine is 0.6 mg/kg bw/day.     

Acute toxicity, 28-day repeated-dose toxicity and toxicokinetic study of timosaponin BII in rats

Timosaponin BII (TBII), a major steroidal saponin isolated from Anemarrhena asphodeloides Bge., displays a variety of promising pharmacological activities, such as neuroprotection, enhancement of learning and memory, vascular protection and inhibition of platelet aggregation; therefore, it has been developed as a pharmaceutical for prevention or treatment of dementia. Given the safety concerns surrounding timosaponins and the absence of studies on the safety of TBII, the potential toxicity of TBII was evaluated in toxicity and toxicokinetic studies in rats. In the acute oral toxicity study, loose stools were observed in rats receiving 4000 mg/kg, and the symptoms recovered within 1 day. In the 28-day repeated-dose oral toxicity and toxicokinetic study, rats receiving 540 mg/kg showed loose stools and a slight deceleration of body weight growth in both sexes, and the females also showed a slight decrease in food consumption. Moreover, urinalysis indicated reversible treatment-related toxicity in rats receiving 540 mg/kg. The toxicokinetic study demonstrated a dose-dependent increase in systematic exposure to TBII after 28 successive days of oral treatment with TBII. The accumulation coefficients of TBII were 4.35, 1.70 and 1.81, respectively, in rats that received 60, 180 and 540 mg/kg. The no-observed-adverse-effect level (NOAEL) is proposed to be 180 mg/kg.     

Acute and oral subchronic toxicity of D-003 in rats

D-003 is a mixture of higher aliphatic primary acids purified from sugar cane wax (Saccharum officinarum) with cholesterol-lowering and antiplatelet effects experimentally proven. The present work reports the results of two studies investigating the acute and subchronic oral toxicity of D-003 in rats. Oral acute toxicity of D-003 (2000 mg/kg) was investigated according to the Acute Toxic Class (ATC) method (an alternative for the classical LD(50) test), which was performed in Wistar rats. The results obtained in this study defined D-003 oral acute toxicity as unclassified. In the subchronic study, rats of both sexes were orally treated with D-003 at 50, 200 and 1250 mg/kg for 90 days. At this time, animals were sacrificed. No evidence of treatment-related toxicity was detected during the study. Thus, data analysis of body weight gain, food consumption, clinical observations, blood biochemical, haematology, organ weight ratios and histopathological findings did not show significant differences between control and treated groups. It is concluded that D-003 orally administered to rats was safe and that no drug-related toxicity was detected even at the highest doses investigated in both acute (2000 mg/kg) and subchronic (1250 mg/kg) studies.     

A 90-day subchronic oral toxicity study of triterpene-enriched extract from Alismatis Rhizoma in rats

Alismatis Rhizoma has been used in East Asia as a traditional treatment for various illnesses and symptoms, and the presence of protostane-type triterpenes has been claimed to provide health benefits. To investigate the subchronic toxicity of triterpene-enriched extract from Alismatis Rhizoma (TEAR), a 90-day oral toxicity study was conducted in rats. Sprague–Dawley rats were randomly divided into four groups (10 rats/sex/group) and received doses of 0, 360, 720, and 1440 mg/kg/d of TEAR for 90 days. Daily clinical observations as well as weekly measurement of body weight and food consumption were conducted. Blood samples were obtained on day 91 to measure changes in hematology and biochemistry. Urine samples were collected on days 0 and 91 for urinalysis. At necropsy, selected organs were weighed and recorded, and histological examination was performed. No mortality or obvious treatment-related clinical signs, hematology, urinalysis parameters, and macroscopic or microscopic examinations were observed. Differences in weight gain, food consumption, biochemistry, and relative organ weight between the treated group and the control group were not considered treatment-related. On the basis of these findings, the no-observed-adverse-effect level for TEAR was 1440 mg/kg/d in both sexes.     

Subchronic (90-day) toxicity study in rats fed gum kondagogu (Cochlospermumgossypium).

Although gum kondagogu (Cochlospermum gossypium) is grouped under gum karaya (Sterculia sp.), it differs significantly in terms of physicochemical properties and chemical composition and does not conform to the confirmatory tests prescribed for gum karaya ([Janaki]). Gum karaya has wide applications in the pharmaceutical and food industries, whereas the use of gum kondagogu is yet to be explored. In this context, a short-term toxicity study on gum kondagogu was undertaken in rats. The gum was fed to rats at 0, 0.2%, 1% and 5% (w/w) in feed, for 90 days. Biochemical parameters were measured to assess the toxicity at the end of the study period. The results indicated no significant changes in growth pattern, haematological indices (RBC, WBC, Hb, PCV, MCV, MCH, MCHC, differential leucocyte counts), biochemical analytes (glucose, urea nitrogen, total protein, albumin, bilirubin, creatinine, sodium and potassium ions), activities of plasma and liver enzymes (alkaline phosphatase, alanine amino-transaminase, aspartate aminotransaminase, lactate dehydrogenase, glutathione S-transferase and gamma-glutamyl transpeptidases and organ to body mass ratio (brain, heart, lungs, liver, kidneys and spleen). Histopathology of the liver and kidney also did not reveal any abnormality. An increased faecal bulk was observed in rats fed with 5% gum kondagogu. However, faecal moisture content of female rats only was significantly different (P=<0.05) as compared to controls. Thus, it can be inferred, based on the present investigations, that gum kondagogu has a potential application as a food additive, similar to gum karaya. Feeding it at a much higher level (5%) than expected for consumption as a food additive also did not result in any toxic effect. Being non-toxic, gum kondagogu has a potential as a food additive with excellent physicochemical properties and a unique chemical composition.     

28-day oral toxicity study of the aqueous extract from spider brake (Pteris multifida Poiret) in rats.

Spider brake (Pteris multifida Poiret) is a very important folk herb and a constituent in most of the traditional herbal beverage formulas in Taiwan; however, little toxicological information is available regarding the safety following repeated exposure. The present study was conducted to evaluate the toxicity of aqueous extract from spider brake (SB) in Sprague-Dawley rats on dietary oral gavage at concentrations of 100, 500, and 1000 mg/kg b.w. day for 28 days. There were no adverse effects on general condition, growth, feed and water consumption, feed conversion efficiency, red blood cell and clotting potential parameters, clinical chemistry values, and organ weights except for neutrophils and lymphocytes being slightly diminished in male and female rats at the highest dose, respectively. Necropsy and histopathology findings revealed no treatment-related changes in any of the organs. The results obtained in this study allowed us to conclude that the SB properly utilized in the traditional oral administration could be devoid of any toxic risk.     

28-day repeated dose oral toxicity of recombinant human holo-lactoferrin in rats

Recombinant human holo-lactoferrin (holo-rhLF) was orally administered, via gavage, to Wistar rats at 1000, 500 and 100mg/kgbw/day for 28 days. The test article, holo-rhLF, was expressed in rice grain, extracted, purified and saturated with iron. During the 28-day period, animals were examined for evidence of toxicity. On day 29, the animals were exsanguinated, examined for gross pathology, and tissues preserved for histopathology. There were no deaths caused by holo-rhLF and in-life physical signs were generally normal. Although statistical differences were noted in some hematology, clinical chemistry and heart/body weight ratios, they were of questionable biological significance. A significantly greater total iron binding capacity (TIBC) was detected in the blood of male animals dosed with holo-rhLF. Serum was analyzed for the presence of IgG and IgE antibodies; demonstrating low levels of IgG antibodies to the human protein, but no increase in IgE antibodies. There was no increase in serum lactoferrin levels. The results of the 28-day oral administration demonstrate a lack of toxicity of holo-rhLF in rats. There were no treatment related, toxicologically relevant changes in clinical signs, growth, food consumption, hematology, clinical chemistry, organ weights or pathology. The no observed adverse effect level (NOAEL) is greater than 1000 mg/kg/day.     

A subchronic oral toxicity study on pyrroloquinoline quinone (PQQ) disodium salt in rats

A subchronic oral toxicity study on pyrroloquinoline quinone (PQQ) disodium salt was performed in rats. Sprague-Dawley rats were randomly divided into four groups (10 rats/sex/group) and administered with PQQ disodium salt at doses of 0 (control), 100, 200 and 400 mg/kg bw/day by gavage for 13 weeks. Daily clinical observations and weekly measurement of body weights and food consumption were conducted. Blood samples were obtained on day 46 and day 91 for measurement of hematology and serum biochemical parameters. Animals were euthanized for necropsy, selected organs were weighted and recorded. Histological examination was performed on all tissues from animals in the control and PQQ disodium salt treatment groups. No mortality or toxicologically significant changes in clinical signs, body weight, food consumption, necropsy findings or organ weights was observed. Differences between treated and control groups in some hematological and serum biochemical examinations and histopathological examination were not considered treatment-related. The no-observed-adverse-effect-level (NOAEL) of PQQ disodium salt in rats was considered to be 400 mg/kg bw/day for both sexes, the highest dose tested.     

28-day oral toxicity study with soft corticosteroid BNP-166 in rats and dogs, followed by a 14-day recovery period

The aim of the present study was to evaluate the soft corticosteroid BNP-166 in rats and dogs treated orally with 0.2, 2.0, and 20.0 mg/kg for 28 days and the reversibility of any abnormalities during a 14-day post-dosing period. The test substance, BNP-166, was well tolerated during the 28-day treatment period. The observed changes were all characteristic for the pharmacological actions of a glucocorticoid. Treatment related changes occurred in the adrenals and thymus, and, to a lesser extent, in the lymph nodes, spleen and liver. There were no statistically significant reductions in the cortisol levels of all groups in the 0.2 and 2 mg/kg treatments. Significant reductions were observed in the high-dose group (20 mg/kg), but levels returned to normal by the end of the 14-day recovery period. Based on the results, the No Observable Adverse Effect Level (NOAEL) of BNP-166 soft corticosteroid in rat and dog after 28-day oral administration is 2 mg/kg. This value is approximately 40 times higher than that of budesonide. Pharmacodynamic and receptor binding studies have shown BNP-166 to have a similar potency to budesonide; therefore, BNP-166 can be considered safer when administered orally than other corticosteroids such as prednisolone or budesonide.     

A subchronic oral toxicity study of almond skins in rats

Almond skins have been suggested to have some potential benefits. To investigate the subchronic toxicity of almond skins, a 90-feeding study was conducted in rats. Sprague–Dawley rats were randomly divided into four groups (20 rats/sex/group) and received a diet containing 0%, 2.5%, 5.0% and 10% (w/w) almond skins for 90 days. Daily clinical observations and weekly measurement of body weights and food consumption were conducted. Ophthalmic examinations were performed at pre-test and termination. Blood samples were obtained on day 46 and day 91 for the measurement of hematology, coagulation and clinical chemistry parameters. Urine samples were collected on day 91 for urinalysis. Animals were euthanized for necropsy. Selected organs were weighted and recorded. Histological examination was performed on all tissues from animals in the control and high-dose groups. No mortality, body weight, ophthalmic abnormalities or treatment-related findings in clinical observations, hematology, coagulation, urinalysis parameters, macroscopic or microscopic examinations were observed. Differences between treated and control groups in weight gain, food consumption, clinical chemistry, and organ weight were not considered treatment-related. The no-observed-adverse-effect-level (NOAEL) for almond skins was considered to be 10% (w/w) for both genders (females, 9.7 g/kg body weight/day; males, 8.2 g/kg body weight/day).     

A 28-day oral dose toxicity study in Wistar rats enhanced to detect endocrine effects of decabromodiphenyl ether (decaBDE)

Decabromodiphenyl ether (decaBDE) is a widely used brominated flame retardant, considered to be of low toxicity. However, previous toxicity studies applied exposure methods with low bioavailability of this compound, and the actual hazard of decaBDE for humans, which are environmentally exposed to decaBDE, may thus be underestimated in current risk assessments. The present 28 days oral toxicity study in Wistar rats was designed to facilitate detection of endocrine and immune modulating effects of decaBDE using an exposure protocol with improved bioavailability. A technical preparation of high purity decaBDE was thus tested by daily exposure through gavage with an emulsion of soy phospholipon/lutrol as a carrier. Most sensitive effect in males were increased weight of seminal vesicle/coagulation gland with BMDL of 0.2mg/kg bw/day and increased expression of hepatic CYP1A and CYP2B (BMDLs 0.5-0.7 mg/kg bw/day). In females the most sensitive effect was decreased activity of P450c17 (CYP17), which is a key enzyme in the androgen synthesis pathway, in adrenals (BMDL 0.18 mg/kg bw/day). These results suggest that decaBDE may represent an as yet unreported hazard for reproductive health.     

A 90-day oral (dietary) toxicity study of rebaudioside A in Sprague-Dawley rats

Rebaudioside A is one of several glycosides found in the leaves of Stevia rebaudiana (Bertoni) Bertoni (Compositae) stevia that has been identified as a potential sweetener. The present study (initiated in April 2006 and completed in October 2006) evaluated the safety of this sweetener when administered as a dietary admix at target exposure levels of 500, 1000, and 2000 mg/kg/day to Sprague-Dawley rats for 90 days. There were no treatment-related effects on the general condition and behavior of the animals as determined by clinical observations, functional observational battery, and locomotor activity assessments. Evaluation of clinical pathology parameters revealed no toxicologically relevant, treatment-related effects on hematology, serum chemistry, or urinalysis. Macroscopic and microscopic findings revealed no treatment-related effects on any organ evaluated. Lower mean body weight gains were noted in males in the 2000 mg/kg/day group throughout the study, which was considered to be test article related; however, given the small magnitude of the difference as compared to controls, this effect was not considered to be adverse. Results of this study clearly demonstrate that dietary administration of high concentrations of rebaudioside A for 90 consecutive days to Sprague-Dawley rats was not associated with any signs of toxicity.     

Acute and subchronic oral toxicity studies in rats with nanoscale and pigment grade titanium dioxide particles

Data generated using standardized testing protocols for toxicity studies generally provide reproducible and reliable results for establishing safe levels and formulating risk assessments. The findings of three OECD guideline-type oral toxicity studies of different duration in rats are summarized in this publication; each study evaluated different titanium dioxide (TiO₂) particles of varying sizes and surface coatings. Moreover, each study finding demonstrated an absence of any TiO₂ -related hazards. To briefly summarize the findings: 1) In a subchronic 90-day study (OECD TG 408), groups of young adult male and female rats were dosed with rutile-type, surface-coated pigment-grade TiO₂ test particles (d₅₀ = 145 nm − 21% nanoparticles by particle number criteria) by oral gavage for 90 days. The no-adverse-effect level (NOAEL) for both male and female rats in this study was 1000 mg/kg bw/day, the highest dose tested. The NOAEL was determined based on a lack of TiO₂ particle-related adverse effects on any in-life, clinical pathology, or anatomic/microscopic pathology parameters; 2) In a 28-day repeated-dose oral toxicity study (OECD TG 407), groups of young adult male rats were administered daily doses of two rutile-type, uncoated, pigment-grade TiO₂ test particles (d₅₀ = 173 nm by number) by daily oral gavage at a dose of 24,000 mg/kg bw/day. There were no adverse effects measured during or following the end of the exposure period; and the NOAEL was determined to be 24,000 mg/kg bw/day; 3) In an acute oral toxicity study (OECD TG 425), female rats were administered a single oral exposure of surface-treated rutile/anatase nanoscale TiO₂ particles (d₅₀ = 73 nm by number) with doses up to 5000 mg/kg and evaluated over a 14-day post-exposure period. Under the conditions of this study, the oral LD₅₀ for the test substance was >5000 mg/kg bw. In summary, the results from these three toxicity studies – each with different TiO₂ particulate-types, demonstrated an absence of adverse toxicological effects. Apart from reporting the findings of these three studies, this publication also focuses on additional critical issues associated with particle and nanotoxicology studies. First, describing the detailed methodology requirements and rigor upon which the standardized OECD 408 guideline subchronic oral toxicity studies are conducted. Moreover, an attempt is made to reconcile the complex issue of particle size distribution as it relates to measurements of nanoscale and pigment-grade TiO₂ particles. Clearly this has been a confusing issue and often misrepresented in the media and the scientific literature. It is clear that the particle-size distribution for pigment-grade TiO₂, contains a small (“tail”) component of nanoscale particles (i.e., 21% by particle number and <1% by weight in the test material used in the 90-day study). However, this robust particle characterization finding should not be confused with mislabeling the test materials as exclusively in the nanoscale range. Moreover, based upon the findings presented herein, there appears to be no significant oral toxicity impact contributed by the nanoscale component of the TiO₂ Test Material sample in the 90-day study. Finally, it seems reasonable to conclude that the study findings should be considered for read-across purposes to food-grade TiO₂ particles (e.g., E171), as the physicochemical characteristics are quite similar.     

28-Day oral toxicity study in rats with high purity barley beta-glucan (Glucagel™)

Beta-glucans are glucose polymers present in cereal grains, particularly barley and oat. Consumption of these grains or concentrated beta-glucan preparations has been shown to lower blood cholesterol. The present study was conducted to assess the safety of a high purity (>75%) barley beta-glucan (Glucagel™). The product was fed to Wistar rats (5/sex/group) at dietary levels of 0% (control), 1%, 5% and 10% for 28 days. Clinical and neurobehavioural observations, growth, feed and water consumption, ophthalmoscopy, haematology, clinical chemistry, urinalysis, organ weights, necropsy and histopathological examination revealed no adverse effects of Glucagel™. High-dose males exhibited lower plasma cholesterol and phospholipids levels and a higher plasma urea level. These slight changes were considered of no toxicological significance. Full and empty caecum weights were increased in mid- and high-dose males. This caecal enlargement was a physiological response to the consumption of a high amount of indigestible carbohydrate and considered of no toxicological concern. In conclusion, feeding Glucagel™ at dietary levels up to 10% for 28 days was tolerated without any signs of toxicity. This dietary level was equivalent to 7.7 g Glucagel™ (5.8 g beta-glucan)/kg body weight/day in male rats and 7.8 g Glucagel™ (5.9 g beta-glucan)/kg body weight/day in female rats.     

Acute, short-term, and subchronic oral toxicity of 1,1,1-trichloroethane in rats.

1,1,1-Trichloroethane (TRI) is a widely used solvent that has become a frequent contaminant of drinking water supplies in the U.S. There is very little information available on the potential for oral TRI to damage the liver or to alter its P450 metabolic capacity. Thus, a major objective of this investigation was to assess the acute, short-term, and subchronic hepatotoxicity of oral TRI. In the acute study, male Sprague-Dawley (S-D) rats were gavaged with 0, 0.5, 1, 2, or 4 g TRI/kg bw and killed 24 h later. No acute effects were apparent other than CNS depression. Other male S-D rats received 0, 0.5, 5, or 10 g TRI/kg po once daily for 5 consecutive days, rested for 2 days, and were dosed for 4 additional days. Groups of the animals were sacrificed for evaluation of hepatotoxicity 1, 5, and 12 days after initiation of the short-term experiment. This dosage regimen caused numerous fatalities at 5 and 10 g/kg, but no increases in serum enzymes or histopathological changes in the liver. For the subchronic study, male S-D rats were gavaged 5 times weekly with 0, 0.5, 2.5, or 5.0 g TRI/kg for 50 days. The 0 and 0.5 g/kg groups were dosed for 13 weeks. A substantial number of rats receiving 2.5 and 5.0 g/kg died, apparently due to effects of repeated, protracted CNS depression. There was evidence of slight hepatocytotoxicity at 10 g/kg, but no progression of injury nor appearance of adverse effects were seen during acute or short-term exposure. Ingestion of 0.5 g/kg over 13 weeks did not cause apparent CNS depression, body or organ weight changes, clinical chemistry abnormalities, histopathological changes in the liver, or fatalities. Additional experiments did reveal that 0.5 g/kg and higher doses induced hepatic microsomal cytochrome P450IIE1 (CYP2E1) in a dose- and time-dependent manner. Induction of CYP2E1 activity occurred sooner, but was of shorter duration than CYP2B1/2 induction. CYP1A1 activity was not enhanced. In summary, 0.5 g/kg po was the acute, short-term, and subchronic NOAEL for TRI, for effects other than transient CYP2E1 induction, under the conditions of this investigation. Oral TRI appears to have very limited capacity to induce P450s or to cause liver injury in male S-D rats, even when administered repeatedly by gavage in near-lethal or lethal dosages under conditions intended to maximize hepatic effects.     

A subchronic 90-day oral rat toxicity study and in vitro genotoxicity studies with a conjugated linoleic acid product

Conjugated linoleic acid (CLA) is the term given to a group of positional and geometric isomers of the essential fatty acid linoleic acid. CLA is found naturally in foods such as dairy and meat products. CLA is reported to have a number of beneficial effects including anticarcinogenic activity. However, safety data are limited. Clarinol™ G80 is a commercial preparation containing equal amounts of the 9cis,11trans and 10trans,12cis CLA isomers in the form of glycerides. In order to support the safety-in-use of Clarinol™ G80 as an ingredient in food, the preparation was tested in two in vitro mutagenicity assays, an Ames test and an in vitro cytogenetics assay, and a 90-day repeat-dose oral toxicity rat study. Clarinol™ G80 was non-mutagenic in both in vitro assays. In the 90-day study, Clarinol™ G80 produced hepatocellular hypertrophy in female rats at the highest dose level (15% w/w). This effect was an adaptive effect in response to feeding high levels of Clarinol™ G80 in the diet and was reversible upon withdrawal of test material. An increase in plasma insulin levels was also observed female rats fed 15% w/w Clarinol™ G80 but there was no effect on plasma glucose levels. A No Observed Adverse Effect Level of 2433 mg/kg bw/day for male and 2728 mg/kg bw/day female rats was identified in the study.     

A repeated dose 28-day oral toxicity study of extract from cultured Lentinula edodes mycelia in Wistar rats

To evaluate the toxicological safety of extract from cultured Lentinula edodes mycelia (L.E.M.), repeated doses (2,000 mg/kg/day) were administered to male and female Wistar rats for 28 days. No mortality or abnormality in the general status or appearance was observed in rats administered L.E.M extract. Body weight and food consumption decreased slightly, particularly in the case of male rats, although the degree of decrease was not as prominent toward the end of administration. Examination of hematology, serum biochemistry, absolute and relative organ weights, autopsy and histopathology revealed only a few statistically significant differences between the treatment and control groups; these differences suggested no clinically significant changes related to toxicity. Consequently, the no observed adverse effect level (NOAEL) of L.E.M. extract was considered to be more than 2,000 mg/kg/day under the conditions of the present study.     

A 90-day subchronic toxicity study and reproductive toxicity studies on ACE-inhibiting lactotripeptide

In recent years there has been an increasing body of literature describing the antihypertensive effects of peptides produced from milk protein. The tripeptides isoleucine–proline–proline (IPP) and valine–proline–proline (VPP), isolated from hydrolysed casein have been shown to lower blood pressure by inhibiting angiotensin I-converting enzyme (ACE). This has led to the use of these tripeptides, collectively referred to as lactotripeptide (LTP) as ingredients of functional foods intended to help control blood pressure. A programme of studies including a 90-day repeat-dose oral gavage toxicity study in the rat and an embryo-fetal (pre-natal) development study in the rabbit was conducted to ensure the safety of this ACE-inhibiting ingredient. In addition, a non-standard pre- and post-natal development study in the rat was performed. This study included direct dosing of the neonates, and was designed specifically to investigate renal development and to ensure that the bioactive peptides were not associated with the same type of fetopathy exhibited by ACE inhibiting drugs. These studies showed that there were no adverse effects of treatment at the highest doses tested.