Safety assessment of the aqueous extract of the flowers of Nymphaea lotus Linn (Nymphaeaceae): Acute, neuro- and subchronic oral toxicity studies in albinos Wistar rats

Background Nymphaea lotus Linn (N. lotus) is a medicinal plant widely used in Cameroon popular medicine, to treat neuropsychiatric conditions, male sexual disorders or as food supplement. However, scientific data on the pharmacotoxic profile of this plant are not available. The safety of N. lotus was assessed in acute, neuro- and subchronic toxicity studies by following the OECD guidelines. Effectively, no data have been published until now in regard to its safety on the nervous system. Methods Aqueous extract of N. lotus at doses of 200, 400 and 600 mg/kg body weight (BW) was evaluated for nitrites contents and orally administered to rats daily for 28 days (5 male, 5 female per group). The control group received distilled water (10 mL/kg) and a satellite group was used to observe reversal effects. Neurotoxicity of the plant was determined using open field test for motor coordination, ataxia and gait analysis. Clinical signs and state of livelihood were recorded during the 24 h, then for 28 days of treatments. At the end of 28-day period, animals were anesthetized and decapitated. The whole brain was homogenized for neurobiochemical analysis. Blood samples were collected with or without anticoagulant for hematological examinations and serum analysis. Specimens of liver, kidney, testis, ovaries, and brain were fixed in 10 % formalin and processed for histopathological examinations. Results Our findings indicate dose-dependent elevation of nitrites contents in the flowers aqueous extract of N. lotus. Acute toxicity study revealed no signs of toxicity neither at the dose 2,000 mg/kg nor at 5,000 mg/kg. Thus the LD50 value of aqueous extract of N. lotus flowers is superior to 5,000 mg/kg. The repeated administration of N. lotus during 28 days, induced no signs of neurobehavioral changes in male, but female rats exhibited dose-dependent response in the open field test, suggesting sex and dose-relative psychotropic effects of N. lotus. The evaluation of neurobiochemistry revealed consistent rise of brain cholesterol by 44.05 %; 158.10 % and 147.62 % respectively in male rats treated with the doses of 200, 400 and 600 mg/kg. In female rats, these levels were significantly increased (p<0.001) only at the dose of 600 mg/kg compared to control. This trend persisted after 14 days withdrawal. Brain potassium and calcium concentrations were increased in all rats compared to their respective control receiving distilled water, suggesting transmembrane current stabilizing properties of brain cells by our extract. Further, serum biochemical analysis demonstrated that 28-day administration of N. lotus flowers increased depending on the dose and sex, the levels of serum urea, proteins, creatinine and bilirubin and reduced γ-glutamyltransferase (GGT) and alkaline phosphatase (ALP) activities. These results suggest liver alterations that are endowed by lower liver relative weight and histology damages observed in female rats treated with the dose of 600 mg/kg of our extract. We also observed a rise in the low-density lipoprotein (LDL) fraction and AI of male rats undergoing N. lotus treatment. In female rats, the latter remains unaltered, confirming the dose- and sex-dependent response of our extract. The levels of white blood cells (WBC) and granulocytes were higher in male irrespective to their control, revealing stimulatory properties of the male hematopoietic system. Such variations (sex- and dose-dependent) are without biological relevance for the majority of the biochemical parameters evaluated, indicating a wide margin of safety for the traditional use of N. lotus. The alkaloids, nitrites and phytosterols contained in N. lotus flowers extract may probably account for its neuroprotective, anti-oxidant, and immunoboosting properties. Conclusions N. lotus do not possesses neurotoxicity but is able to induce behavioral changes in rats. Therefore, the application of this plant as either drug or supplementary food should be carefully considered.

Genotoxicity of polar and apolar extracts obtained from Qualea multiflora and Qualea grandiflora

ETHNOPHARMACOLOGICAL RELEVANCE

The species Qualea grandiflora and Qualea multiflora, which belong to the Vochysiaceae family, are common in the Brazilian savannah (Cerrado biome), and the local inhabitants use these species to treat external ulcers and gastric diseases and as an anti-inflammatory agent. Studies have demonstrated that these plants contain compounds that exhibit pharmacological activities; however, the risks associated with their consumption are not known.

MATERIAL AND METHODS

In the present study, the mutagenicity of polar and apolar extracts from Qualea grandiflora and Qualea multiflora were assessed by employing the Ames assay with and without metabolic activation. Additionally, phytochemical analyses (HPLC-ESI-IT-MS, HPLC-UV-PDA and GC-IT-MS) were performed to identify the chemical constituents present in these species, including the evaluation of physico-chemical properties, such as polarity or apolarity of the organic compounds, which are related to each fraction obtained. These studies provide important information regarding the biochemical behaviour of these compounds.

RESULTS

All extracts exhibited mutagenicity, inducing frameshift mutations and base substitutions in DNA. Phytochemical analysis identified terpenes, ellagic acid derivatives and phytosteroids.

CONCLUSIONS

The mutagenicity observed might be due to the presence of pentacyclic triterpenes and polyphenols, which are able to generate reactive oxygen species (ROS) and result in the potential to cause DNA damage. The genetic risk identified in this present work shows that special attention should be considered for the use of compounds obtained from these plant species in medicinal treatments. Further studies must be conducted to identify safe therapeutic doses.

Contents of phytosterols in vegetables and fruits commonly consumed in China

OBJECTIVE

To quantify five specific dietary phytosterols and phytostanols in vegetables and fruits commonly consumed in China.

METHODS

A total of 34 different kinds of vegetables and 33 kinds of fruits were chosen according to the consuming habit of Chinese people. All the samples were purchased from two shops in Beijing. The contents of phytosterols (beta-sitosterol, campesterol, stigmasterol, beta-sitostanol, and campestanol) were analyzed by GLC method which was established by our laboratory, and the total phytosterols were calculated.

RESULTS

The total phytosterol content in vegetables ranged 1.1-53.7 mg/100 g edible portion. The highest concentration was found in pea, cauliflower, broccoli, and romaine lettuce. The phytosterol contents in fruits ranged 1.6-32.6 mg/100 g, the highest concentration was found in navel orange, tangerine, and mango.

CONCLUSION

The phytosterol contents in vegetables and fruits are not as high as those in edible oils, but because of the large amount of consumption, they also play an important role in increasing the people's phytosterols intake, indicating that increased intake of vegetables and fruits with higher phytosterol contents helps increase the phytosterol intake in China.

No evidence of genotoxic effect in vivo of the phytosterol oxidation products triols and epoxides

Phytosterols (PS) are naturally occurring compounds present in food products of plant origin. Due to reported positive health effects, some food products are also enriched with PS. In the same way as cholesterol is oxidised, PS also oxidise to a variety of oxidation products (POPs). The biological effects and safety aspects of POPs are still unclear. This study investigated whether POPs are genotoxic in vivo, using a flow cytometer-based micronucleus assay in mice. The highest dose of oxidation products administered was 67mg/kg b.w. for epoxides and 9.4mg/kg b.w. for triols. Synthesised and separated triols and epoxides from a mixture of sitosterol and campesterol were investigated. The frequency of micronucleated polychromatic erythrocytes (fMNPCE) in POP-exposed mice did not significantly differ from the control values in either of two experiments performed. The flow cytometer-based method also allows for restriction of the analysis to micronuclei with a high DNA content, indicating an aneugenic potency. Even with this approach, there was no significant increase in the frequency of micronucleated erythrocytes among POP-treated mice compared with control mice. Furthermore, no significant deviation in cell proliferation rate (%PCE) was observed.

Multigenerational exposure to phytosterols in the mouse

Due to beneficial health effects phytosterols (PS) are increasingly added to functional foods. The aim of the present study was to investigate the chronic effects of a dietary PS mixture (5mg/kg/day), containing mainly beta-sitosterol, on the reproduction of the mouse. General reproductive parameters, postnatal development, growth and survival of pups, weight of sex organs, the concentrations of plasma sex steroids and testicular testosterone were monitored across five generations (F(0)-F(4)). PS exposure increased the plasma levels of testosterone and decreased the relative uterine weights in the pups of F(2) and F(4) generations. Furthermore, PS exposure increased the concentrations of plasma estradiol in the female pups of F(3) generation. PS supplement also increased the testicular levels of testosterone in the male pups of F(2) generation. In spite of these transitory changes, PS exposure caused no permanent deleterious effects on the reproduction of the mouse.

Postmetamorphic Xenopus laevis shows decreased plasma triiodothyronine concentrations and phosphorylase activity due to subacute phytosterol exposure

Postmetamorphic South African clawed frogs (Xenopus laevis) were exposed to a phytosterol mixture (ca. 80% beta-sitosterol and less sitostanol, campesterol, and campestanol) for 14 days at 30 mugl(-1) in a flow-through system. The effects of phytosterols (PS) on the plasma thyroid hormone (T(3) and T(4)), testosterone, leptin-immunoreactive peptide and tissue glycogen concentrations were determined. The following enzyme activities were also analyzed from the liver and muscle: glycogen phosphorylase and lipase, and from the liver only: glucose-6-phosphatase. The plasma T(3) concentration was lower in the PS-exposed female frogs. Both muscle lipase and glycogen phosphorylase activities were also lower in the PS-exposed animals. These results could indicate that the basal metabolic rate and locomotion activity of the frogs were decreased. The effects could not be attributed to the possible estrogenicity of the PS mixture. Further studies will be needed to evaluate the possible significance of these effects.

Safety evaluation of phytosterol esters. Part 8. Lack of genotoxicity and subchronic toxicity with phytosterol oxides

Vegetable oil spreads containing phytosterol-esters are marketed as a cholesterol-lowering functional food in more than 20 countries worldwide. An extensive package of safety data has shown phytosterol-esters to be safe for human use. However, even though phytosterols are very stable molecules, oxidation may occur at low levels under extreme heating conditions, resulting in phytosterol oxides. As there is some suggestion of adverse biological effects in the literature for the related cholesterol oxidation products, safety data have been generated for phytosterol oxides. A phytosterol oxide concentrate (POC) was generated by prolonged heating of phytosterol-esters in the presence of oxygen. The genotoxicity and subchronic toxicity of this mixture was assessed in a series of in vitro genotoxicity assays (bacterial mutation, chromosome aberration and micronucleus) and a subchronic feeding study in the rat. Results showed that a phytosterol oxide concentrate containing approximately 30% phytosterol oxides did not possess genotoxic potential and no obvious evidence of toxicity when administered in the diet of the rat for 90 consecutive days. In the latter study, a NOEL was established at an estimated dietary level of phytosterol oxides of 128 mg/kg/day for males and 144 mg/kg/day for females. In conclusion, these materials have been shown to raise no obvious concerns for human safety.

Development of novel water-soluble phytostanol analogs: disodium ascorbyl phytostanyl phosphates (FM-VP4): preclinical pharmacology, pharmacokinetics and toxicology

FM-VP4 is a novel inhibitor of cholesterol absorption that has lipid lowering and body weight reducing properties. In vitro and in vivo studies were performed to investigate the lipid-lowering effects, mechanism of action, pharmacokinetics, and toxicity of FM-VP4. FM-VP4 decreased cholesterol accumulation in Caco-2 cells by approximately 50%; its activity appeared to be independent of pancreatic lipase, p-glycoprotein, or cholesterol incorporation in micelles. In animal studies, FM-VP4 was added to the diet or drinking water and the following results were obtained. In gerbils 2% FM-VP4 produced mean 56 and 53% reduction in total cholesterol (TC) after 4 and 8 weeks, respectively. This reduction was entirely due to the loss of the low-density lipoprotein (LDL) pool, which was reduced to undetectable levels at either time point. At 8 weeks, high-density lipoprotein (HDL) concentration had risen by a mean of 34% whereas total triglyceride (TG) concentrations had decreased by a mean of 60%. FM-VP4 also had a profound effect on body weight in these animals. At 8 weeks, the mean body weight was in the 4% FM-VP4 treatment group 25% lower than in the control group. No hepatic or renal toxicity was associated with these changes. In Apo E-deficient mice, after 4- and 8-week treatments FM-VP4 caused a significant decrease in both TC and TG concentrations compared to controls. After 12 weeks, the areas of atherosclerotic lesion involvement in the aortic roots were decreased by a mean of 80% in the 0.5, 1, and 2% FM-VP4 treatment groups compared to controls. Taken together, these results suggest that FM-VP4 is a potential new drug with lipid-lowering and weight loss potential, without apparent toxicity.

Final report of the amended safety assessment of PEG-5, -10, -16, -25, -30, and -40 soy sterol

PEGs Soy Sterol are polyethylene glycol (PEG) derivatives of soybean oil sterols used in a variety of cosmetic formulations as surfactants and emulsifying agents, skin-conditioning agents, and cleansing and solubilizing agents. When the safety of these ingredients were first reviewed, the available data were insufficient to support safety. New data have since been received and the safety of these ingredients in cosmetics has been substantiated. Current concentration of use ranges from a low of 0.05% in makeup preparations to 2% in moisturizers and several other products. PEGs Soy Sterol are produced by the reaction of the soy sterol hydroxyl with ethylene oxide. In general, ethoxylated fatty acids can contain 1,4-dioxane as a byproduct of ethoxylation. The soy sterols include campesterol, stigmasterol, and beta-sitosterol. The distribution of sterols found in oils derived from common plants is similar, with beta-sitosterol comprising a major component. Impurities include sterol hydrocarbons and cholesterol (4% to 6%) and triterpine alcohols, keto-steroids, and other steroid-like substances (4% to 6%). No pesticide residues were detected. PEGS: Because PEGs are an underlying structure in PEGs Soy Sterols, the previous assessment of PEGs was considered. It is generally recognized that the PEG monomer, ethylene glycol, and certain of its monoalkyl ethers are reproductive and developmental toxins. Given the methods of manufacture of PEGs Soy Sterol, there is no likelihood of ethylene glycol or its alkyl ethers being present. Also, the soybean oil sterol ethers in this ingredient are chemically different from the ethylene glycol alkyl ethers of concern. PEGs are not carcinogenic, although sensitization and nephrotoxicity were observed in burn patients treated with a PEG-based cream. No evidence of systemic toxicity or sensitization was found in studies with intact skin. Plant Phytosterols: Intestinal absorption of ingested plant phytosterols is on the order of 5%, with 95% of the material entering the colon. Absorbed plant phytosterols are transported to the blood. Although there are some data suggesting that sulfates of beta-sitosterol can act as abortifacients in rats and rabbits, other studies of well-characterized plant phytosterols and phytosterol esters demonstrated no effect in an estrogen-binding study, a recombinant yeast assay for estrogen or estrogen-like activity, or a juvenile rat uterotrophic assay for estrogen or estrogen-like activity. In a two-generation reproduction study using rats, plant phytosterol esters in the diet had no effect on any parameter of reproduction or fertility. Subcutaneous injections of beta-sitosterol did reduce sperm concentrations and fertility in rats. Sitosterol inhibited tumor promoting activity of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mice after initiation with 7,12-dimethylbenz[a]anthracene (DMBA), and reduced the tumors produced by N-methylnitrosourea in rats. Phytosterols were not genotoxic in several bacterial, mammalian, and in vitro assay systems. Phytosterols decreased epithelial cell proliferation in the colon of mice and rats, and were cytotoxic for human epidermoid carcinoma of the nasopharynx. PEGs Soy Sterols: The acute oral LD50 in rats of PEG-5-25 Soy Sterol was >10 g/kg. The acute dermal LD50 of a liquid eyeliner containing 2%PEG-5 Soy Sterol was >2 g/kg in rabbits. PEG-5-25 Soy Sterol was not a primary irritant in rabbits when applied undiluted. Undiluted PEG-5 Soy Sterol did not cause sensitization in guinea pigs. PEGs Soy Sterol did not produce ocular toxicity in rabbits. PEG-5 Soy Sterol was negative in the Ames mutagenicity test, with or without metabolic activation. PEG-5 Soy Sterol, at concentrations up to 2%in formulation, did not cause dermal or ocular irritation, dermal sensitization, or photosensitization in clinical studies. Because of the possible presence of 1,4-dioxane reaction product and unreacted ethylene oxide residues, it was considered necessary to use appropriate procedures to remove these from PEGs Soy Sterol before blending them into cosmetic formulations. Based on the systemic toxicity and sensitization seen with PEGs applied to damaged skin, it was recommended that PEGs Soy Sterol should not be used in cosmetic products applied to damaged skin. Although no dermal absorption data were available, oral studies demonstrate that phytosterols and phytosterol esters are not significantly absorbed and do not result in significant systemic exposure. Some small amounts did appear in the ovaries, however. This raises a concern about the potential presence of free phytosterols and beta-Sitosterol, which could have antiestrogenic, antiprogestational, gonadotrophic, antigonadotrophic, and antiandrogenic effects in PEG sterols. These concerns are alleviated by the extensive data showing that well-defined phytosterols and phytosterol esters are not estrogenic and do not pose a hazard to reproduction. Likewise, the absence of impurities in plant phytosterols and phytosterol esters and extensive data demonstrating the absence of any genotoxicity in bacterial and mammalian systems mitigate against the possibility of any carcinogenic effect with those same well-characterized materials. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the PEGs Soy Sterol are safe as used in cosmetic products.

Effects of a phytosterol mixture on male fish plasma lipoprotein fractions and testis P450scc activity

Plant sterols (phytosterols) have been identified as one potential source of reproductive effects in fish living downstream of pulp mills. beta-Sitosterol, the predominant plant sterol in pulp mill effluent, has previously been shown to decrease plasma sex steroid and cholesterol levels and in vitro gonadal steroid production in fish. In this study, male brook trout (Salvelinus fontinalis) and goldfish (Carassius auratus) were exposed to a phytosterol mixture (72% beta-sitosterol) via Silastic intraperitoneal implants to help elucidate the mechanisms of action of phytosterols on steroid depression. As cholesterol is exogenously supplied for gonadal steroidogenesis, changes in plasma cholesterol fractions were examined. In male brook trout, low-density lipoprotein cholesterol and triglyceride levels decreased significantly, 43 and 50%, respectively, in phytosterol-treated fish. It is improbable, however, that these decreases are linked to depressed gonadal steroidogenesis in fish. The activity of P450scc, which converts cholesterol to pregnenolone (the first step in the steroidogenic pathway), was not affected in testis mitochondria isolated from brook trout or goldfish. Further investigation of the mechanisms of action of phytosterols is required.

Effects of phytosterols on zebrafish reproduction in multigeneration test

Zebrafish from mixed sex populations were exposed continuously across three generations to two phytosterol preparations both containing -sitosterol. The phytosterols were isolated from wood and soy beans. Blood vitellogenin levels and sex ratio changes were used as intermediate indicators of the reproduction failures. Both sterol preparations caused vitellogenin induction in the exposed fish. The wood sterol changed the sex ratio of the exposed fish. In generation F1, the predominant sex was male, and in generation F2 it was female. The soy sterol in the used test concentration was lethal to the exposed fish in generation F1. This multigeneration test evidenced that phytosterols containing -sitosterol disrupt the reproduction system of zebrafish by changing the sex ratios and by inducing the vitellogenin production in the exposed fish.

Subchronic toxicity of plant sterol esters administered by gavage to Sprague-Dawley rats

The purpose of this study was to investigate the potential subchronic toxicity of plant sterol esters by a 13-week repeated oral dose in Sprague-Dawley rats. The test article was administered once daily by gavage to male and female rats at dose levels of 0, 1000, 3000 and 9000 mg/kg/day for 13 weeks. At the end of treatment period, 10 rats/sex/group were sacrificed, while six rats/sex in the negative control and highest dose groups were sacrificed after a 4-week recovery period. During the test period, clinical signs, mortality, body weights, food and water consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, gross findings, organ weights and histopathology were examined. Slight decreases in body weight gain were noted at lower doses but were only statistically different from the control animals in the highest dose group. In histopathological examinations, an increase in the incidence of cardiomyopathy with mononuclear cell infiltration was observed in males of the 9000 mg/kg group. Decreased body weight gain and increased incidence of cardiomyopathy observed in the highest dose group were not recovered until the end of the recovery period. There were no adverse effects on mortality, clinical signs, food and water consumption, ophthalmoscopy, urinalysis, hematology, serum biochemistry, necropsy findings and organ weights in any treatment group. Based on these results, it was concluded that the 13-week repeated oral dose of plant sterol esters resulted in the suppression of body weight gains in both sexes and cardiomyopathy in males at a dose level of 9000 mg/kg/day. The target organ was determined to be heart in males, but not in females. The no-observed-adverse-effect level (NOAEL) was considered to be 3000 mg/kg/day for both sexes.

Isolation of various forms of sterol beta-D-glucoside from the seed of Cycas circinalis: neurotoxicity and implications for ALS-parkinsonism dementia complex

The factors responsible for ALS-parkinsonism dementia complex (ALS-PDC), the unique neurological disorder of Guam, remain unresolved, but identification of causal factors could lead to clues for related neurodegenerative disorders elsewhere. Earlier studies focused on the consumption and toxicity of the seed of Cycas circinalis, a traditional staple of the indigenous diet, but found no convincing evidence for toxin-linked neurodegeneration. We have reassessed the issue in a series of in vitro bioassays designed to isolate non-water soluble compounds from washed cycad flour and have identified three sterol beta-d-glucosides as potential neurotoxins. These compounds give depolarizing field potentials in cortical slices, induce alterations in the activity of specific protein kinases, and cause release of glutamate. They are also highly toxic, leading to release of lactate dehydrogenase (LDH). Theaglycone form, however, is non-toxic. NMDA receptor antagonists block the actions of the sterol glucosides, but do not compete for binding to the NMDA receptor. The most probable mechanism leading to cell death may involve glutamate neuro/excitotoxicity. Mice fed cycad seed flour containing the isolated sterol glucosides show behavioral and neuropathological outcomes, including increased TdT-mediated biotin-dUTP nick-end labelling (TUNEL) positivity in various CNS regions. Astrocytes in culture showed increased caspase-3 labeling after exposure to sterol glucosides. The present results support the hypothesis that cycad consumption may be an important factor in the etiology of ALS-PDC and further suggest that some sterol glucosides may be involved in other neurodegenerative disorders.

The safety evaluation of phytosterol esters. Part 6. The comparative absorption and tissue distribution of phytosterols in the rat

As part of an extensive safety evaluation programme, a series of studies has been conducted to determine the fate of phytosterols in the rat. Rats were dosed by oral gavage with 14C-labelled samples of cholesterol, beta-sitosterol or beta-sitostanol or (3)H-labelled samples of beta-sitostanol, campesterol, campestanol or stigmasterol dissolved in sunflower seed oil. Urine and faeces were collected for up to 96 hours after dosing. There was no quantification of biliary excreted material in these studies. Animals were sacrificed and either prepared for whole body autoradiography or tissues and carcass remains were assayed for 14C or (3)H. The overall absorption of phytosterols was low as judged by tissue and carcass levels of radioactivity. Elimination from the body was mainly in the faeces and was initially very rapid, but traces of material were still being excreted at 4 days after dosing. While total absorption of the phytosterols could not be fully quantified without biliary excretion data, it was clear that cholesterol was absorbed to the greatest extent (27% of the dose in females at 24 hours). Campesterol (13%) was absorbed more than beta-sitosterol and stigmasterol (both 4%) which were absorbed more than beta-sitostanol and campestanol (1-2%). The absorption of phytosterols was slightly greater in females than males. For each test material, the overall pattern of tissue distribution of radioactivity was similar, with the adrenal glands, ovaries and intestinal epithelia showing the highest levels and the longest retention of radioactivity.

Safety evaluation of phytosterol esters. Part 3. Two-generation reproduction study in rats with phytosterol esters--a novel functional food

Phytosterol esters (PE) are intended for use as a novel food ingredient with plasma cholesterol lowering activity which works by inhibiting the absorption of cholesterol from the gut. Although PE are naturally present in the normal diet, the levels are insufficiently large to ensure lowering of plasma cholesterol levels. Therefore PE may be added to spreads to achieve the desired cholesterol lowering activity. As part of an extensive programme of safety evaluation studies a two-generation reproduction study has been conducted in Wistar rats, in which the possible effect of PE on male and female reproductive performance and on the growth and development of the offspring was studied. Rats were fed diets containing PE at levels of 0, 1.6, 3.2 and 8.1% (w/w) PE over two successive generations, and a wide range of reproductive and developmental parameters, including sexual maturation parameters and oestrous cycle length, were determined. Macroscopic and microscopic examinations were conducted including a histological examination of selected organs from F1- and F2-weanlings and from F0- and F1-parental animals. Daily clinical observations did not reveal any unusual findings. In both generations, no effects of PE were observed on pup mortality (calculated on litter basis), precoital time, mating index, male and female fertility index, female fecundity index, gestation index, duration of gestation, number of females with stillborn pups, post-implantation loss and pup development. Furthermore, PE had no effect on sexual maturation parameters (preputial separation and vaginal opening) and oestrous cycle length. In addition, there were no dose-related effects on selected organs following histological examination. In conclusion, dietary administration of up to 8.1% PE (equivalent to a dose of 2.5 to 9.1 g PE/kg body weight/day, dependent on the period of the study) during two generations had no effect on reproduction of parental F0- and F1-generation Wistar rats, nor on the development of the F1- and F2-pups, nor on the sexual maturation of the F1-weanlings. Therefore, a nominal dietary PE concentration of 8.1% (equivalent to a dose of 2.5-9.1 g PE/kg body weight/day or 1.54-5.62 g phytosterol/kg body weight/day dependent on the period of the study) was considered to be the no-observed-adverse-effect level following daily oral administration of PE for two successive generations.

Safety evaluation of phytosterol esters. Part 2. Subchronic 90-day oral toxicity study on phytosterol esters--a novel functional food

Phytosterol esters (PE) are intended for use as a novel food ingredient, primarily in margarines and spreads as a functional component with plasma cholesterol lowering activity. Phytosterols and their esters are present naturally in vegetable oils and on average people consume 200 mg/day, but their consumption at this level is not sufficient to lower plasma cholesterol levels. Therefore, through the incorporation of PE into margarines/spreads, the intake can be increased by approximately 10-fold by consuming the PE-containing margarine/spread at normal intake levels. As part of an extensive programme of safety evaluation studies a subchronic rat toxicity study has been conducted in which groups of Alpk:AP(f)SD (Wistar derived) rats (20 males and 20 females/group) were fed diets containing PE at levels of 0, 0.16, 1.6, 3.2 and 8.1% (w/w) in the diet for 90 days. Throughout the study, clinical observations, body weights, and food and water consumption were measured. At the end of the study the rats were subjected to a full post-mortem examination, cardiac blood samples were taken for clinical pathology, selected organs were weighed, and a full tissue list was taken for subsequent histological examination. There were no treatment-related changes that were considered to be of toxicological significance. Therefore, a nominal PE concentration of 8.1% was considered to be the no-observed-adverse- effect level (NOAEL) following daily oral administration to rats for 90 days. This was equivalent to a dose of 6.6 g/kg body weight/day PE or 4.1 g/kg/day phytosterol.

13-week oral toxicity study with stanol esters in rats

Plant sterols and their saturated derivatives, known as stanols, reduce serum cholesterol when consumed in amounts of approximately 2 g per day. Stanol fatty acid esters have been developed as a highly fat-soluble form that may lower cholesterol more effectively than stanols. Stanol esters occur naturally in human diets, but at levels far below those known to lower cholesterol. The present study was conducted to assess the safety of stanol esters upon subchronic ingestion at levels comparable to or exceeding those recommended for lowering cholesterol. Two stanol fatty acid ester preparations, wood-derived stanol esters and vegetable oil-derived stanol esters, were fed to groups of 20 male and 20 female Wistar rats for 13 weeks, at dietary concentrations of 0, 0.2, 1, and 5% total stanols (equivalent to 0, 0.34, 1.68, and 8.39% wood-derived stanol esters and 0, 0.36, 1.78, and 8.91% vegetable oil-derived stanol esters). Both preparations were well tolerated as evidenced by the absence of clinical changes or major abnormalities in growth, food and water consumption, ophthalmoscopic findings, routine hematological and clinical chemistry values, renal concentrating ability, composition of the urine, appearance of the feces, estrus cycle length, organ weights, gross necropsy findings, and histopathological findings. Plasma cholesterol and phospholipids were slightly decreased in males fed the stanol esters. In both sexes, plasma levels of plant sterols were decreased whereas those of stanols tended to increase. Fecal excretion of sterols, including cholesterol, and stanols was markedly increased in the stanol ester groups. Compared to controls, male rats fed stanol esters showed somewhat lower liver weights and more pronounced glycogen depletion. These hepatic changes were considered to reflect an altered nutritional condition and not a pathological condition. Plasma levels of vitamin E, vitamin K1, and, to a lesser extent, vitamin D were decreased in males and females fed the high-dose diets. Hepatic levels of vitamins E and D showed similar changes (vitamin K1 in the liver was not determined). For both preparations, the mid-dose level (1% total stanols in the diet) was a no-observed-adverse-effect level. This dietary level provided approximately 0.5 g total stanols/kg body wt/day.

Genotoxicity evaluation of wood-derived and vegetable oil-derived stanol esters

Plant stanol esters from wood and vegetable oil sources were tested for genotoxicity in bacterial (Salmonella typhimurium) and mammalian cell (L5178Y) gene mutation assays and in a mammalian cell chromosome aberration assay (CHO cells). The two stanol ester formulations were tested separately at doses up to the limit of solubility, with and without the addition of an Aroclor-induced rat liver microsome metabolic activation system (S9 mix). All tests were performed in duplicate and gave negative results for both wood and vegetable oil stanol ester formulations. Thus, plant stanol esters are not genotoxic under the conditions of exposure tested.

Short-term tests of estrogenic potential of plant stanols and plant stanol esters

To test for potential estrogenic activity of plant stanols and plant stanol esters, two short-term tests were performed. These were the E-screen test, which measures a substance's ability to induce proliferation of estrogen-responsive human breast adenocarcinoma (MCF-7) cells in culture, and an in vivo test, which measures uterotrophic activity in immature female rats fed the test substance. Four samples of vegetable oil-derived stanols (containing 88-99% stanols) were tested in the E-screen test, and one sample of wood-derived and one of vegetable oil-derived stanol fatty acid esters were tested in the in vivo test. In the E-screen test, the positive control substance, 17beta-estradiol, at 100 pM, produced a statistically significant, 11.6-fold increase in cell proliferation, as measured by sulforhodamine B staining. None of the stanol preparations produced any increase in cell proliferation when tested at 1, 10, and 100 microM. The highest dose of each stanol sample was associated with microscopic evidence of cytotoxicity and crystalline precipitation in the culture dishes. In the in vivo test, the positive control compound, diethylstilbestrol, produced a significant, dose-related increase in absolute and relative uterus weight in young female rats (17 days old at the start of treatment) fed the compound at 5, 10, and 20 ppb in the diet for 4 days. Neither of the two stanol ester preparations caused any significant change in absolute or relative uterus weight when fed at a concentration of 8.3% in the diet for 4 days. Thus, under the conditions of testing used, neither the free stanols nor the stanol fatty acid ester preparations showed evidence of estrogenic or uterotrophic activity.

Developmental toxicity study of vegetable oil-derived stanol fatty acid esters

In a standard developmental toxicity study, a mixture of vegetable oil-derived stanol fatty acid esters was administered in the diet to groups of 28 mated female HsdCpb:WU Wistar rats at concentrations that provided 0, 1, 2.5, and 5% total stanols (equivalent to 0, 1.75, 4.38, and 8.76% plant stanol esters). Test diets were adjusted with rapeseed oil to maintain an equivalent caloric content of fatty acids at each of the treatment levels. The treatment period extended from day 0 to 21 of gestation. No compound-related toxicity or clinical effects were seen in any of the treated groups. No statistically significant differences were seen in body weights or body weight gain in the low- or mid-dose groups, although slight but statistically significant decreases in mean body weight relative to controls were seen at gestation days 7 and 14 in the high-dose group. The decreases in body weight in the high-dose group may be attributable to the virtual lack of absorption of the dietary stanols. Body weight gains were equivalent to controls throughout the study except for a statistically significant decrease seen only in the 0- to 7-day gestation period in the high-dose group. No significant effects were seen on food consumption in terms of g/rat/day, but a slight, statistically significant increase was seen in the mid-dose group during gestation days 7-14. A significant increase was seen in the high-dose group during the 7- to 21-day period of gestation. Reproductive performance was not affected by the treatment. There were no statistically significant differences in uterine weight, placental weight, fetal weight, number of fetuses, number of implantation sites, number of corpora lutea, and early/late resorptions between the treated and control groups. In addition, there was no biologically meaningful effect on fetal sex ratio. Visceral and skeletal examinations did not show any significant increases in the incidence of malformations, anomalies, or variations that were considered to be treatment related. Dietary plant (8.76% plant stanol esters) stanol esters at concentrations up to 5% total stanols were concluded to have no adverse effects on reproduction or development.

Two-generation reproductive toxicity study of plant stanol esters in rats

Plant stanol esters are intended for use as an ingredient in food to reduce the absorption of cholesterol from the gastrointestinal tract. Consumption of plant stanol esters has a demonstrated diet-derived public health benefit, as shown by numerous clinical studies. Plant stanol esters are ring-saturated analogs of common dietary sterols that are transesterified with fatty acids from vegetable oils such as canola oil. The reproductive and developmental toxicity of plant stanol esters was investigated in male and female Wistar rats during F0 and F1 generations using dietary concentrations of 1.75, 4.38, and 8.76% stanol esters (equivalent to 1, 2.5, and 5% total stanols). No adverse treatment-related effects were noted on reproductive performance of male or female rats in any dose group. Increased food consumption was observed in high-dose F0 generation males throughout the entire premating period and in F1 males at specific time periods during the premating period. This increase in food consumption was also observed in F0 generation females (mid- and high-dose groups) and F1 generation females (low-, mid-, and high-dose groups) at specific time periods throughout the 10-week premating period. At different intervals throughout the gestation and lactation periods, increased food consumption was observed in F0 generation females of the mid- and high-dose groups, while increased food consumption was noted in F1 generation females of the mid- and high-dose groups during gestation, but not during lactation. Such increases in food consumption are expected as a result of the animals' attempt to compensate for the reduced caloric value of the test diet compared to controls. No adverse developmental effects were noted in F1 or F2 pups of the low- and mid-dose groups based on evaluation of the following parameters: litter size, pup mortality, pups weights, and sex ratio. However, a treatment-related effect on body weight and body weight change was observed in both F1 and F2 male and female pups of the high-dose group, particularly during the latter stages of lactation (postnatal days 14 and 21) in F1 pups, and during the majority of the lactation period (postnatal days 4-21). Lower body weight in the high-dose pups is attributed to a reduction in the caloric value of the test diet compared to control. The pups, unlike adult animals, are particularly sensitive to reductions in caloric value of feed since they are in a rapid growth phase of their development. It is likely that they could not increase their food consumption enough to adequately meet their caloric and nutritional needs. In conclusion, dietary concentrations of up to 4.38% plant stanol esters (equivalent to 2.5% total stanols in the diet) are not associated with adverse effects on reproduction, pup mortality, pup body weight, or pup body weight change.

Developmental toxicology of solamargine and solasonine glycoalkaloids in frog embryos

As part of an effort to improve the safety of plant foods, a need exists to define the relative toxicities of structurally different glycoalkaloids and metabolites which may be present in Solanum plant species such as potatoes, tomatoes and eggplants. The objectives of this study were to determine the relative toxicities and the modes of action of the eggplant (Solanum melongena) glycoalkaloids solamargine and solasonine in Xenopus laevis frog embryos, using membrane potential and embryo growth and teratogenicity assays. In the cell membrane assays, adverse effects on embryos were evaluated by measuring membrane potentials using an electrochromic dye, di-4-ANEPPS, as a fluorescence probe for the integrity of the membranes. In the embryo growth and teratogenesis assays, the survival of the embryos and organ malformations was used as an index of embryo toxicity. The relative potencies of glycoalkaloids are similar for frog embryo effects (survival and teratogenicities) and for membrane effects (membrane potential). Experiments with solasonine at pH 6 and 8 suggest that the unprotonated form of the glycoalkaloids appears to be involved in the membrane effects. The nature of the carbohydrate side-chains of the steroidal glycosides governs relative potencies. The possible significance of the findings to food safety and plant physiology and possible application of the membrane assays to bacterial toxins are discussed.

The rhamnose moiety of solamargine plays a crucial role in triggering cell death by apoptosis

Solamargine, solasodine and khasianine steroidal alkaloids are utilized to determine the role of carbohydrate moiety in the mechanism of apoptosis. The C3 side chain of solamargine, khasianine and solasodine contains 4'Rha-Glc-Rha2', 4'Rha-Glc and H, respectively. Solamargine possessed potent cytotoxicity to human hepatoma cells, while the cytotoxicity of khasianine was greatly diminished. Nevertheless, only solamargine could induced "sub-G1" of apoptotic feature in flowcytometry. Thus, the 2'Rha moiety of solamargine may play a crucial role in triggering cell death by apoptosis. In addition, the molecular modeling of solamargine indicated that the 2'Rha moiety was adjacent to the rigid steroid structure, and drastically changed the dihedral angle of the glycosidic bond. The regulations of TNFR I and II expression by different carbohydrate moieties were also distinct. It implied that the carbohydrate moieties of steroidal alkaloids might alter the binding specificity to steroid receptors and consequently regulate the gene expression in different manners.

The effect of some Solanum steroidal alkaloids and glycoalkaloids on larvae of the red flour beetle, Tribolium castaneum, and the tobacco hornworm, Manduca sexta

Evaluation of the inhibitory effect of a series of secondary plant compounds including steroidal alkaloids and glycoalkaloids on larvae of the red flour beetle, Tribolium castaneum, was investigated. Larval growth was inhibited on artificial diets containing 1 mumol g-1 diet of the glycoalkaloids solamargine, solasonine and tomatine, whereas the corresponding aglycones solasodine and tomatidine, and also tomatidenol, were inactive. The inhibitory effect of solamargine and tomatine, but not of solasonine, was completely abolished by addition of 1 mumol g-1 diet cholesterol and/or sitosterol. Nonetheless, synthetic cholesteryl tomatide displayed significant activity at 2 mumol g-1 diet. Parallel studies with the tobacco hornworm, Manduca sexta, showed marked inhibitory activity of tomatine at a dietary concentration of 1 mumol g-1, whereas the other compounds did not affect sterol metabolism or larval development. An appraisal of the factors influencing the mode of action of the active steroidal glycoalkaloids is attempted.

Wood-derived estrogens: studies in vitro with breast cancer cell lines and in vivo in trout

The wood-derived compound, beta-sitosterol (purity > 90%), was shown to be estrogenic in fish. It induced the expression of the vitellogenin gene in the liver of juvenile and methyltestosterone-treated rainbow trout. Structural similarities to beta-sitosterol notwithstanding, cholesterol, citrostadienol, beta-sitostanol, and 5-androstene-3 beta,17 beta-diol, an estrogenic member of the androstenic steroid group, were inactive. An abietic acid mixture (37% abietic acid, 6% dehydroabietic acid, and a remainder of unknown compounds) showed slight hormonal activity in feed, but it was completely inactive when given intraperitoneally in implants. The estrogenic component of the abietic acid preparation was not identified. In addition, to beta-sitosterol and abietic acid, several other wood-derived compounds including betulin, isorhapontigenin, isorhapontin, and pinosylvin were estrogenic in breast cancer cells (MCF-7 or T-47D). However, betulin and pinosylvin, available in sufficient amounts for in vivo testing, did not induce the expression of the vitellogenin gene. Differences in the primary sequences of human and fish estrogen receptors (hormone as well as DNA-binding regions) or uptake and metabolism of the compounds may explain the discrepancy between the two estrogen bioassays. Wood-derived compounds such as beta-sitosterol, present in pulp and paper mill effluents, may account for the weak estrogenicity of debarking effluent seen at the vitellogenin expression bioassay.