Evaluation of Subchronic Toxicity and Genotoxicity of Ethanolic Extract of Aster glehni Leaves and Stems

Aster glehni, a traditional plant on Ulleung Island in the Republic of Korea, has been recognized for its multiple medicinal properties. However, potential toxicity and safety analyses of A. glehni have not been previously investigated. Therefore, this study aimed to evaluate the safety profile of ethanolic extract of A. glehni leaves and stems (EAG) in terms of genotoxicity and subchronic oral animal toxicity under OECD guidelines and GLP conditions. Toxicological assessments were performed at doses of 1,250, 2,500, and 5,000 mg/kg/day in a 13-week oral repeated-dose toxicity study of EAG in male and female SD rats. In addition, an Ames test, an in vitro mammalian chromosomal aberration test, and a micronucleus test were performed. No toxicological changes in clinical signs, body weights, water and food consumption, urinalysis, hematology, clinical biochemistry, gross findings, and histopathological examinations were observed in subchronic oral animal toxicity. In addition, EAG gave negative results when evaluated using in vitro and in vivo genotoxicity tests. In conclusion, the no-observed-adverse-effect level (NOAEL) of EAG was considered to be 5,000 mg/kg/day, and no target organs were identified in both sexes of rats. EAG was also classified as nonmutagenic and nonclastogenic in genotoxicity testing. Collectively, these results show a lack of general toxicity and genotoxicity for EAG that supports clinical work for development as a herbal medicine.

Comparison of Genotoxicity and Pulmonary Toxicity Study of Modified SiO2 Nanomaterials

Surface-modified nano-SiO2 is a common additive in many products. However, the safety of nano-SiO2 products under various modifications is still unclear. In this study, we investigated the genotoxicity and acute pulmonary toxicity of nano-SiO2 with or without modification. The samples used in this study included: sample A (SA, 55.16 nm, 411.3 mg/mL), modified sample A (mSA, 82.29 nm, 37.7 mg/mL), sample B (SB, 22 nm, 358.0 mg/mL), and modified sample B (mSB, 86.64 nm, 37.7 mg/mL). In the genotoxicity study, we conducted an Ames test, chromosomal aberration test (CA), and a micronucleus (MN) test. The SA, mSA, and mSB groups showed negative results in all these genotoxicity tests. Only SB showed a weakly positive reaction in these assays, but the genotoxicity could be reversed after S9 metabolism or modification. In the acute pulmonary toxicity test, the rats were given an intratracheal instillation (IT) (0.5 mL/kg) of diluted samples and sacrificed after 1 or 14 days. The mortality rate, number of leukocytes and cytokines of TNF-α in the bronchoalveolar lavage fluid (BALF), and the pathology in the lungs were determined. The results revealed that mSA posed acute toxicity in rats. After modification, the pulmonary toxicity was increased in mSA but decreased in mSB on Day 1, and no significant difference was observed on Day 14. In conclusion, there was no observed genotoxicity in either SA or SB, while mSA posed acute inhalation toxicity to rats that decreased in mSB after modification. This indicates that the decrease in pH level in SA and decrease in the solid content in SB are considered after the trifluorosilane surface-modified amorphous nano-silica.

Comparative study of Insecticide potential of Methyl parathion and diazinon in Drosophila melanogaster

Several reports indicate that many chemical pollutants which are widely spread in the environment, such as insecticide, pesticide and drugs are mutagenic in various test system. These findings reflect an urgent need to draw more attention to the possible genetic hazards of such pollutants to public health. The present investigation of working hypothesis deals with the effects of two insecticides viz. Methyl Parathion (MeP) and Diazinon (DZ) on non-target organism Drosophila melanogaster. We have carried out the chromosomal aberration test with various concentration for insecticides (MeP and DZ) which infer properties like ectopic pairing, inversion loop, puffing, fusion, and asynapsis. Chromosomal aberration result shows significant effects with DZ even in less concentration (0.02ppm) when compared with MeP (0.2ppm). The present study proposes that diazinon is more cytotoxic than methyl parathion in Drosophila melanogaster.

Genotoxicity of Water Extract from Bark-Removed Rhus verniciflua Stokes

Rhus verniciflua Stokes (RVS) has been traditionally used as an herbal remedy to support the digestive functions in traditional Korean medicine. Additionally, the pharmacological effects of RVS, including antioxidative, antimicrobial and anticancer activities, have been well-reported. The genotoxicity of RVS, however, is elusive; thus, we evaluated the genotoxicity of RVS without bark (RVX) for safe application as a resource of functional food or a medical drug. To evaluate the genotoxicity of RVX, we used a bacterial reverse mutation test, chromosomal aberration test and comet assay, according to the “Organization for Economic Co-operation and Development” (OECD) guidelines. Briefly, for the reverse mutation test, samples (5000, 1667, 556, 185, 62 and 0 μg/plate of RVX or the positive control) were treated with a precultured strain (TA98, TA100, TA1535, TA1537 or WP2µvrA) with or without the S9 mix, in which RVX partially induced a reverse mutation in four bacterial strains. From the chromosomal aberration test and comet assay, the RVX samples (556, 185, 62, 20 and 0 μg/mL of RVX or the positive control) were treated in a Chinese hamster ovary cell line (CHO-K1 cells) in the conditions of the S9 mix absent or S9 mix present and in Chang liver cells and C2C12 myoblasts, respectively. No chromosomal aberrations in CHO-K1 or DNA damage in Chang liver cells and C2C12 myoblasts was observed. In conclusion, our results suggest the non-genotoxicity of RVX, which would be helpful as a reference for the safe application of bark-removed Rhus verniciflua Stokes as functional raw materials in the food, cosmetics or pharmaceutical fields.

GENOTOXIC EFFECT OF CARBARYL ON GILL CELLS OF CHANNA PUNCTATUS

The genotoxicity of carbaryl was evaluated through Chromosomal Aberration Test on gill cells in freshwater fish Channa punctatus. Fishes were acclimatized in laboratory and divided into control and experimental groups. Two sublethal concentrations of carbaryl (0.1ppm and 0.5ppm) were identified and experimental fishes were exposed to these concentrations for a period of 144 hrs. Chromosomal aberrations were increased in carbaryl treated group, both were greater at higher concentration of carbaryl. These finding indicate that carbaryl is able to cause genotoxic effects in Channa punctatus.

Micronucleus Assay in Environmental Biomonitoring

Nowadays many chemicals are widely used in agriculture to ensure high crop yields or in veterinary/human medicine to cure diseases. After their improper usage they may contaminate the environment, persist in it and adversely affect both the target and/or the non-target organisms. One of the ways to detect the occurrence of chemicals in the environment is to assess their impact on aquatic and farm animals; both are directly or indirectly exposed via their feed and water. The micronucleus assay is a standardly used cytogenetic test for the simultaneous detection of clastogenic and aneugenic agents. Additionally, cytotoxic effects are also assessed by analysing the proliferation changes using the cytokinesis-blocked proliferation index. The occurrence of micronuclei is analysed in many types of cells like the peripheral blood cells, bone marrow or cell lines according to standards for micronuclei detection. The analysis of published results has shown that the micronucleus assay is, together with the chromosomal aberration test, one of the most often used test in genotoxicity assessment. Its results have contributed to reassessing the use of multiple chemicals available on the market. Moreover, it is a compulsory test before approving the chemical/ pesticide for the market.

A Toxicological Evaluation of Germanium Sesquioxide (Organic Germanium)

A battery of OECD- and GLP-compliant toxicological studies was performed to assess the safety of a highly purified germanium sesquioxide, an organic form of the naturally occurring, nonessential trace element germanium. Germanium dioxide and germanium lactate citrate (inorganic germaniums) have been shown to induce renal toxicity, whereas germanium sesquioxide (an organic germanium) has been shown to have a more favorable safety profile. However, past toxicity studies on germanium sesquioxide compounds have not clearly stated the purity of the tested compounds. In the studies reported herein, there was no evidence of mutagenicity in a bacterial reverse mutation test or an in vitro mammalian chromosomal aberration test. There was no genotoxic activity observed in an in vivo mammalian micronucleus test at concentrations up to the limit dose of 2000 mg/kg bw/day. In a 90-day repeated-dose oral toxicity study in Han:WIST rats conducted at doses of 0, 500, 1000, and 2000 mg/kg bw/day by gavage, there were no mortalities, treatment-related adverse effects, or target organs identified. The no-observed-adverse-effect-level (NOAEL) was determined to be 2000 mg/kg bw/day.

Comparison of methods used for evaluation of mutagenicity/genotoxicity of model chemicals - parabens

Growing worldwide efforts to replace (reduce) animal testing and to improve alternative in vitro tests which may be more efficient in terms of both time, cost and scientific validity include also genotoxicity/mutagenicity endpoints. The aim of the review article was to summarize currently available in vitro testing approaches in this field, their regulatory acceptance and recommended combinations for classification of chemicals. A study using the combination of Comet Assay performed on two cell lines and the Chromosomal Aberration test on human peripheral lymphocytes was performed with the aim to predict the genotoxic potential of selected paraben esters, serving as a model chemical group. Parabens are widely used in consumer products as preservatives and have been reported to exhibit inconclusive results in numerous genotoxicity studies. The Comet Assay identified Ethylparaben and Benzylparaben as potentially genotoxic. The Chromosomal Aberration test revealed weak genotoxic potential in case of Ethylparaben and positive genotoxicity in case of Butylparaben, Propylparaben and Isopropylparaben. The main reasons for variability seem to be limited water solubility of parabens, determining their bioavailability at the cellular level, and absence of metabolic activation in the Comet Assay. The results confirmed that the Comet Assay should serve as a screening test and should not be used as a stand-alone method for classification of genotoxicity. The weight of evidence approach in risk assessment should be supported with data generated with the use of human relevant in vitro methods based on cells / tissues of human origin.

Genotoxic property of poly herbal formulation of annona squomosa, zingiber officinalis and triticum aestivum plant extracts by in vitro chromosomal aberration test

The present study was aimed to evaluate the genotoxic potential of polyherbal formulations by chromosomal aberration test. Cancer being the second most cause of death among all ailments even after the improvised medications needs alternative sources of treatment. Herbal sources were always among the one as prime treatment sources. Polyherbal formulations were taking the lead in medications because of their broad spectrum of activity and synergic effects. Annona squamosa, Zingiber Officinalis, and Triticum Aestivum formulation with 1:2:3 ratio has shown significant results in the definitive and confirmatory chromosome aberration assays. Indicated the test article PF3 did not induce a statistically significant increase in the percentage of cells with aberrations both in the presence and absence of metabolic activation. PF3 was found non-clostagenic at a maximum dose of 15 µg/ml in the CHO cell line. Inhibition of chromosomal aberration, DNA fragmentation, and maintenance of cellular integrity may prevent the genotoxic effect. Further optimization and in vivo authenticated studies need to be proven.

Safety assessment of Gossence™ (galactooligosaccharides): Genotoxicity and general toxicity studies in Sprague Dawley rats

Galactooligosaccharides (GOS) used as prebiotics are one of the major constituents of the infant milk formulas. GOS (Gossence™) is produced by a patented process of biotransformation of lactose; hence toxicology studies were carried out to assess its safety. The objective of the present study was to evaluate the general and genetic toxicity of Gossence™. In 14-day and subchronic (90-day) oral toxicity studies in Sprague Dawley rats, daily administration of GOS at dose levels of 1000, 2000, or 5000 mg/kg (equivalent to 1347, 2694, and 6735 mg/kg/day of Gossence™, respectively) did not cause any mortality, or clinical signs, and changes in body weights, feed consumption, hematology, clinical chemistry, and urinalysis. In 90-day study, no changes in ophthalmological and neurological findings were observed. Significant increases in the cecum weights (with and/or without content) at dose levels of ≥2000 mg/kg were observed in both 14-day and 90-day studies. Based on the results of 90-day study, the no-observed-adverse-effect-level for GOS is 5000 mg/kg/day which is equivalent to 6735 mg Gossence™/kg/day. In the bacterial reverse mutation test, there was no significant increase in the mean numbers of revertants at the tested concentrations. Gossence™ was not mutagenic up to 5000 µg/plate. In chromosomal aberration test, there was no statistically significant increase in the number of percent aberrant metaphase for the Gossence™. Gossence™ is non-clastogenic (negative) in the in vitro chromosomal aberration test using human peripheral blood lymphocyte during short and prolonged treatment.