Matrine and Oxymatrine: evaluating the gene mutation potential using in silico tools and the bacterial reverse mutation assay (Ames test).

The quinolizidine alkaloids matrine and its N-oxide oxymatrine occur in plants of the genus Sophora. Recently, matrine was sporadically detected in liquorice products. Morphological similarity of the liquorice plant Glycyrrhiza glabra with Sophora species and resulting confusion during harvesting may explain this contamination, but use of matrine as pesticide has also been reported. The detection of matrine in liquorice products raised concern as some studies suggested a genotoxic activity of matrine and oxymatrine. However, these studies are fraught with uncertainties, putting the reliability and robustness into question. Another issue was that Sophora root extracts were usually tested instead of pure matrine and oxymatrine. The aim of this work was therefore to determine whether matrine and oxymatrine have potential for causing gene mutations. In a first step and to support a weight-of-evidence analysis, in silico predictions were performed to improve the database using expert and statistical systems by VEGA, Leadscope (Instem®), and Nexus (Lhasa Limited). Unfortunately, the confidence levels of the predictions were insufficient to either identify or exclude a mutagenic potential. Thus, in order to obtain reliable results, the bacterial reverse mutation assay (Ames test) was carried out in accordance with OECD Test Guideline 471. The test set included the plate incorporation and the preincubation assay. It was performed with five different bacterial strains in the presence or absence of metabolic activation. Neither matrine nor oxymatrine induced a significant increase in the number of revertants under any of the selected experimental conditions. Overall, it can be concluded that matrine and oxymatrine are unlikely to have a gene mutation potential. Any positive findings with Sophora extracts in the Ames test may be related to other components. Notably, the results also indicated a need to extend the application domain of respective (Q)SAR tools to secondary plant metabolites.

Piper auritum ethanol extract is a potent antimutagen against food-borne aromatic amines. Mechanisms of action and chemical composition.

An ethanol extract of Piper auritum leaves (PAEE) inhibits the mutagenic effect of three food-borne aromatic amines (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP); 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx); 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) in the TA98 Salmonella typhimurium strain. Preincubation with MeIQx demonstrated in mutagenesis experiments that inhibition of Cytochrome P450 (CYP), as well as direct interaction between component(s) of the plant extract with mutagens, might account for the antimutagenic observed effect. Gas chromatography/mass spectrometry analysis revealed that safrole (50.7%), α-copaene (7.7%), caryophyllene (7.2%), ß-pinene (4.2%), γ-terpinene (4.1%) and pentadecane (4.1%) as the main components of PAEE. Piper extract and safrole were able to inhibit the rat liver microsomal CYP1A1 activity that participates in the amines metabolism, leading to the formation of the ultimate mutagenic/ molecules. According to this, safrole and PAEE inhibited MeIQx mutagenicity but not that of the direct mutagen 2-nitrofluorene. No mutagenicity of plant extract or safrole was detected. This study show that PAEE and its main component safrole are associate with the inhibition of heterocyclic amines activation due in part to the inhibition of CYP1A subfamily activity.

Disrupted HSF1 regulation in normal and exceptional brain aging.

Brain aging is a major risk factor for cognitive diseases such as Alzheimer's disease (AD) and vascular dementia. The rate of aging and age-related pathology are modulated by stress responses and repair pathways that gradually decline with age. However, recent reports indicate that exceptional longevity sustains and may even enhance the stress response. Whether normal and exceptional aging result in either attenuated or enhanced stress responses across all organs is unknown. This question arises from our understanding that biological age differs from chronological age and evidence that the rate of aging varies between organs. Thus, stress responses may differ between organs and depend upon regenerative capacity and ability to manage damaged proteins and proteotoxicity. To answer these questions, we assessed age-dependent changes in brain stress responses with normally aged wild type and long-lived Dwarf mice. Results from this study show that normal aging unfavorably impacts activation of the brain heat shock (HS) axis with key changes noted in the transcription factor, HSF1, and its regulation. Exceptional aging appears to preserve and strengthen many elements of HSF1 activation in the brain. These results support the possibility that reconstitution of aging brain stress responses requires a multi-factorial approach that addresses HSF1 protein levels, its DNA binding, and regulatory elements such as phosphorylation and protein interactions.

A novel 7-phenoxy-benzimidazole derivative as a potent and orally available BRD4 inhibitor for the treatment of melanoma.

The bromodomain-containing protein 4 (BRD4), which is a key epigenetic regulator in cancer, has emerged as an attractive target for the treatment of melanoma. In this study, we investigate 7-phenoxy-benzimidazole derivative 12, which is a novel BRD4 inhibitor for the treatment of melanoma, by performing scaffold hopping on the previously reported benzimidazole derivative 1. Despite their good oral and intravenous exposure, the compounds obtained by modifying derivate 1 exhibit mutagenicity, which was confirmed by the positive Ames test results. Based on our hypothesis that the cause of the Ames test positivity is the metabolic intermediates generated from those chemical series, we implemented a scaffold hopping strategy to avoid the N-benzyl moiety by relocating the substituent groups to preserve the essential interaction. Based on this strategy, we successfully obtained compound 12; the Ames test results of this compound were negative. Notably, compound 12 not only exhibited a favorable pharmacokinetic (PK) profile but also significant tumor growth inhibition in a mouse melanoma xenograft model, indicating its potential as a therapeutic agent for the treatment of melanoma.

Escaping the cohort of concern: in vitro experimental evidence supports non-mutagenicity of N-nitroso-hydrochlorothiazide.

In recent years, nitrosamine impurities in pharmaceuticals have been subject to intense regulatory scrutiny, with nitrosamine drug substance-related impurities (NDSRIs) treated as cohort of concern impurities, regardless of predicted mutagenic potential. Here, we describe a case study of the NDSRI N-nitroso-hydrochlorothiazide (NO-HCTZ), which was positive in the bacterial reverse mutation (Ames) test but is unstable under the test conditions, generating formaldehyde among other products. The mutagenic profile of NO-HCTZ was inconsistent with that expected of a mutagenic nitrosamine, exhibiting mutagenicity in the absence of metabolic activation, and instead aligned well with that of formaldehyde. To assess further, a modified Ames system including glutathione (3.3 mg/plate) to remove formaldehyde was developed. Strains used were S. typhimurium TA98, TA100, TA1535, and TA1537, and E. coli WP2 uvrA/pKM101. In this system, formaldehyde levels were considerably lower, with a concomitant increase in levels of S-(hydroxymethyl)glutathione (the adduct formed between glutathione and formaldehyde). Upon retesting NO-HCTZ in the modified system (1.6-5000 µg/plate), a clear decrease in the mutagenic response was observed in the strains in which NO-HCTZ was mutagenic in the original system (TA98, TA100, and WP2 uvrA/pKM101), indicating that formaldehyde drives the response, not NO-HCTZ. In strain TA1535, an increase in revertant colonies was observed in the modified system, likely due to a thiatriazine degradation product formed from NO-HCTZ under Ames test conditions. Overall, these data support a non-mutagenic designation for NO-HCTZ and demonstrate the value of further investigation when a positive Ames result does not align with the expected profile.

Tellimagrandin-I and camptothin a exhibit chemopreventive effects in Salmonella enterica serovar Typhimurium strains and human lymphocytes.

Tellimagrandin-I (TL) and camptothin A (CA) are ellagitannins widely found in diverse plant species. Numerous studies demonstrated their significant biological activities, which include antitumor, antioxidant, and hepatoprotective properties. Despite this protective profile, the effects of TL and CA on DNA have not been comprehensively investigated. Thus, the aim of this study was to determine the mutagenic and antimutagenic effects attributed to TL and CA exposure on Salmonella enterica serovar Typhimurium strains using the Ames test. In addition, the cytotoxic and genotoxic effects were examined on human lymphocytes, employing both trypan blue exclusion and CometChip assay. The antigenotoxic effect was determined following TL and CA exposure in the presence of co-treatment with doxorubicin (DXR). Our results from the Ames test indicated that TL or CA did not display marked mutagenic activity. However, TL or CA demonstrated an ability to protect DNA against the damaging effects of the mutagens 4-nitroquinoline-1-oxide and sodium azide, thereby exhibiting antimutagenic properties. In relation to human lymphocytes, TL or CA did not induce significant cytotoxic or genotoxic actions on these cells. Further, these ellagitannins exhibited an ability to protect DNA from damage induced by DOX during co-treatment, indicating their potential beneficial usefulness as antigenotoxic agents. In conclusion, the protective effects of TL or CA against mutagens, coupled with their absence of genotoxic and cytotoxic effects on human lymphocytes, emphasize their potential therapeutic value in chemopreventive strategies.

The Ames room and the misunderstood versions and depictions.

The Ames room illusion is one of the best-known geometrical illusions but its geometrical properties are often misunderstood. This study discusses the differences in the geometrical properties between the original Ames room and what have been often referred to as "Ames rooms" in recent studies.

N-nitrosamine impurity risk assessment in pharmaceuticals: Utilizing In vivo mutation relative potency comparison to establish an acceptable intake for NTTP.

The finding of N-nitrosodiethylamine (NDEA) and N-nitrosodimethylamine (NDMA) in marketed drugs has led to implementation of risk assessment processes intended to limit exposures to the entire class of N-nitrosamines. A critical component of the risk assessment process is establishing exposure limits that are protective of human health. One approach to establishing exposure limits for novel N-nitrosamines is to conduct an in vivo transgenic rodent (TGR) mutation study. Existing regulatory guidance on N-nitrosamines provides decision making criteria based on interpreting in vivo TGR mutation studies as an overall positive or negative. However, point of departure metrics, such as benchmark dose (BMD), can be used to define potency and provide an opportunity to establish relevant exposure limits. This can be achieved through relative potency comparison of novel N-nitrosamines with model N-nitrosamines possessing robust in vivo mutagenicity and carcinogenicity data. The current work adds to the dataset of model N-nitrosamines by providing in vivo TGR mutation data for N-nitrosopiperidine (NPIP). In vivo TGR mutation data was also generated for a novel N-nitrosamine impurity identified in sitagliptin-containing products, 7-nitroso-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo-[4,3-a]pyrazine (NTTP). Using the relative potency comparison approach, we have demonstrated the safety of NTTP exposures at or above levels of 1500 ng/day.

Optimizing the detection of N-nitrosamine mutagenicity in the Ames test.

Accurately determining the mutagenicity of small-molecule N-nitrosamine drug impurities and nitrosamine drug substance-related impurities (NDSRIs) is critical to identifying mutagenic and cancer hazards. In the current study we have evaluated several approaches for enhancing assay sensitivity for evaluating the mutagenicity of N-nitrosamines in the bacterial reverse mutagenicity (Ames) test. Preincubation assays were conducted using five activation conditions: no exogenous metabolic activation and metabolic activation mixes employing both 10% and 30% liver S9 from hamsters and rats pretreated with inducers of enzymatic activity. In addition, preincubations were conducted for both 60 minutes and 30 minutes. These test variables were evaluated by testing 12 small-molecule N-nitrosamines and 17 NDSRIs for mutagenicity in Salmonella typhimurium tester strains TA98, TA100, TA1535, and TA1537, and Escherichia coli strain WP2 uvrA (pKM101). Eighteen of the 29 N-nitrosamine test substances tested positive under one or more of the testing conditions and all 18 positives could be detected by using tester strains TA1535 and WP2 uvrA (pKM101), preincubations of 30 minutes, and S9 mixes containing 30% hamster liver S9. In general, the conditions under which NDSRIs were mutagenic were similar to those found for small-molecule N-nitrosamines.

The ameliorative effect of rosmarinic acid and epigallocatechin gallate against doxorubicin-induced genotoxicity.

Doxorubicin (Dox), an effective anticancer agent, is known for its genotoxic effects on normal cells. Phenolic compounds, renowned for their antitumor, antioxidant, and antigenotoxic properties, have gained prominence in recent years. This study investigates the individual and combined protective effects of rosmarinic acid (RA) and epigallocatechin gallate (EGCG) against Dox-induced genotoxicity using various in vitro test systems. The synergistic/antagonistic interaction of these combinations on Dox's chemotherapeutic effect is explored in breast cancer cell lines. Both RA and EGCG significantly mitigate Dox-induced genotoxicity in comet, micronucleus, and Ames assays. While Dox exhibits higher selectivity against MCF-7 cells, EGCG and RA show greater selectivity against MDA-MB-231 cells. The coefficient of drug interaction reveals a synergistic effect when RA or EGCG is combined with Dox in breast cancer cells. In conclusion, both EGCG and RA effectively reduce Dox-induced genetic damage and enhance Dox's cell viability-reducing effect in breast cancer cells.

Rosmarinic acid (RA) showed protective effect against doxorubicin-induced genotoxicity.Epigallocatechin gallate (EGCG) demonstrated pro-oxidant properties at high concentrations.EGCG and RA selectively targeted MDA-MB-231 cells.Synergistic effect was observed when EGCG or RA was administered together with Dox on breast cancer cells.

Mutagenicity Assessment of Homologous Series of Methyl Ester Sulphonates (MES) Using the Bacterial Reverse Mutation (Ames) Test.

Methyl ester sulphonate (MES) is an anionic surfactant that is suitable to be used as an active ingredient in household products. Four palm-based MES compounds with various carbon chains, namely C12, C14, C16 and C16/18 MES, were assayed by the in vitro bacterial reverse mutation (Ames) test in the Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 and the Escherichia coli strain WP2 uvrA, with the aim of establishing the safety data of the compounds, specifically their mutagenicity. The test was also carried out on linear alkylbenzene sulphonate (LAS) for comparison. The plate incorporation method was conducted according to the Organization for Economic Cooperation and Development (OECD) Test Guideline 471. All compounds were tested at five analysable non-cytotoxic concentrations, varying from .001 mg/plate to 5 mg/plate, with and without S-9 metabolic activation. All tested concentrations showed no significant increase in the number of revertant colonies compared to revertant colonies of the negative control. The Ames test indicated that each concentration of C12, C14, C16, C16/18 MES, and LAS used in this study induced neither base-pair substitutions nor frame-shift mutations in the S. typhimurium strains TA98, TA100, TA1535, and TA1537 and the E. coli strain WP2 uvrA. The results showed that C12, C14, C16 and C16/18 MES have no potential mutagenic properties in the presence and absence of S-9 metabolic activation, similarly to LAS. Therefore, the MES is safe to be used as an alternative to petroleum-based surfactants for household cleaning products.

Characterisation and identification of chemical constituents in aqueous extract of Fomes officinalis Ames based on ultrahigh-performance liquid chromatography tandem quadrupole-Orbitrap high-resolution mass spectrometry.

INTRODUCTION: Fungal species are an attractive resource for physiologically functional food and drug precursor. Fomes officinalis Ames, a medicinal fungus, is traditionally used as a folk medicine in traditional Chinese medicine prescription for the therapy of cough and asthma. The water-soluble substances in Chinese herbal medicines are likely to play an important physiological function. However, information on probing and identifying chemical components of the aqueous extract of Fomes officinalis Ames (AFO) remains unknown. OBJECTIVE: This study was conducted to screen and characterise the chemical components of AFO. MATERIAL AND METHODS: An effective and sensitive ultrahigh-performance liquid chromatography tandem quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS) method with the Full MS/PIL/dd-MS2 acquisition approach was applied for the profiling of chemical components in AFO. An HSS T3 column was used for component separation, and a strategy of simultaneous targeted and untargeted multicomponent characterisation was implemented. Multiple identification approaches were used, including accurate molecular mass and elemental composition matching, literature and database searching, and fragmentation rules elucidation. RESULTS: A total of 115 components, including 20 amino acids and derivatives, six nucleobases, nine nucleosides, 75 dipeptides, two tripeptides, and three other components, were tentatively identified. Among them, the targeted exploring method screened six nucleobases and nine nucleosides including modified nucleosides. To our best knowledge, this is the first time a report has been done on the presence of the 115 compounds in AFO. CONCLUSION: Profiling and characterisation compounds of AFO enriched its material basis, which would lay the foundation for improving potential medicinal and nutritional values and effecting comprehensive quality control of Fomes officinalis Ames.

Progress in Predicting Ames Test Outcomes from Chemical Structures: An In-Depth Re-Evaluation of Models from the 1st and 2nd Ames/QSAR International Challenge Projects.

The Ames/quantitative structure-activity relationship (QSAR) International Challenge Projects, held during 2014-2017 and 2020-2022, evaluated the performance of various predictive models. Despite the significant insights gained, the rules allowing participants to select prediction targets introduced ambiguity in model performance evaluation. This reanalysis identified the highest-performing prediction model, assuming a 100% coverage rate (COV) for all prediction target compounds and an estimated performance variation due to changes in COV. All models from both projects were evaluated using balance accuracy (BA), the Matthews correlation coefficient (MCC), the F1 score (F1), and the first principal component (PC1). After normalizing the COV, a correlation analysis with these indicators was conducted, and the evaluation index for all prediction models in terms of the COV was estimated. In total, using 109 models, the model with the highest estimated BA (76.9) at 100% COV was MMI-VOTE1, as reported by Meiji Pharmaceutical University (MPU). The best models for MCC, F1, and PC1 were all MMI-STK1, also reported by MPU. All the models reported by MPU ranked in the top four. MMI-STK1 was estimated to have F1 scores of 59.2, 61.5, and 63.1 at COV levels of 90%, 60%, and 30%, respectively. These findings highlight the current state and potential of the Ames prediction technology.

Preliminary study on the enhanced bioremediation of PAH-contaminated soil in Beijing and assessment of remediation effects based on toxicity tests.

In this study, we focused on soil contaminated by polycyclic aromatic hydrocarbons (PAHs) at typical coking-polluted sites in Beijing, conducted research on enhanced PAH bioremediation and methods to evaluate remediation effects based on toxicity testing, and examined changes in pollutant concentrations during ozone preoxidation coupled with biodegradation in test soil samples. The toxicity of mixed PAHs in soil was directly evaluated using the Ames test, and the correlation between mixed PAH mutagenicity and benzo(a)pyrene (BaP) toxicity was investigated in an effort to establish a carcinogenic risk assessment model based on biological toxicity tests to evaluate remediation effects on PAH-contaminated soil. This study provides a theoretical and methodological foundation for evaluating the effect of bioremediation on PAH-contaminated soil at industrially contaminated sites. The results revealed that the removal rate of PAHs after 5 min of O3 preoxidation and 4 weeks of soil reaction with saponin surfactants and medium was 83.22%. The soil PAH extract obtained after remediation had a positive effect on the TA98 strain at a dose of 2000 µg·dish-1, and the carcinogenic risk based on the Ames toxicity test was 8.98 times greater than that calculated by conventional carcinogenic PAH toxicity parameters. The total carcinogenic risk of the remediated soil samples was approximately one order of magnitude less than that of the original soil samples.

Temporal and spatial evolution of net primary productivity in the Three-River Headwaters Region under phenological changes and anthropogenic influence.

Understanding the spatiotemporal changes in net primary productivity (NPP) and the driving factors behind these changes in climate-vulnerable regions is crucial for ecological conservation. This study simulates the actual NPP (NPPA) and climate potential NPP (NPPC) in the Three-River Headwaters Region from 2000 to 2020. The Theil-Sen Median method and Mann-Kendall mutation analyses are employed to explore their spatiotemporal variation patterns, while geographic weighted regression and machine learning are used to investigate the influence of anthropogenic activities and climatic factors on NPPA, the results indicate that the average NPPA across the entire region over multiple years is 382.506 g C m - 2 yr - 1 , which is 0.132 times the average annual NPPC over the past 21 years, showing an overall distribution pattern of low in the northwest and high in the southeast. The annual increase in NPPA from 2000 to 2020 is approximately 1.034 g C m - 2 yr - 1 . The source region of the Yangtze River shows the largest improvement in vegetation, with 74.1% of the area showing improvement. Between 2002 and 2003, the annual NPPA in the Three-River Headwaters Region experienced a sudden change, lagging behind the NPPC change by 1 year, and after 2005, the upward trend in NPPA became more pronounced. The impact of anthropogenic activities on NPPA shifted from positive to negative to positive from 2000 to 2020, with significant impact areas mainly concentrated in the northeast and a few areas in the central and southern parts. The proportion of areas with extremely significant impact increased from 1.9% in 2000 to 3.7% in 2020. Over the past 21 years, the main factors influencing NPPA changes in the Three-River Headwaters Region have been soil moisture and precipitation, with the influence of different climate factors on NPP changing over time. Additionally, NPP is more sensitive to changes in altitude in low-altitude areas. This study can provide more accurate theoretical support for ecological environment assessment and subsequent protection efforts in the Three-River Headwaters Region.

Transient early life growth hormone exposure permanently alters brain, muscle, liver, macrophage, and adipocyte status in long-lived Ames dwarf mice.

The exceptional longevity of Ames dwarf (DF) mice can be abrogated by a brief course of growth hormone (GH) injections started at 2 weeks of age. This transient GH exposure also prevents the increase in cellular stress resistance and decline in hypothalamic inflammation characteristic of DF mice. Here, we show that transient early-life GH treatment leads to permanent alteration of pertinent changes in adipocytes, fat-associated macrophages, liver, muscle, and brain that are seen in DF mice. Ames DF mice, like Snell dwarf and GHRKO mice, show elevation of glycosylphosphatidylinositol specific phospholipase D1 in liver, neurogenesis in brain as indicated by BDNF and DCX proteins, muscle production of fibronectin type III domain-containing protein 5 (a precursor of irisin), uncoupling protein 1 as an index of thermogenic capacity in brown and white fat, and increase in fat-associated anti-inflammatory macrophages. In each case, transient exposure to GH early in life reverts the DF mice to the levels of each protein seen in littermate control animals, in animals evaluated at 15-18 months of age. Thus, many of the traits seen in long-lived mutant mice, pertinent to age-related changes in inflammation, neurogenesis, and metabolic control, are permanently set by early-life GH levels.

Genotoxicity and mutagenicity in blood and drinking water induced by arsenic in an impacted gold mining region in Colombia.

Arsenic (As) is one of the most dangerous substances that can affect human health and long-term exposure to As in drinking water can even cause cancer. The objective of this study was to investigate the concentrations of total As in the blood of inhabitants of a Colombian region impacted by gold mining and to evaluate its genotoxic effect through DNA damage by means of the comet assay. Additionally, the concentration of As in the water consumed by the population as well as the mutagenic activity of drinking water (n = 34) in individuals were determined by hydride generator atomic absorption spectrometry and the Ames test, respectively. In the monitoring, the study population was made up of a group of 112 people, including inhabitants of four municipalities: Guaranda, Sucre, Majagual, and San Marcos from the Mojana region as the exposed group, and Montería as a control group. The results showed DNA damage related to the presence of As in blood (p < 0.05) in the exposed population, and blood As concentrations were above the maximum allowable limit of 1 µg/L established by the ATSDR. A mutagenic activity of the drinking water was observed, and regarding the concentrations of As in water, only one sample exceeded the maximum permissible value of 10 µg/L established by the WHO. The intake of water and/or food containing As is potentially generating DNA damage in the inhabitants of the Mojana region, which requires surveillance and control by health entities to mitigate these effects.

Toxicological and chemoprevention studies of Brazilian brown propolis from Araucaria sp.

Brazilian brown propolis (BBP) is a natural product derived predominantly from the south region of Brazil, where Araucaria forests are dominant. Despite its potential as a source of bioactive compounds with leishmanicidal, anti-inflammatory, nociceptive, and antimicrobial properties, BBP has not been comprehensively studied compared to green propolis. Therefore, this study aimed to determine the safety and chemopreventive potential of BBP. The cytotoxicity attributed to BBP was assessed using two different assays, while the Salmonella/microsome assay was employed to evaluate mutagenicity. The acute toxicity attributed to BBP was determined using a zebrafish model, while the chemopreventive potential was investigated utilizing Chinese hamster lung (V79) cell lines. Data demonstrated that BBP exerted cytotoxic effects at concentrations greater than or equal to 10 µg/ml and did not exhibit mutagenicity in Salmonella typhimurium strains TA98 and TA100. However, at the highest concentration tested (4000 µg/plate), BBP induced a significant increase in revertant colonies in S. typhimurium TA102 strain. The LC50 equivalent to 8.83 mg/L was obtained in the acute toxicity evaluation in zebrafish. BBP also showed antigenotoxic effect by significantly reducing chromosomal damage induced by the mutagen doxorubicin in V79 cell cultures at a concentration of 2.5 µg/ml. Compared to Brazilian green and red propolis, BBP exhibited greater toxicity. On the other hand, at lower concentrations, BBP displayed chemopreventive potential, which may be associated with the antioxidant capacity of the extract. These findings contribute to a better understanding of the biological properties and potential applications of BBP in treating various diseases.

Chemopreventive effect and induction of DNA repair by oenothein B ellagitannin isolated from leaves of Eugenia uniflora in Swiss Webster treated mice.

Oenothein B (OeB) is a dimeric ellagitannin with potent antioxidative, antitumor, immunomodulatory, and anti-inflammatory properties. Despite the promising activities of OeB, studies examining the genotoxic or protective effects of this ellagitannin on DNA are scarce. Therefore, to further comprehensively elucidate the chemopreventive profile of OeB, the aim of this study was to evaluate the mutagenic and antimutagenic actions of OeB using Salmonella typhimurium strains with the Ames test. The micronucleus (MN) test and comet assay were used to assess the anticytotoxic and antigenotoxic effects of OeB on mouse bone marrow cells following differing treatments (pre-, co-, and post-treatment) in response to cyclophosphamide (CPA)-induced DNA damage. In addition, histopathological analyses were performed to assess liver and kidney tissues of Swiss Webster treated mice. Our results did not detect mutagenic or antimutagenic activity attributed to OeB at any concentration in the Ames test. Regarding the MN test, data showed that this ellagitannin exerted antigenotoxic and anticytotoxic effects against CPA-induced DNA damage under all treatment conditions. However, no anticytotoxic action was observed in MN test after pre-treatment with the highest doses of OeB. In addition, OeB demonstrated antigenotoxic effects in the comet assay for all treatments. Histopathological analyses indicated that OeB attenuated the toxic effects of CPA in mouse liver and kidneys. These findings suggest that OeB exerted a chemoprotective effect following pre- and co-treatments and a DNA repair action in post-treatment experiments. Our findings indicate that OeB protects DNA against CPA-induced damaging agents and induces post-damage DNA repair.

Genotoxicity evaluation of cannabidiol.

Consumer use of cannabidiol (CBD) for personal wellness purposes has garnered much public interest. However, safety-related data on CBD in the public domain are limited, including a lack of quality studies evaluating its genotoxic potential. The quality of available studies is limited due to the test material used (e.g., low CBD purity) and/or study design, leading some global regulatory agencies to highlight genotoxicity as an important data gap for CBD. To address this gap, the genotoxic potential of a pure CBD isolate was investigated in a battery of three genotoxicity assays conducted according to OECD testing guidelines. In an in vitro microbial reverse mutation assay, CBD up to 5000 µg/plate was negative in Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537, and Escherichia coli strain WP2 uvrA, with and without metabolic activation. Testing in an in vitro micronucleus assay was negative in human TK6 cells up to 10-11 µg/mL, with and without metabolic activation. Finally, an in vivo micronucleus assay conducted in male and female rats was negative for genotoxicity up to 1000 mg/kg-bw/d. Bioanalysis of CBD and its primary metabolite, 7-carboxy CBD, confirmed a dose-related increase in plasma exposure. Together, these assays indicate that CBD is unlikely to pose a genotoxic hazard.