In vitro genotoxicity assessment of functional ingredients: DHA, rutin and α-tocopherol

Genotoxic and antigenotoxic medicinal plant extracts and their main phytochemicals: "A review"

Many medicinal plant extracts have been proven to have significant health benefits. In contrast, research has shown that some medicinal plant extracts can be toxic, genotoxic, mutagenic, or carcinogenic. Therefore, evaluation of the genotoxicity effects of plant extracts that are used as traditional medicine is essential to ensure they are safe for use and in the search for new medication. This review summarizes 52 published studies on the genotoxicity of 28 plant extracts used in traditional medicine. A brief overview of the selected plant extracts, including, for example, their medicinal uses, pharmacological effects, and primary identified compounds, as well as plant parts used, the extraction method, genotoxic assay, and phytochemicals responsible for genotoxicity effect were provided. The genotoxicity effect of selected plant extracts in most of the reviewed articles was based on the experimental conditions. Among different reviewed studies, A total of 6 plant extracts showed no genotoxic effect, other 14 plant extracts showed either genotoxic or mutagenic effect and 14 plant extracts showed anti-genotoxic effect against different genotoxic induced agents. In addition, 4 plant extracts showed both genotoxic and non-genotoxic effects and 6 plant extracts showed both genotoxic and antigenotoxic effects. While some suggestions on the responsible compounds of the genotoxicity effects were proposed, the proposed responsible phytochemicals were not individually tested for the genotoxicity potential to confirm the findings. In addition, the mechanisms by which most plant extracts exert their genotoxicity effect remain unidentified. Therefore, more research on the genotoxicity of medicinal plant extracts and their genotoxicity mechanisms is required.

Genotoxic and Anti-Genotoxic Assessments of Fermented Houttuynia cordata Thunb. Leaf Ethanolic Extract and Its Anti-Cancer Effect in a Dual-Organ Carcinogenesis Model of Colon and Liver in Rats

The incidence of multiple-organ cancers has recently increased due to simultaneous exposure to various environmental carcinogens. Houttuynia cordata Thunb. (H. cordata) is recognized for its many health benefits, including its anti-cancer properties. The fermentation of its leaves has been shown to significantly enhance the bioflavonoid content and its bioactivities. This study aimed to evaluate the effectiveness of fermented H.cordata leaf (FHCL) extracts against combined carcinogens and investigate the underlying mechanisms. The crude ethanolic extract of FHCL was partitioned to obtain hexane- (HEX), dichloromethane- (DCM), ethyl acetate- (ETAC), butanol- (nBA), and residue fractions. The crude ethanolic extract (200-250 μg/mL) and the DCM fraction (50 μg/mL) significantly reduced NO production in RAW264.7 macrophages. In addition, the crude extract and the DCM and ETAC fractions showed anti-genotoxicity against aflatoxin B1 and 2-amino-3,4-dimethylimidazo [4,5-f]quinoline (MeIQ) in Salmonella typhimurium assays (S9+). Despite demonstrating genotoxicity in the Salmonella mutation assay (with and without S9 activation), oral administration of the crude extract at 500 mg/kg of body weight (bw) for 40 days in rats did not induce micronucleated hepatocytes, indicating that the extract is non-genotoxic in vivo. Moreover, the crude extract significantly decreased Phase I but increased Phase II xenobiotic-metabolizing enzyme activities in the rats. Next, the anti-cancer effects of FHCL were evaluated in a dual-organ carcinogenesis model of the colon and liver in rats induced by 1,2-dimethylhydrazine (DMH) and diethylnitrosamine (DEN), respectively. The crude extract significantly reduced not only the number and size of glutathione S-transferase placental form positive foci in the liver (at doses of 100 and 500 mg/kg bw) but also the number of aberrant crypt foci in rat colons (at 500 mg/kg bw). Furthermore, FHCL significantly reduced the expression of proliferating cell nuclear antigen (PCNA) in the colon (at 100 and 500 mg/kg bw) and liver (at 500 mg/kg bw) of the treated rats. In conclusion, FHCL exhibits significant preventive properties against colon and liver cancers in this dual-organ carcinogenesis model. Its mechanisms of action may involve anti-inflammatory effects, the prevention of genotoxicity, the modulation of xenobiotic-metabolizing enzymes, and the inhibition of cancer cell proliferation. These findings support the use of FHCL as a natural supplement for preventing cancer.

QBD approach for green synthesis of Rutin silver nanoparticles- screening for antioxidant, anticancer and anticlastogenic potential

Rutin is a flavonoid glycoside abundant in many plants exhibiting pharmacological activities like antioxidant, anticancer, anti-inflammatory and antimicrobial activities. Plant biomarkers suffer low bioavailability and solubility that lack clinical effectiveness. The smart nanoparticles conversion addresses this limitation with optimal particle size and targeted drug delivery. The present study involves QbD approach for formulation of Rutin silver nanoparticles and evaluation of antioxidant, anticancer and anticlastogenic potential. QbD experimentation involved particle size and drug release as dependent variables over the silver nitrate concentration, methanol and sonication time as independent variables devising 15 formulations (F1 -F15). F12 formulation was found to be optimized with 126.3 nm average size, stable and dispersible characterized by UV, FTIR, SEM and DLS studies. The calibration curve of Rutin was plotted at 352 nm with linearity (LOD = 0.061 μg/ml and LOQ = 0.187 μg/ml). The invitro drug release studies by USP dissolution apparatus I (Basket type) proved the sustained release characteristics with 97.3 % drug release when compared to the Rutin. The pharmacological screening for potential antioxidant and anticancer activity on G361 and MCF 7 cell line of F12 formulation have shown promising results and also enhanced solubility in water compared to Rutin. Anticalstogenic potential as a function of induced micronuclei frequency was evaluated as a characteristic feature in bone marrow cells obtained from mice. Results indicate pre-treatment with the F12 reduced frequency of micronuclei in mouse bone marrow cells caused by Cyclophosphamide (CP) significantly. The protective effect of F12 in suppression was demonstrated at both dosages of 100 and 200 mg/kg. Thus the findings suggest the novel Rutin silver nanoparticles as lead drug serving as antioxidant, anticancer and anticlastogenic agent.

Genotoxicity evaluation of a fish oil concentrate containing Very Long Chain Fatty Acids

Very long chain fatty acids (VLCFAs) are lipids found in fish with a chain length longer than C22. They represent a minor lipid fraction composing of less than 1% of the total lipid. EPAX® EVOLVE 05 is a concentrate of VLCFAs providing roughly 10 times the amount found in fish. Here we report genotoxocity studies performed in cell culture and using a rat model. No genotoxicity was noted in a bacterial reverse mutation test (AMES test). An in vitro micronucleus assay was negative with a 4-hr test item incubation but a 24-hr incubation resulted in a positive signal. This prompted further study using an in vivo Sprague Dawley rat model. Test item exposure was demonstrated by plasma measurements from Sprague Dawley rats with peak absorption at 2-4 h post administration, as expected for fatty acids. The micronucleus assay showed no genotoxicity for fish oil containing VLCFAs. Together, the data shows that VLCFAs up to the test dose of 1200 mg/kg b.w. do not show genotoxicity.

Comparison of the radioprotective effects of the liposomal forms of five natural radioprotectants in alleviating the adverse effects of ionising irradiation on human lymphocytes and skin cells in radiotherapy

This study aims to evaluate the radioprotective effects of liposomes encapsulating curcumin (Lip-CUR), silibinin (Lip-SIL), α-tocopherol (Lip-TOC), quercetin (Lip-QUE) and resveratrol (Lip-RES) in alleviating the adverse effects of ionising irradiation on human lymphoctyes and skin cells in radiotherapy. Liposomes encapsulating the above natural radioprotectants (Lip-NRPs) were prepared by the film hydration method combined with sonication. Their radioprotective effects for the cells against X-irradiation was evaluated using trypan-blue assay and γ-H2AX assay. All prepared Lip-NRPs had a mean diameter less than 240 nm, polydispersity index less than 0.32, and zeta potential more than -23 mV. Among them, the radioprotective effect of Lip-RES was lowest, while that of Lip-QUE was highest. Lip-SIL also exhibited a high radioprotective effect despite its low DPPH-radical scavenging activity (12.9%). The radioprotective effects of Lip-NRPs do not solely depend on the free radical scavenging activity of NRPs but also on their ability to activate cellular mechanisms.

Mutagenicity and genotoxicity assessment of the emerging mycotoxin Versicolorin A, an Aflatoxin B1 precursor

Aflatoxin B1 (AFB1) is the most potent natural carcinogen among mycotoxins. Versicolorin A (VerA) is a precursor of AFB1 biosynthesis and is structurally related to the latter. Although VerA has already been identified as a genotoxin, data on the toxicity of VerA are still scarce, especially at low concentrations. The SOS/umu and miniaturised version of the Ames test in Salmonella Typhimurium strains used in the present study shows that VerA induces point mutations. This effect, like AFB1, depends primarily on metabolic activation of VerA. VerA also induced chromosomal damage in metabolically competent intestinal cells (IPEC-1) detected by the micronucleus assay. Furthermore, results from the standard and enzyme-modified comet assay confirmed the VerA-mediated DNA damage, and we observed that DNA repair pathways were activated upon exposure to VerA, as indicated by the phosphorylation and/or relocation of relevant DNA-repair biomarkers (γH2AX and 53BP1/FANCD2, respectively). In conclusion, VerA induces DNA damage without affecting cell viability at concentrations as low as 0.03 μM, highlighting the danger associated with VerA exposure and calling for more research on the carcinogenicity of this emerging food contaminant.

Toxicological potential of Aloysia gratissima: Insights from chemical analysis and in vitro studies

ETHNOPHARMACOLOGICAL RELEVANCE

Aloysia gratissima leaves are popularly used to treat respiratory, digestive, and nervous system disorders. Several studies have been carried out to determine the biological activity of A. gratissima, such as its antibacterial and anti-edematogenic activities, but despite the beneficial uses of A. gratissima, few studies have examined the toxicological profile of this plant.

AIM OF THE STUDY

This study aimed to determine the chemical composition, cytotoxic, genotoxic, mutagenic potential, and antioxidant activity of an aqueous extract of A. gratissima leaves (AG-AEL).

MATERIAL AND METHODS

The phytochemical constitution of AG-AEL was assessed by colorimetric analyses and High-performance liquid chromatography (HPLC). The inorganic elements were detected by Particle-Induced X-ray Emission (PIXE). The antioxidant, cytotoxicity, genotoxic, and mutagenic activities were evaluated in vitro by Di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH), Sulforhodamine B (SRB) assay, comet assay, and Salmonella/microsome assays.

RESULTS

AG-AEL indicated the presence of terpenoids, flavonoids, and phenolic acids. HPLC detected rutin at 2.41 ± 0.33 mg/100 mg. PIXE analysis indicated the presence of Mg, Si, P, S, K, Ca, Mn, and Zn. The 50% inhibitory concentration was 84.17 ± 3.17 μg/mL in the DPPH assay. Genotoxic effects were observed using the Comet assay in neuroblastoma (SH-SY5Y) cells and mutations were observed in TA102 and TA97a strains. The extract showed cytotoxic activities against ovarian (OVCAR-3), glioblastoma (U87MG), and colon (HT-29) cancer cell lines.

CONCLUSIONS

In conclusion, AG-AEL increased DNA damage, induced frameshift, and oxidative mutations, and showed cytotoxic activities against different cancer cells. The in vitro toxicological effects observed suggest that this plant preparation should be used with caution, despite its pharmacological potential.

Acute toxicity and genotoxicity studies on new melatonergic antidepressant GW117

GW117, a novel derivate compound of agomelatine that acts as both a 5-HT2C receptor antagonist and a MT1/MT2 receptor agonist, likely underlines the potent antidepressant action with less hepatotoxicity than agomelatine. We evaluated the acute toxicity of GW117, and the genotoxicity of GW117 using bacterial reverse mutation test, mammalian chromosomal aberration test in Chinese hamster lung cells (CHL) and mouse bone marrow micronucleus test. The acute toxicity test results showed that maximum tolerated dose (MTD) of GW117 was 2000 mg/kg, under which mean C_max and AUC_0→t was 10,782 ng/mL and 81,046 ng/mL × h, respectively. The result of bacterial reverse mutation test showed that the number of bacterial colonies in each dose group of GW117 did not increase significantly compared with that in the solvent control group with or without S9 metabolic activation system. In vitro chromosome aberration test of CHL cells, the chromosome aberration rate of each dose group of GW117 did not increase with or without S9 metabolic activation system. In mouse micronucleus test, the highest dose was 2000 mg/kg, the micronucleus rate did not increase significantly. Under the conditions of this study, the MTD of a single GW117 administration was 2000 mg/kg, there was no genotoxicity effect of GW117.

The Lipophilic Purine Nucleoside-Tdp1 Inhibitor-Enhances DNA Damage Induced by Topotecan In Vitro and Potentiates the Antitumor Effect of Topotecan In Vivo

The use of cancer chemotherapy sensitizers is a promising approach to induce the effect of clinically used anticancer treatments. One of the interesting targets is Tyrosyl-DNA Phosphodiesterase 1 (Tdp1), a DNA-repair enzyme, that may prevent the action of clinical Topoisomerase 1 (Top1) inhibitors, such as topotecan (Tpc). Tdp1 eliminates covalent Top1-DNA (Top1c) complexes that appear under the action of topotecan and determines the cytotoxic effect of this drug. We hypothesize that Tdp1 inhibition would sensitize cells towards the effect of Tpc. Herein, we report the synthesis and study of lipophilic derivatives of purine nucleosides that efficiently suppress Tdp1 activity, with IC₅₀ values in the 0.3-22.0 μM range. We also showed that this compound class can enhance DNA damage induced by topotecan in vitro by Comet assay on human cell lines HeLa and potentiate the antitumor effect of topotecan in vivo on a mice ascitic Krebs-2 carcinoma model. Thereby, this type of compound may be useful to develop drugs, that sensitize the effect of topotecan and reduce the required dose and, as a result, side effects.

Mitochondrial toxicity evaluation of traditional Chinese medicine injections with a dual in vitro approach

There are technical obstacles in the safety evaluation of traditional Chinese medicine (TCM) injections due to their complex chemical nature and the lack of rapid and accurate in vitro methods. Here, we established a dual in vitro mitochondrial toxicity approach combing the conventional "glucose/galactose" assay in HepG2 cells with the cytotoxic assay in mitochondrial respiration deficient cells. Using this dual in vitro approach, for the first time, we systematically assessed the mitochondrial toxicity of TCM injections. Four of the 35 TCM injections, including Xiyanping, Dengzhanhuasu, Shuanghuanglian, and Yinzhihuang, significantly reduced cellular ATP production in galactose medium in the first assay, and presented less cytotoxic in the respiration deficient cells in the second assay, indicating that they have mitochondrial toxicity. Furthermore, we identified scutellarin, rutin, phillyrin, and baicalin could be the potential mitochondrial toxic ingredients in the 4 TCM injections by combining molecular docking analysis with experimental validation. Collectively, the dual in vitro approach is worth applying to the safety evaluation of more TCM products, and mitochondrial toxic TCM injections and ingredients found in this study deserve more attention.

Toxicological Evaluation of Camellia euphlebia Leaves Aqueous Extract Using Acute and Subacute Toxicity Studies in Mice and Genotoxicity Studies

Camelliaeuphlebia is a novel food source and Chinese folk medicine with multiple pharmacological properties. Our previous exploration has demonstrated the antidepressant-like activity of Camellia euphlebia leaves aqueous extract by reliable animal models of depression; however, a lack of toxicological information limits its pharmacological application. The present study aimed to evaluate the preliminary safety of C. euphlebia extract by determining acute/subacute toxicity in mice and in vivo/in vitro genotoxicity. The oral-medium lethal dose of the extract in mice was found to be higher than 5000 mg/kg body weight in the acute toxicity study. In a 14-days subacute toxicity study, C. euphlebia extract at doses of 400, 800, and 1600 mg/kg did not result in significant changes in food intake, water intake, body weight, relative organ weight, aspartate aminotransferase activity, alanine aminotransferase activity, creatinine level, and number of white blood cells and red blood cells. However, histopathology observation of organs taken from all mice showed that 1600 mg/kg extract caused slight hydropic degeneration in the cytoplasm of hepatocytes. In a 28-days subacute toxicity study, 600 mg/kg extract significantly increased the level of red blood cells but produced no negative side effects on other pathological parameters. Mice treated with the extract at doses of 200, 400, and 600 mg/kg for 28 days did not manifest any histopathological alterations of the liver, kidney, and spleen. Additionally, the extract showed no chromosomal aberrations in the in vivo micronucleus test and in vitro chromosomal aberration test. The results revealed that the extract showed no significant toxic effects and no potential genotoxicity but with the likelihood of transient erythrocytosis and slight hepatotoxicity. Further chronic toxicological evaluation involved in more physiological parameters, especially associated with liver toxicity and erythropoietin level, would be needed to determine its safety and application value.