Mutagenicity Of Extracts Research Articles

Phytochemical profile and determination of cytotoxicity, acute oral toxicity, genotoxicity, and mutagenicity of aqueous and ethanolic extracts of Pseudobombax marginatum (A. St.-Hil.) A. Robyns

ABSTRACT Pseudobombax marginatum, popularly known as “embiratanha,” is widely used by traditional communities as anti-inflammatory and analgesic agent. This study aimed to determine the phytochemical profile as well as cytotoxicity, acute oral toxicity, genotoxicity, and mutagenicity attributed to exposure to aqueous (AqEx) and ethanolic (EtEx) extracts of embiratanha bark. Phytochemical screening was conducted using thin-layer chromatography (TLC). Cell viability was analyzed using MTT assay with human mammary gland adenocarcinoma (MDA-MB-231) and macrophage (J774A.1) cell lines, exposed to concentrations of 12.5, 25, 50, or 100 µg/ml of either extract. For acute oral toxicity, comet assay and micronucleus (MN) tests, a single dose of 2,000 mg/kg of either extract was administered orally to Wistar rats. TLC analysis identified classes of metabolites in the extracts, including cinnamic acid derivatives, flavonoids, hydrolyzable tannins, condensed tannins, coumarins, and terpenes/steroids. In the cytotoxicity assay, the varying concentrations of extracts derived from embiratanha induced no significant alterations in the viability of MDA-MB-231 cells. The lowest concentration of EtEx significantly increased macrophage J774A.1 viability. However, the higher concentrations of AqEx markedly lowered macrophage J774A.1 viability. Animals exhibited no toxicity in the parameters analyzed in acute oral toxicity, comet assay, and MN tests. Further, EtEx promoted a significant reduction in DNA damage index and DNA damage frequency utilizing the comet assay, while the group treated with AqEx exhibited no marked differences. Thus, data demonstrated that AqEx or EtEx of embiratanha may be considered safe at a dose of 2,000 mg/kg orgally under our experimental conditions tested.

Cytotoxicity of water supply in a Palestinian refugee camp and a Syrian informal tented settlement in Lebanon.

Deficient water, sanitation, and hygiene (WASH) significantly account for a high burden of disease across the globe. Lebanon, an Eastern Mediterranean lower-middle-income country with a polluted environment, a fragmented healthcare system, and an ongoing severe economic crisis, faces serious challenges in sustaining safe water supplies, especially in vulnerable communities, while also hosting the world highest refugee population per capita. This study aimed to examine the mutagenicity, and the estrogenic and androgenic activities of water supplies, across both a Palestinian refugee camp and a Syrian informal settlement. Water samples were collected from two targeted camps in Dbayeh and Choueifat, North and South of the Capital City Beirut, respectively, between the months of September and October 2022. Microbial and physicochemical properties of samples were determined, including fecal contamination, total dissolved solids, and various minerals and salts. Organic pollutants were extracted using pre-packed solid phase extraction (SPE) columns, and then mutagenicity of extracts was examined using the Ames test in two Salmonella typhi bacterial strains. The estrogenic and androgenic activities of extracts were assessed using the yeast estrogen and androgen screen tests assays (YES/YAS). Results show excessive levels of total coliforms and total dissolved solids (TDS) in samples from both sites. In addition, the water supply from the Dbayeh Palestinian refugee camp is mutagenic, while the water supply from the Choueifat Syrian informal settlement shows anti-androgen activity. Our findings provide valuable WASH baseline data in two major vulnerable communities in Lebanon, and highlight the importance of a water toxicity testing approach concomitant with a water safety plan, based on a holistic strategy that covers all stages of the water supply chain.

Assessment of mutagenic activity of phlorotannin-enriched extracts of three brown algal species

BACKGROUND: Phlorotannins are unique phenolic compounds produced by brown algae. Due to their considerable biological activity these metabolites are extensively studied in the context of medicinal applications. However, to date, no studies addressed potential genotoxicity of phlorotannins.
 AIM: The objective of this research is an assessment of mutagenic activity of intracellular and cell wall (CW) bound phlorotannins of three brown algal species.
 MATERIALS AND METHODS: Mutagenicity of phlorotannin extracts of Desmarestia aculeata, Fucus serratus, and Ectocarpus siliculosus was assessed by the Ames test, carried out using three tester strains of Salmonella typhimurium (TA97, TA98, and TA100) with and without metabolic activation.
 RESULTS: Intracellular phlorotannin extracts of all tested algae showed relatively low values of minimum inhibitory concentration against S. typhimurium (20–30 μg/ml), with extract of D. aculeata being the most toxic. Intracellular phlorotannins of F. serratus and CW-bound polyphenols of E. siliculosus demonstrated moderate mutagenic activity in the Ames test inducing frameshift mutations with the number of His+ revertants more than twice higher compared to the control. The phlorotannin extracts of D. aculeata showed no mutagenic activity.
 CONCLUSIONS: The brown alga D. aculeata may be regarded as a promising source of phlorotannins for medical applications, as its phlorotannin-enriched extracts have high antibiotic activity and are not mutagenic.

Phytochemical properties and in-vitro cytotoxicity, genotoxicity and mutagenicity assessment of ethanolic and aqueous extracts of Argyrolobium roseum (Camb.)

ABSTRACT The current study aimed to investigate the phenolic and flavonoid contents, cytotoxicity, genotoxicity, and mutagenicity of ethanolic and aqueous extracts of A. roseum (Camb.). The MTT assay was used to determine cytotoxicity, Comet assay was used to determine genotoxicity and mutagenicity of extracts was assessed through Ames test. The results showed that total phenolic contents were higher in aqueous extract (538.26 mg GAE/100 g); however, total flavonoid contents were significantly higher in ethanolic extract (6553.29 mg Eq. of Quercetin/100 g). The cells survival percentage was significantly (P <.05) decreased as concentrations of ethanolic extract increased. However, no significant toxicity was observed in groups treated with 0.031–0.25 mg/ml of ethanolic extract of A. roseum compared to negative control (P > .05). IC50 of ethanolic and aqueous extract of A. roseum was 5.54 mg/ml and 11.39 mg/ml, respectively. The results indicated that all concentration groups of ethanolic and aqueous extract of A. roseum significantly (P < .05) lowered DNA damage than positive control group. The lowest DNA damage was observed at 0.031 and 0.062 mg/ml in both aqueous and ethanolic extracts. Moreover, at higher concentrations of 4, 8, and 16 mg/ml of both ethanolic and aqueous extract observed 100% DNA damage cells (comet cells). Moreover, Ames mutagenicity showed that no significant (P > .05) changes were observed in revertant colonies of both bacterial strains (T 98; T 100) at 0.25, 0.5, and 1 mg/ml concentrations of both aqueous and ethanolic extract of A. roseum as MI index was less than 2. The research concluded that A. roseum extracts exhibited no cytotoxicity, genotoxicity, and mutagenicity at lower concentrations (≤2 mg/ml).

Mutagenicity of the Danube River: The contribution of liquid phase and particulate suspended matter.

Bioassays have been used to complement the chemical characterization of aquatic mutagenicity, but the tests sometimes are done only with water liquid phase (LP). Particle-bound mutagens are important because they can be ingested by filtering organisms. Our objective was to evaluate the mutagenicity of organic extracts of the LP and the water suspended particulate matter (SPM) from 13 sites along Danube River with the Salmonella/microsome microsuspension assay using TA98, YG1041, TA1538, and YG5185 strains. A high incidence of mutagenicity was detected, 84% for LP and 92% for SPM samples. The contribution of SPM to the mutagenicity was relatively small when compared with LP however, for five sites SPM was responsible for the whole mutagenicity, highlighting the importance of analyzing SPM when assessing water mutagenicity. YG1041 was the most sensitive strain and should be considered in future water mutagenicity monitoring programs, but it will depend on the main pollution sources.

Pharmacological Assessment of the Antiprotozoal Activity, Cytotoxicity and Genotoxicity of Medicinal Plants Used in the Treatment of Malaria in the Greater Mpigi Region in Uganda.

We investigated the potential antimalarial and toxicological effects of 16 medicinal plants frequently used by traditional healers to treat malaria, fever, and related disorders in the Greater Mpigi region in Uganda. Species studied were Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis, and Zanthoxylum chalybeum. In addition, the traditional healers indicated that P. hadiensis is used as a ritual plant to boost fertility and prepare young women and teenagers for motherhood in some Ugandan communities where a high incidence of rapidly growing large breast masses in young female patients was observed (not necessarily breast cancer). We present results from various in vitro experiments performed with 56 different plant extracts, namely, 1) an initial assessment of the 16 species regarding their traditional use in the treatment of malaria by identifying promising plant extract candidates using a heme biocrystallization inhibition library screen; 2) follow-up investigations of antiprotozoal effects of the most bioactive crude extracts against chloroquine-resistant P. falciparum K1; 3) a cytotoxicity counterscreen against human MRC-5SV2 lung fibroblasts; 4) a genotoxicity evaluation of the extract library without and with metabolic bioactivation with human S9 liver fraction; and 5) an assessment of the mutagenicity of the ritual plant P. hadiensis. A total of seven extracts from five plant species were selected for antiplasmodial follow-up investigations based on their hemozoin formation inhibition activity in the heme biocrystallization assay. Among other extracts, an ethyl acetate extract of L. calostachys leaves exhibited antiplasmodial activity against P. falciparum K1 (IC50 value: 5.7 µg/ml), which was further characterized with a selectivity index of 2.6 (CC50 value: 14.7 µg/ml). The experiments for assessment of potential procarcinogenic properties of plant extracts via evaluation of in vitro mutagenicity and genotoxicity indicated that few extracts cause mutations. The species T. asiatica showed the most significant genotoxic effects on both bacterial test strains (without metabolic bioactivation at a concentration of 500 µg/plate). However, none of the mutagenic extracts from the experiments without metabolic bioactivation retained their genotoxic activity after metabolic bioactivation of the plant extract library through pre-incubation with human S9 liver fraction. While this study did not show that P. hadiensis has genotoxic properties, it did provide early stage support for the therapeutic use of the medicinal plants from the Greater Mpigi region.

Biomass combustions and biomonitoring of airborne particulate: suggestions for preventive actions?

Abstract Biomass combustions generated by both forest fires and home heating in urban centers produce a huge amount of pollutants which can be adsorbed on the particulate matter (PM) and subsequently carried within the human respiratory system. Moreover the occurrence of forest fires is growing due to climate change and it poses a great risk both to environment and to human health. The aim of this study was to investigate different biological effects of PM collected during a big forest fires phenomenon that occurred in Piedmont (Northern Italy) in autumn 2017. PM2.5 and PM10 were collected near the forest fires and in three other areas of Piedmont (two urban and one rural areas). Mutagenicity of organic extracts was assessed on different strains of Salmonella typhimurium using Ames assay while cytotoxicity (WST-1 and LDH assays) and genotoxicity (Comet assay) were evaluated on human bronchial epithelial cells (BEAS-2B). The estrogenic activity of organic extracts was estimated through a gene reporter assay on MELN cells, in order to analyse the presence of endocrine disruptors adsorbed on PM. The contribution of fires to urban mutagenicity was low moreover samples did not induce any significant cytotoxic or genotoxic effect. A slight increase in estrogenic activity was detected in samples from urban and rural areas, while an anti-estrogenic effect was induced by forest fires samples. The biological effects induced by extracts were low respect to what is normally observed in urban sites but are probably due to the tested concentrations, which are closer to realistic human exposure but are insufficient to show differences among areas. These findings may be helpful for public health policies, suggesting to include in the monitoring of traditional parameters the contribution of biomass combustion to the air quality. Finally the PM biomonitoring could improve the air quality assessment, which is essential to plan strategies focused on environment and health protection. Key messages The PM biomonitoring could improve the air quality assessment, which is essential to plan strategies focused on environment and health protection. Public health policies should consider the contribution of biomass combustion to the air quality in monitoring plans.

Safety and biological activity evaluation of Uncaria rhynchophylla ethanolic extract

Uncaria rhynchophylla (UR) belongs to the Rubiaceae family, and its dried hooks are usually used in traditional medicine. It is effective in treating diseases related to the central nervous system. This study aimed to evaluate the safety of UR extract, investigate its antimutagenic and antioxidative activities, and elucidate its active components. Extraction and fractionation of the UR extract resulted in yields of 6.71%, 0.037%, 0.042%, 0.152%, 0.332%, and 5.132%, for hexane, ether, DCM, EtOAC, and aqueous fractions, respectively. The four indole alkaloids, total phenolic content (TPC), and total flavonoid content (TFC) of UR extract and its subfractions were measured. Alkaloid content was highest in the UR extract. TPC was the highest in the EtOAC fraction (373.7 ± 20.9 mg gallic acid equivalent (GAE)/g), whereas TFC was the highest in the UR extract (33.5 ± 2.4 mg quercetin equivalent (QE)/g). To assess the safety of UR extract mutagenicity, cytotoxicity, and oxidative stress inducibility assays were performed. The UR extract (2000 µg/plate) showed excellent antimutagenic activity (above 90%) against BaP in both TA98 and TA100 strains. The UR extract exhibited efficient DPPH (RC50 239.2 ± 16.5 µg/mL) and ABTS scavenging activity (RC50 458.7 ± 25.0 µg/mL). The UR extract (150 µg/mL) showed cytoprotective activity (65.6% ± 9.2%) against t-BHP. Among the subfractions, the EtOAC fraction possessed the strongest activities, overall. UR generally showed excellent biological activity at nontoxic concentrations (determined in vitro in current work), although the chemical composition of UR requires further investigation prior to its potential future use.

Evaluation of effects of Poincianella bracteosa (Tul.) L.P. Queiroz leaves in Allium cepa and Mus musculus

ABSTRACT Poincianella bracteosa (Tul.) L.P. Queiroz. (Fabaceae) traditionally is used in Brazilian medicine to treat catarrhal infections, diarrhea, hepatitis and anemia. We investigated the phytochemical profile, and mutagenicity and anti-mutagenicity of aqueous extracts of leaves of P. bracteosa in A. cepa cells and in mice. We investigated four concentrations of extract for the A. cepa bioassay and three doses of extract for administration to mice. For the A. cepa assay, we analyzed 5,000 meristematic cells to determine the mitotic index, mean number of chromosome alterations and percentage of damage reduction. For each animal assay, 2,000 normochromatic erythrocytes were evaluated per mouse to determine the number of micronuclei and the protective effect of the extract. Phytochemical analysis of the extract revealed reducing sugars, tannins and alkaloids, which likely did not interfere with the cell cycle of A. cepa or cause damage to the DNA of A. cepa or mice. The extract exhibited a protective effect in both organisms.

Assessment of Biological Toxicity and Ecological Safety for Urban Black-Odor River Remediation.

The judgment and assessment of remediation effect on urban black-odor river still depend on the physical-chemical parameters and lack in ecological safety effects. A set of combined biological toxicity tests were applied to evaluate the ecological effects of one urban black-odor river before and after the remediation. The special growth rate of Chlorella vulgaris and mortality rate of Daphnia magna were used to assess acute toxicity. The Salmonella Typhimurium/Reverse Mutation Assay was applied to test the mutagenicity. The tests by C. vulgaris growth showed that there was no inhibition before and after remediation by overlying water, in contrast promoted the growth of C. vulgaris. The tests by D. magna showed slight toxicity on site 3# before remediation and nontoxic after remediation. The mutagenicity of organic extracts from overlying water at all sampling sites were positive before remediation, but were eliminated after remediation except from 3 of 4 sites on TA98 strain. The addition of the liver microsomal S9 induced the positive mutagenicity on site 4# compared to S9 absence. The results clarified the applicable and the importance of the biological toxicity tests on assessing the remediation effect and potential ecological risk of urban black-odor river.

Effects of Limonium effusum Ethanol Extracts on Cell Proliferation and Mutagenicity

Abstract—Limonium plants have commonly used as antibacterial, styptical, anti-swelling agent, digestive system regulator, anticarcinogenic, and antiviral in alternative medicine. Beside this, different extracts of Limonium plants have mutagenic, cytotoxic and genotoxic effects. Different parts of Limonium effusum (Boiss.) Kuntze ethanol extracts were used to determine the mutagenic and cytotoxic effects. Ames test was carried out with Salmonella typhimurium TA98, and TA100 strains to determine the mutagenicity. Ames test results showed that root 1000 μg/plate of plant has mutagenic effect and root extracts have weak mutagenicity with TA98 strain. MTT test was carried out with MDBK (Madin-Darby Bovine Kidney) cells to determine the cytotoxicity. Cytotoxicity results showed that root 50, 25, 12.5 and 6.25 μg/mL extracts were increased the proliferation rates in 24 h treatment. All doses of root extracts decreased the rates in 96 h. All concentrations of stem decreased the proliferation rates in 96 h. Leaf extracts increased the rates in 24 h but decreased in 48, 72, and 96 h.

Development of transient mutagenic activity following the chlorination of the sunscreen UV filter dioxybenzone (benzophenone-8) in bromide-rich water.

The mutagenicity of four organic UV filters namely oxybenzone (benzophenone-3), dioxybenzone (benzophenone-8), avobenzone, and octyl methoxycinnamate, in chlorinated bromide-rich water (artificial seawater) was investigated. Mutagenicity was evaluated using Ames test in Salmonella typhimurium TA98 without S9 mix. Chemical analysis using high-resolution mass spectrometry was carried out to elucidate the mutagenic transformation products. Among the studied UV filters, only dioxybenzone exhibited a clear mutagenic activity following chlorination in seawater at ratio 1:10 (UV filter:chlorine). In contrast, no mutagenic activity was detected when chlorine was added at higher doses (ratio 1:1000). High-resolution mass spectrometry analysis showed that mutagenic extracts contained several brominated transformation products of dioxybenzone. Time course analysis of the transformation products at increasing chlorine doses showed that they were unstable and disappeared more quickly at higher chlorine doses. This instability explained the absence of mutagenic activity of dioxybenzone when 1000-fold excess chlorine was added, as no transformation products were detected. Relevance of these findings to the context of swimming pool is discussed. Further investigations taking into consideration the mutagenicity of not only the intermediate transformation products but also the final disinfection byproducts are needed to determine the overall impact of high levels of chlorine on the overall mutagenicity. This study highlights the importance of considering the reactivity of organic UV filters and their transformation products in disinfected recreational waters when sunscreen formulations are prepared.

Evaluation of cytotoxic potential, oral toxicity, genotoxicity, and mutagenicity of organic extracts of Pityrocarpa moniliformis

ABSTRACTThe objective of this study was to determine the cytotoxicity of organic extracts of P. moniliformis in vitro and identify the acute toxicity and genotoxicity in vivo. The leaves were extracted using three organic solvents (cyclohexane [EP1], ethyl acetate [EP2], and methanol [EP3]). Phytochemical qualitative analysis was performed by thin layer chromatography (TLC). Cytotoxicity tests were performed on human embryonic kidney (HEK) cells and J774 murine macrophages. Acute toxicity in mice was measured after intraperitoneal (ip) administration of 2000 mg/kg, while evaluation of genotoxicity and mutagenicity were assessed using the comet assay and the micronucleus (MN) test, respectively. The TLC analysis of the extracts revealed the presence of flavonoids, triterpenes, steroids, and saponins. In the cytotoxicity assay, extracts EP1 and EP3 altered proliferation of HEK cells, and all organic extracts increased the viability of J774 cells. In the toxicity tests, no deaths or behavioral alterations were observed in mice exposed to the acute dose of the extracts. Although some extracts led to changes in hematological and histological parameters, these results did not indicate physiological changes. In relation to the MN test and comet assay, no significant changes were detected in the DNA of the animals tested with the extracts EP1, EP2, and EP3. Thus, extracts of P. moniliformis were not considered to be toxic and did not induce formation of MN or damage to cellular DNA in the genotoxicity tests.

The mutagenicity of organic extracts in source water and peripheral water with different disinfection ways

This study aimed to determine mutagen contamination, to compare the differences between inlet and outlet distribution, and the possible impacts on public health. Water samples were collected from four different waterworks in Guangzhou, China. The Ames test was conducted to investigate the potential mutagenicity caused by organic extracts from drinking water sources and peripheral water. Organic content was extracted with XAD-2 resin column and organic solvents, and toxicity was tested in three doses of extract equivalent, 0.2, 0.4 and 0.8 L source water. The results of the Ames test showed that all the organic extracts from water samples could induce different levels of mutagenic potentials in the absence of S9 mix, which indicated mutagenicity and strain. Comparing with TA98, TA100 was more sensitive in genotoxicity. Mutagenic enhancement factors were found in both drinking water sources and peripheral water. Water treatment technologies with different disinfection ways could increase the mutagenicity of water, but the biological significance of mutagenicity of the organic extracts remained to be further confirmed. The results suggested that it was necessary to concern the relationship between source water, water treatment unit and the mutagenicity factors of water.

Toxicological evaluation of standardized Kaempferia parviflora extract: Sub-chronic and mutagenicity studies.

Kaempferia parviflora (KP), also known as Krachai-dam in Thailand, belongs to the family Zingiberaceae and has been used traditionally to improve blood flow and treat inflammatory, allergic, and gastrointestinal disorders. The objective of this study was to investigate the safety profile of a standardized hydroalcoholic KP rhizome extract via mutagenicity and sub-chronic toxicity evaluations using in vitro and in vivo techniques. The in vitro mutagenicity of KP extract was assessed via reverse mutation tests using Salmonella typhimurium TA98, TA100, TA1535, and TA1537, and Escherichia coli WP2 uvrA. The sub-chronic toxicity profile was evaluated after daily oral administration of KP extract to Sprague-Dawley rats for 90 days. General toxicological parameters were monitored weekly. After the treatment period, blood was collected for hematological and biochemical analyses and certain organs were removed for macroscopic and histopathological analyses. Reverse mutation tests revealed that KP extract did not induce gene mutations at any of the concentrations tested. In the sub-chronic toxicity test, a few changes were observed, including increased salivation in the animals administered high-dose KP extract (249 mg/kg body weight (bw)/day). No toxicologically relevant changes were observed in the biochemical analysis. Sub-chronic administration of KP extract increased platelet levels in animals administered low-dose KP extract (25 mg/kg bw/day). However, the hematological and biochemical parameters remained within normal physiological ranges for the animal species. No toxicological changes were observed in the macroscopic and histopathological analyses performed in this study. These results demonstrate that KP extract is not genotoxic and that 90-day oral administration of the doses tested did not result in toxicity. Therefore, KP extract has a high safety margin for daily use.

Safety assessment of Piper cernuum Vell. (Piperaceae) leaves extract: Acute, sub-acute toxicity and genotoxicity studies

Ethnopharmacological relevancePiper cernuum Vell (Piperaceae) is a native species from Atlantic rain forest, popularly known as pariparoba. Its leaves have been commonly used by rural and urban communities from State of São Paulo, Brazil, to treat pain (orally and topically), and hepatic and renal complications. Aim of the studyIn this study we evaluated the acute and sub-acute toxicity, genotoxicity and mutagenicity of hydroalcoholic extract obtained from P. cernuum leaf using in vivo and in vitro methods. Material and methodsIn the acute toxicity study, mice were orally treated with P. cernuum extract (2000 mg/kg, p.o.). General behavior and mortality were observed for up to 14 days. In the sub-acute toxicity study, P. cernuum extract was given orally as a single administration to the rats at doses of 50 or 250 mg/kg/day, for 28 days. General behavior, body weight, biochemical and hematological parameters, organ coefficients and pathological morphology were analyzed. The P. cernuum mutagenicity was evaluated using mammalian cell micronucleus assay. Additionally, in vitro toxicity profile of the extract was assessed through cytotoxicity, hemolytic activity, and genotoxicity assay. ResultsData from comet assay demonstrates that high concentrations of P. cernuum extract induce genotoxicity. However, no evidence of hemolytic, cytotoxic or mutagenicity activity was found. In addition, the acute and sub-acute toxicity studies did not show significant changes in body weight, general behavior, hematology and biochemical parameters, organ weight and liver and kidney histopathological analysis. ConclusionsTogether, the results herein obtained indicate that P. cernuum leaves extract did not present significant toxicity when administered to male or female rats. Additionally, no significant alteration in hematological, biochemical and morphological parameters were observed. Data obtained in vitro shows that extract did not present cytotoxicity and mutagenicity. However, the extract induces in vitro genotoxicity, but in high concentration. Further studies are necessary to evaluate the safety of long-term exposure to P. cernuum leaves extract added to in vivo genotoxicity.

Evaluation of genotoxicity and mutagenicity of aqueous extracts of Rhazya stricta Decne. and Thymus vulgaris L.

Traditional herbal medicines have been part of human healthcare systems since ancient times. The studies on herbal medicines have mainly focused on their beneficial aspects and hence their harmful effects have been usually overlooked. Throughout Middle East and South Asia, Rhazya stricta Decne. and Thymus vulgaris L. are used as traditional medicines for various diseases. We evaluated R. stricta and T. vulgaris aqueous extracts for their genotoxicity and mutagenicity through comet assay and Ames Salmonella mutagenicity test respectively. An overall treatment effect (p < 0.0001) showed higher genotoxicity of T. vulgaris extract indicated by increased tail moments in comet assay compared to the extract of R. stricta and the combined extract. Further, an overall dose effect (p < 0.0001) showed higher genotoxicity at 1 mg/ml which further increased at 5 mg/ml doses of the extracts compared to 0 mg/ml. The genotoxicity did not show any further increase at 10 mg/ml. The extracts were also tested for their mutagenicity through Ames Salmonella test. R. stricta and T. vulgaris were not mutagenic to TA100 and TA98 when extracts tested separately. However, combined extracts of R. stricta and T. vulgaris was weakly mutagenic to TA98 with number of revertants 92 ± 8 at the highest concentration tested. This study implies that the herbal medicines should be used cautiously as they may cause long term harmful effects along with the intended beneficial activity.

Assessment of the phenolic content, mutagenicity and genotoxicity of ethanolic extracts of stem bark and leaves from Strychnos pseudoquina A. St.-hil

Strychnos pseudoquina is a plant species whose stem bark is used as bitter tonic beverage. The phytochemical analysis, as well as quantification of phenolic constituents and antioxidant activity of ethanolic extracts from S. pseudoquina stem bark, and leaves were conducted. The extracts were tested for mutagenicity (Ames test) and DNA-damaging activity (Plasmid Cleavage test). Leaves recorded the largest amount of flavonoids. The performed high-performance liquid chromatography (HPLC) showed flavonoids such as isorhamnetin and strychnobiflavone (phytochemical markers of the investigated species) in stem barks, but not in leaves. The proanthocyanidin content and antioxidant activity were significantly higher in stem barks than in leaves. Stem bark and leaf extracts presented mutagenic activity against TA98 and TA100 strains with, and without, metabolic activation (S9). The Plasmid Cleavage test did not indicate DNA-damaging activity. Our results suggest that extracts deriving from S. pseudoquina should be used with extreme caution, mainly the stem bark extract, which is widely used in folk medicine.

A Simple and Effective Method for Extracting Potential Mutagens from Sediment Samples in the Classroom Laboratory Setting.

We describe a simple and effective method for the extraction of potential mutagens from sediment samples. This method is straightforward and does not require expensive laboratory equipment, thus enabling instructors to analyze the presence of mutagenic substances in a conventional classroom setting. Additionally, we found that students felt encouraged to add the Ames test to the list of analyses they traditionally employ with sediment samples. This link between the environment and the Ames test provided an authentic learning context for students, bridging the gap between the "real-world" and the classroom laboratory, and thus making the educational experience more engaging and meaningful.

Multidimensional Toxicity of Rhamnolipid Extracts Obtained From Creosote‐Contaminated Soil

In this study, a comprehensive research on the toxicity of rhamnolipids and their influence on the toxicity of water extracts obtained from creosote‐contaminated soil is performed. The obtained extracts contain organic compounds from the studied soil, which are eluted by pure water as well as solutions of rhamnolipids at different concentrations (ranging from 150 to 1500 mg L−1 where 150 mg L−1 corresponds with 1× critical micelle concentration (CMC). GC‐MS analyses allow for classification of the organic compounds into groups representing (i) 2‐ and 3‐ring polycyclic aromatic hydrocarbons (PAHs), (ii) 4‐ and 5‐ring PAHs, (iii) monoaromatic phenols, (iv) N‐heterocyclic compounds, and (v) other organic compounds. The addition of rhamnolipids reduces the elution of polar compounds and promoted the elution of hydrophobic compounds from soil (the elution of polycyclic hydrocarbons increases with increasing concentration of rhamnolipids). Moreover, HPLC‐MS analyses indicates a drop of the concentration of rhamnolipids compared to the initial concentration, suggesting a sorption of rhamnolipids on the soil matrix. Experiments regarding the toxicity toward activated sludge microorganisms (dehydrogenase activity assay), phytotoxicity (Phytotestkits), mutagenicity (Ames test), and cytotoxicity (MTT test) of extracts with and without rhamnolipids are also conducted. It is found that rhamnolipids increased the toxicity of the extracts toward microorganisms of activated sludge, phytotoxicity, cytotoxicity as well as mutagenicity toward Salmonella typhimurium TA 1537. The increasing toxicity in the presence of rhamnolipids can both be associated with increased bioavailability of toxic organic compounds as well as the toxicity of rhamnolipids.