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Melanoma is the most aggressive and lethal type of skin cancer, characterized by therapeutic resistance. In this context, the present study aimed to investigate the cytotoxic potential of manool, a diterpene from Salvia officinalis L., in human (A375) and murine (B16F10) melanoma cell lines. The analysis of cytotoxicity using the XTT assay showed the lowest IC

Made available in DSpace on 2021-06-26T04:30:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-03-17 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Copaifera langsdorffii Desf. is a plant found in South America, especially in Brazil. Oleoresin and the leaves of this plant is used as a popular medicinal agent. However, few studies on the chemical composition of aerial parts and related biological activities are known. This study aimed to examine the cytotoxic, genotoxic, and antigenotoxic potential of C. langsdorffii aerial parts hydroalcoholic extract (CLE) and two of its major compounds afzelin and quercitrin. The cytotoxic and antigenotoxic potential of CLE was determined as follows: 1) against genotoxicity induced by doxorubicin (DXR) or methyl methanesulfonate (MMS) in V79 cells; 2) by direct and indirect-acting mutagens in Salmonella typhimurium strains; and 3) by MMS in male Swiss mice. The protective effects of afzelin and quercitrin against DXR or MMS were also evaluated in V79 and HepG2 cells. CLE was cytotoxic as evidenced by clonogenic efficiency assay. Further, CLE did not induce a significant change in frequencies of chromosomal aberrations and micronuclei; as well as number of revertants in the Ames test demonstrating absence of genotoxicity. In contrast, CLE was found to be antigenotoxic in mammalian cells. The results also showed that CLE exerted inhibitory effect against indirect-acting mutagens in the Ames test. Afzelin and quercitrin did not reduce genotoxicity induced by DXR or MMS in V79 cells. However, treatments using afzelin and quercitrin decreased MMS-induced genotoxicity in HepG2 cells. The antigenotoxic effect of CLE observed in this study may be partially attributed to the antioxidant activity of the combination of major components afzelin and quercitrin. Univ Franca, Lab Mutagenese, Franca, SP, Brazil Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Sao Paulo, Brazil Univ Estadual Paulista, Fac Ciencias Farmaceut Araraquara, Araraquara, SP, Brazil Univ Estadual Paulista, Fac Ciencias Farmaceut Araraquara, Araraquara, SP, Brazil FAPESP: 2011/1360-7

Background: EGFR mutations are present in approximately 15–50% of non-small cell lung cancer (NSCLC), which are predictive of anti-EGFR therapies. At variance, NSCLC patients harboring KRAS mutations are resistant to those anti-EGFR approaches. Afatinib and allitinib are second-generation pan-EGFR drugs, yet no predictive biomarkers are known in the NSCLC context. In the present study, we evaluated the efficacy of pan-EGFR inhibitors in a panel of 15 lung cancer cell lines associated with the KRAS mutations phenotype. Methods: KRAS wild-type sensitive NCI-H292 cell line was further transfected with KRAS mutations (p.G12D and p.G12S). The pan-EGFR inhibitors’ activity and biologic effect of KRAS mutations were evaluated by cytotoxicity, MAPK phospho-protein array, colony formation, migration, invasion, and adhesion. In addition, in vivo chicken chorioallantoic membrane assay was performed in KRAS mutant cell lines. The gene expression profile was evaluated by NanoString. Lastly, everolimus and pan-EGFR combinations were performed to determine the combination index. Results: The GI50 score classified two cell lines treated with afatinib and seven treated with allitinib as high-sensitive phenotypes. All KRAS mutant cell lines demonstrated a resistant profile for both therapies (GI50 < 30%). The protein array of KRAS edited cells indicated a significant increase in AKT, CREB, HSP27, JNK, and, importantly, mTOR protein levels compared with KRAS wild-type cells. The colony formation, migration, invasion, adhesion, tumor perimeter, and mesenchymal phenotype were increased in the H292 KRAS mutated cells. Gene expression analysis showed 18 dysregulated genes associated with the focal adhesion-PI3K-Akt-mTOR-signaling correlated in KRAS mutant cell lines. Moreover, mTOR overexpression in KRAS mutant H292 cells was inhibited after everolimus exposure, and sensitivity to afatinib and allitinib was restored. Conclusions: Our results indicate that allitinib was more effective than afatinib in NSCLC cell lines. KRAS mutations increased aggressive behavior through upregulation of the focal adhesion-PI3K-Akt-mTOR-signaling in NSCLC cells. Significantly, everolimus restored sensibility and improved cytotoxicity of EGFR inhibitors in the KRAS mutant NSCLC cell lines.

Cervical cancer is the fourth most common cancer in women. Although cure rates are high for early stage disease, clinical outcomes for advanced, metastatic, or recurrent disease remain poor. To change this panorama, a deeper understanding of cervical cancer biology and novel study models are needed. Immortalized human cancer cell lines such as HeLa constitute crucial scientific tools, but there are few other cervical cancer cell lines available, limiting our understanding of a disease known for its molecular heterogeneity. This study aimed to establish novel cervical cancer cell lines derived from Brazilian patients. We successfully established one (HCB-514) out of 35 cervical tumors biopsied. We confirmed the phenotype of HCB-514 by verifying its' epithelial and tumor origin through cytokeratins, EpCAM and p16 staining. It was also HPV-16 positive. Whole-exome sequencing (WES) showed relevant somatic mutations in several genes including BRCA2, TGFBR1 and IRX2. A copy number variation (CNV) analysis by nanostring and WES revealed amplification of genes mainly related to kinases proteins involved in proliferation, migration and cell differentiation, such as EGFR, PIK3CA, and MAPK7. Overexpression of EGFR was confirmed by phospho RTK-array and validated by western blot analysis. Furthermore, the HCB-514 cell line was sensitive to cisplatin. In summary, this novel Brazilian cervical cancer cell line exhibits relevant key molecular features and constitutes a new biological model for pre-clinical studies., Barretos Cancer Hospital Research Support Department (NAP) for sample collection, Barretos Cancer Hospital Biobank for sample processing, Dr. Flávia de Paula and Gabriela Fernandes for technical support of STRs and BRCA2 Sanger validation, respectively, and Dr. Laura Musselwhite (Duke University) for revising the manuscript. This study was supported by grants from the FINEP (MCTI/FINEP/MS/SCTIE/DECIT-01/2013 - FPXII- BIOPLAT - Process number 01.13.0469.00) and Barretos Cancer Hospital. PhD scholarship from FINEP (Grant numbers 384088/2014-7 and 380434/2015-6) and Barretos Cancer Hospital to MNR.

Color Index (C.I.) Disperse Red 1 (DR1) is a widely used textile azo dye found in rivers. As it may not be completely removed by conventional treatments, humans can be exposed through drinking water. Studies have supported in vitro toxicity and mutagenicity of commercial DR1. This study aimed to investigate the mutagenic and toxicogenomic effects of commercial DR1 in multiple tissues/organs of Swiss male mice. For that, animals were orally exposed to the dye (by gavage), at single doses of 0.0005, 0.005, 0.5, 50, or 500 mg/kg bw. The two lowest doses were equivalent to the ones found in two Brazilian rivers receiving influx of textile discharges. Cytotoxicity, micronucleated cell frequencies (for all doses tested), primary DNA damage (comet assay), and gene expression profiling of (0.0005 and 0.005 mg/kg of bw) were investigated 24 hr after animal exposure to commercial DR1. Data showed increased frequencies of micronucleated polychromatic erythrocytes in bone marrow cells after treatment with 0.5 and 50 mg/kg bw. At 0.005 mg/kg bw, commercial DR1 induced an increase of primary DNA damage in liver, but not in kidney cells. Additionally, upregulation of genes involved in the inflammatory process (IL1B) (0.0005 and 0.005 mg/kg bw) and cell-cycle control (CDKN1A) in liver cells, and apoptosis (BCL2 and BAX) in leukocytes (0.005 mg/kg bw) were also detected. In conclusion, the commercial DR1 was genotoxic (chromosome aberrations and primary DNA damage) and modulated gene expression in mice, and such effects were dependent on the doses and tissues analyzed. Environ. Mol. Mutagen. 59:822-828, 2018. © 2018 Wiley Periodicals, Inc.

Rosmarinic acid (RA) is a polyphenolic compound that shows a number of interesting biological activities, such as antiapoptotic, antifibrotic, antioxidant, hepatoprotective, antineurodegenerative, and anti-inflammatory properties. The aim of this study was to investigate the ability of RA to prevent 1,2-dimethylhydrazine (DMH)-induced primary DNA damage and aberrant crypt foci (ACF) in Wistar rat colon. The animals were treated by gavage with doses of 4, 8, and 16 mg/kg body weight/day. Next, the animals received a single subcutaneous injection of 40 mg/kg DMH and were killed 4 h later for the evaluation of DNA damage using the comet assay. In addition, two doses of 40 mg/kg DMH were administered weekly for 2 weeks and the animals were killed 2 weeks after the last injection for the evaluation of ACF formation in rat colon. The results showed that RA exerted no genotoxic/carcinogenic effects. Treatment with different doses of RA combined with DMH led to a significant reduction in the extent of DNA damage and in the frequency of ACF compared with animals treated with DMH alone. These findings suggest that RA reduces DNA damage and suppresses the formation of ACF.

Salvia officinalis (sage) is a perennial woody subshrub native to the Mediterranean region that is commonly used as a condiment and as an anti-inflammatory, antioxidant and antimicrobial agent due to its biological activities. Manool is the most abundant micro-metabolite found in Salvia officinalis essential oils and extracts. We therefore decided to evaluate the cytotoxic, genotoxic and antigenotoxic potential of manool in Chinese hamster lung fibroblasts (V79) and human hepatoma cells (HepG2). Cytotoxicity was assessed by the colony-forming assay in V79 cells and toxic effects were observed at concentrations of up to 8.0 μg/mL. The micronucleus test was used to evaluate the genotoxicity and antigenotoxicity of manool in V79 and HepG2 cells at concentrations of 0.5-6.0 μg/mL and 0.5-8.0 μg/mL, respectively. For evaluation of antigenotoxicity, the concentrations of manool were combined with methyl methanesulfonate (MMS, 44 μg/mL). The results showed a significant increase in the frequency of micronuclei in cultures of both cell lines treated with the highest concentration tested, demonstrating a genotoxic effect. On the other hand, manool exhibited a protective effect against chromosome damage induced by MMS in HepG2 cells, but not in V79 cells. These data suggest that some manool metabolite may be responsible for the antigenotoxic effect observed in HepG2 cells.

Usnic acid is one of the most common and abundant metabolites found in various lichen genera, which are important sources of biologically active compounds. The aim of this study was to evaluate the genotoxic and antigenotoxic potential of (+)-usnic acid (UA) by the micronucleus and comet assays in V79 cell cultures and Swiss mice. For assessment of genotoxicity, V79 cells were treated with 15, 30, 60, and 120μg/mL UA, established based on clonogenic efficiency cytotoxic assay. Swiss mice were treated with UA doses of 25, 50, 100, and 200mg/kg body weight. The same concentrations of UA were combined with methyl methanesulfonate (MMS) for evaluation of antigenotoxicity. The in vitro results demonstrated that UA induced DNA damage at concentrations of 60 and 120μg/mL in the comet assay. However, no genotoxic effect was observed in the micronucleus test using V79 cells at the concentrations tested. No genotoxic effects were observed for the different UA treatments in in vivo test system. Combined administration of UA and MMS significantly reduced the frequencies of micronuclei and DNA damage in vitro and in vivo when compared to treatment with MMS alone. Although the mechanisms underlying the protective effect of UA are not completely understood, the antioxidant activity of this metabolite may explain its protective effect against MMS-induced genotoxicity.

(-)-Cubebin (CUB) is a lignan isolated from dry seeds of Piper cubeba. We aimed to assess its genotoxic potential and influence on chromosomal damage (frequency of micronuclei - MN) induced by doxorubicin (DXR) in V79 cells and by urethane (URE) in somatic Drosophila melanogaster cells. Our findings indicate an absence of a CUB-mediated genotoxic effect at the concentrations tested. The results also revealed that CUB significantly reduced the frequency of MN induced by DXR, with a mean reduction of 63.88%. In a previous study, our research group demonstrated an absence of CUB-mediated mutagenic effects through the wing Somatic Mutation and Recombination Test (SMART) in Drosophila. In the present study, we used the standard and high bioactivation versions of the SMART to estimate the antigenotoxic effects of CUB associated with URE. At lower concentrations, the recombination level decreased, but at the highest concentration, the recombination level increased. Our data and previous studies suggest that CUB may act as a free radical scavenger at low concentrations, a pro-oxidant at higher concentrations when it interacts with the enzymatic system that catalyzes the metabolic detoxification of DXR or URE, and/or an inducer of recombinational DNA repair.

Copaifera lansdorffii Desf. is known as 'copaiba', 'copaiva' or 'pau-de-oleo', and is found in part of Brazil. The present study was undertaken to evaluate the genotoxic potential of C. langsdorffii leaf hydroalcoholic extract (CLE) and its influence on the genotoxicity induced by the chemotherapeutic agent doxorubicin (DXR) using the Swiss mouse peripheral blood micronucleus test. HPLC analysis of CLE using two monolithic columns linked in series allowed quantification of two major flavonoid heterosides, quercitrin and afzelin. Animals were treated with CLE by gavage at doses of 10, 20, 40 and 80mg kg � 1 body weight per day, each for 20days. Peripheral blood samples were collected at 24 and 48h, and 7, 15 and 21days after the beginning of the treatment. For the antigenotoxicity evaluation, the animals treated with different concentrations of CLE received DXR (15mgkg � 1 body weight, intraperitoneal) at day 20. The peripheral blood samples were collected 24 and 48h after the treatment with DXR. The results demonstrated that CLE itself was not genotoxic in the mouse micronucleus assay. In animals treated with CLE and DXR, the number of micronucleus was significantly decreased compared with animals receiving DXR alone. The putative antioxidant activity of one or more of the active compounds of CLE may explain the effect of this plant on DXR genotoxicity. Copyright © 2012 John Wiley & Sons, Ltd.

Solanum lycocarpum A. St. Hil. (Solanaceae) is a hairy shrub or small much-branched tree of the Brazilian Cerrado. S. lycocarpum fruits are commonly used in traditional medicine in powder form or as folk preparations for the treatment of diabetes and obesity, as well as for controlling cholesterol levels. The aim of the present study was to chemically characterize the hydroalcoholic extract (SL) of S. lycocarpum by determination of total flavonoids and total poyphenols and quantification of steroidal alkaloids, as well as to evaluate its mutagenic and/or antimutagenic potential on V79 cells and Swiss mice using chromosomal aberrations and bone marrow micronucleus assays, respectively. Three concentrations of SL (16, 32, and 24 µg/mL) were used for the evaluation of its mutagenic potential in V79 cells and four doses (0.25, 0.50, 1.0, and 2.0 g/kg body weight) were used for Swiss mice. In the antimutagenicity assays, the different concentrations of SL were combined with the chemotherapeutic agent doxorubicin (DXR). HPLC analysis of SL gave contents of 6.57 % ± 0.41 of solasonine and 4.60 % ± 0.40 of solamargine. Total flavonoids and polyphenols contents in SL were 0.04 and 3.60 %, respectively. The results showed that not only SL exerted no mutagenic effect, but it also significantly reduced the frequency of chromosomal aberrations induced by DXR in both V79 cells and micronuclei in Swiss mice at the doses tested.

Betulinic acid (BA) is a pentacyclic triterpene that can be isolated from many medicinal plants around the world. The aim of this study was to evaluate the genotoxic potential of BA and its effect on the genotoxicity induced by different mutagens in V79 cells using the cytokinesis-block micronucleus assay. Different BA concentrations were combined with methyl methanesulfonate (MMS), doxorubicin (DXR), camptothecin (CPT), and etoposide (VP-16). The frequencies of micronuclei in cultures treated with different BA concentrations did not differ from those of the negative control. Treatment with BA and MMS resulted in lower micronucleus frequencies than those observed for cultures treated with MMS alone. On the other hand, a significant increase in micronucleus frequencies was observed in cultures treated with BA combined with DXR or VP-16 when compared to these mutagens alone. The results showed no effect of BA on CPT-induced genotoxicity. Therefore, BA was not genotoxic under the present experimental conditions and exerted a different influence on the genotoxicity induced by different mutagens. The modulatory effect of BA depends on the type of mutagen and concentrations used.

Baccharis dracunculifolia DC (Asteraceae), a native plant from Brazil, have been used as an antipyretic, stomachic and health tonic in Brazil. The objective of the present study was to investigate the potential mutagenic effect of B. dracunculifolia ethyl acetate extract (Bd-EAE) and its influence on the mutagenicity induced by the chemotherapeutic agent doxorubicin (DXR) using the rat bone marrow and peripheral blood micronucleus test. Wistar rats were divided into 10 treatment groups. Five groups received DXR (90 mg/kg body weight, b.w., intraperitoneally) to induce mutagenicity and three of these groups received a single oral dose of Bd-EAE at a concentration of 6, 12 or 24 mg/kg b.w. prior to DXR administration. A vehicle-treated control group and Bd-EAE control groups were also included. The results showed that Bd-EAE itself was not mutagenic, in the rat micronucleus assay. In animals treated with Bd-EAE and DXR, the number of MNPCEs was significantly decreased compared to animals receiving DXR alone. HPLC analysis of the extract obtained permitted the identification of the following phenolic compounds: caffeic acid, p-coumaric acid, aromadendrin-4'O-methyl ether, 3-prenyl-p-coumaric acid (drupanin), 3,5-diprenyl-p-coumaric acid (artepillin C) and baccharin. The putative antioxidant activity or the interference of one or more of the active compounds of Bd-EAE with mutagenic metabolic pathways may explain its effect on DXR mutagenicity.

Manool, a diterpene isolated from Salvia officinalis, was evaluated by the XTT colorimetric assay for cytotoxicity and selectivity against different cancer cell lines: B16F10 (murine melanoma), MCF-7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), HepG2 (human hepatocellular carcinoma), and MO59J, U343 and U251 (human glioblastoma). A normal cell line (V79, Chinese hamster lung fibroblasts) was used to compare the selectivity of the test substance. Manool exhibited higher cytotoxic activity against HeLa (IC50 = 6.7 ± 1.1 µg/mL) and U343 (IC50 = 6.7 ± 1.2 µg/mL) cells. In addition, in the used experimental protocols, the treatment with manool was significantly more cytotoxic for different tumor cell lines than for the normal cell line V79 (IC50 = 49.3 ± 3.3 µg/mL), and showed high selectivity. These results suggest that manool may be used to treat cancer without affecting normal cells.

The fruits of Solanum lycocarpum, known as wolf-fruit, are used in folk medicine, and because of that we have evaluated both the genotoxic potential of its glycoalkaloidic extract (SL) and its influence on the genotoxicity induced by methyl methanesulfonate. Furthermore, the potential blocking effect of SL intake in the initial stage of colon carcinogenesis in Wistar rats was investigated in a short-term (4-week) bioassay using aberrant crypt foci (ACF) as biomarker. The genotoxic potential was evaluated using the Swiss mice peripheral blood micronucleus test. The animals were treated with different doses of SL (15, 30 and 60 mg/kg b.w.) for 14 days, and the peripheral blood samples were collected at 48 h, 7 days and 14 days after starting the treatment. For antigenotoxicity assessment, MMS was administered on the 14th day, and after 24 h the harvesting of bone marrow and liver cells was performed, for the micronucleus and comet assays, respectively. In the ACF assay, male Wistar rats were given four subcutaneous injections of the carcinogen 1,2-dimethylhydrazine (DMH, 40 mg/kg b.w.), twice a week, during two weeks to induce ACF. The treatment with SL (15, 30 and 60 mg/kg b.w.) was given for four weeks during and after carcinogen treatment to investigate the potential beneficial effects of SL on DMH-induced ACF. The results demonstrated that SL was not genotoxic in the mouse micronucleus test. In animals treated with SL and MMS, the frequencies of micronucleus and extensions of DNA damage were significantly reduced in comparison with the animals receiving only MMS. Regarding the ACF assay, SL significantly reduced the frequency of ACF induced by DMH.

Baccharis dracunculifolia (Asteraceae), the main botanical source of green propolis, also known as 'alecrim-do-campo' and 'vassourinha', is a shrub of the Brazilian 'cerrado' and is native to the South and Southeast of Brazil. The effects of B. dracunculifolia ethyl acetate extract (Bd-EAE) were evaluated on the 1,2-dimethylhydrazine (DMH)-induced DNA damage and aberrant crypt foci (ACF) in the colon of male Wistar rats by the comet and ACF assays, respectively. The animals were treated by gavage with doses of 6, 12, and 24 mg/kg body weight/day. Animals were also administered a single subcutaneous injection of 40 mg/kg DMH and were killed after 4 h for evaluation of DNA damage. Also, two doses of 40 mg/kg of DMH were administered weekly for 2 weeks, and animals were killed 2 weeks after the last injection for evaluation of ACF development in the colon. The results showed a significant reduction in the frequency of DNA damage and ACF in the group treated with the Bd-EAE plus DMH in comparison with those treated with DMH alone, suggesting that Bd-EAE reduced DNA damage and suppressed the formation of ACF and also exerted a protective affect against colon carcinogenesis.

This study evaluated the antiproliferative activity of the Brazilian green propolis and Baccharis dracunculifolia extracts and their major compounds artepillin C and baccharin in different tumor cell lines. The lowest IC50 values observed for Brazilian green propolis and B. dracunculifolia extracts were 41.0 ± 4.5 µg/mL for U343 and 44.9 ± 7.1 µg/mL for HepG2, respectively. Regarding artepillin C and baccharin, the lowest IC50 values were 20.1 ± 2.9 for U343 and 13.0 ± 1.5 µg/mL for B16F10, respectively. For the association of artepillin C plus baccharin, the lowest IC50 result was 35.2 ± 0.5 µg/mL for B16F10. Artepillin C and baccharin were more cytotoxic than both Brazilian green propolis and B. dracunculifolia extracts. No additive or synergistic effect was observed for the association of artepillin C plus baccharin.

Natural products are some of the important sources of new anticancer drugs. The Brazilian flora is considered one of the most diverse in the word, although not many large-scale pharmacological and phytochemical studies have been conducted to date. With this in mind, in the present study we evaluated the antiproliferative activity of Solanum lycocarpum fruit glycoalkaloid extract (SL) and its major compounds, solamargine (SM) and solasonine (SS), against different tumor cell lines: murine melanoma (B16F10), human colon carcinoma (HT29), human breast adenocarcinoma (MCF-7), human cervical adenocarcinoma (HeLa), human hepatocellular liver carcinoma (HepG2) and human glioblastoma (MO59J, U343 and U251). The antiproliferative activity was evaluated using XTT assay and results were expressed as IC50. The most pronounced antiproliferative activity was observed for SM, with IC50 values ranging from 4.58 to 18.23 μg/mL. The lowest IC50 values were observed against HepG2, being 9.60 μg/mL for SL, 4.58 μg/mL for SM and 6.01 μg/mL for SS. Thus, SL, SM and SS demonstrated antiproliferative activity against the tumor cell lines tested, and were most effective against the HepG2 cell line.

Solanum lycocarpum St.-Hil (Solanaceae) is a hairy shrub or small much-branched tree of the Brazilian Cerrado, popularly known as “fruit-of-wolf”. Considering that the induction of chromosomal mutations is involved in the process of carcinogenesis, and that S. lycocarpum is often used in folk medicine, it becomes relevant to study its effect on genetic material. In this sense, the aim of present study was to determine the possible cytotoxic, genotoxic and antigenotoxic potentials of S. lycocarpum fruits glycoalkaloid extract (SL) in Chinese hamster lung fibroblasts (V79 cells). The cytotoxicity was evaluated by the colony forming assay, apoptosis and necrosis assay, Trypan blue exclusion dye method and mitotic index. Genotoxic and antigenotoxic potential were evaluated by comet and chromosomal aberrations assays. Four concentrations of SL (4, 8, 16 and 32μg/mL) were used for the evaluation of its genotoxic potential. The DNA damage-inducing agent methyl methanesulfonate (MMS, 22μg/mL) was utilized in combination with extract to evaluate a possible protective effect. The results showed that SL was cytotoxic at concentrations above 32μg/mL by the colony forming assay. For apoptosis and necrosis assay, the concentration of 64μg/mL of SL showed statistically significant increase in cell death by apoptosis and necrosis, while the concentrations of 128 and 256μg/mL of SL demonstrated statistically significant increase in cell death by necrosis, compared with the control group. Analysis of cell viability by Trypan blue exclusion indicated >96% viability for treatments with concentrations up to 32μg/mL of SL. No significant differences in MI were observed between cultures treated with different concentrations of SL (4, 8, 16 and 32μg/mL) alone or in combination with MMS and the negative control, indicating that these treatments were not cytotoxic. The comet and chromosomal aberrations assays revealed that SL does not display genotoxic activity. Moreover, the different concentrations of SL showed protective effect against both genomic and chromosomal damages induced by MMS.

Copaifera lansdorffii Desf. is known as 'copaíba', 'copaiva' or 'paú-de-óleo', and is found in part of Brazil. The present study was undertaken to evaluate the genotoxic potential of C. langsdorffii leaf hydroalcoholic extract (CLE) and its influence on the genotoxicity induced by the chemotherapeutic agent doxorubicin (DXR) using the Swiss mouse peripheral blood micronucleus test. HPLC analysis of CLE using two monolithic columns linked in series allowed quantification of two major flavonoid heterosides, quercitrin and afzelin. Animals were treated with CLE by gavage at doses of 10, 20, 40 and 80 mg kg(-1) body weight per day, each for 20 days. Peripheral blood samples were collected at 24 and 48 h, and 7, 15 and 21 days after the beginning of the treatment. For the antigenotoxicity evaluation, the animals treated with different concentrations of CLE received DXR (15 mg kg(-1) body weight, intraperitoneal) at day 20. The peripheral blood samples were collected 24 and 48 h after the treatment with DXR. The results demonstrated that CLE itself was not genotoxic in the mouse micronucleus assay. In animals treated with CLE and DXR, the number of micronucleus was significantly decreased compared with animals receiving DXR alone. The putative antioxidant activity of one or more of the active compounds of CLE may explain the effect of this plant on DXR genotoxicity.

Baccharis dracunculifolia (Asteraceae), the main botanical source of green propolis, is a shrub of the Brazilian 'cerrado'. In folk medicine it is used as an anti-inflammatory agent, mainly for the treatment of gastrointestinal diseases. The aim of the present study was to evaluate the genotoxic and antigenotoxic effects of B. dracunculifolia ethyl acetate extract (Bd-EAE) on Chinese hamster lung fibroblasts (V79 cells) by the comet assay. Methyl methanesulfonate (MMS; 200 microM) was used as an inducer of DNA damage. Genotoxicity was evaluated using four different concentrations of Bd-EAE: 12.5, 25.0, 50.0 and 100.0 microg ml(-1). Antigenotoxicity was assessed before, simultaneously, and after treatment with the mutagen. The results showed a significant increase in the frequency of DNA damage in cultures treated with 50.0 and 100.0 microg ml(-1) Bd-EAE. Regarding its antigenotoxic potential, Bd-EAE reduced the frequency of DNA damage induced by MMS. However, this chemopreventive activity depended on the concentrations and treatment regimens used. The antioxidant activity of phenolic components present in Bd-EAE may contribute to reduce the alkylation damage induced by MMS. In conclusion, our findings confirmed the chemopreventive activity of Bd-EAE and showed that this effect occurs under different mechanism.