Evaluation of the in vitro schistosomicidal, leishmanicidal, and trypanocidal activities of the capsaicin metabolite, Capsicum frutescens, and Capsicum baccatum extracts and of their analysis of the main constituents by HPLC/UV and CG/MS.

Neglected tropical diseases are significant causes of death and temporary or permanent disability for millions living in developing countries. Unfortunately, there is no effective treatment for these diseases. Thus, this work aimed to conduct a chemical analysis using HPLC/UV and GC/MS to identify the major constituents of the hydroalcoholic extracts of Capsicum frutescens and Capsicum baccatum fruits, evaluating these extracts and their constituents' schistosomicidal, leishmanicidal and trypanocidal activities. The results obtained for the extracts of C. frutescens are better when compared to those obtained for C. baccatum, which can be related to the different concentrations of capsaicin (1) present in the extracts. The lysis of trypomastigote forms results for capsaicin (1) led to a significant value of IC50 = 6.23 µM. Thus, the results point to capsaicin (1) as a possible active constituent in these extracts.

HPLC method for quantifying verbascoside in Stizophyllum perforatum and assessment of verbascoside acute toxicity and antileishmanial activity.

We report the chemical composition of the crude leaf extracts obtained from Stizophyllum perforatum (Cham.) Miers (Bignoniaceae), a simple high-performance liquid chromatography-diode array detection (HPLC-DAD) method based on mangiferin as an internal standard to quantify verbascoside, and the verbascoside acute oral toxicity and antileishmanial activity. HPLC-high-resolution mass spectrometry-DAD (HPLC-HRMS-DAD) analyses of the crude ethanol S. perforatum leaf extracts (CE-1 and CE-2) revealed that verbascoside was the major constituent in both extracts. CE-1 was purified, and verbascoside and casticin, among other compounds, were isolated. The developed HPLC-DAD method was validated and met the required standards. Investigation of the CE-2 acute toxicity indicated a lethal dose (LD50) greater than 2,000 mg/kg of body weight. Both CE-1 and CE-2 exhibited antileishmanial activity. The isolated compounds, verbascoside and casticin, also displayed antileishmanial activity with effective concentrations (IC50) of 6.23 and 24.20 µM against promastigote forms and 3.71 and 18.97 µM against amastigote forms of Leishmania amazonensis, respectively, but they were not cytotoxic to J774A.1 macrophages. Scanning electron microscopy of the L. amazonensis promastigotes showed that the parasites became more rounded and that their plasma membrane was altered in the presence of verbascoside. Additionally, transmission electron microscopy demonstrated that vacuoles emerged, lipids accumulated, kinetoplast size increased, and interstitial extravasation occurred in L. amazonensis promastigotes exposed to verbascoside. These findings suggest that S. perforatum is a promising candidate for further in vivo investigations against L. amazonensis.

Metabolic response induced by abiotic elicitors in Anacardium othonianum seedlings.

Applying elicitors in plants growing under natural conditions change the metabolic content of volatile compounds extracted from their tissues. Here, we have investigated how abiotic elicitors influence the volatile composition of the ethyl acetate extract of Anacardium othonianum seedlings propagated in vitro and ex-vitro cultures. Abiotic factors such as salicylic acid, silver nitrate, light quality, and cultivation mode affected the composition of volatile compounds in ethyl acetate extract of A. othonianum leaves seedlings. GC/MS analysis demonstrated that α-tocopherol was the main metabolite in cultures added with chemical elicitors, reaching 22.48 ± 4.06% in the case of 30 µM salicylic acid. Higher concentrations of salicylic acid decreased the amount of α-tocopherol. The addition of AgNO3 had a linear effect on α-tocopherol. Thus, the production of this metabolite indicates that salicylic acid and AgNO3 elicitors positively affect α-tocopherol production at specific concentrations helping to understand how plant culture can be better manipulated.

In vivo evaluation of analgesic and anti-inflammatory activity of hydroalcoholic extracts from Handroanthus impetiginosus and their chemical composition by UPLC/MS analysis.

This study demonstrates in vivo analgesic and anti-inflammatory properties of hydroalcoholic extracts of leaves, bark and flowers from the Handroanthus impetiginosus (Bignoniaceae) plant, recognized as 'Ipê roxo' in Brazil. The extracts were evaluated in male Swiss albino mice via oral administration. Moreover, results of the in vivo paw oedema test induced by carrageenan revealed that extracts of leaves and bark displayed relevant anti-inflammatory activity potential at the dosage of 100 mg/kg, 300 mg/kg, and 500 mg/kg. Likewise, the results obtained for leaves and flowers extracts suggested potent analgesic action in the conventional hot plate test. UPLC/MS analysis of the hydroalcoholic extracts samples identified metabolites belonging to several classes, mainly naphthoquinones and iridoids derivatives as well as flavonoids. Thus, the obtained results indicate that the extracts of H. impetiginosus plant parts could be considered as a complementary herbal medicine for the treatment of pain and inflammation disorders.

In vivo study of anti-inflammatory and antinociceptive activities of Copaifera pubiflora Benth oleoresin.

Copaifera pubiflora Benth oleoresin (CPO) is used as an anti-inflammatory, wound healing, and antimicrobial. This paper reports the cytotoxic, anti-inflammatory, and antinociceptive activities of CPO. CPO (10 mg/kg) did not affect locomotor capacity in the open-field and rotarod tests and was not cytotoxic to CHO-k1, THP-1, and L929 cell lines. It was active in the formalin test at 3 mg/kg by 86 ± 3% and 96 ± 3%, respectively, for the first and second phases. At 10 mg/kg, CPO inhibited 90 ± 7%, the pain in the mechanical hyperalgesia test. In the tail-flick test, CPO at 3 mg/kg affected the tail-flick latencies in mice by 77 ± 20%, which in combination with naloxone was only partially reduced. At 3 mg/kg CPO inhibited 80 ± 12% the carrageenan-induced paw edema, and at 3 mg/kg it reduced by 91 ± 5% the nociception on acetic acid-induced abdominal writhing. Therefore, CPO possesses anti-inflammatory and antinociceptive activities.

Chemical study of Adenocalymma axillarum crude leaf extract and isolated compounds

Abstract Adenocalymma axillarum (K.Schum.) L.G. Lohmann is a liana belonging to the family Bignoniaceae. In traditional medicine, the genus Adenocalymma is used to treat fever, skin ailments, and body, joint, and facial muscle pains, and it is also applied as cosmetic. Biological assays conducted with the A. axillarum crude leaf ethanol extract have indicated leishmanicidal activity and absence of cytotoxicity. This study aimed to analyze the A. axillarum leaf ethanol crude extract by high-performance liquid chromatography-high-resolution mass spectrometry- diode array detector (HPLC-HRMS-DAD) and to evaluate the leishmanicidal and cytotoxic activities of this crude extract, its fractions, and isolated compounds. HPLC-HRMS-DAD analysis of this extract revealed that it consisted mainly of flavonoids, with nine major compounds. Extract purification yielded 4-hydroxy-N-methylproline, 6-β-hydroxyipolamiide, quercetin-3-O-robinobioside, hyperin, isorhamnetin-3-O-robinobioside, and 3'-O-methylhyperin, which were identified by Nuclear Magnetic Resonance. The isolated compounds were inactive against Leishmania amazonensis promastigotes and human lung fibroblast cells.

Influence of Asiatic acid on cell proliferation and DNA damage in vitro and in vivo systems.

Asiatic acid (AA) is a triterpene with promising pharmacological activity. In the present study, in vitro and in vivo assays were conducted to understand the effect of AA on cell proliferation and genomic instability. AA was cytotoxic to human tumor cell lines (M059J, HeLa, and MCF-7), with IC50 values ranging from 13.91 to 111.72 µM. In the case of M059J, AA exhibited selective cytotoxicity after 48 h of treatment (IC50 = 24 µM), decreasing the percentage of cells in the G0/G1 phase, increasing the percentage of cells in the S phase, and inducing apoptosis. A significant increase in chromosomal damage was observed in V79 cell cultures treated with AA (40 µM), revealing genotoxic activity. In contrast, low concentrations (5, 10, and 20 µM) of AA significantly reduced the frequencies of micronuclei induced by the mutagens doxorubicin (DXR), methyl methanesulfonate, and hydrogen peroxide. A reduction of DXR-induced intracellular free radicals was found in V79 cells treated with AA (10 µM). The antigenotoxic effect of AA (30 mg/kg) was also observed against DXR-induced chromosomal damage in Swiss mice. Significant reductions in p53 levels were verified in the liver tissue of these animals. Taken together, the data indicate that AA exerted antiproliferative activity in M059J tumor cells, which is probably related to the induction of DNA damage, leading to cell cycle arrest and apoptosis. Additionally, low concentrations of AA exhibited antigenotoxic effects and its antioxidant activity may be responsible, at least in part, for chemoprevention.

Betulinic acid modulates urethane-induced genotoxicity and mutagenicity in mice and Drosophila melanogaster.

Betulinic acid (BA) is a pentacyclic triterpenoid found in several plant species. Urethane (URE) is a known promutagen. Here, we examine the genotoxicity and mutagenicity of BA alone or in combination with URE using the bone marrow micronucleus assay in mice bone marrow cells and the Somatic Mutation and Recombination Test in Drosophila melanogaster. Findings revealed that BA alone was not genotoxic, but reduced the frequency of micronucleus when compared to the positive control. No significant differences were observed in the cytotoxicity. Biochemical analyzes showed no significant differences for liver (AST and ALT) or renal (creatinine and urea) function parameters, indicating the absence of hepatotoxic and nephrotoxic effects. BA alone did not increase the frequency of mutant spots, but reduced the total frequency of mutant spots when co-administered with URE in both ST and HB crosses. In addition, BA reduced the recombinogenic effect of URE at the highest concentrations of both crosses. In conclusion, under experimental conditions, BA has modulatory effects on the genotoxicity induced by URE in mice, as well as in somatic cells of D. melanogaster. We suggest that the modulatory effects of BA may be mainly due to its antioxidant and apoptotic properties.

(±)-Licarin A and its semi-synthetic derivatives: In vitro and in silico evaluation of trypanocidal and schistosomicidal activities.

This paper reports the synthesis of (±)-licarin A 1, a dihydrobenzofuran neolignan, resultant of an oxidative coupling reaction of isoeugenol and horseradish peroxidase (HRP) enzyme. Following, three semi-synthetic derivatives from this compound were obtained: benzylated (±)-licarin A 2, methylated (±)-licarin A 3 and acetylated (±)-licarin A 4. After structural elucidation and assignment by Nuclear Magnetic Resonance of 1H, 13C and DEPT, all compounds were evaluated in vitro against Trypomastigote forms of Trypanosoma cruzi (T. cruzi), the etiologic agent of Chagas disease, and Schistosoma mansoni (S. mansoni) worms, the etiologic agent of schistosomiasis. Compound (4) was the most active against S. mansoni adult worms, displaying worm viability reduction at 25 µM and mortality of all worms at 100 and 200 µM within 24 h. Compound 1 was the second most active, showing worm viability reduction at 50 µM and mortality of 25% and 100% of worms in 24h at concentrations of 100 and 200 µM, respectively. In addition, theoretical calculations aiming at finding molecular properties that showed the correlation for schistosomicidal and trypanocidal activities of (±)-licarin A and three of its semi-synthetic derivatives were also performed.

Usnic acid attenuates genomic instability in Chinese hamster ovary (CHO) cells as well as chemical-induced preneoplastic lesions in rat colon.

Usnic acid (UA) is one of the pharmacologically most important compounds produced by several lichen species. To better understand the mechanism of action (MOA) of this important substance, this study examined the genotoxicity attributed to UA and its influence on mutagens with varying MOA using the micronucleus (MN) test in Chinese hamster ovary cells (CHO). Additional experiments were conducted to investigate the effect of UA on colon carcinogenesis in Wistar rats employing the aberrant crypt focus (ACF) assay. In vitro studies showed a significant increase in the frequency of MN in cultures treated with the highest UA concentration tested (87.13 µM). In contrast, UA concentrations of 10.89, 21.78, or 43.56 µM produced an approximate 60% reduction in chromosomal damage induced by doxorubicin, hydrogen peroxide, and etoposide, indicating an antigenotoxic effect. In the ACF assay, male Wistar rats treated with different UA doses (3.125, 12.5, or 50 mg/kg b.w.) and with the carcinogen 1,2-dimethylhydrazine exhibited a significantly lower incidence of neoplastic lesions in the colon than animals treated only with the carcinogen. Data suggest that the MOA responsible for the chemopreventive effect of UA may be related to interaction with DNA topoisomerase II and/or the antioxidant potential of the compound.

Effect of salicylic acid and silver nitrate on rutin production by Hyptis marrubioides cultured in vitro / Efeito do ácido salicílico e nitrato de prata na produção de rutina por Hyptis marrubioides cultivada in vitro

ABSTRACT: Hyptis marrubioides (Lamiaceae) is a medicinal plant that is native from Brazilian Cerrado. In vitro propagation techniques make use of elicitors to alter metabolic pathways, affecting how molecules are produced both qualitatively and quantitatively. This research aimed to evaluate how abiotic elicitors salicylic acid (SA) and silver nitrate (SN) at concentrations of 30µM or 60µM influence Hyptis marrubioides seedling growth by two different in vitro culture methods. The rutin content was quantified by HPLC-DAD. Compared to an untreated culture, the H. marrubioides methanolic extracts cultured in MS medium for 10 days followed by culture in MS medium containing SN (30µM) for 20 days had 1.28 times higher rutin content. In a second experiment, seedlings were cultured in MS medium for 20 days, and then the desired elicitor was added to the culture and allowed to remain in contact with the medium for three and six days. SA (30µM) gave the best results: rutin production was 16.56-foldhigher than the control after six days. SN (30µM) increased the rutin content by 1.17-fold. At the two concentrations evaluated during the elicitation experiments, neither SA nor SN altered the growth parameters shoot length, leaf number, and fresh and dry weight of H. marrubioides seedlings grown in vitro as compared to the control. Based on these results, the abiotic elicitors SA and SN successfully provide Hyptis marrubioides with increased rutin content in vitro.

RESUMO: Hyptis marrubioides (Lamiaceae) é uma planta medicinal nativa do Cerrado brasileiro. Técnicas de propagação in vitro fazem uso de elicitores para alterar as vias metabólicas, afetando a produção de moléculas qualitativa e quantitativamente. Este trabalho teve como objetivo avaliar como os elicitores abióticos ácido salicílico (SA) e nitrato de prata (SN) nas concentrações de 30µM ou 60µM influenciam no crescimento de plântulas de Hyptis marrubioides por dois diferentes métodos de cultivo in vitro. O teor de rutina foi quantificado por CLAE-DAD. Em comparação com uma cultura não tratada, os extratos metanólicos de H. marrubioides cultivados em meio MS por 10 dias, seguidos de cultura em meio MS contendo SN (30µM) por 20 dias, apresentaram 1,28 vezes maior teor de rutina. Em um segundo experimento, as plântulas foram cultivadas em meio MS por 20 dias, e então o elicitor desejado foi adicionado à cultura e deixado em contato com o meio por três e seis dias. SA (30µM) forneceu os melhores resultados na produção de rutina, sendo 16,56 vezes maior do que o controle após seis dias. SN (30µM) aumentou o teor de rutina em 1,17 vezes. Nas duas concentrações avaliadas durante os experimentos de elicitação, nem SA nem SN alteraram os parâmetros de crescimento, como comprimento da parte aérea, número de folhas ou peso fresco e seco das plântulas de H. marrubioides cultivadas in vitro em relação ao controle. Com base nestes resultados, os elicitores abióticos SA e SN forneceram com sucesso Hyptis marrubioides in vitro com maior conteúdo de rutina.

Assessment of the antioxidant, cytotoxic, and genotoxic potential of the Annona muricata leaves and their influence on genomic stability.

The popular use of Annona muricata L. is based upon a range of medicinal purposes, and the plant exhibits biological activities including antihyperglycemic, antiparasitic, and antitumor activities. The objectives of this study were to examine the antioxidant, cytotoxic, and genotoxic potential of the hydroalcoholic extract of A. muricata leaves (AMEs), as well as its effects on genotoxicity induced by methyl methanesulfonate (MMS) and hydrogen peroxide (H2O2). The results using 2,2-diphenyl-1-picrylhydrazyl assay showed that AME was able to scavenge 44.71% of free radicals. The extract significantly reduced the viability of V79 cells in the clonogenic assay at concentrations ≥8 µg/ml. No significant differences in micronucleus (MN) frequency were observed between V79 cell cultures treated with different concentrations of the extract (0.125, 0.25, 0.5, and 1 µg/ml) and negative control. When AME concentrations were combined with MMS, data revealed no marked differences from mutagen alone. In contrast, significant reductions in the frequencies of MN were noted in cultures treated with AME combined with H2O2 compared to H2O2 alone. In vivo studies found no significant differences in the frequencies of micronucleated polychromatic erythrocytes (MNPCEs) between animals treated with different AME doses compared to control. Animals treated with AME doses of 125 and 250 mg/kg and MMS exhibited significantly higher frequencies of MNPCE compared to mutagen alone. In conclusion, under current experimental conditions, AME was not genotoxic and exerted a modulatory effect on DNA damage depending upon the experimental conditions. The extract did not influence markedly MMS-induced genotoxicity in in vitro test system. However, the extract increased DNA damage induced by mutagen in mice. In V79 cells, AME reduced the genotoxicity produced by H2O2, and this protective effect was attributed in part to the antioxidant activity of AME.

Impact of light quality on flavonoid production and growth of Hyptis marrubioides seedlings cultivated in vitro

ABSTRACT Hyptis marrubioides Epling, Lamiaceae, a species from Brazilian Cerrado, has been used against gastrointestinal infections, skin infections, pain, and cramps. Herein, H. marrubioides seedlings were cultured in vitro under different wavelengths (white, blue, green, red, and yellow) with 50 µmol m-2 s-1 irradiance and a 16-h photoperiod. After 20 and 30 days of cultivation, shoot length, leaf number, fresh mass, and dry mass were evaluated. The flavonoid rutin content was determined by the HPLC-DAD method. The shoots were longer in plants cultivated under yellow (16.603 ± 0.790 cm, 1.8-fold), red (15.465 ± 0.461 cm, 1.7-fold), and green (14.677 ± 0.737 cm, 1.6-fold) lights than in control plants exposed to white light (9.203 ± 0.388 cm). The number of leaves increased in plants exposed to red (23.425 ± 1.138, 1.1-fold) and green (22.725 ± 1.814, 1.1-fold) lights, compared to control plants (20.133 ± 0.827). Fresh (0.665 ± 0.048 g, 1.2-fold) and dry (0.066 ± 0.005 g, 1.3-fold) mass of seedlings were the highest in seedlings grown under red light, compared to seedlings grown under white light (0.553 ± 0.048 and 0.028 ± 0.004, respectively). However, rutin production was higher under white (0.308 mg g-1 of dry weight) and blue lights (0.298 mg g-1 of dry weight). Thus, red light induces plant growth and increases leaf number and dry weight in in vitro-cultivated H. marrubioides, whereas blue and white lights promote the greatest rutin accumulation.

Toxicogenetic study of Persea americana fruit pulp oil and its effect on genomic instability.

Persea americana Mill., commonly known as avocado, is a tree native to Central America that is widely used as a food source and for the treatment of diseases. This plant has various biological properties such as analgesic, anti-inflammatory and total cholesterol-lowering activity. In view of its pharmacological potential, we conducted a toxicogenetic study of the fruit pulp oil of P. americana (PAO) and investigated its influence on genotoxicity induced by methyl methanesulfonate (MMS) and doxorubicin. V79 cells and Swiss mice were used for the assays. The results showed no genotoxic effects of PAO in the in vitro or in vivo test systems. However, the highest PAO dose tested led to an increase in the levels of aspartate aminotransferase, indicating hepatic/tissue damage. This effect may be related to high concentrations of palmitic acid, the main component of PAO. Furthermore, PAO was effective in reducing the chromosome damage induced by MMS and doxorubicin. These results contribute to the safety assessment of PAO as a medicinal plant for human use.

Curcumin Generates Oxidative Stress and Induces Apoptosis in Adult Schistosoma mansoni Worms.

Inducing apoptosis is an interesting therapeutic approach to develop drugs that act against helminthic parasites. Researchers have investigated how curcumin (CUR), a biologically active compound extracted from rhizomes of Curcuma longa, affects Schistosoma mansoni and several cancer cell lines. This study evaluates how CUR influences the induction of apoptosis and oxidative stress in couples of adult S. mansoni worms. CUR decreased the viability of adult worms and killed them. The tegument of the parasite suffered morphological changes, the mitochondria underwent alterations, and chromatin condensed. Different apoptotic parameters were determined in an attempt to understand how CUR affected adult S. mansoni worms. CUR induced DNA damage and fragmentation and increased the expression of SmCASP3/7 transcripts and the activity of Caspase 3 in female and male worms. However, CUR did not intensify the activity of Caspase 8 in female or male worms. Evaluation of the superoxide anion and different antioxidant enzymes helped to explore the mechanism of parasite death further. The level of superoxide anion and the activity of Superoxide Dismutase (SOD) increased, whereas the activity of Glutathione-S-Transferase (GST), Glutathione reductase (GR), and Glutathione peroxidase (GPX) decreased, which culminated in the oxidation of proteins in adult female and male worms incubated with CUR. In conclusion, CUR generated oxidative stress followed by apoptotic-like-events in both adult female and male S. mansoni worms, ultimately killing them.

Evaluation of mutagenic, recombinogenic and carcinogenic potential of (+)-usnic acid in somatic cells of Drosophila melanogaster.

The main of this study was to evaluate the mutagenic and carcinogenic potential of (+) - usnic acid (UA), using Somatic Mutation and Recombination Test (SMART) and the test for detecting epithelial tumor clones (wts) in Drosophila melanogaster. Larvae from 72 ± 4 h from Drosophila were fed with UA (5.0, 10.0 or 20.0 mM); urethane (10.0 mM) (positive control); and solvent (Milli-Q water, 1% Tween-80 and 3% ethanol) (negative control). ST cross produced increase in total mutant spots in the individuals treated with 5.0, 10.0 or 20.0 mM of UA. HB cross produced spot frequencies in the concentration of 5.0 mM that were higher than the frequency for the same concentration in the ST cross. In the highest concentrations the result was negative, which means that the difference observed can be attributed, in part, to the high levels of P450, suggesting that increasing the metabolic capacity maximized the toxic effect of these doses. In the evaluation of carcinogenesis using the wts test, the results obtained for the same concentrations of UA show a positive result for the presence of tumors when compared to the negative control. We conclude that UA has recombinogenic, mutagenic and carcinogenic effects on somatic cells in D. melanogaster.

Modulatory Effect of Betulinic Acid on the Genotoxicity Induced by Different Mutagens in V79 Cells.

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.

In vitro cytotoxicity, genotoxicity and antigenotoxicity assessment of Solanum lycocarpum hydroalcoholic extract.

CONTEXT: Solanum lycocarpum A. St.-Hil. (Solanaceae), popularly known as 'fruta-do-lobo' (wolf fruit), 'lobeira' and 'jurubebão', is commonly used by native people of Central Brazil in powder form or as a hydroalcoholic extract for the management of diabetes and obesity and to decrease cholesterol levels. OBJECTIVE: The present study determines the possible cytotoxic, genotoxic and antigenotoxic activities of hydroalcoholic extract of the S. lycocarpum fruits (SL). MATERIALS AND METHODS: The clonogenic efficiency assay was used to determine the cytotoxicity. Three concentrations of SL (16, 32 and 64 µg/mL) were used for the evaluation of its genotoxic and antigenotoxic potential on V79 cells using the micronucleus and comet assays. In the antigenotoxicity assays, the cells were treated simultaneously with SL and the alkylating agent methyl methanesulphonate (MMS, 44 µg/mL for the micronucleus assay and 22 µg/mL for the comet assay) as an inducer of micronuclei and DNA damage. RESULTS: The results showed that SL was cytotoxic at concentrations up to 64 µg/mL. No significant differences in the rate of chromosome or DNA damage were observed between cultures treated with SL and the control group. In addition, the frequencies of micronuclei and DNA damage induced by MMS were significantly reduced after treatment with SL. The damage reduction percentage ranged from 68.1% to 79.2% and 12.1% to 16.5% for micronucleus and comet assays, respectively. DISCUSSION AND CONCLUSION: SL exerted no genotoxic effect and exhibited chemopreventive activity against both genomic and chromosome damage induced by MMS.

Antimicrobial activity of the essential oil of Tetradenia riparia (Hochst.) Codd. (Lamiaceae) against cariogenic bacteria.

In Brazilian folk medicine, Tetradenia riparia (Hochst.) Codd. (Lamiaceae) is used to treat toothaches and dental abscesses and diseases induced by worms, bacteria, or fungi. This paper aims to investigate the chemical composition and the antibacterial effects of the essential oil obtained from Tetradenia riparia leaves (TR-EO) grown in Southeastern Brazil against a representative panel of oral pathogens. We evaluated the antibacterial activity of TR-EO in terms of the minimal inhibitory concentration (MIC). We identified aromadendrene oxide (14.0%), (E,E)-farnesol (13.6%), dronabinol (12.5%), and fenchone (6.2%) as the major constituents of TR-EO. TR-EO displayed MIC values between 31.2 and 500 µg/mL, with the lowest MIC value being obtained against Streptococcus mitis (31.2 µg/mL), S. mutans (62.5 µg/mL), S. sobrinus (31.2 µg/mL), and Lactobacillus casei (62.5 µg/mL). In time-kill experiments, TR-EO demonstrated bactericidal activity against S. mutans within the first 12 h, resulting in a curve profile similar to that of chlorhexidine. These results revealed that the essential oil of Tetradenia riparia displays promising activity against most of the selected cariogenic bacteria, including Streptococcus mutans.

Antimicrobial Activity of the Essential Oil of Plectranthus neochilus against Cariogenic Bacteria.

This work used the broth microdilution method to investigate the antimicrobial activity of the essential oil obtained from the leaves of Plectranthus neochilus (PN-EO) against a representative panel of oral pathogens. We assessed the antimicrobial activity of this oil in terms of the minimum inhibitory concentration (MIC). PN-EO displayed moderate activity against Enterococcus faecalis (MIC = 250 µg/mL) and Streptococcus salivarus (MIC = 250 µg/mL), significant activity against Streptococcus sobrinus (MIC = 62.5 µg/mL), Streptococcus sanguinis (MIC = 62.5 µg/mL), Streptococcus mitis (MIC = 31.25 µg/mL), and Lactobacillus casei (MIC = 31.25 µg/mL), and interesting activity against Streptococcus mutans (MIC = 3.9 µg/mL). GC-FID and GC-MS helped to identify thirty-one compounds in PN-EO; α-pinene (1, 14.1%), ß-pinene (2, 7.1%), trans-caryophyllene (3, 29.8%), and caryophyllene oxide (4, 12.8%) were the major chemical constituents of this essential oil. When tested alone, compounds 1, 2, 3, and 4 were inactive (MIC > 4000 µg/mL) against all the microorganisms. These results suggested that the essential oil extracted from the leaves of Plectranthus neochilus displays promising activity against most of the evaluated cariogenic bacteria, especially S. mutans.