Chemical Composition and Antibacterial Activity of the Essential Oil of Vitex agnus-castus L. (Lamiaceae)

ABSTRACT Abnormal multiplication of oral bacteria causes dental caries and dental plaque. These diseases continue to be major public health concerns worldwide, mainly in developing countries. In this study, the chemical composition and antimicrobial activity of the essential oil of Vitex agnus-castus leaves (VAC‒EO) collected in the North of Brazil against a representative panel of cariogenic bacteria were investigated. The antimicrobial activity of VAC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by using the broth microdilution method in 96-well microplates. The chemical constituents of VAC-EO were identified by gas chromatography (GC‒FID) and gas chromatography‒mass spectrometry (GC‒MS). VAC‒EO displayed some activity against all the investigated oral pathogens; MIC values ranged from 15.6 to 200 μg/mL. VAC-EO had promising activity against Streptococcus mutans (MIC= 15.6 μg/mL), Lactobacillus casei (MIC= 15.6 μg/mL), and Streptococcus mitis (MIC= 31.2 μg/mL). The compounds 1,8-cineole (23.8%), (E)-β-farnesene (14.6%), (E)-caryophyllene (12.5%), sabinene (11.4%), and α-terpinyl acetate (7.7%) were the major chemical constituents of VAC‒EO. VAC-EO displays antimicrobial activity against cariogenic bacteria. The efficacy of VAC-EO against S. mutans is noteworthy and should be further investigated.

Chemical composition, antioxidant and antibacterial activities of essential oils from leaves and flowers of Eugenia klotzschiana Berg (Myrtaceae)

ABSTRACT Many essential oils (EOs) of different plant species possess interesting antimicrobial effects on buccal bacteria and antioxidant properties. Eugenia klotzschiana Berg (pêra-do-cerrado, in Portuguese) is a species of Myrtaceae with restricted distribution in the Cerrado. The essential oils were extracted through the hydrodistillation technique using a modified Clevenger apparatus (2 hours) and chemically characterized by GC-MS. The major compounds were α-copaene (10.6 %) found in oil from leaves in natura, β-bisabolene (17.4 %) in the essential oil from dry leaves and α-(E)-bergamotene (29.9 %) in oil from flowers. The antioxidant activity of essential oils showed similarities in both methods under analysis (DPPH and ABTS˙+) and the results suggested moderate to high antioxidant activity. The antibacterial activity was evaluated by determining minimum inhibitory concentrations (MICs), using the microdilution method. MIC values below 400 µg/mL were obtained against Streptococcus salivarius (200 µg/mL), S. mutans (50 µg/mL), S. mitis (200 µg/mL) and Prevotella nigrescens (50 µg/mL). This is the first report of the chemical composition and antibacterial and antioxidant activities of the essential oils of E. klotzschiana. These results suggest that E. klotzschiana, a Brazilian plant, provide initial evidence of a new and alternative source of substances with medicinal interest.

Bioassay-guided fractionation and antimicrobial and cytotoxic activities of Cassia bakeriana extracts

ABSTRACT The antimicrobial potential of extracts of bark and leaves of Cassia bakeriana Craib, Fabaceae, against aerobic and anaerobic oral bacteria was evaluated by the microdilution broth method. For crude ethanol extracts and organic fractions tested, the bark dichloromethane phase showed a significant antibacterial effect, with MIC values ranging from 12.5 to 100 µg/ml for most of the microorganisms tested. Thus, a bioassay-guided fractionation of this fraction was performed. This fractionation led to isolation of the 1,8-dihydroxy-anthraquinone-3-carboxylic acid, also known as cassic acid or rhein. It is the first time that this bioactive anthraquinone has been isolated from this plant. Rhein exhibited good selectivity and high activity against anaerobic microorganisms, with MIC values ranging between 3.12 µg/ml (11.0 µM) and 25 µg/ml (88.0 µM). These results were considered very promising since the most active samples and rhein showed greater selectivity against oral microorganisms than toxicity to Vero cells.

Antibacterial activity of (-)-cubebin isolated from Piper cubeba and its semisynthetic derivatives against microorganisms that cause endodontic infections

Abstract Recent publications have highlighted the numerous biological activities attributed to the lignan (-)-cubebin (1), Piper cubeba L. f., Piperaceae, and ongoing studies have focused on its structural optimization, in order to obtain derivatives with greater pharmacological potential. The aim of this study was the obtainment of (1), its semisynthetic derivatives and evaluation of antibacterial activity. The extract of the seeds of P. cubeba was chromatographed, subjected to recrystallization and was analyzed by HPLC and spectrometric techniques. It was used for the synthesis of: (-)-O-methylcubebin (2), (-)-O-benzylcubebin (3), (-)-O-acetylcubebin (4), (-)-O-(N, N-dimethylamino-ethyl)-cubebin (5), (-)-hinokinin (6) and (-)-6.6'-dinitrohinokinin (7). The evaluation of the antibacterial activity has been done by broth microdilution technique for determination of the minimum inhibitory concentration and the minimum bactericidal concentration against Porphyromonas gingivalis, Prevotella nigrescens, Actinomyces naeslundii, Bacteroides fragilis and Fusobacterium nucleatum. It was possible to make an analysis regarding the relationship between structure and antimicrobial activity of derivatives against microorganisms that cause endodontic infections. The most promising were minimum inhibitory concentration =50 µg/ml against P. gingivalis by (2) and (3), and minimum inhibitory concentration =100 µg/ml against B. fragilis by (6). Cytotoxicity assays demonstrated that (1) and its derivatives do not display toxicity.

RP-HPLC analysis of manool-rich Salvia officinalis extract and its antimicrobial activity against bacteria associated with dental caries

In this paper we screened the dichloromethane extract from the aerial parts of Salvia officinalis L., Lamiaceae, against a representative panel of microorganisms that cause caries, conducted a bioassay-guided fractionation to establish themselves the most active metabolite (manool) and determined the Salvia officinalis fraction with the manool highest concentration to be used to activate an ingredient in oral care products such as toothpastes and mouthwashes. Both manool and S. officinalis extract showed very promising minimal inhibitory concentration values (between 6.24 and 31.36 µg.ml-1) and time kill curves against the primary causative agents of dental caries (Streptococcus mutans) revealed that, at twice its minimal bactericidal concentration (12.48 µg.ml-1), manool required 6 h to completely kill the bacteria. Salvia officinalis extract at twice its minimal bactericidal concentration (31.36 µg.ml-1 ) needed 12 h. The results achieved with Salvia officinalis extract motivated us to develop and validate an analytical RP-HPLC method to detect and determine manool in this extract. The validation parameters were satisfactorily met and evaluated allows us to consider the developed method suitable for use in different labs. In conclusion, our results evidenced that the manool-rich S. officinalis extract can be considered an analytically validated alternative to develop novel and effective antimicrobial agents against the main bacteria responsible for dental caries.

Evaluation of antimicrobial activity of extracts of Tibouchina candolleana (melastomataceae), isolated compounds and semi-synthetic derivatives against endodontic bacteria

This work describes the phytochemical study of the extracts from aerial parts of Tibouchina candolleana as well as the evaluation of the antimicrobial activity of extracts, isolated compounds, and semi-synthetic derivatives of ursolic acid against endodontic bacteria. HRGC analysis of the n-hexane extract of T. candolleana allowed identification of b-amyrin, a-amyrin, and b-sitosterol as major constituents. The triterpenes ursolic acid and oleanolic acid were isolated from the methylene chloride extract and identified. In addition, the flavonoids luteolin and genistein were isolated from the ethanol extract and identified. The antimicrobial activity was investigated via determination of the minimum inhibitory concentration (MIC) using the broth microdilution method. Amongst the isolated compounds, ursolic acid was the most effective against the selected endodontic bacteria. As for the semi-synthetic ursolic acid derivatives, only the methyl ester derivative potentiated the activity against Bacteroides fragilis.

Antimicrobial activity of Aegiphila sellowiana Cham., Lamiaceae, against oral pathogens / Atividade antimicrobiana de Aegiphila sellowiana Cham., Lamiaceae, contra patógenos orais

The antimicrobial activity of Aegiphila sellowiana Cham., Lamiaceae, against oral pathogens is reported. The Minimal Inhibitory Concentrations (MICs) for inhibiting the microorganisms growth were determined using the broth microdilution method from the CLSI M7-A7 protocol. Chlorhexidine was used as the positive control. The ethanol crude extract of the aerial parts of A. sellowiana exhibited activity against the microorganisms tested in this work; however, the activity decreased after partition with n-hexane, dichloromethane, and ethyl acetate. Among the tested fractions, the n-hexane fraction was found to be the most effective against the evaluated oral pathogens. GC-MS analysis of this latter fraction revealed that fatty acids esters, steroids, and aliphatic sesquiterpene hydrocarbons are its major constituents. These compounds may be responsible for the activity of the n-hexane fraction, but other chemical constituents of the dichloromethane, ethyl acetate, and hydroalcoholic fraction may potentialize their activities in the crude extract.

A atividade antimicrobiana de Aegiphila sellowiana Cham., Lamiaceae, contra patógenos da cavidade bucal foi avaliada empregando-se o método de microdiluição em caldo, segundo o protocolo CLSI M7-A7, utilizando-se clorexidina como controle positivo. O extrato etanólico bruto das partes aéreas de A. sellowiana, obtido por maceração, exibiu atividade contra os microrganismos testados neste trabalho, entretanto, os valores de CIM (concentração inibitória mínima) aumentaram após a partição com n-hexano, diclorometano e acetato de etila. Entre as frações testadas, a fração n-hexânica foi a mais efetiva contra os patógenos bucais avaliados, com valores de CIM entre 140 e 350 µg/mL-1. Dados obtidos por CG-EM revelaram que ésteres de ácidos graxos, esteróides e hidrocarbonetos sesquiterpênicos alifáticos são os constituintes majoritários desta fração. Embora esses compostos possam ser os responsáveis pela atividade da fração n-hexânica, outros constituintes químicos presentes nas frações em diclorometano, acetato de etila e hidroalcoólica podem potencializar suas atividades no extrato bruto.

Avaliação do efeito da hipotermia por crioimersão corporal, nos neutrófilos e linfócitos sanguíneos de ratos submetidos ao exercício físico agudo / Evaluation of the effect of hypothermia by cold water immersion on blood neutrophils and lymphocytes of rats submitted to acute exercise

O estresse sistêmico induzido pelo exercício libera substâncias bioativas determinantes da mobilização neutrofílica. A crioterapia diminui a reação inflamatória e atenua a elevação da perfusão sanguínea induzida pelo exercício. O objetivo deste trabalho foi analisar a influência da hipotermia decorrente da crioimersão corporal (CIC) imediata ao esforço físico agudo nas concentrações neutrofílicas e linfocíticas no sangue. Os ratos do grupo controle (AI) foram mantidos em repouso enquanto os do grupo AII foram submetidos ao protocolo de CIC a 10ºC por 10 minutos. Enquanto os animais dos grupos BI, BII, BIII e BIV realizaram o esforço físico agudo (EFA) em água a 31ºC durante 100 minutos com sobrecarga corpórea de 5% do peso corporal, os dos grupos CI, CII, CIII e CIV foram submetidos ao EFA seguido imediatamente de CIC. Nos grupos B e C, os animais foram sacrificados nos períodos de 06 (I), 12 (II), 24 (III) e 48 (IV) horas posteriores ao EFA. Através da microscopia óptica realizou-se a contagem dos neutrófilos e linfócitos. Utilizou-se do Teste T Student para análise estatística considerando-se nível de significância p < 0,05. Observou-se uma significativa neutrofilia nos grupos AII, BI, BII, BIII, BIV, CI, CII e CIII em relação a AI, diferentemente do grupo CIV, que apresentou quantidade de neutrófilos igual ao grupo controle. Os valores de linfócitos nos grupos BII, BIII, BIV, CI e CII foram significativamente menores do que AI, e nos grupos AII, BI, CIII e CIV foram iguais a AI. A neutrofilia e a linfopenia posteriores ao intenso exercício agudo são mantidas por 48 horas ou mais, porém, mediante a aplicação da crioimersão corporal imediata ao exercício, são normalizadas em 24 horas.

Systemic stress induced by exercise increases bioactive substances in plasma which leads to neutrophilic mobilization. Cryotherapy causes a decrease in the inflammatory reaction and attenuates high blood perfusion after exercise. The objective of this work was to analyze the influence of cold water immersion (CWI) after acute exercise on neutrophil and lymphocyte mobilization. A control group of rats (AI) was kept at rest and a second group (AII) was submitted to CWI at 10º C for 10 minutes. The animals of Groups BI, BII, BIII and BIV were submitted to acute exercise which consisted in swimming in water at 31º C for 100 minutes with a load equivalent to 5% of the body weight. Groups CI, CII, CIII and CIV were submitted to CWI immediately after acute exercise. The animals were sacrificed at 6 (I), 12 (II), 24 (III) and 48 (IV) hours after the exercise and neutrophil and lymphocyte cells were counted for all groups by optic microscopy. The Student t-test was used for statistical analysis with a significance level of p< 0.05. A significant increase in the number of neutrophils was observed in Groups AII, BI, BII, BIII, BIV, CI, CII and CIII compared to AI. The neutrophil count of the CIV Group was similar to the Control Group. There was a significant drop in the number of lymphocytes in Groups BII, BIII, BIV, CI and CII when compared to Group AI. The lymphocyte count of Groups AII, BI, CIII and CIV were similar to the Control Group. The changes in neutrophil and lymphocyte counts caused by acute exercise were reverted to normal at 24 hours by cold water immersion.

Recorrência de glomerulosclerose focal e segmentar em dois transplantes renais sucessivos / Recurrence of focal segmental glomerulosclerosis in 2 sucessive renal transplantations

Um paciente com síndrome nefrótica idiopática foi estudado desde o início de sua doença e durante a recorrência em dois sucessivos transplantes. Glomerulosclerose segmentar foi demonstrada no rim original com progressäo para insuficiência renal terminal em 15 meses. Recorrência da síndrome nefrótica surgiu 3 dias após o primeiro transplante, e a biópsia demostrou glomerulosclerose segmentar em evidência de rejeiçäo, evoluindo para insuficiência renal terminal em 14 meses. Novo transplante foi realizado com recorrência do síndrome nefrótica no segundo dia e a biópsia demonstrou-se sugestiva de glomerulosclerose segmentar sem sinais de rejeiçäo. Atualmente, 5 meses após, a funçäo renal permanece normal, com proteinúria maciça