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To assess the activities of essential oils derived from the trunk bark of Cinnamomum zeylanicum (EOCz) and Cinnamomum cassia (EOCc) as well as cinnamaldehyde on bacterial biofilms of clinical interest. Antimicrobial activity was assessed by the broth microdilution method to determine minimum inhibitory concentrations (MICs). Antibiofilm activity was assessed by quantifying the biomass and determining the number of viable cells. The chemical composition of the essential oils was determined. The results showed that the major component of EOCz and EOCc was cinnamaldehyde. For the assayed substances, biofilm biomasses were reduced by up to 99.9%, and Streptococcus pyogenes, Pseudomonas aeruginosa, and Escherichia coli biofilms were sensitive to all of the concentrations and substances analysed. In cell viability tests, 2 mg/ml of cinnamaldehyde reduced the number of viable cells by 5.74 Log CFU/ml. EOCz, EOCc, and cinnamaldehyde exhibited antimicrobial and antibiofilm activities. This work describes substances with potential use against infections caused by bacterial biofilms.

Two new biflavonoids, 5-hydroxy-7-methoxyflavone-(4' --> O --> 8")-4"',5",7"-trihydroxyflavone and 5-hydroxy-7-methoxyflavone-(4' --> O --> 8")-5",7"-dihydroxy-4"'-methoxyflavone, and the glucopyranoside derivative, 1-O-(4-hydroxyphenyl)-6-O-(4-hydroxybenzoyl)-beta-D-glucopyranoside, as well as the known biflavones lanaraflavone, amentoflavone and podocarpusflavone, the triterpenes lupeol and friedelin, the lignans eudesmin and epieudesmin, the flavonol glycoside rutin, the steroids beta-sitosterol, stigmasterol, 3beta-O-beta-D-glucopyranosylsitosterol, 7-oxostigmast-5-en-3beta-ol and 7-oxostigmasta-5,22-dien-3beta-ol, the carbohydrates alpha- and beta-glucopyranose and 1-O-(4-hydroxybenzoyl)-beta-D-glucopyranoside, and the norsesquiterpene 6,9-dihydroxymegastigma-4,7-dien-3-one, have been isolated from leaves and branches of Ouratea semiserrata. The structures of these compounds were established from spectral data, including two-dimensional NMR experiments and mass spectra.

Diversas espécies do gênero Solanum apresentam glicoalcalóides e flavonóides com grande variedade de atividades biológicas. O flavonóide tiliroside (1), uma fração rica em glicoalcalóides denominada GB e o glicoalcalóide solasonina (2) foram obtidos dos tricomas de galhos jovens e frutos de Solanum crinitum Lam e o alcalóide estereoidal solasodina (3), extraído das partes aéreas de S. jabrense Agra & M. Nee, tiveram sua atividade citotóxica avaliada frente a células do carcinoma de Ehrlich e da leucemia humana K562. O efeito antiproliferativo destas substâncias mostrou comportamento dose-dependente após avaliação através do método do MTT, para ambos os casos. Os resultados indicaram atividade citotóxica para 1, GB e 2, com IC 50 = 69,50 µM, 19,5 µg mL -1 e 74,20 µM, respectivamente, quando ensaiadas frente ao carcinoma de Ehrlich, e IC 50 = 118,40 µM, 13,65 µg mL -1 , 60,35 µM e 76,92 µM para 1, GB, 2 e 2a (derivado peracetilado da solasonina) frente a leucemia K562. A baixa atividade da aglicona solasodina (3) indicou a importância da presença dos açúcares na estrutura do glicoalcalóide e permitiu postular a substância 2, presente na fração rica em glicoalcalóides (GB), como um dos principios ativos. Além disso, os resultados mostraram a possibilidade de biomonitoramento através do ensaio do MTT na busca de metabólitos com atividade citotóxica.Steroidal alkaloids, flavonoids and their glycosides occurring in numerous species of Solanum genus are known to possess a variety of biological activities. The flavonoid tiriloside (1), a rich in glycoalkaloids total fraction named GB and the glycoalkaloid solasonine (2) isolated from thricomes of young branches and fruits from Solanum crinitum Lam, and the aglycone solasodine (3) isolated from Solanum jabrense Agra & M. Nee, were assayed against murine Ehrlich carcinoma and human K562 leukaemia cultured cells. The exposure in vitro of these cancer cells to these products resulted in a dose-dependent growth inhibition evaluated by the MTT method. The results indicated significant cytotoxic activities with IC 50 = 69.50 µM, 19.5 µg mL -1 , and 74.20 µM for 1, GB and 2, respectively, against Ehrlich carcinoma, and IC 50 = 186.50 µM, 13.65 µg mL -1 and 76.92 µM, for 1, GB, 2 and 2a, respectively, against K562 leukaemia cells. The low activity of the aglycone 3 indicates that the role of the sugar moiety is very important in the cytotoxic activity of glycoalkaloid solsonine. The cytotoxic activity revealed by the GB fraction may be attributed to the presence of 2. Additionally, these results show the viability of the MTT assay for monitoring phytochemical bioactive compounds. K562 Leukaemia Vol. 13, No. 6, 2002 Kolaviron for the treatment of various diseases, including hepatitis and laryngitis, 3 and several Leguminosae plants containing isoflavonoids with potent estrogenic activity. 4 Many plants in the Solanaceae family accumulate steroidal alkaloids based on a C 27 cholestane skeleton, e.g. solasodine and tomatidine. These compounds are essentially nitrogen analogues...

BackgroundThe emergence of multidrug-resistant bacteria is a worldwide concern and in order to find an alternative to this problem, the occurrence of antimicrobial compounds in Plectranthus amboinicus essential oil was investigated. Thus, this study aims to determine susceptibility of Staphylococcus aureus isolated from food to antibiotics, P. amboinicus essential oil (PAEO) and carvacrol.MethodsLeaves and stem of P. amboinicus were used for extraction of essential oil (PAEO) by hydrodistillation technique and EO chemical analysis was performed by gas chromatography coupled to a mass spectrometer. S. aureus strains (n = 35) isolated from food and S. aureus ATCC 6538 were used to evaluate the antimicrobial and antibiofilm activity of PAEO and carvacrol. All strains (n = 35) were submitted to antimicrobial susceptibility profile by disk diffusion method. Determination of MIC and MBC was performed by microdilution technique and antibiofilm activity was determined by microtiter-plate technique with crystal violet assay and counting viable cells in Colony Forming Units (CFU).ResultsCarvacrol (88.17%) was the major component in the PAEO. Antibiotic resistance was detected in 28 S. aureus strains (80%) and 12 strains (34.3%) were oxacillin and vancomycin-resistant (OVRSA). From the 28 resistant strains, 7 (25%) showed resistance plasmid of 12,000 bp. All strains (n = 35) were sensitive to PAEO and carvacrol, with inhibition zones ranging from 16 to 38 mm and 23 to 42 mm, respectively. The lowest MIC (0.25 mg mL−1) and MBC (0.5 mg mL−1) values were observed when carvacrol was used against OVRSA. When a 0.5 mg mL−1 concentration of PAEO and carvacrol was used, no viable cells were found on S. aureus biofilm.ConclusionThe antibacterial effect of carvacrol and PAEO proves to be a possible alternative against planktonic forms and staphylococcal biofilm.

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ENT-16α α α α α,17-DIHYDROXYKAURAN-19-OIC ACID ISOLATED FROM ORATEA SEMISERRATA AND THE STEREOCHEMISTRY DEFIANCES OF THE CHIRAL CARBONS C-4 AND C-16. Phytochemical investigation of the leaves and branches of a specimen of Ouratea semiserrata led to the isolation and characterization of ent-16α α α α α,17-dihydroxykauran-19-oic acid, along with other natural products. This diterpenoid and its derivatives were used to unambiguous 1 H and 13 C chemical shifts assignments and to indicate some mistake data described in the literature as consequence mainly of the stereochemicals of the chiral carbons C-4 and C-16. The HRMS spectra were also analysed.Keywords: Ouratea semiserrata; Ochnaceae; ent-16α α α α α,17-dihydroxykauran-19-oic acid; 1 H and 13 C spectral data; HRMS spectra. ARTIGO INTRODUÇÃOA investigação química de um espécimen de Ouratea semiserrata, família Ochnaceae, conduziu ao isolamento do ácido ent-16α,17-diidroxicauran-19-óico (1), além de outros terpenóides, derivados da β-D-glicopiranose, rutina (flavonóide glicosilado), biflavonóides e lignóides.A família Ochnaceae apresenta-se constituída de 600 espécies distribuídas em 39 gêneros encontrados em regiões pantropicais. No Brasil podem ser encontradas 53 espécies 1,2 . O nosso interesse pelo gênero Ouratea começou com a investigação química da espécie Ouratea hexasperma, que conduziu ao isolamento e elucidação estrutural de biisoflavonóides 3 e uma biflavona (2) com atividade inibidora do crescimento de células tumorais 4 . Após a definição estrutural do diterpeno caurânico 1 com base na interpretação de dados espectrais, principalmente os fornecidos pelos espectros de ressonância magnética nuclear de hidrogênio (RMN 1 H) e carbono-13 (RMN 13 C) uni-(1D) e bidimensional (2D) 5 , verificou-se a existência de informações de RMN 13 C e estereoquímicas registradas na literatura que requerem reavaliação. Esta constatação promoveu a necessidade de preparar uma publicação restringindo-se particularmente ao ácido ent-16α,17-diidroxicauran-19-óico (1) e seus derivados 1a-1c, incorporando-se informações importantes para possibilitar avaliações de dados de RMN 13 C e estereoquímicos encontrados na literatura (e.g.)6-12 , na tentativa de evitar, ou no mínimo reduzir, a utilização de dados equivocados.Artigos publicados em periódicos estrangeiros conceituados estabeleceram uma confusão sobre as estereoquímicas α (abaixo do plano estereoquímico) e β (acima) de grupo hidroxila localizado no átomo de carbono C-16 de diterpenos 16,17-diidroxicaurânicos e na definição dos carbonos 18 e 19 sustentados pelo carbono C-4. Estes fatos serviram como estímulo para uma abordagem destes aspectos estereoquímicos. A montagem de moléculas com modelo molecular permite definir com relativa facilidade estas configurações e afastar a confusão observada na literatura.O prefixo ent-representa enantio-da palavra enantiômero e revela inversão de configuração de todos os centros quirais envolvidos numa substância com configuração absoluta definida; rel-(relativa), ou asterisco (*), é usado p...

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