A bstract Few in vitro screening studies on the biological activities of plant extracts that are intended for oral administration consider the effect of the gastrointestinal system. This study investigated this aspect on extracts of Camellia sinensis (green tea) and Salvia officinalis (sage) using antimicrobial activity as amodel for demonstration. Both the crude extracts and their products after exposure to simulated gastric fluid (SGF) as well as simulated intestinal fluid (SIF) were screened for antimicrobial activity. The chromatographic profiles of the crude plant extracts and their SGF as well as SIF products were recorded and compared qualitatively by means of high performance liquid chromatography coupled to mass spectrometry. The effect of epithelial transport on the crude plant extracts was determined by applying them to an in vitro intestinal epithelial model (Caco-2). The crude extracts for both plants exhibited reduced antimicrobial activity after exposure to SGF, while no antimicrobial activity was detected after exposure to SIF. These results suggested chemical modification or degradation of the antimicrobial compounds when exposed to gastrointestinal conditions. This was confirmed by a reduction of the peak areas on the LC–UV–MS chromatograms. From the chromatographic profiles obtained during the transport study, it is evident that some compounds in the crude plant extracts were either not transported across the cell monolayer or they were metabolised during passage through the cells. It can be deduced that the gastrointestinal environment and epithelial transport process can dramatically affect the chromatographic profiles and biological activity of orally ingested natural products.

Abstract Few in vitro screening assays for biological activities of plant extracts consider the potential effect of the gastrointestinal system on orally consumed plant extracts. Crude water and methanol extracts of Tarchonanthus camphoratus (wild camphor) and Agathosma betulina (‘buchu’) were prepared and exposed to simulated gastric fluid and simulated intestinal fluid during dissolution studies to address this aspect. The crude extracts and resulting simulated gastric fluid and simulated intestinal fluid products were screened for antimicrobial activity against Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922) and Proteus vulgaris (ATCC 33420). The T. camphoratus crude extract exhibited antimicrobial activity which was reduced after exposure to simulated gastric fluid. After exposure to simulated intestinal fluid no antimicrobial activity was detected, which suggests chemical alteration or degradation of the active compounds. For A. betulina, the crude water extract and simulated gastric fluid product exhibited no antimicrobial activity, while the simulated intestinal fluid product exhibited antimicrobial activity. This suggests activation of antimicrobial constituents during exposure to simulated intestinal fluid. The chemical composition profiles of the crude extracts and products were determined by means of liquid chromatography coupled to an ultraviolet detector (LC-UV) and a mass spectrometer (LC-MS) to qualitatively assess the effect of exposure to simulated gastrointestinal conditions on the chemical composition of the extracts. In many cases, the peak area of compounds decreased after exposure to simulated gastric fluid and simulated intestinal fluid, while the peak area of other compounds increased. Thus, it can be deduced that the antimicrobial activity and chemical composition was altered after exposure to intestinal conditions during dissolution studies.

Heteropyxis natalensis (Heteropyxidaceae) is traditionally used to treat respiratory disorders, and as a decongestant and antimicrobial agent. The seasonal variation of the hydrodistilled essential oil was investigated. Three trees in the Johannesburg Botanical Garden (Gauteng) indicated similar chemical profiles with fluctuation in the levels of the two major constituents (1,8-cineole and limonene). Little variation between the antimicrobial activity of seasonally collected samples was documented, with standard deviations of ±0.3 to ±3.3 depending on the pathogen studied. Moderate antimicrobial activity (3.0–16.0 mg/ml) was noted for most pathogens tested with Cryptococcus neoformans exhibiting the highest sensitivity (2.0–3.0 mg/ml). The chemogeographical variation of the oil composition from five of the seven distinct localities studied all contains 1,8-cineole and limonene as major constituents. The antimicrobial study of these samples indicated little variability between localities (standard deviation of ±0.5 to ±3.8). As observed in the seasonal variation study, C. neoformans displayed the highest sensitivity (0.5–2.0 mg/ml). One oil sample (Lagalametse), was distinctly different both chemically and microbiologically.

An aerobic, Gram-negative, rod shaped and polarlagellated bacterium, designated strain MS586, was isolated from soybean rhizosphere in Mississippi. The taxonomic position of MS586 was determined using a polyphasic approach. Analysis of the housekeeping genes supported the novel position of MS586. The results were also supported by average nucleotide identity (ANI) values. Based on these data, it is proposed that strain MS586 represents a novel species, Pseudomonas mississippiensis, within the genus Pseudomonas. The type strain is MS586. Strain MS586 showed a broad-spectrum of antimicrobial activity against plant pathogenic bacteria and fungi that are economically important in agriculture. Preliminary studies using transposon-based mutagenesis showed that the gltB gene was associated with production of antifungal activity against the indicator fungus Geotrichum candidum. The research findings of strain MS586 have provided insights into its potential use as a biocontrol agent in plant disease management.

For centuries medicinal plants have been used all over the world for the treatment and prevention of various ailments, particularly in developing countries where infectious diseases are endemic and modern health facilities and services are inadequate. In recent years the use of and search for drugs derived from plants have been accelerated. Ethnopharmacologists, botanists, microbiologists, and natural-product chemists are trying to discover phytochemicals and “leads” which could be developed for the treatment of infectious diseases. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. The evaluation of these plants for biological activity is necessary, both to substantiate their use by communities, and also to discover possible new drug or herbal preparations. Twenty five plants selected through ethno-botanical surveys in Mozambique which are used to treat respiratory diseases, wounds, viruses, stomach ailments and etc., were collected and investigated for antimicrobial activity. Acetone extracts of selected plants were tested for antibacterial, antimycobacterial and anti-HIV-1 activity. Antibacterial activity was evaluated using the agar diffusion method. Five Gram positive (Bacillus cereus, Bacillus pumilus, Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis) and five Gram negative (Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Serratia marcescens) bacterial species were used in this study. The extracts of each plant were tested at concentrations ranging from 0.125 to 5.0 mg/ ml. Most of the plant extracts inhibited the growth of the Gram-positive microorganisms. The minimum inhibitory concentration of eight plants (Cassia abbreviata, Elephanthorrhiza elephantina, Hemizygia bracteosa, Hoslundia opposita, Momordica balsamina, Rhoicissus tomentosa and Salvadora australis) against Gram-positive bacteria was found to be 0.5 mg/ml. Gram-positive bacteria were found to be susceptible to extracts of Lippia javanica at concentration of 0.125 mg/ml. Among the 22 acetone extracts tested, two were found to have activity against Gram-negative bacteria at a concentration of 5.0 mg/ml (Adenia gummifera and Momordica balsamina). Rhoicissus revoilli inhibited E. cloacae, a Gram-negative strain, at a concentration of 2.5 mg/ml. To evaluate antimycobacterium activity ten plants species were tested against H37Rv, a drug-sensitive strain of Mycobacterium tuberculosis at concentrations ranging from 0.5 to 5.0 mg/ml using BACTEC radiometric method. Four of the plant species tested (Cassia abbreviata, Hemizigya bracteosa, Lippia javanica and Melia azedarach) were observed to be active against the H37Rv. (ATCC 27294) strain of TB at a concentration of 0.5 mg/ml which was the lowest concentration used in this study. Seventeen plant species, were screened for anti-HIV bioactivity in order to identify their ability to inhibit the enzymes glycohydrolase (á -glucosidase and â- glucuronidase) and eleven species were further tested against Reverse transcriptase. It was found that 8 plant species (Cassia abbreviata, Elephantorrhiza elephantina, Rhoicissus tomentosa, Pseudolachnostylis maprouneifolia, Lippia javanica, Litogyne gariepina, Maerua junceae and Momordica balsamina) showed inhibitory effects against á-glucosidase and â-glucuronidase at a concentration of 200 ìg/ml. The results of the tests revealed that the plant extracts of Melia azedarach and Rhoicissus tomentosa appeared to be active, showing 49 and 40% inhibition of the enzyme activity respectively. Lippia javanica was found to have the best activity exhibiting a minimum inhibitory concentration of 0.125 mg/ml. The extracts also showed positive activity against Mycobacterium tuberculosis at concentration of 0.5 mg/ml and HIV-enzyme glycohydrolase was (á-glucosidase and â-glucuronidase) inhibited by 62 % and 73 % respectively. Considering its medicinal use local for HIV and various infections, it was therefore, selected for identifying its bioactive constituents. In the initial screening of plants used in Mozambique Hoslundia oppositademonstrated good antitubercular activity. It was therefore, selected to identify its bioactive constituents. A Phytochemical investigation of L. javanica led to the isolation of eight compounds, 4-ethyl-nonacosane (1), (E)-2(3)-tagetenone epoxide (2), myrcenone (3), piperitenone (4), apigenin (5), cirsimaritin (6), 6-methoxyluteolin 4'-methyl ether (7), 6-methoxyluteolin and 3',4',7-trimethyl ether (8). Three known compounds, 5,7-dimethoxy-6-methylflavone (9), hoslunddiol (10) and euscaphic acid (11) were isolated from H. opposita. This is the first report of compounds (1), (2), (5-8) from L. javanica and of compound (9) from H. opposita. The compounds were tested against Mycobacterium tuberculosis and HIV-1 reverse transcriptase for bioactivity. It was found that compounds (2), (4) and (9) inhibited the HIV-1 Reverse transcriptase enzyme by 91%, 53% and 52% respectively at 100 ìg/ml. Of all the compounds tested against a drug-sensitive strain of Mycobacterium tuberculosis, euscaphic acid (11) was found to exhibit a minimum inhibitory concentration of 50 ìg/ml against this strain. The present study has validated scientifically the traditional use of L. javanica and H. opposita and a few other Mozambican medicinal plants to some extent. / Thesis (PhD)--University of Pretoria, 2010. / Plant Science / unrestricted

This research investigated the mechanism of action in bacteria of 3,4-methylenedioxy-β-nitropropene (BDM-I), a very broad spectrum antimicrobial lead compound in development as an anti-infective drug. The thesis proposes that BDM-I inhibits bacterial protein tyrosine phosphatases, a novel mechanism of action for an antimicrobial agent and a new target in microorganisms. This very open investigation was directed by considerable biological information on the effects of BDM-I in microorganisms and animals which provided insights into possible and improbable cellular targets. The biological effects of BDM-I were investigated using biochemical and cell-based assays, transmission electron microscopy and whole genome DNA microarray analysis. The specific experiments and order of execution were largely dependent on information gained as the project progressed. BDM-I was shown not to target the metabolic pathways of the major classes of antibacterial drugs, which supports a novel mechanism of action. Investigation of several species-specific effects suggested that cell signalling pathways were a possible target. Based on the structure of BDM-I and review of the scientific literature on cell signalling in bacteria, the hypothesis that BDM-I acted by inhibition of protein tyrosine phosphatases (PTP) was supported by demonstrating inhibition of human and bacterial PTP's in an enzyme assay. This mechanism was consistent with other demonstrated effects: inhibition of the intracellular pathogen, Chlamydia trachomatis; inhibition of swarming in Proteus spp. and inhibition of pigment production in Serratia marcescens; and with kill kinetics in bacteria and yeast. A pilot global genome analysis of BDM-I treated Bacillus subtilis did not detect differential expression of PTP genes but has provided many avenues for further investigation. This research further supports the development of BDM-I as a broad spectrum anti-infective drug.

Preliminary studies have shown that manuka honey affects the cell cycle of MRSA by impeding cell division, but mode of action was unknown. Cell division depends on the formation of septa and cleavage of peptidoglycan at cytokinesis. This study investigated how manuka honey might alter the cell cycle of EMRSA-15. Physiological and chemical changes in the bacteria exposed to manuka honey were determined using time to kill studies, confocal and electron microscopy. Data indicated that honey had a bactericidal effect on MRSA, inhibiting the cell cycle cytokinesis. Increased septum formation was noted in honey treated cells by transmission electron microscopy. Cell division components including FtsZ and Endo-B-N-Acetylglucosaminidase were investigated using cell wall turbidity assays, zymography, immunofluorescence and immuno gold labelling. Manuka honey treated MRSA cells showed a marked reduction in hydrolase activity after 12 hours compared to untreated cells. The immunofluorescence indicated an initial increase in FtsZ production followed by a significant decrease by 24 hours. PCR of FtsZ showed a 10% increase in production after 1 and 4 hours. Localization by gold labelling gave inconclusive results. Immunofluorescence of Endo-B-N-Acetylglucosaminidase showed a decrease in the amount of enzyme over 24 hours and localization by gold labelling indicated altered distribution of this enzyme. PCR showed no significant difference in expression. 2-D electrophoresis showed a differing proteomic profile between control cells and those treated with honey, with a potential target protein being identified. Methylglyoxal (an antibacterial component of manuka honey) was investigated after a report named this as potentially the active component of manuka honey. Results showed it has an effect but is not wholly responsible for the effects induced by manuka honey. It was concluded that increased numbers of cells with septa were formed and alteration in production of proteins and enzymes resulted in MRSA cells exposed to bactericidal concentrations of manuka honey. The work was also carried out with artificial honey controls, indicating that effects seen were not due to sugar content within honey or methylglyoxal content.

Made available in DSpace on 2014-06-12T15:55:46Z (GMT). No. of bitstreams: 2 arquivo8492_1.pdf: 1402042 bytes, checksum: b8f221ce546d7c25fd4f01c95011a7de (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Phthirusa pyrifolia é uma planta hemiparasita conhecida como Erva-depassarinho e muito utilizada na medicina popular. Visando conhecer melhor as substâncias contidas nas folhas desta planta, o presente trabalho teve como objetivos, a Purificação e Caracterização parcial de uma lectina, bem como Aplicações Biomédicas envolvendo esta proteína. As folhas da planta foram coletadas no campus da Universidade Federal de Pernambuco, lavadas, secas, trituradas e o Extrato Bruto (EB) a 10% (p/v) em solução de 0,15M NaCl foi obtido por agitação a 4ºC durante 4h, seguido de filtração e centrifugação. No período de dois anos, novos extratos foram obtidos para avaliação do ciclo sazonal na Atividade Hemaglutinante Específica (AHE) da lectina. Este ensaio evidenciou que o EB obtido no mês de março apresentou maior AHE, sendo submetido, então, à precipitação salina com sulfato de amônio. Do fracionamento salino resultou a F20-40%, com maior AHE. Inicialmente, uma alíquota da F20-40% foi cromatografada por afinidade em Sephadex G-100 utilizando 0,3M glicose como eluente. Em seguida os picos que apresentaram Atividade Hemaglutinante (AH) foram reunidos, dialisados, liofilizados e aplicados em cromatografia de troca iônica de CMcellulose. A amostra adsorvida na coluna foi eluída com solução 0,5M Tris-HCl, pH 8,5. O pico que apresentou AH foi dialisado, liofilizado, submetido à SDS-PAGE e a banda de protéica visualizada foi denominada PpyLL. O gel eletroforético na ausência do agente redutor mostrou a lectina com uma banda de 15,6 kDa e em presença de agente redutor, duas bandas com massas moleculares de 15,6 kDa e 7,8 kDa. PpyLL é uma glicoproteína ácida com pH ótimo 7,5, termoestável até 70ºC, apresenta afinidade por eritrócitos humanos tipo O+ e não foi inibida por açúcares simples, mas por frutose- 1,6-bifosfato e pelas glicoproteínas caseína, azocaseína e albumina de soro bovino. A Fluorimetria mostrou que a 70ºC, a lectina apresentou uma alta intensidade de fluorescência do aminoácido Triptófano, alterando assim a sua conformação. No Teste de Avaliação da atividade antimicrobiana, a PpyLL mostrou atividade contra as bactérias Staplylococcus epidermidis, Streptococcus faecalis, Bacillus subtilis e Klebsiella pneumoniaee, e contra os fungos Fusarium lateritium e Rhizoctonia solani. A nova lectina obtida através de um protocolo de purificação envolvendo cromatografias de afinidade e troca iônica apresenta características de grande relevância, as quais permitem a sua aplicação em processos biotecnológicos

There is an increasing interest in how therapeutic drugs could alter the human gut microbiota composition and function. While some knowledge is accumulating on the antimicrobial impact of some psychotropics on isolated strains or the gut microbiota of animal models, information about other classes of psychotropics and representative species from the human gut is poorly investigated. The antimicrobial effect of psychotropic drugs is usually neglected as a confounding factor when investigating gut microbiome biomarkers, knowing that patients are generally put in long-term medication. The purpose of the present study was to investigate (in vitro and ex-vivo) the antimicrobial activity of some oral commonly prescribed psychotropics from different therapeutic classes on colonic microbiota diversity and metabolism and the potential capacity of probiotics to alleviate related dysbiosis. The findings of this study revealed an important in vitro inhibitory activity of psychotropic drugs, which were also expressed as drastic alterations in gut microbiota composition ex-vivo. Indeed, the relative abundances of Firmicutes and Actinobacteria were lowered while the Proteobacteria population was increased. Families of Lachnospiraceae, Lactobacillaceae, and Erysipelotrichaceae were also declined by psychotropics (aripiprazole) treatment. These microbial changes were translated into a decrease of the major SCFA (butyrate, acetate, and propionate) at the metabolic level. The addition of a probiotic combination (Lactobacillus rhamnosus and Bifidobacterium longum) concomitantly with a psychotropic (aripiprazole) had a protective effect by attenuating the decline of microbiota composition and increasing the concentrations of SCFA. These findings provide evidence that psychotropics, through their antimicrobial effect, have the potential to alter the human gut microbiota composition and metabolism, while probiotics can mitigate the related dysbiosis.

Nós avaliamos a atividade antimicrobiana do mel coletado de ninhos de 12 espécies de abelhas nativas sem ferrão comumente encontrados no Brasil e 25 amostras de mel de Apis mellifera não pasteurizados que foram identificadas como sendo unifloral e uma amostra de mel multifloral. A atividade antimicrobiana de cada amostra de mel foi testada contra cinco espécies de bactérias patogênicas, uma espécie de fungo patogênico e uma espécie de levedura patogênica, comparando esta atividade com o mel terapêutico de manuka produzido por abelhas Apis mellifera na Nova Zelândia a partir do néctar de Leptospermum scoparium (Myrtaceae). Cinco das treze amostras de mel das abelhas sem ferrão foram bactericidas e oito foram fungicidas contra o fungo patogênico Trichophyton rubrum. Somente a levedura Candida albicans foi resistente a todas as amostras de mel. As amostras de mel de Apis mellifera que apresentaram atividade bactericida foram caju, romã e cana, nenhuma das amostras de mel de A. mellifera afetou o fungo T. rubrum. Os meis de Nannotrigona testaceicornis, Plebeia remota, Tetragona clavipes e Scaptotrigona depilis todos com alto nível de atividade antimicrobiana, foram significativamente mais eficiente em termos de atividade antimicrobiana que o mel de manuka, especialmente contra Escherichia coli, Klebsiella pneumoniae e T. rubrum. O mel artificial feito com os principais açúcares encontrados no mel e com teor de água semelhante, não teve atividade antimicrobiana em nossas análises. Nós também fizemos análises de espectrometria de massas das amostras de mel e encontramos alguns \"fingerprint\" característicos que foram associadas com a atividade antimicrobiana. / We evaluated the antimicrobial activity of honey collected from nests of 12 species of native stingless bees commonly found in Brazil and 25 unpasteurized honey samples of Apis mellifera that were identified as being unifloral and one multifloral honey sample. The antimicrobial activity of each honey sample was tested against five species of pathogenic bacteria, a pathogenic fungal species and a pathogenic yeast species, comparing this activity with therapeutic manuka honey produced by Apis mellifera bees in New Zealand from the nectar of Leptospermum scoparium (Myrtaceae). Five of thirteen samples of honey from the stingless bees were bactericidal and eight were fungicidal against the pathogenic fungus Trichophyton rubrum. Only the yeast Candida albicans was resistant to all honey samples. The Apis mellifera honey samples that showed bactericidal activity were caju, romã e cana, none of the A. mellifera honey samples affected the fungus T. rubrum. The honeys from Nannotrigona testaceicornis, Plebeia remote, Tetragona clavipes and Scaptotrigona depilis all had a high degree of antimicrobial activity, they were significantly more efficient in terms of antimicrobial activity than manuka honey, especially against Escherichia coli, Klebsiella pneumoniae and T. rubrum. Artificial honey, made with the main sugars found in honey and with similar water content, had no antimicrobial activity in our analyses. We also made mass spectrometry analyses of the honey samples and found some fingerprint characteristics that were associated with antimicrobial activity.