Antimicrobial Activity Of Plant Extracts Research Articles

Evaluation of antimicrobial activity of plant extracts from Brazilian savanna on cariogenic cocci

This study evaluated the antimicrobial activity of 138 aqueous extracts of 23 plants from Brazilian savanna on cariogenic cocci. Aqueous extracts were prepared from leaves, stems and barks of the plants. The initial screening of antimicrobial activity was performed by the agar diffusion method. Minimal inhibitory concentration (MIC) and minimal bactericidal concentrations were determined using broth dilution method. Time-kill curve were also determined on cells in suspension. The initial screening of antimicrobial activity evidenced that leaves extracts from M. ilicifolius, P. americana, J. cuspidifolia and bark extracts of P. rotundifolia were active on some strains but not all tested microorganisms. Only leaves, bark and stems extracts of M. urundeuva and P. cattleianum were able to inhibit all tested strains. The inhibitory activities of M. urundeuva and P. cattleianum were similar. In general, MBCs were four up to thirty two times higher than MICs. Time-kill curve of the extracts from P. cattleianum and M. urundeuvashowed that a log reduction of the planktonic bacterial inoculum was achieved within 60 minutes of contact.Descriptors: Bacteria; Prevention & Control; Plant Extracts; Dental Caries.

ANTIMICROBIAL ACTIVITY OF SELECTED INDIAN FOLK MEDICINAL PLANTS: MYRISTICA FATUA, ALSTONIA BOONEI, HELICTERES ISORA, VITEX ALTISSIMA AND ATALANTIA RACEMOSA

Objective: To determine antimicrobial activity of methanol, ethyl acetate and acetone extracts of Myristica fatua, Alstonia boonei, Helicteres isora, Vitex altissima and Atalantia racemosa against different species of pathogens, Streptococcus feacalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphyllococcus aureus, and Candida albicans.Methods: Antimicrobial activity of plant extracts was measured by agar well diffusion method.Results: Acetone extracts of Alstonia boonei showed the highest inhibitory effect against Escherichia coli (21.00 ± 1.00 mm) and Streptococcus faecalis (19.00 ± 1.00 mm). All the extracts of Heliteres isora leaves showed different zone of inhibition observed in all the tested pathogens ranges between (8.13 ± 1.53 – 15.25 ± 1.23 mm). Ethyl acetate extract of Vitex altissima showed highest activity against Bacillus sublilis (19.67 ± 1.53 mm). Methanol and acetone leaves extracts of Atalantia racemosa have good fungal activity against the Candida albicans (19.33 ± 1.26 mm - 16.00 ± 1.00 mm). Methanol extract of Myristica fatua showed high antimicrobial activity against Pseudomonas aeruginosa (15.10 ± 0.17 mm) and Bacillus subtilis (14.23 ± 0.21 mm).Conclusion: The results from the study suggest that the leaves Myristica fatua, Alstonia boonei, Helicteres isora, Vitex altissima and Atalantia racemosa showed good antimicrobial activity against the different pathogens. They are used as the alternative source for the control and treatment of microbial infections.Keywords: Antimicrobial activity, Leaves extracts, Well diffusion method, Pathogenic strains.

ANTIMICROBIAL ACTIVITIES OF SOME SAUDI ARABIAN HERBAL PLANTS.

Background:Several edible plants are used in Kingdom of Saudi Arabia since early time to control microbial infections. In the present study, twenty-four Saudi Arabian medicinal plants d according to traditionally used were select and investigated for the antimicrobial activitiesMaterials and Methods:This study was designed at evaluating the antimicrobial activities of the methanol extracts of twenty-four species of sixteen plant families used in the traditional medicine by Saudi Arabian people for the treatment of numerous ailments of the microbial and non-microbial origin against four Gram-positive, four Gram-negative bacteria and four fungi and yeast using the agar well diffusion method.Results:Of most of the plants tested were found to be active against two to eight organisms. Five plants were active against eight organisms. The data appeared that extracts of Echium arabicum (SY-176), Rhantarium epapposum (SY-Rumex vesicarus (SY-181), Ziziphus nummularia (SY-188), Caylusea hexagyna (SY-197) and Artemisia monosperma (SY-198) have anti-microbial activity against the most of tested bacteria, fungi and yeast. Whereas (SY-, the extracts of Teucrium oliverianum (SY-175), Zilla spinosa (SY-187), and Rhazya stricta (SY-195) have poor action against the tested bacteria, fungi and yeast.Conclusion:The antimicrobial activity of plant extracts against bacteria was more effective than against fungi

Identification of and antimicrobial activity of plant extracts against Pseudomonas putida from rot fruiting bodies of Pleurotus eryngii

Recently, rot disease caused by bacteria has seriously affected the yield of Pleurotus eryngii in China, as well as spreading so quickly that brought enormous economy loss to the mushroom industry. Therefore, we isolated and identified the pathogen according to morphologic characteristic and 16S rDNA sequence, which demonstrated that the pathogen was Pseudomonas putida. Simultaneously, the active ingredients of twelve plants were extracted and their antimicrobial activities against the pathogen were evaluated by measuring the inhibition zone. Four better essential oils were selected for further investigation of their disease control efficiency by spraying them on the surface of the mushroom. Overall, the extract of Ginkgo biloba presented the highest efficiency in controlling the rot disease. The results from this research suggest that the extract of plants has a good potential for controlling rot disease in P. eryngii.

Antibacterial, antioxidant and anti-proliferative properties and zinc content of five south Portugal herbs

Context: Crataegus monogyna L. (Rosaceae) (CM), Equisetum telmateia L. (Equisataceae) (ET), Geranium purpureum Vil. (Geraniaceae) (GP), Mentha suaveolens Ehrh. (Lamiaceae) (MS), and Lavandula stoechas L. spp. luisieri (Lamiaceae) (LS) are all medicinal. Objective: To evaluate the antioxidant, antiproliferative and antimicrobial activities of plant extracts and quantify individual phenolics and zinc. Material and methods: Aerial part extracts were prepared with water (W), ethanol (E) and an 80% mixture (80EW). Antioxidant activity was measured with TAA, FRAP and RP methods. Phenolics were quantified with a HPLC. Zinc was quantified using voltammetry. Antibacterial activity (after 48 h) was tested using Enterococcus faecalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. Antiproliferative activity (after 24 h) was tested using HEP G2 cells and fibroblasts. Results: Solvents influenced results; the best were E and 80EW. GP had the highest antioxidant activity (TAA and FRAP of 536.90 mg AAE/g dw and 783.48 mg TE/g dw, respectively). CM had the highest zinc concentration (37.21 mg/kg) and phenolic variety, with neochlorogenic acid as the most abundant (92.91 mg/100 g dw). LS was rich in rosmarinic acid (301.71 mg/100 g dw). GP and LS inhibited the most microorganisms: B. cereus, E. coli and S. aureus. GP also inhibited E. faecalis. CM had the lowest MIC: 5830 μg/mL. The antibacterial activity is explained by the phenolics present. LS and CM showed the most significant anti-proliferative activity, which is explained by their zinc content. Conclusion: The most promising plants for further studies are CM, LS and GP.

Antimicrobial and anti-Quorum Sensing activities of selected medicinal plants of Ethiopia: Implication for development of potent antimicrobial agents.

BackgroundTraditional medicinal plants have been used as an alternative medicine in many parts of the world, including Ethiopia. There are many documented scientific reports on antimicrobial activities of the same. To our knowledge, however, there is no report on the anti-Quorum Sensing (Quorum Quenching, QQ) potential of traditional Ethiopian medicinal plants. As many of the opportunistic pathogenic bacteria depend on Quorum Sensing (QS) systems to coordinate their virulence expression, interference with QS could be a novel approach to control bacterial infections. Thus, the aim of this study was to evaluate selected medicinal plants from Ethiopia for their antimicrobial activities against bacterial and fungal pathogens; and to assess the interference of these plant extracts with QS of bacteria.MethodsAntimicrobial activities of plant extracts (oil, resins and crude extracts) were evaluated following standard agar diffusion technique. The minimum inhibitory concentrations (MIC) of potent extracts were determined using 96 well micro-titer plates and optical densities were measured using an ELISA Microplate reader. Interference with Quorum Sensing activities of extracts was determined using the recently established E. coli based reporter strain AI1-QQ.1 and signaling molecule N-(ß-ketocaproyl)-L-homoserine lactone (3-oxo-C6-HSL).ResultsPetroleum ether extract of seed of Nigella sativa exhibited the highest activity against both the laboratory isolated Bacillus cereus [inhibition zone (IZ), 44 ± 0.31 mm] and B. cereus ATCC 10987 (IZ, 40 ± 2.33 mm). Similarly, oil extract from mature ripe fruit husk of Aframomum corrorima and mature unripe fruit of A. corrorima revealed promising activities against Candida albicans ATCC 90028 (IZ, 35 ± 1.52 mm) and Staphylococcus aureus DSM 346 (IZ, 25 ± 1.32 mm), respectively. Antimicrobial activities of oil extract from husk of A. corrorima and petroleum ether extract of seed of N. sativa were significantly higher than that of the control antibiotic [Gentamycin sulfate, (IZ, 25–30 mm)]. The lowest MIC value (12.5 mg/mL) was recorded for oil from husk of A. corrorima against Pseudomonas aeruginosa. Of the total eighteen extracts evaluated, two of the extracts [Methanol extract of root of Albiza schimperiana (ASRM) and petroleum ether extract of seed of Justica schimperiana (JSSP)] interfered with cell-cell communication most likely by interacting with the signaling molecules.ConclusionTraditional medicinal plants from Ethiopia are potential source of alternative medicine for the local community and scientific research in search for alternative drugs to halt challenges associated with the emerging antimicrobial resistance. Furthermore, the Quorum Quenching activities observed in two of the plant extracts calls for more comprehensive evaluation of medicinal plants for the control of many bacterial processes and phenotypic behaviors such as pathogenicity, swarming, and biofilm formation. Being the first assessment of its kind on the potential application of Ethiopian traditional medicinal plants for interference in microbial cell-cell communication (anti-Quorum Sensing activities), the detailed chemistry of the active compounds and possible mechanism(s) of actions of the bio-molecules responsible for the observed interference were not addressed in the current study. Thus, further evaluation for the nature of those active compounds (bio-molecules) and detailed mechanism(s) of their interaction with microbial processes are recommended.

Antimicrobial Activity of Extracts from Native Plants of Temperate Australia

Introduction: Significant effort has been invested in looking at the antimicrobial activity of plant extracts from tropical regions of Australia, with less interest in those from more temperate environments. We sought to redress this imbalance by examining antimicrobial activities of extracts from native plants of Victoria. Methods: Sixteen plant samples were obtained around the Ballarat region of Victoria. Plant material was desiccated, ground and extracted with methanol at room temperature. Methanol extracts were subsequently dissolved in water, filtered and freeze dried. Extracts were dissolved in water and their activity determined against eight bacterial species. Plant extracts that showed appreciable antibacterial activity in the initial antimicrobial screen were examined further with both their MICs and MBCs determined. Results: Ten of the sixteen plant extracts showed antimicrobial activity. Extracts of Eucalyptus, Melaleuca, Prostanthera and Westringia were particularly active with MICs as low as 0.25 mg/ml against organisms including P. aeruginosa and S. aureus. Conclusion: The current study demonstrates the antimicrobial activity of plant extracts from temperate Australia. These may serve as precursors for future chemotherapy agents.

Antimicrobial and antioxidant activity of methanol extracts of Arnebia benthamii (Wall ex. G. Don) Johnston—a critically endangered medicinal plant of North western Himalaya

Arnebia benthamii is one of the promising folklore medicinal plants which is being traditionally used over the years for the treatment of various prevailing diseases in the area. The aim of this research work was to evaluate the antimicrobial activity and antioxidant activity of methanolic plant extract. Antimicrobial activity of the plant extract (250–500 μg/ml concentration) was analyzed against Escherichia coli CD0006, Pseudomonas aeruginosa CD0023, Shigella flexneri CD0033, Klebsiella pneumonia CD0049, Salmonella typhimurium CD0003, Staphylococcus aureus CD0001, Aspergillus versicolor CDF0011, Candida albicans CDF0032, Candida kruesie CDF0016, Candida parapsilosis CDF0013, Aspergillus flavus CDF0024, and Acremonium spp. CDF0027. The free radical scavenging assay of the plant extracts was evaluated by various antioxidant methods. Comparative analysis reveals that the aerial part exhibited the highest antibacterial activities against almost all tested bacterial strains with the highest inhibition zone diameter (IZD) (30 ± 0.54) was recorded on P. aeruginosa CD0023 and E. coli CD0006. All the fungal strains except C. parapsilosis CDF0013 were more or less inhibited by both aerial and root part extracts of the plant. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values recorded revealed that the P. aeruginosa CD0023 was inhibited by the least concentration of 75 μg/ml of the aerial part methanol extract. The antioxidant activity of the aerial and root part extracts was almost of the same strength with the root part slightly showing a higher scavenging effect in a concentration-dependent manner in superoxide anion and hydroxyl radicals. The plant has got a broad spectrum antimicrobial and antioxidant activity and has a promising potential for treating diseases.

Diversity of antagonistic bacteria isolated from medicinal plant Peganum harmala L.

The antimicrobial activity of plant extract of Peganum harmala, a medicinal plant has been studied already. However, knowledge about bacterial diversity associated with different parts of host plant antagonistic to different human pathogenic bacteria is limited. In this study, bacteria were isolated from root, leaf and fruit of plant. Among 188 bacterial isolates isolated from different parts of the plant only 24 were found to be active against different pathogenic bacteria i.e. Escherichia coli, Methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecium, Enterococcus faecalis and Pseudomonas aeruginosa. These active bacterial isolates were identified on the basis of 16S rRNA gene analysis. Total population of bacteria isolated from plant was high in root, following leaf and fruit. Antagonistic bacteria were also more abundant in root as compared to leaf and fruit. Two isolates (EA5 and EA18) exhibited antagonistic activity against most of the targeted pathogenic bacteria mentioned above. Some isolates showed strong inhibition for one targeted pathogenic bacterium while weak or no inhibition for others. Most of the antagonistic isolates were active against MRSA, following E. faecium, P. aeruginosa, E. coli and E. faecalis. Taken together, our results show that medicinal plants are good source of antagonistic bacteria having inhibitory effect against clinical bacterial pathogens.

Micropropagation and Evaluation of Phenolic Content, Antioxidant and Antimicrobial Activities of Vernonia cinerea (Linn.) Less

Vernonia cinerea, belonging to the family Asteraceae, is of wide medicinal application. This study investigated the antimicrobial, antioxidant activities and the total phenolic contents of wild plant of Vernonia cinerea with its respective shoot cultures.Nodal explants of V. cinerea were cultured on Murashige and Skoog (MS) medium supplemented with various combinations of BAP (0.5-2.5 mg/L) and NAA (0.1-0.5 mg/L) including various concentrations of Gibberllic acid for subculturing. The antimicrobial activity of plant extracts was tested using agar well diffusion and macrodilution methods for zone of inhibition (ZI), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).The free radical scavenging test was conducted using 2,2, diphenyl-1-picryl hydrazyl (DPPH) reagent while total phenolic contents (TPC) were measured by Folin–Ciocalteau reagent. Maximum shoot proliferation of 11.42 ± 2.26 cm was obtained from MS medium supplemented with 0.5 mg/L BAP + 0.1 mg/L NAA. All extracts displayed moderate antimicrobial potential against the tested pathogens in the range of 9.0-13.1 mm ZI, with highest MIC of 0.78 mg/mL and 1.56 mg/mL fromMPE and WPE, respectively.The IC50 values of 4.49 and 5.10 μg/mL was obtained in WPE and MPE. The MPE had TPC of 6.66 ± 0.83 mg GAE/g compared to the WPE with TPC of 5.43 ± 1.31 mg GAE/g. The crude methanol extracts of wild and micropropagated plants of V. Cinerea showed high amounts of phenolic compounds, which could present them as candidates for future search for antimicrobial and antioxidant agents for different ailments.Keywords: Micropropagation, Antioxidant, DPPH, Phenolic Compound, Vernonia cinerea

Research Regarding the Antimicrobial Activity of Plant Extracts

The investigations regarding the use of plant extracts for their antimicrobial activity is becoming more intense nowadays. The goal of this paper was to evaluate the antimicrobial activity of several plant extracts in order to provide a better understanding of the essential role of the use of plant natural compounds as a primary source of antimicrobial products. Hydroalcoholic extracts of five medicinal plants were tested for their antimicrobial activity against Pythium sp. The plants considered for study were marigold (Tagetes patula), horsetail (Equisetum arvense), elderberry (Sambucus nigra), burdock (Arctium lappa) and liquorice (Glycyrrhiza glabra). The plant materials used for extractions were obtained from healthy dried plants collected from natural populations on non-polluted lands. The experiments demonstrated that plants possess strong antimicrobial activity and that plant based products cand be effective in controlling microbial growth inhibition. Plant extracts may potentially control the growth and development of pathogenic microorganisms thus representing an alternative in plant protection management and human and veterinary medicine also.

Evaluation of the Antimicrobial Activities from Secondary Metabolites in Plant Families (Boraginaceae, Fabaceae, Lamiaceae, and Lauraceae)

For several decades, there has been an increased interest in the antimicrobial activities of different extracts obtained from traditional medicinal plants. There are more than 20,000 species of plants used in traditional medicines. Drugs can be derived from natural products, which are usually secondary metabolites and their derivatives. The increased prevalence of antibiotic‐resistant bacteria emerging from the extensive use of antibiotics may render the current antimicrobial agents insufficient to control at least some bacterial infections. Therefore, the search for new antimicrobial agents is an important line of research.The objective of this study was to determine the antimicrobial activities of plant extracts from Sassafras albidum, Ehretia anacua, Melissa officinalis, Eysenhardtia texana, and Melissa odorata. The ethanol and aqueous extracts were prepared for each of the five plant species and tested against Staphylococcus aureus and Pseudomonas aeruginosa. To test the antimicrobial activity, the disk diffusion method was performed using streptomycin as a positive control. Zone of inhibitions were measured using a vernier caliper. Results showed an antimicrobial potential for the Ehretia anacua (family: Boraginaceae) ethanol extract against Staphylococcus aureus; therefore, it was tested for more antibacterial and antifungal activities, using acetone, ethanol, and diethyl ether extracts. Ehretia anacua was also subjected to qualitative and quantitative phytochemical analysis to determine the exact constituents exhibiting these biological activities.

Antimicrobial activity of plant extracts against sexually transmitted pathogens

Comprehensive management of sexually transmitted infections (STIs) using vaginal or rectal microbicide-based intervention is one of the strategies for prevention of HIV infection. Herbal products have been used for treating STIs traditionally. Herein, we present in vitro activity of 10 plant extracts and their 34 fractions against three sexually transmitted/reproductive tract pathogens – Neisseria gonorrhoeae, Haemophilus ducreyi and Candida albicans. The plant parts were selected; the extracts/fractions were prepared and screened by disc diffusion method. The minimum inhibitory and minimum cidal concentrations were determined. The qualitative phytochemical analysis of selected extracts/fractions showing activity was performed. Of the extracts/fractions tested, three inhibited C. albicans, ten inhibited N. gonorrhoeae and five inhibited H. ducreyi growth. Our study demonstrated that Terminalia paniculata Roth. extracts/fractions inhibited growth of all three organisms. The ethyl acetate fraction of Syzygium cumini Linn. and Bridelia retusa (L.) Spreng. extracts was found to inhibit N. gonorrhoeae at lowest concentrations.

Comparação de métodos para avaliação da atividade antimicrobiana e determinação da concentração inibitória mínima (cim) de extratos vegetais aquosos e etanólicos

Vários estudos estão sendo conduzidos para a descoberta de novos agentes antimicrobianos provenientes de plantas, para que possam ser utilizados em produtos farmacêuticos, cosméticos e na indústria alimentícia. A ausência de padronização de métodos utilizados para a avaliação de extratos vegetais com potencial antimicrobiano dificulta a comparação de resultados. Considerando a necessidade de estabelecer um método com resultados consistentes para avaliar a atividade antimicrobiana dos extratos vegetais, este trabalho propôs-se a avaliar a atividade antimicrobiana e determinar a concentração mínima inibitória de extratos de plantas da família Myrtaceae sobre diferentes micro-organismos, utilizando três métodos para avaliação de antimicrobianos. Os métodos empregados foram microdiluição em caldo e difusão em ágar por disco e poço. Foram avaliados os extratos de Psidium guajava, Myrciaria cauliflora e Syzygium cumini sobre bactérias Gram-positivas, negativas e levedura. Em geral, a inibição promovida pelos extratos no teste de difusão em ágar por poço foi maior do que os valores obtidos por disco, independentemente do extrato vegetal testado. Contudo, a atividade inibitória de todos os micro-organismos só pôde ser determinada com o método de microdiluição em caldo, que também apresentou os resultados mais reprodutíveis, e mostrou-se o mais econômico e confiável para se avaliar a atividade antimicrobiana de extratos vegetais quando comparado aos outros métodos

Plantas e constituintes químicos empregados em Odontologia: revisão de estudos etnofarmacológicos e de avaliação da atividade antimicrobiana in vitro em patógenos orais

Produtos derivados de plantas podem representar estratégia promissora na odontologia. Desse modo, o objetivo deste trabalho foi levantar na literatura os estudos sobre o uso popular de plantas em afecções orais, bem como os estudos de avaliação da atividade antimicrobiana in vitro de extratos vegetais e compostos isolados sobre patógenos orais, no período de 1996 a 2011. Quarenta e sete famílias botânicas foram referidas, com maior número de citações para Anacardiaceae, sendo Anacardium occidentale L., a espécie mais citada. O levantamento sobre estudos de avaliação antimicrobiana relacionou extratos de sessenta e seis espécies vegetais pertencentes a trinta e oito famílias botânicas, destacando-se Anacardiaceae, com pesquisas realizadas de forma predominante com as folhas, investigadas pelo método de difusão em ágar. Cinquenta e oito substâncias isoladas de plantas foram avaliadas, demonstrando que Terminalia chebula Retz (Combretaceae) representa a espécie vegetal com atividade antimicrobiana in vitro mais significativa, apresentando halo de inibição de 32,97 mm contra Staphylococcus aureus, microrganismo encontrado em infecções orais; enquanto ácido tetra iso-alfa isolada de Humulus lupulus L. (Canabinaceae) apresentou maior halo de inibição para Streptococcus mutans (26,0 mm). Os resultados apresentados devem estimular o desenvolvimento dos estudos de validação na garantia do uso seguro e eficaz de espécies vegetais em odontologia.

Antimicrobial activity of Turkish Viurnum species

Antimicrobial activities of aqueous and ethanolic extracts of Viburnum opulus L., V. orientale Pallas, V. tinus L. and V. lantana L. against Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 (MRSA), Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae RSKK 574 and Candida albicans ATCC 10231 were carried out. The disc diffusion and tube dilution techniques were used to determine the antimicrobial activities of plant extracts. The ethanolic extracts of tested species of Viburnum exhibited better antimicrobial activity than that of aqueous extracts. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18044 Bangladesh J. Bot. 42(2): 355-360, 2013 (December)

Use of Plant Extracts to Control and Treat AB5 Enterotoxin-Related Diarrhea

Plants contain a broad spectrum of small molecules with potential antimicrobial properties. Here, we review the antimicrobial activities of plant extracts against enterotoxic bacteria encoding AB5 toxins, including Vibrio cholerae, Shigella dysenteriae and enterotoxic Escherichia coli strains. Several plant extracts have strong antimicrobial effects and the potential to boost Oral Rehydration Therapy, which is the first line of treatment for acute diarrhea.

English

In vitro antibacterial activities of five extracts from dietary medicinal plants were investigated by agar-well diffusion method (AWD), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against 13 foodborne pathogenic bacteria reference strains; four Gram positive bacteria including Staphylococcus aureus (NCINB 50080), Bacillus cereus (NCINB 50014), Citrobacter freundi (ATCC 8090) and Listeria innocua (ATCC 33090) as well as nine Gram negative bacterial reference strains including Escherichia coli (ATCC 11775), E. coli O157 (ATCC 700728), Salmonella typhimurium (ATCC 13311), Shigella boydii (ATCC 9207), Shigella sonnei (ATCC 25931), Shigella flexneri (ATCC 12022), Pseudomonas aeruginosa (NCINB 50067), Klebsiella pneumoniae (NCTC 9633) and Proteus mirabilis (ATCC 14153). Four ethanolic extracts underwent acetone wash then analyzed for their principal components using gas chromatography-mass spectrometry (GC-MS), Oleamide was the predominant compound in onion, garlic, wheat germ and Nigella sativa which have great antibacterial effect. The tested acetone extracts exhibit variable antibacterial activity against foodborne pathogens which differ according to the compounds clarified in the GC-MS analysis. Garlic extract showed the best antibacterial activities, GC-MS analysis showed the presence of five compounds including; tetrasulfide, monosilane, oleamide, stearoylamide and vitamin E.  Testing for the presence of 91 pesticides in the tested extracts using GC-MS analysis proved complete absence of pesticides which indicate that the antibacterial activities showed was due to the active components in the tested extracts and not due to the pesticides contaminants. Antimicrobial activities of plant extracts revealed that garlic has greatest inhibitory effect against S. aureus NCINB 50080 followed by S. Typhimurium ATCC 13311 with zone of inhibition 28 mm, 30 mm for AWDT and and 2.61 µg/ml for MIC, respectively. The best hindrance abilities was shown with garlic extracts with mean zone of inhibition (23.46 mm) followed by onion (18.15 mm), wheat germ  extract (17.38 mm), mint (17.15 mm) then Nigella sativa (15.69 mm). Results of MIC and MBC confirm the antibacterial activities of the tested extracts.   Key words: Antibacterial activity, agar well diffusion test (AWDT) minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), seed, bulb, ethanolic extracts.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry

BackgroundWith the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7).MethodsAntimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1β and TNF-α) using ELISA.ResultsIn determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1β in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL).ConclusionsAll plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.

Are Plant Extracts a Potential Therapeutic Approach for Genital Infections?

More than 40% of the new drugs registered from 1981 to 2006 were obtained, derived or inspired from natural compounds. The influence of natural products in the anti-infective area is quite marked, being a great percentage of drugs derived or extracted from natural products. Vaginal infections are one of the most common reasons a women visits a gynecologist. Given the high popularity of natural therapies among women who suffer from chronic infections, it is urgent for women's healthcare providers to be knowledgeable about such therapies. Additionally, many phytotherapeutic products have been suggested as natural sources of antimicrobial compounds. The increased resistance to conventional antibiotics is one of the main factors justifying the search and development of new antimicrobial agents, especially those of natural origin. Currently, phytochemicals are considered by the scientific community as very attractive targets for potential drug discovery and therapy. In this review, we will focus on the most relevant reports published during the last twenty years about the antimicrobial activity of plant extracts upon microorganisms most frequently involved in genital infections, such as Candida spp., Gardnerella vaginalis, Trichomonas vaginalis and Human papillomavirus. The relationship between their composition and the antimicrobial effects will be highlighted and vaginal therapeutic delivery systems that vehicle plant extracts both commercialized and under investigation will be included.