Análisis fitoquímico preliminar y actividad antifúngica In vitro del extracto etanólico de las hojas de Solanum hispidum pers. Colectadas en la localidad Obraje - Perú / Preliminary phytochemical analysis and in vitro antifungal activity of the ethanolic extract of the leaves of Solanum hispidum pers. collected in the locality in Obraje - Peru

RESUMEN Objetivo . Analizar y determinar la actividad antifúngica in vitro del extracto etanólico de las hojas de Solanum hispidum Pers. Materiales y métodos . Se realizó el análisis fitoquímico preliminar cualitativo mediante reacciones de color y precipitación. Se investigó la actividad antifúngica in vitro frente a Candida albicans, Aspergillus brasilensis y Trichophyton mentagrophytes usando el método de difusión en pozo de agar y el ensayo de la concentración mínima inhibitoria (CMI). Resultados . El análisis fitoquímico preliminar cualitativo mostró la presencia de compuestos fenólicos, taninos, flavonoides, esteroides, alcaloides y saponinas. La actividad antifúngica in vitro fue demostrada para todos cultivos fúngicos con halos de inhibición entre 23 a 26 mm. Los valores de la CMI fueron de 125, 250 y 125 µg/mL para C. albicans, A. brasilensis y T. mentagrophytes, respectivamente. Conclusiones. El extracto etanólico de las hojas de Solanum hispidum Pers contiene importantes metabolitos secundarios y tiene moderada actividad antifúngica.

ABSTRACT Objective. To analyze and determine the in vitro antifungical activity of the ethanolic extract of the leaves of Solanum hispidum Pers. Materials and methods. We carried out a preliminary qualitative phytochemical analysis by color and precipitation reactions. We evaluated the in vitro antifungical activity against Candida albicans, Aspergillus brasilensis and Trichophyton mentagrophytes by using the agar well diffusion method and the minimum inhibitory concentration (MIC) assay. Results. Preliminary qualitative phytochemical analysis showed the presence of phenolic compounds, tannins, flavonoids, steroids, alkaloids and saponins. In vitro antifungal activity was demonstrated for all fungal cultures with inhibition halos between 23 to 26 mm. The MIC values were 125, 250, and 125 μg/mL for C. albicans, A. brasilensis, and T. mentagrophytes, respectively. Conclusions. The ethanolic extract of the leaves of Solanum hispidum Pers. contains important secondary metabolites and has moderate antifungical activity.

Antimycobacterial and antimalarial activities of endophytic fungi associated with the ancient and narrowly endemic neotropical plant Vellozia gigantea from Brazil

BACKGROUND Endophytic fungi, present mainly in the Ascomycota and Basidiomycota phyla, are associated with different plants and represent important producers of bioactive natural products. Brazil has a rich biodiversity of plant species, including those reported as being endemic. Among the endemic Brazilian plant species, Vellozia gigantea (Velloziaceae) is threatened by extinction and is a promising target to recover endophytic fungi. OBJECTIVE The present study focused on bioprospecting of bioactive compounds of the endophytic fungi associated with V. gigantea, an endemic, ancient, and endangered plant species that occurs only in the rupestrian grasslands of Brazil. METHODS The capability of 285 fungal isolates to produce antimicrobial and antimalarial activities was examined. Fungi were grown at solid-state fermentation to recover their crude extracts in dichloromethane. Bioactive extracts were analysed by chromatographic fractionation and NMR and displayed compounds with antimicrobial, antimycobacterial, and antimalarial activities. FINDINGS Five fungi produced antimicrobial and antimalarial compounds. Extracts of Diaporthe miriciae showed antifungal, antibacterial, and antimalarial activities; Trichoderma effusum displayed selective antibacterial activity against methicillin-resistant Staphylococcus aureus and Mycobacterium intracellulare; and three Penicillium species showed antibacterial activity. D. miriciae extract contained highly functionalised secondary metabolites, yielding the compound epoxycytochalasin H with high antimalarial activity against the chloroquine-resistant strain of Plasmodium falciparum, with an IC50 approximately 3.5-fold lower than that with chloroquine. MAIN CONCLUSION Our results indicate that V. gigantea may represent a microhabitat repository hotspot of potential fungi producers of bioactive compounds and suggest that endophytic fungal communities might be an important biological component contributing to the fitness of the plants living in the rupestrian grassland.

In vitro susceptibility of nematophagous fungi to antiparasitic drugs: interactions and implications for biological control / Suscetibilidade in vitro de fungos nematófagos à antiparasitários: interações e implicações para o controle biológico

Abstract The fast anthelmintic resistance development has shown a limited efficiency in the control of animal's endoparasitosis and has promoted research using alternative control methods. The use of chemicals in animal anthelmintic treatment, in association with nematophagous fungi used for biological control, is a strategy that has proven to be effective in reducing the nematode population density in farm animals. This study aims to verify the in vitro susceptibility of the nematophagous fungi Arthrobotrys oligospora, Duddingtonia flagrans and Paecilomyces lilacinus against the antiparasitic drugs albendazole, thiabendazole, ivermectin, levamisole and closantel by using the Minimum Inhibitory Concentration (MIC). MICs ranged between 4.0 and 0.031 µg/mL for albendazole, thiabendazole and ivermectin, between 0.937 and 0.117 µg/mL for levamisole, and between 0.625 and 0.034 µg/mL for closantel. The results showed that all antiparasitic drugs had an in vitro inhibitory effect on nematophagous fungi, which could compromise their action as agents of biological control. D. flagrans was the most susceptible species to all drugs.

Resumo O desenvolvimento rápido da resistência anti-helmíntica demonstrou a eficiência limitada no controle de endoparasitoses em animais, e promoveu a investigação em métodos de controles alternativos. O uso de produtos químicos no tratamento anti-helmíntico animal, em associação com fungos nematófagos utilizados para o controlo biológico, é uma estratégia que tem provado ser eficaz na redução da densidade da população de nematódeos em animais agrícolas. Este estudo teve como objetivo verificar a suscetibilidade in vitro dos fungos nematófagos Arthrobotrys oligospora, Duddingtonia flagrans e Paecilomyces lilacinus frente aos antiparasitários albendazol, tiabendazol, ivermectina, levamisol e closantel, usando a concentração inibitória mínima (MIC). Os MICs variaram entre 4,0 e 0,031 μg/mL para albendazol, tiabendazol e ivermectina, entre 0,937 e 0,117 μg/mL para o levamisol, e entre 0,625 e 0,034 μg/mL para closantel. Os resultados mostraram que todos os antiparasitários tiveram um efeito inibidor in vitro sobre os fungos nematófagos, o que poderia comprometer suas atividades como agentes de controle biológico. D. flagrans foi a espécie mais sensível a todas as drogas.

Estimation of antioxidant, antimicrobial activity and brine shrimp toxicity of plants collected from Oymyakon region of the Republic of Sakha (Yakutia), Russia

BACKGROUND: Several plants are reported to be produced various biological active compounds. Lichens from the extreme environments such as high altitude, high UV, drought and cold are believed to be synthesized unique types of secondary metabolites than the other one. Several human pathogenic bacteria and fungi have been muted into drug resistant strains. Various synthetic antioxidant compounds have posed carcinogenic effects. This phenomenon needs further research for new effective drugs of natural origin. This manuscript aimed to screen new source of biological active compounds from plants of subarctic origin. RESULTS: A total of 114 plant species, including 80 species of higher plants, 19 species of lichens and 15 species of mosses, were collected from Oymyakon region of the Republic of Sakha (Yakutia), Russia (63˚20′N, 141˚42′E - 63˚15′N, 142˚27′E). Antimicrobial, DPPH free radical scavenging and brine shrimp (Artemia salina) toxicity of all crude extract were evaluated. The obtained result was analyzed and compared with commercial standards. A total of 28 species of higher plants showed very strong antioxidant activity (DPPH IC50, 0.45-5.0 µg/mL), 13 species showed strong activity (DPPH IC50, 5-10 µg/mL), 22 species showed moderate antioxidant activity (DPPH IC50,10-20 µg/mL) and 17 species showed weak antioxidant activity (DPPH IC50 more than 20 µg/mL). Similarly, 3 species of lichen showed strong antioxidant activity, one species showed moderate and 15 species showed weak DPPH reducing activity. In addition, 4 species of mosses showed moderate antioxidant activity and 11 species showed weak antioxidant activity. Similarly, extracts of 51 species of higher plants showed antimicrobial (AM) activity against Staphylococcus aureus and 2 species showed AM activity against Candida albicans. Similarly, 11 species of lichen showed AM activity against S. aureus and 3 species showed AM activity against Escherichia coli. One species of moss showed AM activity against S. aureus. And finally, one species of higher plant Rheum compactum and one species of lichen Flavocetraria cucullata showed the toxicity against Brine shrimp larvae in 100 µg/mL of concentration. CONCLUSION: The experimental results showed that subarctic plant species could be potential sources of various biologically active natural compounds.

Antibacterial and antifungal activities of crude plant extracts from Colombian biodiversity

On a global scale, people have used plants to treat diseases and infections, and this has raised interest on the plant biodiversity potencial in the search of antimicrobial principles. In this work, 75 crude n-hexanes, dichloromethane and methanol extracts from the aerial parts of 25 plants belonging to four botanical families (Asteraceae, Euphorbiaceae, Rubiaceae and Solanaceae), collected at the Natural Regional Park Ucumari (Risaralda, Colombia), were evaluated for their antibacterial and antifungal activities by the agar well diffusion method. The antibacterial activities were assayed against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis, and three Gram-negative ones named, Klebsiella pneumoniae, Escherichia coli and Pseudomonas aeruginosa. In addition, the same plant extracts were tested against the yeast Candida albicans and the fungi Aspergillus fumigatus and Fusarium solani. Overall, the plant extracts examined displayed better bactericide rather than fungicide activities. In general, the best antibacterial activity was showed by the plant extracts from the Rubiaceae family, followed in order by the extracts from the Euphorbiaceae and Solanaceae ones. It is important to emphasize the great activity displayed by the methanol extract of Alchornea coelophylla (Euphorbiaceae) that inhibited four out of five bacteria tested (B. Subtilis, P. aeruginosa, S. aureus and E. coli). Furthermore, the best Minimal Inhibitory Concentration for the extracts with antifungal activities were displayed by the dichloromethane extracts from Acalypha diversifolia and Euphorbia sp (Euphorbiaceae). The most susceptible fungus evaluated was F. Solani since 60% and 20% of the dichloromethane and methanol extracts evaluated inhibited the growth of this phytopathogenic fungus. The antimicrobial activity of the different plant extracts examined in this work could be related to the secondary metabolites contents and their interaction and susceptibility of pathogenic microorganism evaluated.

Alrededor del mundo, la gente ha usado las plantas para tratar enfermedades e infecciones, este potencial ha hecho que se incremente el interés en la biodiversidad vegetal como fuente de principios antimicrobianos. En este trabajo, se evaluaron 75 extractos crudos de n-hexano, diclorometano y metanol, obtenidos a partir de la parte aérea de 25 especies de plantas proveniente de cuatro familias botánicas (Asteraceae, Euphorbiaceae, Rubiaceae y Solanaceae), colectadas en el Parque Regional Natural Ucumari (Risaralda, Colombia); los cuales fueron evaluados por sus actividades antibacteriana y antifúngica a través del método de difusión en pozo. La actividad antibacteriana fue ensayada frente a las bacterias Gram-positivas Staphylococcus aureus y Bacillus subtilis, y las g-negativas Klebsiella pneumoniae, Escherichia coli y Pseudomonas aeruginosa. Adicionalmente, las mismas plantas fueron evaluadas frente a la levadura Candida albicans y los hongos Aspergillus fumigatus y Fusarium solani. En general, las plantas ensayadas mostraron mejor actividad antibacteriana que antifúngica; donde la familia Rubiaceae fue la que presentó mayor actividad antibacteriana, seguida por las familias Euphorbiaceae y Solanaceae. El extracto metanólico de Alchornea coelophylla (Euphorbiaceae) fue el que presentó mejor actividad antibacteriana al inhibir cuatro de las bacteria ensayadas (B. Subtilis, P. aeruginosa, S. aureus y E. coli); y los extractos de diclorometano de Acalypha diversifolia y Euphorbia sp. (Euphorbiaceae) fueron los que tuvieron la menor Concentración Mínima Inhibitoria en la actividad antifúngica. El hongo evaluado más susceptible fue F. Solani, el cual fue inhibido por el 60% y el 20% de los extractos de diclorometano y metanol, respectivamente. Se considera que la actividad biológica de estos extractos, se relaciona con los metabolitos secundarios que ellos contienen y las diferentes susceptibilidades de los microorganismos patogénicos evaluados.

A novel antifungal protein from seeds of Sesbania virgata (Cav.) Pers. (Leguminosae-Faboideae) / Uma nova proteína antifúngica obtida de sementes de Sesbania virgata (Cav.) Pers. (Leguminosae-Faboideae)

A novel antifungal protein with a molecular mass around 50 kDa was purified from seeds of Sesbania virgata (Cav.) Pers. using ammonium sulfate fractionation followed by gel filtration on a Sephadex G-75 Superfine (Sigma) column and reverse-phase high performance liquid chromatography on a C8 column. The protein, designated FP1-A, with a novel N-terminal sequence AMVHSPGG(S)FS(P), showed growth inhibitory activity of filamentous fungi Aspergillus niger, Cladosporium cladosporioides, Colletotrichum gloeosporioides and Fusarium solani.

Uma nova proteína com atividade antifúngica, com massa molar de cerca de 50 kDa, foi purificada de sementes de Sesbania virgata (Cav.) Pers. utilizando precipitação com sulfato de amônia, filtração em gel em coluna de Sephadex G-75 Superfine (Sigma) e cromatografia líquida de alta eficiência em fase reversa (coluna C8). A proteína purificada foi designada FP1-A, com a sequência N-terminal AMVHSPGG(S)FS(P), apresentando atividade inibitória do crescimento dos fungos filamentosos Aspergillus niger, Cladosporium cladosporioides, Colletotrichum gloeosporioides e Fusarium solani.

Resposta in vitro de fungos agentes de micoses cutâneas frente aos antifúngicos sistêmicos mais utilizados na dermatologia / In vitro response of cutaneous mycosis fungal agents to the most widely used systemic antifungals in dermatology

FUNDAMENTOS - A alta frequência das micoses cutâneas justifica a necessidade de avaliar a possível contribuição da determinação do perfil de susceptibilidade aos antifúngicos in vitro. OBJETIVO - Avaliar se existe variabilidade nos isolados fúngicos quanto à susceptibilidade in vitro de fungos filamentosos, previamente isolados de micoses cutâneas, frente aos antifúngicos fluconazol, cetoconazol, itraconazol e terbinafina. MÉTODOS - Os fungos foram isolados e identificados por meio da metodologia clássica e o teste de susceptibilidade aos antifúngicos foi realizado segundo o método de microdiluição em caldo, de acordo com protocolo preconizado pelo Clinical Laboratory Standards Institute (CLSI), documento M38-A. RESULTADOS - Das 80 amostras de fungos filamentosos identificadas, o gênero Trichophyton representou 81 por cento. As quatro drogas analisadas apresentaram grande variação nos gêneros Trichophyton e Microsporum. O gênero Fusarium foi resistente a todas as drogas testadas. A terbinafina foi o antimicótico mais eficaz contra a maioria dos isolados fúngicos. CONCLUSÃO - Houve uma grande variabilidade nos perfis de resposta aos antifúngicos testados. O estabelecimento de um método-teste de referência permitirá ao clínico maior objetividade na escolha de uma terapia adequada.

BACKGROUND - The high frequency of cutaneous mycosis justify the need to evaluate the possible contribution of in vitro profile of susceptibility to antifungal agents. OBJECTIVE - To evaluate whether there is variability in in vitro susceptibility by filamentous fungi, previously isolated from cutaneous mycosis, to fluconazole, ketoconazole, itraconazole and terbinafine. METHODS - Fungi were isolated and identified by classical methods and the antifungal susceptibility test was performed using the method of broth microdilution, according to a protocol recommended by the Clinical Laboratory Standards Institute (CLSI), through M38-A document. RESULTS - Amongst the 80 filamentous fungi identified, Trichophyton genus represented 81 percent. The four examined drugs showed great variation for Trichophyton spp and Microsporum spp. Fusarium spp was resistant to all tested drugs. Terbinafine was the most effective drug against the majority of the isolated fungi. CONCLUSION - There was great variability in response profiles to the tested antifungals. The definition of a reference test method will offer higher objectivity for physicians to choose the appropriate therapy.

Chemical composition, toxicity and larvicidal and antifungal activities of Persea americana (avocado) seed extracts / Composição química, toxicidade, atividade larvicida e antifúngica de extratos de semente de Persea americana (abacate)

The present study had the aim of testing the hexane and methanol extracts of avocado seeds, in order to determine their toxicity towards Artemia salina, evaluate their larvicidal activity towards Aedes aegypti and investigate their in vitro antifungal potential against strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis through the microdilution technique. In toxicity tests on Artemia salina, the hexane and methanol extracts from avocado seeds showed LC50 values of 2.37 and 24.13mg mL-1 respectively. Against Aedes aegypti larvae, the LC50 results obtained were 16.7mg mL-1 for hexane extract and 8.87mg mL-1 for methanol extract from avocado seeds. The extracts tested were also active against all the yeast strains tested in vitro, with differing results such that the minimum inhibitory concentration of the hexane extract ranged from 0.625 to 1.25mg L-¹, from 0.312 to 0.625mg mL-1 and from 0.031 to 0.625mg mL-1, for the strains of Candida spp, Cryptococcus neoformans and Malassezia pachydermatis, respectively. The minimal inhibitory concentration for the methanol extract ranged from 0.125 to 0.625mg mL-1, from 0.08 to 0.156mg mL-1 and from 0.312 to 0.625mg mL-1, for the strains of Candida spp., Cryptococcus neoformans and Malassezia pachydermatis, respectively.

O presente estudo teve como objetivo testar os extratos hexânico e metanólico das sementes do abacate, a fim de determinar sua toxicidade em Artemia salina, avaliar a atividade larvicida frente ao Aedes aegypti, bem como verificar o potencial antifúngico in vitro contra cepas de Candida spp, Cryptococcus neoformans e Malassezia pachydermatis, através da técnica de microdiluição. Os extratos hexânico e metanólico das sementes de abacate apresentaram no teste de toxicidade frente à Artemia salina, valores de LC50 2,37 e 24,13mg L-1, respectivamente; contra as larvas do Aedes aegypti os resultados obtidos foram LC50 16,7mg L-1 para o extrato hexânico e 8,87mg L-1 para o extrato metanólico das sementes do abacate. Os extratos testados também foram ativos contra todas as cepas de leveduras, testadas in vitro, apresentando diferentes resultados, onde o MIC do extrato hexânico variou de 0,625 a 1,25mg mL-1, de 0,312 a 0,625mg mL-1 e de 0,031 a 0,625mg mL-1 para as cepas de Candida spp., Cryptococcus neoformans e Malassezia pachydermatis, respectivamente. O intervalo de MIC para o extrato metanólico foi de 0,125 a 0,625mg mL-1, 0,08 a 0,156mg mL-1 e de 0,312 a 0,625mg mL-1, para as exemplares de Candida spp., Cryptococcus neoformans e Malassezia pachydermatis, respectivamente.

Actividad antifúngica de extractos orgánicos del árbol Fagara monophylla (Rutaceae) en Venezuela

Anti-fungi activity of organic extracts from the tree Fagara monophylla (Rutaceae) in Venezuela. The tree Fagara monophylla ranges throughout Tropical America. The genus Fagara has a diversity of alkaloid compounds with antibiotic properties; nevertheless, there are few reports antifungal activity of its organic compounds. Organic extracts from Venezuelan F. monophylla were tested for antimicrobial activity against Aspergillus terreus, A. flavus, Penicillium digitatum, P. funiculosum, P. citrinum, Paecilomyces and Candida albicans. Minimal Inhibitory Concentration (MIC) was determined. The susceptibility trials of organic fractions (Hex., CH2Cl2 and MeOH) showed that the highest inhibition was presented by MeOH against A. flavus (55 mm), P. digitatum (60 mm), P. funiculosum (56 mm) and C. albicans (26 mm). The activities of MeOH/EtOAc fractions 1 and 2 suggest a combined effect against A. flavus, P. digitatum and P. funiculosum. The MIC of 1 MeOH/ EtOAc subfraction activity was lower against C. albicans (32 µg/ml) and moderate (128 µg/ml) against P. digitatum. This organic extract has a great antifungal potential. The phytochemical proves and TLC testing on the organic extract, and the MeOH/EtOAc subfraction, respectively, indicated the presence of alkaloid compounds. Rev. Biol. Trop. 55 (3-4): 767-775. Epub 2007 December, 28.

Fagara monophylla está distribuida en América Tropical. El género Fagara tiene diversidad de compuestos alcaloides con propiedades antibacterianas; sin embargo existe escasa información acerca de su actividad antifúngica. Evaluamos extractos de F. monophylla in vitro con los hongos Aspergillus terreus, A. flavus, Penicillium digitatum, P. citrinum, P. funiculosum, Paecilomyces y Candida albicans determinando la Concentración Mínima Inhibitoria (CMI). Hicimos pruebas de susceptibilidad con las fracciones Hex., CH2Cl2 y la MeOH. La mayor inhibición la presentó la fracción MeOH frente a A. flavus (55 mm), P. digitatum (60 mm), P. funiculosum (56 mm) y C. albicans (26 mm). Las actividades mostradas por las fracciones 1 y 2 de MeOH/EtOAc sugieren la acción de un efecto combinado frente a A flavus, P, digitatum y P. funiculosum. La CMI de la subfracción 1 MeOH/EtOAc frente a Candida albicans fue baja (32 µg/ml), y para P. digitatum la CMI fue moderada (128 µg/ml). Este extracto orgánico posee gran potencial de actividad antifúngica. Las pruebas fitoquímicas y los ensayos realizados por TLC al extracto orgánico y a la subfracción 1 MeOH/EtOAc, respectivamente, mostraron la presencia de alcaloides.

Antimicrobial activity of wax and hexane extracts from Citrus spp. peels

Antibacterial and antifungal properties of wax and hexane extracts of Citrus spp. peels were tested using bioautographic and microdilution techniques against three plant pathogenic fungi (Penicillium digitatum, Curvularia sp., and Colletotrichum sp.), two human pathogens (Trichophyton mentagrophytes and Microsporum canis), and two opportunistic bacteria (Escherichia coli and Staphylococcus aureus). Two polymethoxylated flavonoids and a coumarin derivative, were isolated and identified from peel extracts, which presented antimicrobial activity especially against M. canis and T. mentagrophytes: 4',5,6,7,8-pentamethoxyflavone (tangeritin) and 3',4',5,6,7,8-hexamethoxyflavone (nobiletin) from C. reticulata; and 6,7-dimethoxycoumarin (also known as escoparone, scoparone or scoparin) from C. limon.

Phaeomycotic cyst--a case report.

Phaeomycotic cyst or subcutaneous phaeohyphomycosis is the most common type of phaeohyphomycosis. Fonsecaea pedrosoi as the causative agent of subcutaneous phaeohyphomycosis was earlier reported in India. Here a case of a patient of 22-year-old farmer is presented with a soft cystic swelling on the left wrist. Direct examination of the aspirate from the swelling showed dematiaceous hyphae. Culture grew Fonsecaea pedrosoi. The patient responded to antifungal therapy.

Antioxidant and antimicrobial activities of Bauhinia racemosa L. stem bark

The present study was carried out to evaluate the antioxidant and antimicrobial activities of a methanol extract of Bauhinia racemosa (MEBR) (Caesalpiniaceae) stem bark in various systems. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. About 50, 100, 250, and 500 æg MEBR inhibited the peroxidation of a linoleic acid emulsion by 62.43, 67.21, 71.04, and 76.83 percent, respectively. Similarly, the effect of MEBR on reducing power increased in a concentration-dependent manner. In DPPH radical scavenging assays the IC50 value of the extract was 152.29 æg/ml. MEBR inhibited the nitric oxide radicals generated from sodium nitroprusside with an IC50 of 78.34 æg/ml, as opposed to 20.4 æg/ml for curcumin. Moreover, MEBR scavenged the superoxide generated by the PMS/NADH-NBT system. MEBR also inhibited the hydroxyl radical generated by Fenton's reaction, with an IC50 value of more than 1000 æg/ml, as compared to 5 æg/ml for catechin. The amounts of total phenolic compounds were also determined and 64.7 æg pyrocatechol phenol equivalents were detected in MEBR (1 mg). The antimicrobial activities of MEBR were determined by disc diffusion with five Gram-positive, four Gram-negative and four fungal species. MEBR showed broad-spectrum antimicrobial activity against all tested microorganisms. The results obtained in the present study indicate that MEBR can be a potential source of natural antioxidant and antimicrobial agents.

Production of heptaene antifungal antibiotic by Streptomyces purpeofuscus CM 1261.

A strain of Streptomyces purpeofuscus CM 1261 isolated from a sample of compost collected locally was found to possess strong antagonistic activity against 4 human pathogenic fungi i.e., Candida albicans, Aspergillus niger, Microsporum gypseum and Trichophyton sp. The active antifungal compound produced by it was found to be a heptaene group of polyene antifungal antibiotic.

In vitro evaluation on inhibitory nature of some Neem formulations against plant pathogenic fungi.

Different Neem formulations derived from the Neem tree (Azadirachta indica) have been found to be potential fungicides against a broad spectrum of plant pathogenic fungi. Some Neem formulations viz. Achook (0.15% EC), Bioneem (0.03% EC), Nimbecidine (0.03% EC) and Neemark (0.03% EC) were examined against some plant pathogenic fungi such as (Fusarium oxysporum, Alternaria solani, Curvularia lunata, Helminthosporium sp. and Sclerotium rolfsii). Among these Achook (0.15% EC) was found to be more active in terms of Minimum Inhibition Concentration (MIC) value followed by Bioneem, Neemark and Nimbecidine. Remarkably, although all these formulations are oil based, Neem oil itself did not exhibit any fungicidal activity.

Antifungal activity (invitro) of certain polyene macrolide antibiotics against various plant pathogens.

Certain polyene macrolides were developed from different actinomycetes at Research and Development of Hindustan Antibiotics Limited. These antibiotics were screened for the antifungal activity against various plant pathogens. IC50 and MIC of each of the antibiotic against the plant pathogens was found out and is being reported.

Studies of the antifungal compounds produced by Erwinia herbicola.

The organic phase of a wide spectrum, antimycotic and diffusable toxin from Erwinia herbicola showed a highly significant inhibitory activity against Pyricularia oryzae spores in spore well bioassay. Germ tube lengths were inhibited more in wells containing 5 microliters equivalent of bacterial toxin than 1 microliter. No significant difference between the germ tube in an equal mixture of Dimethyl sulphoxide: ethanol and controls. Thin layer chromatography using the chloroform extraction of the organic phase showed a significant antagonism on Cladosporium cucumerinum. The retardation factor values for inhibitory zones in solvent 1 were 0.07 for lower spot and 0.26 for upper spot.

Effect of some antibiotics on Macrophomina phaseolina, a charcoal rot fungus of soybean.

Effect of agrimycin-100, ampicillin, griseofulvin and tetracycline on colony growth of Macrophomina phaseolina, incitant of charcoal rot of soybean has been studied in vitro. Amongst them tetracycline posed most effective inhibiting the growth by 73.9% at 1000 micrograms/ml concentration. On the basis of effectiveness antibiotics have been listed as tetracycline greater than ampicillin greater than griseofulvin greater than agrimycin-100.