Isolamento e atividade antibacteriana de fungos endofíticos de Piper glabratum Kunth / Isolation and antibacterial activity of Piper glabratum Kunth endophytic fungi

Devido a capacidade dos endófitos em colonizar diferentes espécies de plantas, inclusive as medicinais, produzindo substâncias de interesse biotecnológico como antibióticos, o objetivo deste trabalho foi isolar fungos endofíticos de folhas de Piper glabratum Kunth e avaliar a atividade antibacteriana contra bactérias patogênicas humanas. O isolamento dos fungos endofíticos foi realizado utilizando-se a desinfestação superficial com hipoclorito de sódio 3%. Para avaliação da atividade antibacteriana, foi obtido extrato de 20 fungos endofíticos isolados que foram testados o extrato diretamente na fase aquosa, a fração obtida com acetato de etila e com clorofórmio P.A. Foi utilizado o teste de difusão em discos contra as bactérias patogênicas humanas Escherichia coli, Staphylococcus aureus, Salmonella enterica e Shigella flexneri. Em placas de Petri com meio Muller Hinton (MH) contendo as bactérias foram inseridos quatro discos de papel estéreis inoculados com 10 µL de cada extrato metabólito. Avaliou-se a atividade antimicrobiana pela formação de halos de inibição. Foi possível isolar 98 de P. glabratum, com frequência de isolamento de 98%. Dentre os 20 fungos avaliados quanto a atividade antimicrobiana, catorze isolados apresentaram atividade antibacteriana para pelo menos uma das quatro bactérias patogênicas testadas, destacando-se potencial de inibição para a bactéria S. aureus a partir dos testes realizados diretamente com o extrato bruto e com acetato de etila.

Endophytes are able to colonize different species of plants, including medicinal plants, producing substances of biotechnological interest such as antibiotics. Therefore, the aim of this study was to isolate endophytic fungi from Piper glabratum Kunth leaves and evaluate the antibacterial activity against human pathogenic bacteria. The isolation of endophytic fungi was performed using the surface disinfection method with 3% sodium hypochlorite. In order to evaluate the antibacterial activity, extracts from 20 endophytic fungi were tested, with the extract directly into the aqueous phase and the fraction obtained with ethyl acetate and chloroform P.A. The method of disk diffusion was used against human pathogenic bacteria Escherichia coli, Staphylococcus aureus, Shigella flexneri and Salmonella enterica. In Petri dishes with medium Muller Hinton (MH) containing bacteria, four sterile paper disks inoculated with 10 µL of each metabolite extract were inserted. The antimicrobial activity was evaluated due to the formation of the inhibition halo. It was possible to isolated 98 endophytic fungi from P. glabratum with isolation frequency of 98%. The results of the test showed that extracts from 20 endophytic fungi have inhibited the activity against fourteen isolates and antibacterial activity for at least one of the four tested pathogenic bacteria, emphasizing the potential for inhibition of S. aureus from the tests performed directly with the crude extract and ethyl acetate.

Evaluation of foliar fungal endophyte diversity and colonization of medicinal plant Luehea divaricata (Martius et Zuccarini)

Endophyte microorganisms are organisms that live inside plants without causing any apparent damage to their hosts. Since all plants exhibit endophyte microorganisms, it is believed that mutual association is of great importance in nature. Luehea divaricata (Martius & Zuccarini), known popularly in Brazil as agoita-cavalo, is a big-sized tree with a wide distribution in the country that possesses medicinal qualities for: dysentery, leucorrhea, rheumatism, blennorrhoea, tumors, bronchitis, and depuration. This research aims at isolating and molecularly characterizing fungi isolates from L. divaricata by sequence analysis of ITS1-5.8S-ITS2 rDNA. Further, the colonization of endophyte in the host plant by Light and Scanning Electron Microscopy will also be investigated. Whereas, genera Alternaria, Cochliobolus, Diaporthe, Epicoccum, Guignardia, Phoma, and Phomopsis, were identified; rDNA sequence analysis revealed intra-species variability among endophyte isolates of the genus Phomopsis sp. Light and Scanning Electron Microscopy techniques showed the presence of endophyte fungi inside L. divaricata leaves, inhabiting inter- and intra-cellular spaces. These types of extensive colonization and dissemination were reported throughout all the leaf parts in palisade parenchyma, esclerenchyma, spongy parenchyma, adaxial epidermis, and vascular bundle indicating colonization of endophytes in múltiple structural sub-niches in the host plant.