RESUMO
In the present study, we evaluated the antifungal potential of cytochalasins produced by Diaporthe taxa against phytopathogenic fungi. Using molecular methods, seven endophytic fungal strains from the medicinal plants Copaifera pubiflora and Melocactus ernestii were identified as Diaporthe miriciae, while two isolates were identified to the genus level (Diaporthe sp.). All crude extracts of Diaporthe species produced via solid-state fermentation were evaluated by 1H NMR analyses. Crude extracts of the isolates D. miriciae UFMGCB 6350, 7719, 7646, 7653, 7701, 7772, and 7770 and Diaporthe sp. UFMGCB 7696 and 7720 were demonstrated to produce highly functionalized compounds. The extracts of D. miriciae UFMGCB 7719 and 6350 were selected as representative Diaporthe samples and subjected to bioassay-directed fractionation to isolate cytochalasins H and J. Cytochalasins H and J were evaluated for activities against the fungal plant pathogens Colletotrichum fragariae, Colletotrichum gloeosporioides, Colletotrichum acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis obscurans, and Phomopsis viticola using microdilution broth assays. Cytochalasins H and J exhibited the most potent activities against the Phomopsis species tested. Our results showed that Diaporthe species were potential producers of different cytochalasins, which exhibit potential for controlling fungal diseases in planta and (or) maintaining antagonism.
Assuntos
Antifúngicos/farmacologia , Colletotrichum/efeitos dos fármacos , Citocalasinas/farmacologia , Endófitos/isolamento & purificação , Proteínas Fúngicas/farmacologia , Plantas Medicinais/microbiologia , Antifúngicos/química , Ascomicetos/química , Citocalasinas/química , Endófitos/química , Proteínas Fúngicas/química , Espectroscopia de Ressonância MagnéticaRESUMO
The fungal endophyte community associated with Baccharis trimera, a Brazilian medicinal plant, was characterized and screened for its ability to present antimicrobial activity. By using molecular methods, we identified and classified the endophytic fungi obtained into 25 different taxa from the phyla Ascomycota and Basidiomycota. The most abundant species were closely related to Diaporthe phaseolorum, Pestalotiopsis sp. 1, and Preussia pseudominima. The differences observed in endophytic assemblages from different B. trimera specimens might be associated with their crude extract activities. Plants that had higher α-biodiversity were also those that contributed more to the regional (γ) diversity. All fungal isolates were cultured and their crude extracts screened to examine the antimicrobial activities. Twenty-three extracts (12.8%) displayed antimicrobial activities against at least one target microorganism. Among these extracts, those obtained from Epicoccum sp., Pestalotiopsis sp. 1, Cochliobolus lunatus, and Nigrospora sp. presented the best minimum inhibitory concentration values. Our results show that the endophytic fungal community associated with the medicinal plant B. trimera included few dominant bioactive taxa, which may represent sources of compounds with antifungal activity. Additionally, the discovery of these bioactive fungi in association with B. trimera suggests that Brazilian plants used as folk medicine may shelter a rich fungal diversity as well as taxa able to produce bioactive metabolites with antimicrobial activities.
Assuntos
Antifúngicos/farmacologia , Ascomicetos/fisiologia , Baccharis/microbiologia , Basidiomycota/fisiologia , Endófitos/fisiologia , Fungos/efeitos dos fármacos , Pradaria , Plantas Medicinais/microbiologia , Ascomicetos/classificação , Ascomicetos/isolamento & purificação , Basidiomycota/classificação , Basidiomycota/isolamento & purificação , Biodiversidade , Brasil , Endófitos/classificação , Endófitos/isolamento & purificação , Testes de Sensibilidade MicrobianaRESUMO
La polyvalence fonctionnelle des végétaux se matérialise à travers les nombreux usages que les peuples du Nord-Cameroun en font. Ils ont mis sur place un savoir -: faire local qui leur a permis d'exploiter de manière efficace leur environnement végétal. La disparition des essences de valeur les oblige à développer d'autres stratégies en relation avec une nouvelle ère marquée par la consommation de produits manufacturés. Le présent article récapitule les principaux usages des plantes par les peuples du Nord-Cameroun, évalue leurs stratégies de mise en valeur des herbacées et des ligneux et interroge sur la validité des dispositions en cours portant sur la préservation du patrimoine végétal mis en péril par l'homme et par la nature.
The functional versatility of plants can be seen in their numerous uses by the people of Northern Cameroon. They have implemented local know-how which has allowed them to effectively exploit their botanical environment. The disappearance of valuable species has forced them to develop other strategies, with a new era marked by the consumption of manufactured products. This article summarizes the principal uses of plants by the people of Northern Cameroon, evaluates their strategies for extracting value from grasses and woods, and questions the validity of the measures currently in place to preserve the botanical heritage at risk due to the actions of man and nature.