Chaetoglobosinas produzidas porRecebido em 1/10/07; aceito em 7/5/08; publicado na web em 19/9/08 CHAETOGLOBOSINS PRODUCED BY Chaetomium globosum, ENDOPHYTIC FUNGUS FOUND IN ASSOCIATION WITH Viguiera robusta Gardn (ASTERACEAE). Endophytes live in association with host plants during all or part of their life cycle without causing any apparent disease. They are considered outstanding and underexploited sources of novel bioactive compounds. Chaetomium globosum was isolated as an endophytic fungus from the healthy leaves of Viguiera robusta. C. globosum is a remarkable producer of chaetoglobosins, which are typically cytotoxic. In this work, chaetoglobosins B (1), D (2) and E (3) have been produced by the endophytic C. globosum strain. Chaetoglobosin B was evaluated against Jurkat (leukemia) and B16F10 (melanoma) tumoral cells and showed 89.55% and 57.10% of inhibition at 0.1 mg mL -1 , respectively. Chaetoglobosin B also showed weak antibacterial activity against Staphylococcus aureus (MIC 120 µg/mL) and Escherichia coli (MIC 189 µg/mL).
RESUMO:O Ageratum conyzoides, vegetal conhecido popularmente no Brasil é constituído por várias substâncias químicas, dentre elas os flavonóides, aos quais já foi atribuída a atividade antitumoral. Neste estudo foi avaliado o efeito das frações clorofórmica e metanólica do extrato AcOEt das folhas sobre o crescimento do tumor de Ehrlich. Foi constatado que o tratamento com as frações metanólicas, nas doses de 50 mg/kg de peso foi eficaz, inibindo o crescimento tumoral. A porcentagem de inibição para a fração metanólica estabilizada foi de 69,84% e de 68,25% para a fração metanólica não estabilizada. Estudos posteriores se fazem necessários para esclarecer quais os mecanismos envolvidos nesta inibição do crescimento tumoral.Unitermos: Ageratum conyzoides, Asteraceae, atividade antitumoral, tumor de Ehrlich.ABSTRACT: "Antitumoral activity of the Ageratum conyzoides L. (Asteraceae)". Ageratum conyzoides, a popular vegetal in Brazil, is composed by many chemical compounds, including flavonoids, and antitumoral activity has been attributed to it. In this assay the effect of chloroform and methanol fractions from EtOAc extract of the leaves on the growth of the Ehrlich tumor was evaluated. Under our experimental conditions we have observed that the treatment with methanol fractions, under the dosage of 50 mg/kg was efficient on inhibiting the tumoral growth. There was an inhibition percentage of 69.84% to the stabilized methanol fraction and 68.25% to the nonstabilized fraction. Further studies are necessary to clarify which mechanisms are involved in the inhibition of the tumoral growth.
The Cerrado is the second largest biome in Brazil and presents an immeasurable and still underexplored ecological diversity. Despite the exuberance of its endemic species, it is one of the 25 global hotspots, due to a high natural biodiversity wealth along with an expressive environment destruction. In this study, we surveyed the knowledge on medicinal use of Cerrado plants held by individuals living in a predominantly Cerrado region. A semi-structured individual questionnaire for qualitative socio-economic characterization and medicinal use of plants was applied to Public Health Service users of the city of Assis, State of Sao Paulo, Brazil. This study was approved by the Ethics Committee of the Assis Regional Hospital (Protocol 4812010). Out of 149 respondents, 90.6% reported knowledge and/or use of plants for therapeutic purposes. Among 115 mentioned plant species, only 11.4% belong to the Cerrado. We also evaluated how matching were the reported uses and the respective published data from scientific studies on the plants’ medicinal properties. It was verified that for the few Cerrado plants cited, the respondents described several medicinal applications not scientifically described. More precisely, 60.5% of all medicinal applications were not found in the scientific literature. Besides that, many of the therapeutic effects described in the literature for the Cerrado species were not cited by the interviewed population. Our results indicate a relative unawareness of people on the medicinal potential of the native species of their residence region. We suggest that strengthening connection between popular and scientific knowledge, along with spreading such knowledge, could contribute for an improved valuation about the Cerrado biome and consecutive preservation of it.
Três fungos endofíticos isolados de Viguiera robusta (Asteraceae) foram cultivados em três meios de cultivo distintos (Czapek, arroz e extrato de malte) e também em culturas binárias em extrato de malte. Para a extração dos cultivos em extrato de malte foi utilizada a resina diaion HP-20, que promove a adsorção dos metabólitos produzidos pelo fungo, aumentando o rendimento dos extratos. Os extratos e frações obtidos foram submetidos à análise química por meio de técnicas cromatográficas e RMN 1 H e a ensaios diversos biológicos para a comparação de seus perfis. O estudo químico do extrato de Chaetomium globosum (VR-10), cultivado em arroz, levou a isolamento da substância S1 (chaetoglobosina E), que apresenta elevada atividade citotóxica e é uma ferramenta importante em biologia química. Também de C. globosum foi isolado a substância S2 (dimetil-tereftalato), o qual já foi identificado como metabólito de fungo endofítico e também de planta. De Pestalotiopsis guepini (VR-8), cultivado em Czapek, foi isolada a substância S3 (tirosol), relatado na literatura como molécula sinalizadora em Candida albicans. Do fungo Cladosporium sphaerospermum (VR-2), após cultivo em arroz, foram isoladas três substâncias: marcfortina A (S4), a marcfortina B (S5) e a marcfortina C (S6) e (S7), substâncias com pronunciada atividade antiparasitária. Foi desenvolvido um método via CLAE-DAD-MS/MS para identificação rápida de derivados de marcfortina, o qual possibilitiou a identificação da substância S7 (marcfortina D) no extrato bruto de C. sphaerospermum. A análise conformacional da marcfortina A (S4) foi realizada através de experimentos de NOE-diff e técnicas de modelagem molecular. Os resultados obtidos nos bioensaios após diferentes cultivos dos fungos endofíticos indicaram que estes são fontes promissoras de substâncias bioativas, constituindo ferramentas importantes na busca por novos compostos.
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