Este trabalho apresenta o relato de experiência do curso “O biocombustível da biodiversidade”. Foram selecionados 20 alunos da Escola Estadual Ana Libória, com o objetivo de apresentar o potencial energético da biodiversidade que os cerca. O curso foi executado em várias etapas: abordagem do tema, conceitos referentes à química e óleos vegetais, normas de segurança em laboratório, vidrarias e suas funções seguida de uma sequência de atividades práticas correlatas, como: coletas de material, métodos de extração de óleos vegetais, métodos cromatográficos e reacionais. O curso proporcionou a integração dos alunos com o ambiente de pesquisa na Universidade Federal de Roraima - UFRR e a vivência na prática dos conceitos e teorias.
Rationale
Annona species are of interest for the isolation of bioactive molecules; however, studies of Annona jahnii Saff. are limited. The exploration of bioactive metabolites of endophytes isolated from this species is unprecedented and allows the preservation of the host plant, in addition to enabling the discovery of compounds with promising biological activities.
Methods
Ethyl acetate extracts from the cultured media of five fungi were obtained. The antioxidant capacity of the extracts was measured using the 1,1‐diphenyl‐2‐picrylhydrazyl free radical method. Antimicrobial activity was determined using the microdilution method in broth in 96‐well plates. The exploration of the metabolic profile of the extracts and dereplication of the compounds were performed using ultra‐high‐performance liquid chromatography/electrospray ionization/tandem mass spectrometry (UHPLC/ESI‐MS/MS) combined with analysis using molecular networking (MN).
Results
A total of 1818 MS features were detected in the five selected extracts, of which 39 compounds were putatively identified. The secondary metabolites with the highest abundance were alkaloids, naphthopyrons, and cytochalasins. Other secondary metabolites include fumonisins, coumarin, and a meroterpenoid. Most of these compounds are related to specific biological properties such as antioxidant, anti‐inflammatory, antimicrobial, antiviral, and antitumor activities. Extracts F398 and F403 showed inhibitory activity of the four pathogens tested. Extracts F475 and F506 did not inhibit the growth of Staphylococcus aureus, and F407 did not inhibit the growth of Escherichia coli in addition to having potent antioxidant activity, with IC50 values of 10 μg/mL or less.
Conclusions
The use of UHPLC/ESI‐MS/MS data combined with MN proved useful in the dereplication of bioactive molecules of complex extracts that are still unexplored. These initial investigations should significantly assist in further research and increase the efficiency and speed in the discovery of new sources of secondary metabolites and new natural products.
A cromatografia em coluna é experimento que possibilita a discussão de diversos conteúdos de química, no entanto, requer um extenso período na sua realização. Nesta perspectiva, o objetivo deste trabalho é propor um experimento envolvendo a técnica de separação clássica, cromatografia em coluna, de fácil e rápida execução e que permite aplicação em disciplinas experimentais de química orgânica. Os resultados mostraram que os solventes empregados na eluição foram eficientes na separação de faixas de coloração bem definidas, retomando conceitos pioneiros que originaram a cromatografia em coluna, além de permitir que o experimento seja realizado em um período de duas horas.
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