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This experiment encourages students to use deductive reasoning skills to understand the correlation between different techniques used in a chemistry laboratory and to extract and analyze curcuminoids using natural products and processed food from a grocery store. Turmeric pigments were used to teach continuous or discontinuous extraction, vacuum or atmospheric pressure distillation, and thin-layer chromatography (TLC) in an introductory organic chemistry laboratory course in three laboratory sessions of 3−4 h each. Pigment extracts from the rhizome of turmeric, commercial dehydrated vegetable soup, and chicken-flavored instant bouillon (with turmeric as an ingredient) were used. The three techniques were discussed in the first laboratory session before students proposed a methodology to identify pigments in food extracts through a problem-based format. Students were assessed in a final exam where they presented a more detailed discussion of the chemistry laboratory techniques used. These results were compared to exam results from previous years. On the basis of students' and teacher's feedback, the sequence of laboratory experiments was considered interesting, and students were motivated to participate more actively during instruction.

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The extensive marine biodiversity has proved to be a promising source of substances with biomedical potential. In this study, the cytotoxicity of the Brazilian octocoral Phyllogorgia dilatata (Gorgoniidae) was evaluated against two tumor cell lines and three bacterial strains. The methanol/dichloromethane crude extract presented no antibacterial activity up to the highest concentration tested (512 µg/mL), however it revealed a noteworthy antiproliferative effect against HCT-116 (80%) and MCF-7 (54%) cell lines at 50 μg/mL. Therefore, guided by the cytotoxic activity, a multistep chemical fractionation of the extract provided the subfraction 5 (PDPH2-5) with IC 50 values of 3.18 and 17.80 μg/mL against HCT-116 and MCF-7, respectively. The LC-HRMS/MS analysis of PDPH2-5 showed ions of m/z 219.1742 and 219.1743, characterized as (E,E) and (Z,E) germacrone, after a LC-DAD-SPE/NMR analysis of the hexanic fraction and comparisons of NMR data with the literature. Previously reported assessments to the cytotoxic activity of the (E,E)-diastereoisomer disclosed higher IC 50 values than that obtained for the PDPH2-5 fraction, suggesting, herein, a potentiated effect of the diastereoisomeric mixture. Such remark encourage further bioactivity studies with stereoisomer mixtures and reduce the urge for compound isolation.

This paper describes the methodological approach followed in preparation, implementation and evaluation of the video tutorial "Thin Layer Chromatography", performed by 3 professors, 4 undergraduate and 1 PhD teaching assistants students, all of them from the Organic Chemistry Department of the Universidade Federal Fluminense (UFF). Alongside to video preparation, a survey with 127 undergraduate students (Chemistry, Chemical Engineering and Pharmacy courses) enrolled in 14 different Organic Chemistry laboratory classes was conduct along 2013, seeking to know the types of resources textbooks they had access in elementary, middle and high schools, as well as their frequency of use. Similarly, there was a survey with 6 instructors who taught these subjects also in 2013, seeking to ascertain the types of educational resources used in their undergraduate classes, as well as its frequency of use. Results indicated that the most common teaching resources in elementary, middle and high schools were the blackboard and chalk, and rarely videos, games and library visits. These answers were in agreement with the undergraduate p ofesso 's o es. áfte the i itial esea h, tuto ial ideo lass as applied i 9 of 1 O ga i Che ist la o ato lasses mentioned above. To assess the helpfulness of the tuto ial, stude ts' a d i st u to s' itte feed a k post-video-tutoring exam video form, content, sound and image quality as well as its length. The video content was considered from good to excellent, just the sound and length considered reasonable. With these results, it was possible to make adjustments and corrections improving, without prejudice, the final product.Keywords: Video process; chemistry teaching; thin layer chromatography. ResumoEste trabalho descreve o percurso metodológico seguido na elaboração, aplicação e avaliação da produção da videoaula C o atog afia e Ca ada Delgada , ealizada po p ofesso es, alu os de o ito ia e 1 alu a de douto ado i ulados ao Departamento de Química Orgânica (GQO) da Universidade Federal Fluminense (UFF). Paralelamente à elaboração do vídeo foi realizada uma pesquisa no ano de 2013, com 127 alunos dos cursos de Química, Engenharia Química e Farmácia da UFF, de 14 turmas das disciplinas de Química Orgânica Experimental I, V e XI, buscando saber os tipos de recursos didáticos que tiveram acesso no ensino fundamental, médio e superior, assim como sua frequência de uso. Do mesmo modo, realizou-se uma pesquisa com 6 professores desse departamento que ministraram essas disciplinas também em 2013, visando saber os tipos de recursos didáticos que usavam em suas aulas de graduação, assim como sua frequência de utilização. Dessa pesquisa foi possível concluir que os recursos didáticos mais comuns no ensino médio e fundamental foram o quadro e giz, mas também o vídeo, jogos e visitas à biblioteca, além de outros, sendo que esses últimos recursos eram menos usados no ensino superior, o que está em concordância com as respostas dos Professores que lecionam na graduação. Após a pesquisa inicial o vídeo fo...