Scientific reports are important tools for show results of experimental activities undertaken at undergraduate level. The aims of this research were detecting difficulties of undergraduate students in the elaboration of reports in the experimental chemistry subjects of students of the Science: Biology and Chemistry course at the Federal University of Amazonas in different periods (2nd to 10th). Results and discussion and theoretical bibliographic were topics reported with the most difficulty. The students showed little reading habit, however, which increases with the time they spend in university, also reflecting the retention rate in the experimental subjects. These results point to possibilities to reduce the difficulties in the elaboration of experimental reports by intervention alternatives more appropriate to the desired learning process, based on the students’ reality. Detecting these points becomes an important to assist them in the learning process of academic writing.

Failing classes is one of the main causes students are held back in universities, which in turn has several academic, social and economic impacts. This study aims to identify factors associated with students flunking General Chemistry, as well as to propose institutional interventions that can remedy these setbacks. The methodology used was based on a conceptual model of nontraditional undergraduate students, evaluating student academic outlook and relating that with institutional data on subject pass rate. Results showed it was possible to correlate variables that influence pass rates in General Chemistry, highlighting the following: busy schedule, study method, high class load per semester, deficiencies in basic chemistry and math, and socioeconomic factors. Results in this work help identify challenges that can aid in developing strategies to eradicate or minimize failing in General Chemistry in higher education institutions in Brazil.

Piquiá (Caryocar villosum - Caryocaraceae) is a native fruit from the Amazon region rich in bioactive substances. Fruit pulp extracts were analyzed by HPLC, together with extracts obtained from fruit pulp industry residual parts, byproducts such as husks (shells) and seeds. Extracts were prepared with two ethanolic solvent systems. Phenolic substances ellagic and gallic acids were detected with standards and quantified by HPLC. Cytotoxic, antioxidant and anti-inflammatory activities in vitro were also evaluated. Shell extracts showed free radicals scavenger capacity in ABTS (IC50: 3.93 ± 0.12 µg mL-1) and DPPH models (IC50: 7.81 ± 0.34 µg mL-1), low cytotoxicity in human fibroblasts, but high at tumor strains, and also a high anti-inflammatory potential observed by the inhibition of nitric oxide production. At low concentrations (20 µg mL-1), excellent antioxidant activities were verified in cellular assays, with percentages of 70.69 ± 2.77%, 79.89 ± 6.50% and 79.48 ± 8.6% for shell, pulp and seed extracts, respectively. With this set of results, C. villosum fruit extracts become a high potential raw material to be used in pharmaceutical and cosmetic applications.

The essential oils of branches and leaves of Endlicheria citiodora were obtained by hydrodistillation and analysed using GC-FID, GC-MS and both NMR 13C and ¹H, resulting in the identification of methyl geranate as major constituent (93%) in both oils. Cytotoxicity, tyrosinase-inhibition and antioxidant activities were studied and characterized. High antioxidant potential (15.52 and 13.53 µg/mL), low cytotoxicity and tyrosinase inhibition (53.85%) were observed. This is the first paper reporting the biological activities and composition of the essential oils of this species.