Márcia Silva do Nascimento

Antibacterial Activity of Labdane Diterpenoids from Stemodia foliosa

As part of a continuing interest in exploring the chemistry of Brazilian medicinal plants, three new labdane diterpenoids, 6alpha-acetoxymanoyl oxide (1), 6alpha-malonyloxymanoyl oxide (2), and 6alpha-malonyloxy-n-butyl ester manoyl oxide (3), together with the known betulinic acid, lupeol, sitosterol, and stigmasterol, were isolated from the aerial parts of Stemodia foliosa. The structures of 1-3 were established on the basis of interpretation of spectroscopic data, including HRESIMS, and 1D and 2D NMR techniques. All compounds were tested against a bacteria panel consisting of Staphylococcus aureus, Bacillus cereus, B. subtilis, B. anthracis, Micrococcus luteus, Mycobacterium smegmatis, and M. phlei. Compound 2 showed moderate activity against these strains, with MIC values in the range 7-20 microg/mL.

Identificação de antocianidinas em acerolas do Banco Ativo de Germoplasma da Universidade Federal Rural de Pernambuco

The red color of mature acerola is due to the presence of anthocyanins. These pigments were extracted and purified from 12 genotypes cultivated at the Active Germoplasm Bank of the Rural Federal University of Pernambuco in order to determine their composition. The aglycon forms of the anthocyanins were revealed by acid hydrolysis. Anthocyanins and anthocyanidins were separated by using high-performance liquid chromatography (HPLC) using a C18 reversed phase analytical column. Anthocyanidins were identified by comparing HPLC elution order and retention times relative to authentic standards and to anthocyanidins obtained from acid hydrolysis of Isabel, Patricia and Red Globe grapes, plum, red onion, strawberry and Tommy Atkins mango skin. The chromatograms showed that the acerola genotype anthocyanins profile is simple, showing three to five peaks, similar between them. After the acid hydrolysis, the chromatograms revealed the presence of two aglycons which were identified as cyanidin and pelargonidin. By comparing chromatograms of anthocyanins and anthocyanidins and analyzing the retention times, the presence of anthocyanins with different glycosylation patterns and the absence of acylation in their molecules could be clearly seen. The aglycons identified (cyanidin and pelargonidin) were found in different proportions in these acerola genotypes.

Extract of Bowdichia virgilioides and maackiain as larvicidal agent against Aedes aegypti mosquito

The larvicidal activities of extracts of three hardwood species (Hymenaea stigonorcapa, Anadenanthera colubrina and Bowdichia virgilioides) against 4th instar larvae of Aedes aegypti were evaluated using WHO guidelines. Extracts of H. stignocarpa and A. colubrina showed weak activity. The highest larvicidal effect was obtained with the cyclohexane extract of the heartwood of B. virgilioides, which caused 100% mortality at concentrations at 50 and 100 µg/mL. Fraction toluene/EtOAc (8:2) from this extract showed larvicidal activity (LC₅₀ = 34.90 ± 1.27 µg/mL). A mixture of two compounds identified as medicarpin and maackiain exhibited a very good larvicidal activity (sub-fraction 2, LC₅₀ = 17.5 ± 1.87 µg/mL) and maackiain showed to be a strong larvicidal compound (LC₅₀ = 21.95 ± 1.34 µg/mL). This result can be of value in the search for new natural larvicidal compounds from other hardwood plant extracts and presents the first report of B. virgilioides being used to control a mosquito vector.