Angela M. C. Arriaga

Further diterpenoids isolated from Pterodon polygalaeflorus

From fruits of Pterodon polygalaeflorus (Leguminosae) the new diterpene 6a-hydroxyvouacapane, the known diterpenoids vouacapane-6a,7b,14b,19-tetraol and methyl 6a,7b-dihydroxyvouacapan-17b-oate and the flavonoid taxifolin were isolated. Structural determinations were accomplished by spectroscopic analysis, including two-dimensional NMR, chemical transformation of the new diterpene and comparison with literature data.

Constituents of bowdichia virgilioides

The isolation and (13)C-NMR data of flavone derivatives from Bowdichia virgilioides roots are reported.

Estudo químico e biológico de Tephrosia toxicaria Pers.

The ethanol extracts from leaves, stems, pods and roots were assayed against the 3rd instar Aedes aegypti larvae and the highest activity was observed in the roots extracts (LC50 47.86 ppm). This extract was submitted to partition with hexane, chloroform, ethyl acetate and methanol. The respective fractions were bioassayed and the best larvicidal activities were identified in the hexane (LC50 23.99 ppm) and chloroform (LC50 13.80 ppm) fractions. Antioxidant activity (DDPH method) was observed in the ethanol extract (IC50 276 µg/mL) from roots of T. toxicaria. Fractions from this extract were also tested and the highest antioxidant activity (IC50 89 µg/mL) was found in the methanol fraction. The flavonoids iso-obovatin (1), obovatin (2), 6a,12a-dehydro-β-toxicarol (3), 6a,12a-dehydro-α-toxicarol (4) and α-toxicarol (5) were isolated and bioassayed against A. aegypti. The flavonoid 5 showed the best larvicidal activity (LC50 24.55 ppm). The antioxidant activity of 2 was investigated and showed IC50 3.370 µg/mL. The antioxidant and larvicidal activities of Tephrosia toxicaria are reported for the first time.

Effects of Myrcia ovata Cambess. essential oil on planktonic growth of gastrointestinal microorganisms and biofilm formation of Enterococcus faecalis

The essential oil from the leaves of Myrcia ovata Cambess., commonly used in Brazil for the treatment of gastric illnesses, was screened for antimicrobial activity and action in the formation of microbial biofilms by Enterococcus faecalis. The oil was obtained by hydrodistillation using a clevenger-type system. Its chemical composition was analyzed using GC and GC-MS. Both MIC and MBC of the essential oil were determined by broth microdilution techniques and agar dilution method. The essential oil showed antimicrobial activity against E. faecalis, Escherichia coli, Pseudomonas aeruginosa, Salmonella choleraesuis, Staphylococcus aureus, Streptococcus pneumoniae and Candida parapsilosis. The results showed that the essential oil of M. ovata Cambess. was effective against the formation of biofilm by E. faecalis when compared with the control. Four volatile compounds, representing 92.1 % of the oil, were identified and geranial was the major component (50.4 %). At the best of our knowledge, this is the first report of the chemical composition and antimicrobial activity of the essential oil from leaves of M. ovata.

Avaliação da atividade larvicida de saponinas triterpênicas isoladas de Pentaclethra macroloba (Willd.) Kuntze (Fabaceae) e Cordia piauhiensis Fresen (Boraginaceae) sobre Aedes aegypti

The larvicidal activity of the four monodesmoside saponins (1-4) isolated from Pentaclethra macroloba and one bidesmoside saponin (5) from Cordia piauhiensis was evaluated on 3rd instar larvae of Aedes aegypti. The larvae were exposed to serial concentrations (500, 250, 100, 50, 25 and 12.5 mg/mL) saponins for a period of 24 h. The results indicate that, only the saponins 1-3 showed high larvicidal activity, with LC50 ranging of 18,6-27,9 mg/mL. These results suggest that these can be used as natural larvicidal agents.

Chemical constituents of Simarouba versicolor

From the roots, stems and fruits of Simarouba versicolor (Simaroubaceae) were isolated quassinoids (3, 5-7), triterpenoids (8-14), a mixture of steroids (15-17), the flavonoid kaempferol (18) and the squalene derivative 11,14-diacetoxy-7,10; 15,18-diepoxy-6,19-dihidroxy-6,7,10,11,14,15,18,19-octahydrosqualene (19). Spectral data were used for structural characterization.

Rotenoids from Tephrosia toxicaria with larvicidal activity against Aedes aegypti, the main vector of dengue fever

In the search for new larvicides from plants, we have investigated the potential activity of the rotenoids deguelin (1), 12a-hydroxy-α-toxicarol (2) and tephrosin (3), isolated from the bioactive ethanol extract of roots of Tephrosia toxicaria Pers., against Aedes aegypti, the main vector of dengue. The absolute configuration of these compounds was determined by circular dichroism (CD) spectra. The LC50 values of the compounds evaluated justify the potential of T. toxicaria as a new natural larvicide.

Chemical Composition and Larvicidal Effects of Essential Oil from Bauhinia acuruana (Moric) against Aedes aegypti

Abstract The essential oil from leaves of Bauhinia acuruana Moric was obtained by hydrodistillation and analyzed by gas chromatography (GC-FID) and gas chromatography/mass spectrometry (GC/MS). In total, thirty compounds comprising 91.4% of the total peak area were identified. The main constituents of the essential oil were the sesquiterpenes spathulenol (23.4 ± 0.08%), epi-α-cadinol (20.7 ± 0.12%) and caryophyllene oxide (16.4 ± 0.04%). The essential oil was tested against Aedes aegypti larvae and showed LC50 value of 56.2 ± 0.4 μg/mL.

Unequivocal assignments of flavonoids from Tephrosia sp. (Fabaceae).

1H and 13C NMR chemical shifts of praecansone B, pongaflavone and dehydrorotenone isolated from Tephrosia egregia Sandw and obovatin from T. toxicaria Pers. were unambiguously assigned by 1D and 2D NMR experiments including 1H, 1H COSY, gHMQC and gHMBC, allowing the correction of literature assignments.Copyright

Zanthoxylum articulatum Engler (Rutaceae) Essential Oil: Chemical Composition and Larvicidal Activity

Abstract The leaves of Zanthoxylum articulatum Engler (Rutaceae), collected in Jacobina-Bahia, Northwest of Brazil, was subjected to hydrodistillation and its essential oil was characterized by GC/MS. Twelve compounds were identified representing 90.4% of the oil. Oxygenated sesquiterpenes (65.4%) were the major constituents with viridiforol (35.4%), spathulenol (9.9%), elemol (9.7%) and globulol (6.5%) being the main compounds. The oil was examined with respect to its larvicidal properties against the larvae of a mosquito (Aedes aegypti) and showed LC50 77.62 ± 0.64 ppm.