Ângela M.C. Arriaga

Antibacterial and Antioxidant Activities of Ursolic Acid and Derivatives

Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3β-formyloxy-urs-12-en-28-oic acid at the concentration of 64 μg/mL in combination with kanamycin against Escherichia coli (27), a multidrug-resistant clinical isolate from sputum, with reduction of MIC value from 128 μg/mL to 8 μg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

Study of technical CNSL and its main components as new green larvicides

Larvicidal activities against Aedes aegypti of technical cashew (Anarcadium Occidentale L.) nut shell liquid (CNSL) and its main constituents, cardanol, cardol and their products of hydrogenation were evaluated. In addition, the structure-activity relationship is also discussed.

Estudo fitoquímico e avaliação da atividade larvicida de Pterodon polygalaeflorus Benth (Leguminosae) sobre Aedes aegypti

Chemical investigation of the hexane and methanol extracts of the fruits of Pterodon polygalaeflorus (Leguminosae) resulted in the isolation and identification of furanic diterpenes: 6-a-acetoxivouacapane, 6-a-hidroxyvouacapane and vouacapane, which is related by the first time as a natural product. The structures of these compounds were established by spectroscopic analysis, including 2D NMR experiments. The 6-a-acetoxivouacapane, the hexane and methanol extracts, and the essential oil were evaluated on 3rd instar larvae of Aedes aegypti and only the hexane extract showed good larvicidal activity with LC50 23.99 ± 0.75 µg/mL.

Chemical composition and larvicidal activity of Rollinia leptopetala (Annonaceae)

The aim of present study was to describe the chemical composition of the essential oils from the leaf and stem of Rollinia leptopetala R. E. Fries (Annonaceae) and to evaluate the larvicidal activities of these essential oils, of the methanol extract from roots of this plant and of the oxoaporphine alkaloid, liriodenine (1) against the third-instar of Aedes aegypti larvae. The methanol extract from the roots showed larvicidal activity with LC 50 64.6 ± 1.5 ppm. Higher activity was observed for the isolated alkaloid liriodenine (1), LC 50 3.6 ± 0.4 ppm. The essential oils from the leaves and stems, also exhibited larvicidal activity with LC 50 104.7 ± 0.2 and 34.7 ± 0.3 ppm, respectively. These results suggest R. leptopetala as a source of natural larvicidal compounds. This is the first report about the chemical composition and larvicidal activity of the leaf and stem essential oils of R. leptopetala.

Ocorrência e atividade biológica de quassinóides da última década

Quassinoids, the bitter principles of the Simaroubaceae family, are a group of structurally complex and highly oxygenated degraded triterpenes. They are divided into five groups according to their basic skeleton, C-18, C-19, C-20, C-22 and C-25. In recent years, attention has been focused on quassinoids because several of them have shown promising biological activities. This paper features a review of some characteristics of these compounds, updating known information with discoveries from the last decade and covering chemical structures, basic skeletons, occurrence in genus and species, besides detailed studies of biological activities such as antitumor, antimalarial, phytotoxic, antifeedant, insecticidal, anti-inflammatory and antiulcer.

Volatile Constituents from Roots of Bowdichia virgilioides Kunt

Abstract The oil from roots of Bowdichia virgilioides (Leguminosae) was analyzed by GC and GC/MS. The major constituents found were 2-tridecanone (54.6%), 4-ethyl-2-methoxyphenol (11.0%) and 2-pentadecanone (9.9%).

A new eremophilane-type sesquiterpene from the phytopatogen fungus Lasiodiplodia theobromae (Sphaeropsidaceae)

O fungo fitopatogenico Lasiodiplodia theobromae, isolado de goiaba, foi cultivado em arroz por 32 dias a temperatura ambiente. Extracao com CH2Cl2:MeOH (3:7), seguido de fracionamento cromatografico do extrato forneceu o esteroide ergosterol. Da cultura fungica em meio de Czapeck por 40 dias a temperatura ambiente, foram isolados a isocumarina cis-4-hidroximeleina e um sesquiterpeno do tipo eremofilano. O sesquiterpeno eremofilano esta sendo descrito pela primeira vez na literatura. Este e o primeiro relato do isolamento de um sesquiterpeno eremofilano para o genero Lasiodiplodia.

Composition of the Essential Oil of Tephrosia egregia Sandw

Abstract The essential oils obtained from fresh leaves and stems of Tephrosia egregia Sandw (Leguminosae) were analyzed by GC and GC/MS. Nine and 10 volatile compounds have been identified in the leaf and stem oils, respectively. The major components of the leaf oil were geijerene (50.3%) and pregeijerene (21.0%), whereas the stem oil contained geijerene (39.0%) and pregeijerene (13.8%) as main constituents.

Volatile constituents from leaves of Guazuma ulmifolia Lam

Abstract The oil from leaves of Guazuma ulmifolia Lam. was analyzed by GC and GC/MS. The major constituents found were precocene I (56.0%), β-caryophyllene (13.7%) and (2Z,6E)-farnesol (6.6%).

Volatile Constituents from Fruit Shells of Passiflora edulis Sims.

Abstract The essential oil from fruit shell of Passiflora edulis Sims, was analyzed by GC and GC/MS. The major constituents found were 2-tridecanone (62.1%), (9Z)-octadecenoic acid (16.6 %), 2-pentadecanone (6.2%), hexadecanoic acid (3.2%), 2-tridecanol (2.1%), octadecanoic acid (2.0%) and caryophyllene oxide (2.0%).