Estudo comparativo entre as metodologias preconizadas pelo CLSI e pelo EUCAST para avaliação da atividade antifúngica

The international organizations CLSI and EUCAST developed reference methodologies for activity evaluation antifungal. The aim of this work was to compare the recommended methodologies by the CLSI and EUCAST in the antifungal activity evaluation of crude extracts of Azadirachta indica and green propolis. The results showed that the MIC values determined by the EUCAST methodology were smaller than that determined by the CLSI. Nevertheless, both methodologies were satisfactory to detect and evaluate antifungal activity of the crude extracts and isolated compounds. The EUCAST methodology showed advantage by making possible to obtain results in less time.

Atividade antioxidante do extrato de sementes de limão (Citrus limon) adicionado ao óleo de soja em teste de estocagem acelerada

The aim of this work was to evaluate antioxidant activity of lemon seeds added to soybean oil, submitted to accelerated incubator-storage test and to determine its synergistic effect with the synthetic antioxidant TBHQ. The treatments Control, TBHQ (50 mg/kg), LSE (2,400 mg/kg Lemon Seed Extract), Mixture 1 (LSE + 50 mg/kg TBHQ) and Mixture 2 (LSE + 25 mg/kg TBHQ) were prepared and subjected to the accelerated incubator-storage test at 60 ºC for 12 days; samples were taken every 3 days and analyzed regarding peroxide value and conjugated dienes. The results showed that antioxidant activity of the tested treatments were: TBHQ = Mixture 1 = Mixture 2 > LSE > Control.

Atividade antibacteriana de floroglucinóis e do extrato hexânico de Hypericum brasiliense Choysi

Three phloroglucinols were obtained from Hypericum brasiliense: japonicine A (1), isouliginosin B (2) and uliginosin B (3). Bioautography and disk diffusion methods were used to determine antibacterial activity of the hexanic extract. Strains of the Coagulase Negative Staphylococcus and American Methicillin Resistant Staphylococcus aureus clones showed a growth inhibition zone ranging from 10 to 12 mm and 7 to 15 mm, respectively. Minimal inhibitory concentration (MIC) values were used to measure antistaphylococcal activity for all phloroglucinols. Isouliginosin B and uliginosin B presented MIC values of 1.5 and 3.0 µg/mL, respectively, while japonicine A displayed MIC value of 50.0 µg/mL.

Derivados oleananos e ursanos e sua importância na descoberta de novos fármacos com atividade antitumoral, anti-inflamatória e antioxidante

Oleanolic and ursolic acids are triterpenes that exist abundantly in the plant kingdom. They show antitumor activity and their cytotoxic activity was already evaluated against a broad range of cell lines. The inhibition of enzymes involved in the metabolism of DNA and the induction of apoptosis are known events that have been related to the antitumour activity of these triterpenes. The antiinflamatory and antioxidant activities also seem to play an important role in their antitumour activity. In this review, it is presented an overview of the importance of the potential antitumour, antiinflamatory and antioxidant activities of these triterpenoid derivatives. Also, we propose a structural-activity relationship to triterpenes containing oleanane or ursane skeleton and their cytotoxic activity.

Síntese e avaliação da atividade antimicrobiana de novas 4-tiazolidinonas obtidas a partir de formilpiridina tiossemicarbazonas

Twelve novel 4-thiazolidinone derivatives (2a-l) have been synthesized by reacting formilpyridine thiosemicarbazones (1a-l) and anhydride maleic in toluene. Their chemical structures were confirmed by IR, ¹H and 13C NMR. The new compounds were submitted to in vitro evaluation against pathogenic Gram-positive, Gram-negative bacteria and yeasts. The findings obtained showed that the compounds 2a, 2d, 2e and 2g were effective against some of the bacterial strains used, whereas the compounds 2d, 2e and 2i exhibited a moderate antifungal activity against the yeast strains evaluated. An initial structure activity relationship (SAR) was established.

Constituintes químicos e atividade antioxidante de extratos das folhas de Terminalia fagifolia Mart. et Zucc

Phytochemical investigation of ethanolic leaves extracts of T. fagifolia led to the isolation of (+)-catechin, sitosterol-3-O-β-D-glucopyranoside, α- and β-tocopherol, a mixture of lupeol, α- and β-amyrin, sitosterol and a mixture of glicosid flavonoids (CP-13). The structures of these compounds were identified by ¹H and 13C NMR spectral analysis and comparison with literature data. Absolute configuration of the catechin was determinate by circular dichroism. Antioxidant activity (EC50), evaluated by 2,2-diphenyl-1-picrylhidrazyl (DPPH) assay system, decreased in the order: (+)-catechin > hydroalcoholic fraction > CP-13 > aqueous fraction > EtOH extract.

Composição fenólica, atividade antibacteriana e antioxidante da própolis vermelha brasileira

Propolis is a resinous hive product collected by honeybees from various plant sources. It has a complex chemical composition, constituted by various phenolic compounds. Extracts of increasing polarity (n-hexane, chloroform, and ethanol) were obtained from a sample of red propolis from the state of Alagoas. Assays were carried out for determination of contents of phenolics, along with antibacterial and antioxidant activities. The EEP, fractions and sub-fractions showed strong biological activities and were related with phenolic the content compounds contents. The sub-fractions were more bioactive than the EEP and fractions, demonstrating that the antioxidant and antibacterial activities are not a result of synergistic effect between the various chemical compounds in propolis.

Constituintes químicos e atividade inseticida dos extratos de frutos de Trichilia elegans E T. catigua (Meliaceae)

Phytochemical investigation of the fruits extracts of Trichilia elegans and Trichilia catigua (Meliaceae) has led to the identification of the limonoids 11β-acetoxyobacunone, cedrelone, methylangolensate and epimeric mixture of photogedunin besides known coumarins (scoparone, scopoletin, umbeliferone) and the steroids stigmasterol, β-sitosterol, sitostenone and campesterol. The structures of the compounds were proposed by spectroscopic analysis and comparison with literature data. An evaluation of the insecticidal activity of the fruits extracts of Trichilia ssp. was carried out and the extracts of T. elegans revealed to have strong insecticidal activity and the extracts of T. catigua showed moderate larval mortality on Spodoptera frugiperda.

Avaliação da atividade antioxidante do ácido fítico de germe de milho

The obtained corn germ phytic acid (CGPA) antioxidant potential was evaluated through the deoxyribose, bathophenanthroline (BPS) and DPPH• assays. In the concentration of 130.5 μM of CGPA the hydroxyl radical maximum sequestering antioxidant activity was 29.3% while standard phytic acid (SPA) presented this maximum activity of 18.2% in the concentration of 33.2 μM of SPA. The BPS assays revealed that the chelation activity towards Fe2+ increased concurrently with the increase of CGPA concentration and its Fe2+ contact time. Finally, DPPH• assay showed that CGPA and SPA did not present electron-donating capacity to DPPH•.

Alcaloides iboga de Peschiera affinis (Apocynaceae) - Atribuição inequívoca dos deslocamentos químicos dos átomos de hidrogênio e carbono: atividade antioxidante

Six known alkaloids iboga type and the triterpen α- and β-amyrin acetate were isolated from the roots and stems of Peschiera affinis. Their structures were characterized on the basis of spectral data mainly NMR and mass spectra. 1D and 2D NMR spectra were also used to unequivocal ¹H and 13C chemical shift assignments of alkaloids. The ethanolic extract of roots, alkaloidic and no-alkaloidic fractions and iso-voacristine hydroxyindolenine and voacangine were evaluated for their antioxidative properties using an autographic assay based on β-carotene bleaching on TLC plates, and also spectrophotometric detection by reduction of the stable DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical.

Constituintes químicos do caule de Spathelia excelsa (rutaceae) e atividade frente a Aedes aegypti

Phytochemical investigation from the stems of Spathelia excelsa (Rutaceae) collected in Amazonas yielded deacetylspathelin (1), 7,8-dimethoxyflindersine (2), new glabretal-type triterpenoid 3β-angeloyl-21,24-epoxy-7α, 21α, 23α, 25-tetrahydroxy-4α, 4β, 8β, 10β-tetramethyl-25-dimethyl-14, 18-cyclo-5α, 13α, 14α, 17α-cholestane (3), in addition to the known steroids β-sitosterol and stigmasterol. Their structures were established on the basis of spectral data. The compounds 1 and 3 were assayed on Aedes aegypti (larvicidal and adulticidal activities and compound 3 exhibited larvicidal properties with LC50 of 4,8 µg/mL.

Toxicidade e atividade antioxidante de flavonoides das cascas das raízes de Lonchocarpus filipes

The phytochemical investigation of dichloromethane extract from root bark of Lonchocarpus filipes Benth (Leguminosae) afforded four flavonoids including three dibenzoylmethane derivatives rarely found in nature. The structures were established based on their spectral data (¹H and 13C NMR, 2D-NMR) as being: lanceolatin B (1), pongamol (2), (E)-7-O-methylpongamol (3) and (E)-9-O-methylpongamol (4). Compound (4) is described herein for the first time as a natural product. The extracts and the isolated compounds (1), (2) and (3) displayed high toxicity in the brine shrimp lethality assay. Only compound (2) showed antioxidant activity using a DPPH radical scavenging assay. This is the first report on the phytochemical study of Lonchocarpus filipes.

Composição química e atividade alelopática do óleo volátil de Hydrocotyle bonariensis Lam (araliaceae)

The volatile oil obtained from the leaves of Hydrocotyle bonariensis Lam (Araliaceae) was analyzed by GC, Chiral-GC and GC-MS. It was identified 14 compounds and the monoterpene (+)-limonene (53.6%) and sesquiterpene γ-muurolene (10.5%) were the main components. The allelopathic effects of the oil were evaluated against two seeds, Lactuca sativa and Allium cepa. The results show that the oil exhibited inhibition effects in the germination and seedling growth of plants species relative to the control.

Compostos bioativos do café: atividade antioxidante in vitro do café verde e torrado antes e após a descafeinação

This study aimed to evaluate the effect of coffee decaffeination with dichloromethane on the in vitro antioxidant activity of this matrix. It were determined the content of total phenolics, chlorogenic acid and caffeine of the coffee samples. The assessment of the antioxidant potential was investigated by DPPH radical scavenging method, reducer power and Fe2+chelation activity. The process of decaffeination and roasting caused changes in the levels of the compounds investigated. The results show that the decaffeination by the dichloromethane method reduces the in vitro antioxidant potential of coffee.

Óleos essenciais das folhas de Vernonia Remotiflora e Vernonia Brasiliana: composição química e atividade biológica

The chemical composition of the essential oils, obtained by hidrodistillation, from leaves of two Vernonia species (V. remotiflora and V. brasiliana), was determined by GC-FID and GC-MS. Both essential oils were predominantly constituted by sesquiterpenes (92.0 - 93.4%). The main constituents of the oil from V. brasilana were (E)-caryophyllene (36.7%), germacrene D (35.5%), and α-humulene (11.7%), while (E)-caryophyllene (42.2%) and bicyclogermacrene (20.0%) were the major ones in the oil from V. remotiflora. Although with moderate activity both oils showed acetylcholinesterase and antibacterial activities.