Avaliação do potencial antioxidante de extratos ativos de plantas obtidos por extração com fluido supercrítico

The aim of this work was to evaluate the antioxidant properties of ginger and rosemary extracts, obtained by supercritical extraction. The extracts were characterized by HPLC, GC-MS, phenolic compounds content and antioxidant activity. The main active compounds were identified and high content of phenolic compounds was observed. The extracts presented high antioxidant activity against the free radicals ABTS•+ (350 and 200 mM Trolox/g, for ginger and rosemary, respectively) and DPPH•+ (145 and 80 mM Trolox/g, for ginger and rosemary, respectively). These results suggested that the attained extracts are potential substitutes of synthetic antioxidants used in chemical, food and pharmaceutical industries.

Chemical composition and analgesic activity of the leaves and branches of Marlierea tomentosa Camb.

This paper describes the isolation of five phytoconstituents from Marlierea tomentosa. The triterpenes α-amyrin (1) and β-amyrin (2), and the flavonoids quercitrin (3) and isoquercetin (4), were isolated from the leaves. The branches afforded the triterpene arjunolic acid (5). The antinociceptive activity of crude extract, fractions and compound 5 were tested using the writhing and formalin tests in mice. The crude extract, some fractions, particularly dichloromethane and butanol (leaves), ethyl acetate (branches) and arjunolic acid (5) (81.2% inhibition) were more active against the writhing test than the two reference drugs, acetylsalicylic acid and indomethacin.

In vitro antimicrobial and antioxidant activities of a crude extract and fractions from Buddleja thyrsoides Lam. Leaves

Crude extract and fractions of Buddleja thyrsoides were investigated regarding antioxidant activities by DPPH, total phenolic contents by Folin-Ciocalteau and antimicrobial activity by the broth microdilution method. Total phenolics varied from 214.07 ± 3.6 to 438.4 ± 0.3 mg g-1. Crude extract, ethyl acetate, dichloromethane and butanolic fractions exhibited a weak scavenging activity (SC50=186.04 ± 10.8, 137.70 ± 8.5, 146.89 ± 9.0 and 165.71 ± 3.2 µg mL-1, respectively). A correlation between the antioxidant activities and total phenolic contents could be shown (r=0.857, p<0.01). The lowest value of MIC was observed with butanolic fraction against Saccharomyces cerevisiae (MIC and MFC at 62.5 µg mL-1). Dichloromethane and ethyl acetate fractions were effective against Staphylococcus aureus with MIC value at 250 and 500 µg mL-1 respectively.

Composição química e atividade biológica de extrato oleoso de própolis: uma alternativa ao extrato etanólico

Propolis is mostly used as hydroalcoholic extract. Recently there has been a growing number of patents dealing with new solvents for preparing propolis extracts. This study aimed to prepare edible oil propolis extracts and compare their chemical composition and biological activity with ethanolic propolis extracts. ESI-MS and spectrophotometric methods were used for qualitative and quantitative analyses, respectively. Antibacterial activity was evaluated by diffusion in agar. Cytotoxicity was tested by MTT assay using tumor cell lines. The oil is able to extract bioactive compounds from propolis. Further studies are needed to improve extraction efficiency and to characterize the active components.

Constituintes químicos de Sebastiania macrocarpa Muell. Arg. (Euphorbiaceae)

The chemical investigation of the methanolic extract of the aerial part of Sebastiania macrocarpa allowed the isolation of the mixture of steroids β-sitosterol and stigmasterol, gallic acid, and scopoletin. The hexane extract of the roots allowed the isolation of the triterpene lupeol and of the macrociclic diterpene (+)-tonantzitlolone. The structures of all compounds isolated were identified on the basis of their spectral data and by comparison of their spectral data with values described in the literature. This is the first report involving the chemical investigation of this species.

Óleo da castanha de caju: oportunidades e desafios no contexto do desenvolvimento e sustentabilidade industrial

The new millennium is marked by a growing search for renewable fuels and alternative raw materials from biomass in the petrochemicals industry. However, there are many challenges to overcome regarding technological and human resources aspects. In this scenario, cashew nut oil, which is rich in natural phenols, is considered to be very promising for the development of synthetic and functional products and as a feedstock for production of fine chemicals and a wide variety of new materials.

Estudos químicos e biológicos de Microgramma vacciniifolia (Langsd. & Fisch.) Copel (Polypodiaceae)

Chemical studies with aerial parts of Microgramma vacciniifolia (Langsd. & Fisch.) Copel. afforded ²-sitosterol, hopan-22-ol, 6-metoxiapinenin-7-O-²-D-allopyranoside and a mixture containing ethyl esters of carboxilic acids. The structures of the coumpounds were elucidated by spectroscopy and GC-MS analysis. The total phenolics contents of the crude extract and fractions were determined by Folin-Ciocalteau method. The antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH). The AcOEt fraction showed better activity in DPPH assay (9.9 ± 0.03 µg/mL), and presented also higher contents of the total phenolic (93.60 ± 1.11 µg/mg). Antimicrobial and allelopathic effects of the crude etanolic extract and fractions also were evaluated. In addition, the combination of biological activities was discussed.

Extracción de compuestos con actividad antioxidante de frutos de guayaba cultivada en Vélez-Santander, Colombia

The effects of the extraction system (50% methanol or 50% methanol pH 2.0), volume/material ratio, temperature, time and extractions with 70% acetone were evaluated in the total phenolic compounds (TPC) extraction and in antioxidant activities (AA) using FRAP and ABTS assays in guava fruit. The best yield was obtained when 0.5 g of guava were extracted first with 20 mL 50% methanol and then four times with 20 mL 70% acetone during 30 min at 50 °C. Among the different trials guava fruit exhibited high levels of AA as well as TPC.

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.

Composição molecular e origem paleobotânica de âmbares da bacia do Araripe, Formação Santana

The terpenoid composition of seven amber samples from Araripe Basin (Santana Formation, Crato Member) has been analyzed by gas chromatography-mass spectrometry to determine their botanical origin. The diterpenoids, which have been identified in the fossil resin extracts are derived primarily from the abietane class, e.g., dehydroabietane, 4-epidehydroabietol, 16,17,18-trisnorabieta-8,11,13-triene, 7-oxo-16,17,19-trisnorabieta-8,11,13-trieno, dehydroabietic acid, ferruginol, hinokiol and hinokione. Their composition is certainly typical for conifers, and angiosperms can be excluded as the botanical source, as no triterpene was identified. The terpenoid characteristics strongly support a relationship to the Araucariaceae or Podocarpaceae families. In addition, the fossil record of the embedding sediments (pollen and fossil leaves) also supports the proposal of these paleobotanical origins for the ambers.

Degradação de benzeno, tolueno e xilenos em águas contaminadas por gasolina, utilizando-se processos foto-Fenton

In this work the potentiality of photo-Fenton processes were investigated toward the degradation of aromatic hydrocarbons (BTXs) from water contaminated with gasoline. The main results demonstrated that BTXs can be quickly degraded by photo-Fenton process assisted by solar or artificial UV-A radiation, degradation that leads to generation of characteristic phenolic transient species (ie. phenol, hydroquinone and catechol). In the treatment of contaminated water by photo-Fenton processes assisted by solar light, complete BTXs removal was observed in reaction times of about 5 min. Mineralization of about 90% was also observed by applying a multiple H2O2 addition system.

Characterization of the major nutritional components of Caryocar brasiliense fruit pulp by nmr spectroscopy

Pequi (Caryocar brasiliense Camb.), a typical fruit of Brazilian Cerrado, is well known in regional cookery and used in folk medicine to treat various illnesses. Mass spectrometry and chromatographic methods have identified the organic composition of pequi fruit pulp; however, NMR spectroscopy is used for the first time to characterize the nutritional components of organic and aqueous-ethanolic extracts. This spectroscopic technique determined the triacylglycerols in the pequi organic fraction, which is constituted mainly by oleate and palmitate esters, and detected the carbohydrate mixtures as the major components of aqueous and ethanolic fractions, respectively. In this study, presence of phenolic compounds was only evidenced in the ethanolic fraction.

Determinación de vitamina C, compuestos fenólicos totales y actividad antioxidante de frutas de guayaba (Psidium guajava L.) cultivadas en Colombia

Some physicochemical parameters, vitamin C, total phenolic compounds and antioxidant activity (AA) measured by ABTS, FRAP and DPPH methods were determinated in four different varieties of ripe guava produced in Colombia. Samples were statistically similar in their titratable acidity. Soluble solids were statistically similar and higher in "Pear", "Pink Regional", and "White Regional", but lower in "Apple" guavas. Vitamin C was statistically lower in "Pear" guava. Phenolics, ABTS-, FRAP-, and DPPH-AA were statistically lower in "Apple" guava if compared in wet basis. "Pink Regional" and "White Regional" contained the highest levels in vitamin C, phenolics and antioxidant activity.

Enriquecimento de compostos fenólicos de folhas de Inga edulis por extração em fase sólida: quantificação de seus compostos majoritários e avaliação da capacidade antioxidante

A phenolic fraction was obtained from of the acetone-water-acetic acid extract of Inga edulis leaves, by liquid-liquid partition and SPE-C18 cartridges. This method provided an increase of 108, 66, 51, 50 and 36% of flavonols, proanthocyanidins, total polyphenols, gallotannins and flavanols, respectively. The major phenolics in purified fraction were procyanidin B2, catechin and myricetin-3-O-α-L-rhamnopyranoside, which achieved increases of 111, 47 and 45%, respectively, after SPE. Acid hydrolysis confirmed the presence of procyanidins, prodelphinidins and glycosylated flavonoids.

Determinação de compostos fenólicos por cromatografia líquida de alta eficiência isocrática durante estacionamento da erva-mate

Different phenolic compound, 5- caffeoylquinic acid (5-CQA), caffeic acid (AC) and rutin (Ru) contents of yerba-mate (Ilex paraguariensis) Brazilian samples of 06 different regions of São Mateus - Paraná, during natural and accelerated industrial storage, were evaluated. For quantification, a reverse phase HPLC isocratic method was developed and validated using methanol:water (35:65 v/v) acidified with 0.5% acetic acid as mobile phase and a photodiode array detector. The six sample global average contents were (34.90 and 36.10 mg g-1) for 5-CQA, (0.18 mg g-1 and 0.23 mg g-1) for AC and (7.12 and 7.18 mg g-1) for Ru, respectively, for the natural and accelerated storage systems. The results showed that the 5-CQA and Ru content are kept constant during the storage while AC content increase only during accelerated storage.