Utilização de detecção por espalhamento de luz evaporativo para a análise de produtos naturais

The interest in the use of evaporative light scattering detector (ELSD) for the analysis of different classes of natural products has grown over the years. This is because this detector has become an excellent alternative compared to other types of detectors, such as the refractive index detector and the ultraviolet (UV) detector. This review describes the basic principles of ELSD functioning and discusses the advantages and disadvantages in using an ELSD for the analysis of organic compounds. Additionaly, an overview, covering the last 23 years, of ELSD applications in natural products analysis (saponins, terpenes, carbohydrates, glycosides, alkaloids, steroids, flavonoids, peptides, polyketides, coumarins and iridoids) is presented and discussed.

Ácidos fenólicos, flavonoides e atividade antioxidante em méis de Melipona fasciculata, M. flavolineata (Apidae, Meliponini) e Apis mellifera (Apidae, Apini) da Amazônia

Honey produced by three stingless bee species (Melipona flavolineata, M. fasciculata and Apis mellifera) from different regions of the Amazon was analyzed by separating phenolic acids and flavonoids using the HPLC technique. Data were subjected to multivariate statistical analysis (PCA, HCA and DA). Results showed the three species of honey samples could be distinguished by phenolic composition. Antioxidant activity of the honeys was determined by studying the capacity of inhibiting radicals using DPPH assay. Honeys with higher phenolic compound contents had greater antioxidant capacity and darker color.

Fitoquímica e quimiossistemática de Euxylophora paraensis (Rutaceae)

Phytochemical studies of the leaves and stem have led to the identification of the known coumarins isooxypeucedanin, oxypeucedanin hydrate, xanthotoxin, isopimpinellin, 8-methoxymarmesin and marmesin, flavonoids quercetin-3-O-α-L-rhamnopyranoside, myricetin-3-O-α-L-rhamnopyranoside and hesperidin, alkaloids skimmianine and N-methylflindersine and limonoid limonin. The compounds isolated and the chemical profile of Euxylophora obtained from the literature clearly indicate its phytochemical affinities with other Rutoideae species.

Implicações químicas na sistemática e filogenia de Bignoniaceae

Our solemn homage to the great Master Otto R. Gottlieb who knew how to teach the mystery of evolutionary relationships between chemistry and its natural sources. The micromolecular chemical study of the family Bignoniaceae shows a profile predominantly characterized by the occurrence of metabolites derived from acetic acid biosynthetic pathways such as terpenoids, quinones, flavonoids and special aromatic derivatives. Analysis of different chemosystematic parameters for the metabolite data collected, provided valuable information for the systematic characterization of the Bignoniaceae family within the Angiosperm derived taxa.

Seasonal variation of the major secondary metabolites present in the extract of Eremanthus mattogrossensis Less (Asteraceae: Vernonieae) leaves

The species Eremanthus mattogrossensis, known as "veludo do cerrado" (cerrado velvet), is native to the Brazilian Cerrado. Because the amount of metabolites present in plants may be influenced by biological and environmental factors, here we conducted an HPLC-DAD-MS/MS investigation of the metabolite concentrations found in the MeOH/H2O extract of the leaves of this species. The main compounds were identified and quantified, and the metabolites were grouped by chemical class (caffeoylquinic acids, flavonoids, and sesquiterpene lactone). Statistical analysis indicated a straight correlation between the quantity of metabolites and seasonality, suggesting that environmental properties elicit important metabolic responses.

Chemotaxonomy of three genera of the annonaceae family using self-organizing maps and 13C NMR data of diterpenes

The Annonaceae family is distributed throughout Neotropical regions of the world. In Brazil, it covers nearly all natural formations particularly Annona, Xylopia and Polyalthia and is characterized chemically by the production of sources of terpenoids (mainly diterpenes), alkaloids, steroids, polyphenols and, flavonoids. Studies from 13C NMR data of diterpenes related with their botanical occurrence were used to generate self-organizing maps (SOM). Results corroborate those in the literature obtained from morphological and molecular data for three genera and the model can be used to project other diterpenes. Therefore, the model produced can predict which genera are likely to contain a compound.

Flavonoides e outros compostos isolados de Mimosa artemisiana Heringer e Paula

This the first phytochemical investigation of Mimosa artemisiana (Leguminosae-Mimosoideae) describing the isolation and identification of quercitrin, myricitrin, 3,5,4´-trihydroxi-6,7-dimethoxyflavone (6,7-dimethylkaepferol), flavolignans, 3-O-β-D-glucopyranosil sitosterol, lupeol, sitostenone, stigmastenone, campestenone, sitosterol, stigmasterol, campesterol, methyl indole-3-carboxilate and indole-3-carboxaldehyde in the extracts from the leaves and wood of this plant. This is the first registry of 6,7-dimethoxy,4'-hydroxy-flavona and the flavonolignans in this genera. The isolation of all metabolites was made by chromatographic methods and the structures were established on the basis of IR, MS, ¹H and 13C NMR spectra analysis, comparison with literature data and GC-MS of mixtures analysis.

Flavonoides e sesquiterpenos de Croton pedicellatus Kunth

The chemical investigation of the ethanolic extract from leaves of Croton pedicellatus yielded the bis-nor-sesquiterpenes blumenol A and blumenol A glucoside, along with the flavonoids: tiliroside, 6"-O-p-coumaroyl-β-galactopyranosyl- kaempferol, 6"-O-p-coumaroyl-β-glucopyranosyl-3"-methoxy- kaempferol, kaempferol, 3-glucopyranosyl-quercetin and alpinumisoflavone, as well as 4-hydroxy-3,5-dimethoxybenzoic acid. The identification of all isolated compounds was performed by spectrometric methods, including HR-ESI-MS, 1D and 2D NMR experiments, and by comparison with previously-described physical and spectral data.

Chemical profiling of six samples of Brazilian propolis

Six samples of Brazilian propolis from Minas Gerais and Paraná states were analyzed to identify the constituents (GC/MS and HPLC/MS) and to determine their contents (HPLC and external standardization). All samples contained characteristic constituents of green propolis, but the samples from Minas Gerais had higher contents of prenylated phenylpropanoids and caffeoylquinic acids. Kaempferide and two other flavonoids were among the major constituents of the samples from Minas Gerais. Luteolin 5-O-methyl ether was detected only in samples from Paraná. Baccharis dracunculifolia was a source of resins for all samples analyzed, but the samples from Paraná had more complex plant origin.

Atividade de extratos de Arrabidaea chica (Humb. & Bonpl.) Verlot obtidos por processos biotecnológicos sobre a proliferação de fibroblastos e células tumorais humanas

Arrabidaea chica (H&B) Verlot is a plant popularly known as Pariri and this species is a known source of anthocyanins, flavonoids and tannins. This report describes an approach involving enzymatic treatment prior to extraction procedures to enhance A chica crude extract anticancer activity. Anticancer activity in human cancer cell lines in vitro using a 48 h SRB cell viability assay was performed to determine growth inhibition and cytotoxic properties. The final extraction yield without enzyme treatment was higher (24.28%) compared to the enzyme-treated material (19.03%), with an enhanced aglycones anthocyanin ratio as determined by HPLC- DAD and LC-MS with direct infusion.

Síntese, caracterização e estudo das propriedades de um novo complexo mononuclear contendo quercetina e íon Ga(III)

Flavonoids are one of the most important compound groups applied as medicine given their antioxidant properties, but several intrinsic properties can be improved through structural modifications to their molecules. Here, the synthesis and characterization of a new gallium (III) complex with quercetin is described. Electrochemical properties, as well as antioxidant and cytotoxic activities, were investigated and compared to the free flavonoid molecule. The mononuclear complex obtained, [Ga(C15H9O7)3].2H2O.2CH3OH.CH3CH2OH, seems more active as a DPPH radical scavenger given its lower oxidation potential compared to quercetin. The new complex cytotoxic responses have shown to be more effective than those of the free flavonoid and of lapachol used as a control.

Flavonoides e terpenoides de Croton muscicarpa (Euphorbiaceae)

A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Müll. Arg.. Their structures were identified as the terpenoids 6α-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4'-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4'-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, ¹H and 13C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY) and comparison with data from the literature.

Actividad insecticida sobre Spodoptera frugiperda (Lepidóptera: Noctuidae) de los compuestos aislados de la parte aérea de Piper septuplinervium (Miq.) c. dc. y las inflorescencias de Piper subtomentosum Trel. & Yunck. (Piperaceae)

The bioassay-guided purification of ethanolic extracts from inflorescences of Piper subtomentosum Trel. & Yunck and aerial part of Piper septuplinervium (Miq. ) C. DC. led to isolation of five flavonoids, uvangoletin (1), galangin (2), chrysin (5), 5-hydroxy-4',7-dimethoxy-flavone (6), pinostrobin (7); one amide, N-p-coumaroil-tyramine (4); one acylglycerol, monopalmitin (3); one derivative of acid, protocatechuic acid (8); and glycosydated sterol, daucosterol (9). Their structures were elucidated on the basis of spectroscopy and spectrometry data and by comparison with data reported in the literature. The isolated compounds were tested against Spodoptera frugiperda. The results showed galangin and protocatechuic acid to be the most active (LC 50 13.63 and 17.16 ppm, respectively).

Constituintes químicos e atividade antioxidante de folhas e galhos de Eugenia copacabanensis Kiaersk (Myrtaceae)

Phytochemical investigation of Eugenia copacabanensis allowed for the isolation and identification of following compounds: β-sitosterol, β-sitosterol-glucoside, eight triterpenes, (mixture of α- and β-amyrins, ursolic acid, 30-hydroxy-ursolic acid, betulin, friedelin, friedelan-3,4-lactone, and taraxerol), a mixture of three sesquiterpenes, (clovandiol, globulol, and viridiflorol), three flavonoids (kaempferol-3-O-β-D-rhamnoside, quercetin-3-O-α-L-arabinoside, and quercetin), and a mixture of four coumaroyl esters (octacosanyl, heptacosanyl, hexacosanyl, and tetracosanyl coumarates). The structures of these compounds were assigned based on comparison with literature data and spectroscopic analysis, including analysis by two-dimensional NMR techniques. Total phenolic content and total flavonoids were evaluated. Antioxidant activities of methanol extracts and fractions were measured by the 1,2-diphenyl-2-picryl-hidrazyl free radical scavenging assay.

Chemical constituents isolated from turnera subulata Sm. and electrochemical characterization of phaeophytin b

Turnera subulata Sm., known as "Chanana" or "flor-do-Guarujá" in Brazilian folklore, is a plant species belonging to the subfamily Turneroideae of family Passifloraceae, which is used for various medicinal purposes in Brazil. The phytochemical study conducted here led to the isolation and identification of ten compounds present in T. subulata: two mixtures of steroids, sitosterol and stigmasterol (nonglycosylated and glycosylated); a mixture of flavonoids, 5,7,4′-trihidroxiflavona-8-C-α-glucopyranoside and 5,7,3′,4′-tetrahidroxiflavona-8-C-α-glucopyranosidel; and four phaeophytins, phaeophytin purpurin-18-phytyl ester, a rare natural product, phaeophytin a , 13²-hydroxy-(13²-S)-phaeophytin a , and phaeophytin b Phaeophytin b exhibited electrochemical activity similar to that of phthalocyanines.