41 research outputs found
Identification and determination of 3-deoxyglucosone and glucosone in carbohydrate-rich foods
BACKGROUND: α-Dicarbonyl compounds (α-DCs) such as 3-deoxyglucosone (3-DG) and glucosone are markers of both Maillard and degradation reactions of sugars and also of certain enzymatic processes. However, quantitation of these compounds is not straightforward when more abundant carbohydrates are present in real samples. Therefore in this work a GC/MS method was developed to separate monosaccharides, 3-DG and glucosone and applied to analyze them in carbohydrate-rich food products. Difructose anhydrides (DFAs), known markers of sugar degradation, were also determined. The effect of time and temperature in the production and storage of these compounds was also evaluated. RESULTS: Under optimized conditions, good separation between monosaccharides and α-DCs was achieved. Must syrups showed the highest concentrations of 3-DG and glucosone (average values 9.2 and 5.8 mg g-1 respectively). Coffee substitutes based on carob, chicory and blends showed the highest content of DFAs. Heating and storage assays proved that production of 3-DG was influenced by temperature, while glucosone was more affected by storage time. CONCLUSION: The proposed method allows the rapid quantitation of 3-DG and glucosone along with carbohydrates and DFAs in different food products, which is essential to determine their degradation level. Moreover, the α-DC content in several foods is reported for the first time.This work was financed by projectsCTQ2012-32957 funded by
Ministerio de EconomĂla y Competitividad and AGR-7626 funded
by Junta de AndalucĂaPeer Reviewe
Influence of seasonality and habitat on chemical composition, cytotoxicity and antimicrobial properties of the Libidibia ferrea
Libidibia ferrea Mart, belonging to the Fabacee family, is a medicinal plant known for its biological properties and production of phenolic compounds. Previous studies reveal the biological activity of its phenolic constituents, making it very promising for the development of new medicines. Seasonality and geographic distribution of species can modify the production of secondary metabolites in Fabaceae species in terms of the preferentially activated metabolic pathways and, consequently, interfere with the medicinal properties of these species. Studying the influence of seasonality on the production of phenolic constituents is essential to establish conditions for âcultivation,â species collection, standardization, production, and safety in traditional medicine. This unprecedented study proposed to evaluate the influence of seasonal variations and habitat on the production of phenolic compounds and biological properties of the ethanolic extracts of the stem bark from L. ferrea, whose specimens were collected from the Caatinga and the Atlantic Forest, biomes of Brazil. Antimicrobial activity was determined by broth microdilution. Cytotoxicity was evaluated through a colorimetric assay using MTT. ABTS and DPPH radical reduction methods estimated antioxidant capacities. Folin-Ciocalteu and AlCl3 spectrophotometric methods quantified total phenolics and flavonoids, respectively. In turn, radial diffusion quantified tannin content. PCA score plot and HCA dendogram were obtained by multivariate analysis of 1H NMR data. The cytotoxicity against C6 glioma cells was observed only for Atlantic Forest extracts (EC50 = 0.13â0.5 mg mLâ1). These extracts also showed selectivity against Gram-positive bacteria Bacillus subtilis (ATCC 6633) [MICs 500â2000 Όg mLâ1], B. cereus CCT 0096) [MIC = 250 Όg mLâ1], Staphylococcus aureus (ATCC 6538) [MICs = 250â500 Όg mLâ1], S. epidermidis (ATCC 12228) [62.5â1000 Όg mLâ1], mainly to Staphylococcus sp. Caatinga extracts showed higher production of flavonoids and antioxidants in the summer [7.36 ± 0.19 Όg QE mgâ1 extract; IC50ABTS = 4.86 ± 0.05 Όg mLâ1], spring [5.96 ± 0.10 Όg QE mgâ1 extract; IC50ABTS = 5.96 ± 0.08 Όg mLâ1 ], winter [4.89 ± 0.25 Όg QE mgâ1 extract; IC50ABTS = 6.72 ± 0.08 Όg mLâ1 ]. Regarding habitat, two discriminating compound patterns in the studied biomes were revealed by NMR. The results indicated that the Caatinga biome offers better conditions for activating the production of phenolics [336.34 ± 18.1 ÎŒgGAE mgâ1 extract], tannins [328.38 ± 30.19 ÎŒgTAE mgâ1 extract] in the summer and flavonoids in winter, spring, and summer. The extracts that showed the best antioxidant activities were also those from the Caatinga. In turn, extracts from the Atlantic Forest are more promising for discovering antibacterial compounds against Staphylococcus sp and cytotoxic for C6 glioma cells. These findings corroborated the traditional use of L. ferrea bark powder for treating skin wounds and suggest the cytotoxic potential of these extracts for glioblastoma cell lines