Browsing by Author "Lopes, Graciliana"
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- Influence of different fertilization regimes on the amounts of organic acids of Brassica oleracea L. var. costata DC.Publication . Ribeiro, Bárbara; Sousa, Carla; Lopes, Graciliana; Pereira, David M.; Taveira, Marcos; Dopico-García, Sonia; Pereira, J.A.; Bento, Albino; Rodrigues, M.A.; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.
- Influence of two fertilization regimes on the amounts of organic acids and phenolic compounds of tronchuda cabbage (Brassica oleracea L. Var. costata DC)Publication . Sousa, Carla; Valentão, Patrícia; Rangel, Joana; Lopes, Graciliana; Pereira, J.A.; Ferreres, Frederico; Seabra, Rosa M.; Andrade, Paula B.A phytochemical study was undertaken on tronchuda cabbage ( Brassica oleracea L. var. costata DC) cultivated under conventional and organic practices and collected at different times. Six organic acids (aconitic, citric, ascorbic, malic, shikimic, and fumaric acids) were identified and quantified by HPLC-UV. Qualitative and quantitative differences were noted between internal and external leaves. Analysis of the phenolics of the internal leaves was achieved by HPLC-DAD, and the phenolic profile obtained was revealed to be distinct from that of the external leaves. By this means were identified and quantified 11 compounds: 3- p-coumaroylquinic acid, kaempferol 3-O-sophoroside-7-O-glucoside, kaempferol 3- O-(caffeoyl)sophoroside-7- O-glucoside, kaempferol 3- O-(sinapoyl)sophoroside-7- Oglucoside, kaempferol 3- O-(feruloyl)sophoroside-7- O-glucoside, kaempferol 3- O-sophoroside, two isomeric forms of 1,2-disinapoylgentiobiose, 1-sinapoyl-2-feruloylgentiobiose, 1,2,2¢-trisinapoylgentiobiose, and 1,2¢-disinapoyl-2-feruloylgentiobiose. In general, internal leaves exhibited more constant chemical profiles.
- Multivariate analysis of Tronchuda Cabbage (Brassica oleracea L. var. costata DC) phenolics: influence of fertilizersPublication . Sousa, Carla; Pereira, David M.; Pereira, J.A.; Rodrigues, M.A.; Bento, Albino; Dopico-García, Sonia; Lopes, Graciliana; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.A field experiment was carried out to investigate the effect of fertilization level on the phenolic composition of tronchuda cabbage (Brassica oleracea L. var. costata DC) external and internal leaves. Eight different plots were constituted: a control without fertilization, one with organic matter, and six experiments with conventional fertilizers (nitrogen, boron, and sulfur, two levels each). The phenolic compounds were analyzed by reversed-phase HPLC-DAD. External and internal leaves revealed distinct qualitative composition. In the internal leaves were found 15 phenolics (5 kaempferol and 10 cinnamic acid derivatives), whereas the external leaves presented 3-p-coumaroylquinic acid and 13 kaempferol derivatives. Principal component analysis (PCA) was applied to assess the relationships between phenolic compounds, agronomical practices, and harvesting time. Samples obtained with conventional practices were quite effectively separated from organic samples, for both types of leaves. In general, samples developed without any fertilization presented the highest phenolics amounts: external and internal leaves contained 1.4- and 4.6-fold more phenolic compounds than the ones that received conventional fertilizer, respectively, and the internal leaves presented 2.4 times more phenolics than the ones grown with organic amendment. Additionally, samples from organic production exhibited higher total phenolics content than those from conventional practices, collected at the same time. Samples harvested first were revealed to be distinct from the ones collected later. The results show that it is possible to grow tronchuda cabbage without excess fertilizers, with highest amounts of phenolics and reduced environment contamination.
- Phenolic compounds in Brassica oleracea L. var. costata DC: effect of fertilization conditionsPublication . Dopico-García, Sonia; Sousa, Carla; Lopes, Graciliana; Pereira, David M.; Pereira, J.A.; Bento, Albino; Rodrigues, M.A.; Valentão, Patrícia; Seabra, Rosa M.; Andrade, Paula B.
- Quantitation of nine organic acids in wild mushroomsPublication . Valentão, Patrícia; Lopes, Graciliana; Valente, Miguel; Barbosa, Paula; Andrade, Paula B.; Silva, Branca M.; Baptista, Paula; Seabra, Rosa M.The organic acids composition of six wild edible mushroom species ( Amanita caesarea, Boletus edulis, Gyroporus castaneus, Lactarius deliciosus, Suillus collinitus, and Xerocomus chrysenteron) was determined by an HPLC-UV detector method. The results showed that all of the samples presented a profile composed of at least five organic acids: citric, ketoglutaric, malic, succinic, and fumaric acids. Several samples also contained oxalic, ascorbic, quinic, and shikimic acids. In a general way, the quantitation of the identified compounds indicated that malic acid, followed by the pair citric plus ketoglutaric acids, were the main compounds in the analyzed species, with the exception of A. caesarea, in which malic and ascorbic acids were the most abundant compounds. The relative amounts and the presence/absence of each identified compound may be useful for the differentiation of the species.
- Rumex induratus leaves: phenolic compounds and antioxidant capacityPublication . Valentão, Patrícia; Ribeiro, Vitor; Lopes, Graciliana; Rodrigues, M.A.; Gil Izquierdo, Angel; Ferreres, Frederico; Seabra, Rosa M.The phenolic composition of Rumex induratus was determined by HPLC-DAD-MS/MS-ESI and HPLC/DAD. The results showed a profile composed by caffeoyl-hexoside. two p-coumaroyl-hexoside isomers, feruloyl-hexoside, sinapoyl-hexoside. 6-C-hexosyl-quercetin. 8-C-hexosyl-luteolin, 6-C-hexosyl- luteolin, 6.C-hexosyl-apigenin. 3-O- hexosyl-quercetin, 3-O-rutinosyl-quercetin. 7.O.hexosyI-diosnietin, 3.O-rutinosyl-isorhamnetin, 7-0.(acetyl)-pentohexosyl-diosmetin, 6-C-hexnsyl-genkwanin and four unidentified O.glycosyl_C-glycosylflavones. R. induratus was also investigated for its capacity to act as a scavenger of DPPH and superoxide radicals. Good antioxidative results were obtained against both radicals.
- Screening of antioxidant compounds during sprouting of Brassica oleracea L. var. costata DCPublication . Sousa, Carla; Lopes, Graciliana; Pereira, David M.; Taveira, Marcos; Valentão, Patrícia; Seabra, Rosa M.; Pereira, J.A.; Baptista, Paula; Ferreres, Frederico; Andrade, Paula B.The changes in antioxidant compounds of Brassica oleracea L. var. costata DC seeds were monitored during the first twelve days of seedling development. Sprouts were screened at time intervals of two days for phenolic compounds and organic acids. The identified phenolic compounds included esters of sinapic acid with glucose, gentiobiose and kaempferol, as well as sinapoylcholine. The organic acids were oxalic, aconitic, citric, pyruvic, malic, shikimic, and fumaric acids. During germination, a depletion of phenolic compounds was observed, although no qualitative changes were seen. Among individual compounds, kaempferol, choline and glucose esters of sinapic acid showed a marked decrease between days two and six, whereas the changes in gentiobiose esters of sinapic acid were smaller. The total organic acids content increased rapidly during the first four days, with less significant variations thereafter. Malic acid, the major organic acid found in sprouts, greatly contributed to this result though oxalic, pyruvic, and fumaric acids also increased in the same manner. In contrast, aconitic, citric and shikimic acids showed decreases between days two and twelve of germination.