Flavonoids patterns of French honeys with different floral origin

The flavonoid profiles of 12 different unifloral French honey samples were analysed by HPLC to evaluate if these substances could be used as markers of the floral origin of honey. In this analysis, the characteristic flavonoids from propolis and/or beeswax (chrysin, galangin, tectochrysin, pinocembrin and pinobanksin) were separated from those originating mainly from nectar and/or pollen (polyhydroxylated flavonoid aglycones), which would be related to their floral origin. All the analysed samples contained a common flavonoid profile consisting of polyhydroxylated flavonoid aglycones including 8-methoxykaempferol, kaempferol, quercetin, isorhamnetin, luteolin and apigenin, suggesting that flavonoid analysis does not generally prove differences between French monofloral honey samples. However, some individual honey samples showed potential floral markers. Thus, heather honey was characterized by the presence of myricetin, calluna honey by ellagic acid and citrus honey by the flavanone hesperetin. In other samples, the relative amount of 1 individual flavonoid could be related to the floral origin. Thus, sunflower honeys contained an important relative amount of quercetin, and in alder honey only 8-methoxykaempferol was detected. This preliminary study shows that flavonoid and phenolic compound analyses could be a very valuable complementary biochemical technique in the objective determination of the floral origin of some specific monofloral honey samples, but further studies with a larger number of samples is necessary to confirm the observed differences

A simple extractive technique for honey flavonoid HPLC analysis

A simple technique for routine analysis of flavonoids from honey has been described utilising a combination of filtration through the resin Amberlite XAD-2 and extraction with ethyl ether. The proposed method is less complex than other methods for honey flavonoid analysis reported previously. The HPLC conditions for flavonoid analysis have also been improved. This technique was applied to the analysis of flavonoids in 27 honey samples from the La Alcarria region (Spain). The total flavonoid content of the different samples ranged between 5 and 20 μg flavonoid/g honey. The major flavonoids in these samples were the flavanones pinocembrin and pinobanksin and the flavone chrysin. A total of 18 different flavonoids were detected in the honey samples analysed

Avaliação de biorreguladores no metabolismo secundário de beterrabas inteiras e minimamente processadas

O objetivo do trabalho foi verificar o efeito de biorreguladores em beterrabas minimamente processadas e inteiras (não processadas) sobre alguns aspectos do metabolismo secundário. Para o processamento mínimo, as beterrabas foram descascadas, sanificadas, sendo em seguida cortadas em retalhos com 2 mm de espessura, enxaguadas e centrifugadas. Nas beterrabas inteiras foram somente retiradas as folhas e os talos e sanificadas. Os tratamentos aplicados foram: etileno 1000 mL L-1, 1-metilciclopropeno (1-MCP) 300 nL L-1 e ácido salicílico 500 mg L-1. Após os tratamentos, as beterrabas foram embaladas e armazenadas a 5 ºC durante 10 dias. As injúrias causadas durante o processamento mínimo induziram o aumento na atividade da fenilalanina amônia-liase (PAL) nos tratamentos com etileno e 1-MCP e também o controle. A aplicação de ácido salicílico diminuiu a atividade desta enzima. Os tratamentos aplicados nas beterrabas minimamente processadas e inteiras não influenciaram a concentração de fenóis totais e de betalaínas, mas o teor de betalaínas foi reduzido em mais de 50% em beterraba minimamente processada em comparação com a beterraba inteira

Antioxidant, tyrosinase inhibitory, and acetylcholinesterase inhibitory activities of green tea (Camellia sinensis L.) seed and its pericarp

10.1007/s10068-012-0099-9Food Science and Biotechnology213761-76

Chemical constituents and pharmacological profile of Gunnera manicata L. extracts

Gunnera perpensa L. (Gunneraceae) is a native South African plant widely used in traditional medicine as an antibacterial and antifungal. In southern Brazil there is the native species called Gunnera manicata L. that also belongs to the Gunneraceae. Nevertheless, there is no information about chemical and pharmacological properties of South American Gunnera species. Therefore this study aimed at assessing the phytochemical and pharmacological profiles of aqueous and methanol Brazilian G. manicata extracts. The results showed that antimicrobial activity in an agar diffusion assay was effective against Staphylococcus aureus and Candida albicans . Phenolic compounds were investigated by liquid chromatography coupled with a tandem mass spectrometer (LC-MS/MS) and all extracts presented gallic acid and only the methanol extract obtained from the leaves exhibited hyperoside. Rutin, quercetin and chlorogenic acid were not found in the samples analysed. Total phenolic content was higher in methanol extract and total flavonoid content was low in all extracts. Antioxidant activity was evaluated by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical test, and all samples presented good to moderate antioxidant activity. These results encourage complementary studies on the chemical composition of the plant extracts focusing on isolation and structure elucidation of their active compounds