Honeybee-collected pollen from five Portuguese Natural Parks: Palynological origin, phenolic content, antioxidant properties and antimicrobial activity

Abstract

a b s t r a c tThe aim of this study was to determine the palynological origin, phenolic content, antioxidant and antimicrobial properties of pollen from five Portuguese Natural-Parks [Parque Nacional Peneda Gerês (PNPG); Parque Natural do Montesinho (PNM); Parque Natural do Alvão (PNA); Parque Natural da Serra da Estrela (PNSE) and Parque Natural do Douro Internacional (PNDI)]. Eight families were found in the mixture of bee pollen: Rosaceae, Cistaceae, Boraginaceae, Asteraceae, Fagaceae, Ericaeae, Myrtaceae and Fabaceae. The phenolic compounds content, determined by the Folin-Ciocalteu method, varied between 10.5 and 16.8 mg of gallic acid equivalents/g of extract (mg GAE/g) found in bee pollen from PNM and PNDI, respectively. The free radical scavenging measured showed the highest effective extract -PNM with EC 50 2.16, followed by PND with 2.24 mg/mL. In the b-carotene bleaching assay the same behaviour as in the DPPH method was verified. We also verified that the presence of pollen differentially affected the growth of bacteria Gram-positive, Gram-negative and yeasts under study, depending this on the microorganism and the pollen used. This is an important study since, as far we know, it is the first time that Portuguese bee pollen from Natural Parks was studied, and their characterization can increase their economic value.

Foliar phenolic compounds of ten wild species of Verbenacea as antioxidants and specific chemomarkers

“…The current results support the proposal made by Morais et al (2011) on the significant role of the qualitative phenolic composition, aside from the phenolic and flavonoid contents, in determining the antioxidant potentials of plant extracts.…”

“…High correlations between the kinetic behavior of antioxidant assays and the phenolic and flavonoid contents, and unclear associations between the antioxidant activities and the phenolic and flavonoid contents in different samples have also been found by other authors (Morais et al, 2011). The current results support the proposal made by Morais et al (2011) on the significant role of the qualitative phenolic composition, aside from the phenolic and flavonoid contents, in determining the antioxidant potentials of plant extracts.…”

Flavonoid composition and antioxidant capacity of the edible flowers ofAgave durangensis(Agavaceae)

“…The correlation between the phenol content in a given sample and the antioxidant activity is, at present, a controversial issue, since while authors like Dobre et al (2011) have been able to establish that correlation, some others like Negri et al (2011) have reported no correlations between these two parameters. Our results agree with those reported by Morais, Moreira, Feás, and Estevinho (2011), who did not find a strong relation between phenol content and antioxidant capability. Synergic or antagonistic effects among phenols, or compounds of different chemical nature, as the result of a particular chemical composition, could be defining the antioxidant properties in such a way that not only the phenol concentration is determinant.…”

Fatty Acids and Proximate Composition of Beebread

“…As bee pollen contains all the essential amino acids required for the human organism, it is referred to as 'the only perfectly complete food' (7). Notwithstanding, there are only few papers published on the FA composition of the bee bread.…”