Propolis is produced by honeybees and used to seal their hives for defensive purposes and has been used in ethnopharmacology since ancient times. It is a lipophilic material containing a large ...collection of naturally produced plant organic molecules, including flavonoids. The flavonoid galangin is consistently found in propolis, independent of the hive geographical location and its X-ray crystal and molecular structure is reported. The antioxidant scavenging of superoxide by galangin and propolis is here presented. Using a cyclic voltammetry technique developed in our lab, we show that galangin is an excellent scavenger of the superoxide radical, perhaps even better than quercetin. Our results show that galangin displays a Superoxide Dismutase (SOD) function. This is described experimentally and theoretically (DFT). Two modes of scavenging superoxide are seen for galangin: (1) superoxide radical extraction of H atom from the hydroxyl moieties located in position 3 and 5 of galangin, which are also associated with proton incorporation defining the SOD action; (2) π-π interaction among several superoxide radicals and the galangin polyphenol ring that evolve towards release of O2 and H2O2. We describe these two actions separately as their relative sequence, and/or combination, cannot be defined; all these processes are thermodynamically spontaneous, or subjected to mild barriers.
Parasitic nematodes infect more than two billion people worldwide particularly in developing countries. We previously reported nematicidal activity of natural honey using model nematode ...Caenorhabditis elegans. In this study, characterization of nematicidal effects of natural honey and its glycoproteins has been carried out. Chromatographically separated honey glycoproteins showed potent anti-C. elegans activity (LD50 = 100 ng proteins/μL). Honey glycoproteins with molecular masses of ∼260 kD and ∼160 kD comprised of ‘major royal jelly protein-1’-containing complexes. In these complexes, MRJP1 was present in different glycosylation forms. Quantitative PCR based gene expression assays described molecular functions of C. elegans affected by honey and honey glycoproteins. Expression of 14 gene transcripts associated with key cellular and molecular functions including energy metabolism, cytoskeleton, cell division, transcription and translation was analyzed. Acacia honey exerted a concentration-dependent alteration of gene transcripts involved in the citric acid cycle (mdh-1 and idhg-1) and cytoskeleton (act-1, act-2, and arp6). Likewise, MRJP1-containing glycoproteins caused down-regulation of arp-6 and idhg-1; and up-regulation of act-1 and mdh-1 gene transcripts. Consistent down-regulation of isocitrate dehydrogenase encoding idhg-1 gene which is among the rate-controlling enzymes of the citric acid cycle was considered as main biochemical factor involved in the nematicidal activity of honey and MRJP-containing glycoproteins. Acacia honey suppressed the expression of gene transcripts encoding actin-2, while honey glycoproteins did not. Hence, honey partly exerted anti-C. elegans activity by decreasing the transcription of actin-2 gene transcripts, demonstrated by a defect in the movement and egg laying. Moreover, arp-6 gene transcripts encoding actin-related protein 6 was significantly and constantly down-regulated by honey and honey proteins.
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•Chromatographically separated honey glycoproteins showed potent anti-C. elegans activity.•Honey glycoproteins with molecular masses of ∼260 kDa and ∼160 kDa comprised of ‘MRJP-1’-containing complexes.•Honey glycoproteins caused regulation of gene transcripts involved in TCA cycle, cytoskeleton and reproduction.
Natural honey contains glycoconjugates as minor components. We characterized acacia honey glycoconjugates with molecular masses in the range of 2–5 kDa. The glycoconjugates were separated by RP-HPLC ...into three peaks (termed RP-2-5 k-I, RP-2-5 k-II, and RP-2-5 k-III) which demonstrated paralyzing effects on the model nematode C. elegans (ED50 of 50 ng glycoconjugates/μL). To examine molecular mechanisms underlying the nematicidal effects of honey glycoconjugates, expressional analyses of genes that are essential for the growth, development, reproduction, and movement of C. elegans were carried out. Quantitative PCR-based assays showed that these molecules moderately regulate the expression of genes involved in the citric acid cycle (mdh-1 and idhg-1) and cytoskeleton (act-1 and act-2). MALDI-ToF-MS/MS analysis of RP-HPLC peaks revealed the presence of paucimannose-like N-glycans which are known to play important roles in invertebrates e.g., worms and flies. These findings provided novel information regarding the structure and nematicidal function of honey glycoconjugates.
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•Glycoconjugates of honey showed C. elegans paralyzing activity.•Exposure of honey glycoconjugates caused altered regulation of C. elegans genes transcripts involved in the citric acid cycle, cytoskeleton, body morphogenesis, embryo development.•Characterization of nematicidal glycoconjugates from honey by mass spectrometry revealed paucimannose like N-Glycans which are known to play important roles in survival of invertebrates e.g., worms and flies.
Fifty six Brazilian bee pollen samples were characterised, and their botanical and geographical origins were studied. The samples were also classified based on physicochemical and biological ...properties. The characterisation was done using Soxhlet extraction and micro-Kjeldahl methods, ashing at 550 °C, transmittance, microscopy, spectrophotometry, inductively coupled plasma optical emission spectrometry and high-performance liquid chromatography. As expected, the values of proteins (7.9–32.2 g/100 g), lipids (3.2–13.5 g/100 g), ash (1.9–3.6 g/100 g), carbohydrates (54.9–82.8 g/100 g), K (3.4–9.8 g/kg), Ca (0.9–4.1 g/kg), Mg (0.6–2.4 g/kg), Fe (46–1180 mg/kg), Na (20–374 mg/kg), Mn (25–215 mg/kg), Zn (30–101 mg/kg), Cu (7.4–19.7 mg/kg), total phenolics (6.5–29.2 mg GAE/g) and flavonoids (0.3–17.5 mg QE/g) as well as the phenolic profiles varied among the samples. In general, the products had high antioxidant capacity (ORAC: 133–563 μmol TE/g; DPPH: 9.4–155 μmol TE/g) and the antimicrobial capacity varied according to the sample and microorganism tested. The instrumental colour parameters could be used as indicators of some minerals. Based on multivariate approaches, bee pollen from Southern Brazil seemed to have a higher biological potential, whereas products from the Northeast region had higher calcium and magnesium levels. Similarities were identified in bee pollen containing C. nucifera or Brassica, and monofloral bee pollen seemed to have higher mineral content than heterofloral bee pollen.
•Brazilian bee pollen could be a good source of some minerals.•The antioxidant capacity of Brazilian bee pollen was higher than in some red fruits.•Instrumental colour parameters could be used as indicators of some minerals.•The composition of the samples varies according to the geographical origin.•There are similarities in bee pollen containing specific pollen types.
Bee products are a well-known remedy against numerous diseases. However, from the consumers’ perspective, it is essential to define factors that can affect their sensory acceptance. This ...investigation aimed to evaluate the volatile and sensory profiles, and sugar composition of beeswax, beebread, pollen, and honey. According to the HS-SPME/GC-MS results, 20 volatiles were identified in beeswax and honey, then 32 in beebread, and 33 in pollen. Alkanes were found to dominate in beeswax, beebread, and pollen, while aldehydes and monoterpenes in honey. In the case of sugars, a higher content of fructose was determined in beebread, bee pollen, and honey, whereas the highest content of glucose was assayed in beeswax. In the QDA, the highest aroma intensity characterized as honey-like and sweet was found in honey, while the acid aroma was typical of beebread. Other odor descriptors, including waxy, pungent, and plant-based aromas were noted only in beeswax, honey, and pollen, respectively.
The aim of this study was to evaluate the concentration of 5-hydroxymethylfurfural (HMF), furfural, polycyclic aromatic hydrocarbons (PAHs), and pesticide residues, as well as assessment of cancer ...risk of the Polish-origin bee products. The bee product samples were prepared using a modified QuEChERS method, then PAHs and pesticides were analysed by gas chromatography-mass spectrometry (GC-MS), neonicotinoids by high-performance liquid chromatography with a diode array detector (HPLC-DAD), and HMF and furfural by spectrophotometry (HPLC-UV/Vis). The results showed that the highest furfural content was found in bee bread from the northeast part of Poland; moreover, samples obtained from the same region were also characterized with a higher level of HMF. The total sum of PAHs ranged from 324.0 to 866.4 μg/kg; the highest content of PAH4 (the sum of benzoaanthracene, chrysene, benzobfluoranthene and benzoapyrene) was 21.0 μg/kg, but only benzoaanthracene and chrysene were detected in the samples. Imidacloprid and acetamiprid were found only in bee bread from the northeast part of Poland, while clothianidin was detected in honey samples. The acceptable cancer risk has been calculated for PAHs due to ingestion of honey, while increasing the risk of cancer was calculated for bee bread and bee pollen. Due to the high concentration of PAHs and excessively high recommended consumption dose, regular consumption of bee bread and pollen may pose a severe threat to human health and should be strictly limited.
•Content of contaminants varied significantly across bee products.•Beeswax was characterized by the highest total PAHs concentration.•The PAHs in bee products come from petro- and pyrogenic combustions.•The cancer risk assessment of bee products depends on the concentration of PAHs.
Bee pollen, a natural resource collected by bees, is rich in many nutrients, therefore it may represent a useful dietary supplement. Different uses of bee pollen are proposed due to its beneficial ...health properties, which includes the capacity to improve animal performance and promote immunostimulation. Animal nutrition can directly affect adults and their offspring, and larval stage is a critical moment for fish due to high mortality related to immune challenges. Thus, the present study attempted to evaluate the effects of adding bee pollen to a zebrafish diet, specifically, analyzing the effects on reproduction and immunity transference to descendants. Zebrafish adults received control diets based on commercial flakes and live food Artemia sp. nauplii or bee pollen-supplemented diets, administered three times a day, at the same time. The animals received the diets over 60 d, and throughout this period, they were tested for: egg production per female, total number of eggs, embryo viability rate, larval survival rate after exposure to spring viremia of carp virus and to Salmonella enterica serovar Typhimurium, and larval neutrophil recruitment after tail wounding. Bee pollen supplementation failed to improve egg production and embryo viability, and was unable to substitute flakes in zebrafish breeders. Instead, the offspring of breeders fed with bee pollen supplemented diets showed longer survival upon virus exposure and higher neutrophil migration to wounds. These results indicate that bee pollen can influence vertical immunity through important mechanisms related to offspring immunity in the early stages, when larval immune system is not fully developed.
•Bee pollen in the diet did not alter zebrafish egg and embryo viability.•Bee pollen influenced the vertical immunity of zebrafish.•Bee pollen improved larval resistance to viral infection and neutrophil migration.•Bee pollen did not alter larval resistance to bacterial infection.
An accurate, economic and green methodology for Pb(II) monitoring in bee products is proposed. Complexed metal traces were preconcentrated on Nylon membranes using the coacervation phenomenon based ...on room temperature reaction between the cationic surfactant hexadecyltrimethylammonium bromide and the bile salt sodium cholate. The increase in solid surface fluorescence signal of dyes 8-hydroxyquinoleine and o-phenanthroline due to Pb(II) presence was used for the metal quantification. Experimental variables that influence on preconcentration step and fluorimetric sensitivity were optimized using uni-varied assays. Pb(II) concentration was determined on membranes by solid surface fluorescence at λ
= 470 nm (λ
= 445 nm), using a solid sample holder. The calibration at optimal experimental conditions showed a LOD of 4.2 × 10
mg Kg
with a linear range of 1.28 × 10
mg Kg
to 8.73 mg Kg
and was successfully applied to Pb(II) quantification in different bee products produced in central west region of Argentina. The proposed methodology was applied to all samples after appropriate dilution. Accuracy methodology was evaluated by comparison of the obtained results with those found by ICP-MS, with percentage relative error under 8%. The precision was better than 0.0344 CV for Pb(II) determination.
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