Otilia Bobis

Total and individual carotenoids and phenolic acids content in fresh, refrigerated and processed spinach (Spinacia oleracea L.).

The carotenoid and phenolic acid contents in fresh, stored and processed (blanched, frozen and boiled) spinach were comparatively determined by spectrophotometric and HPLC analyses. The major carotenoids identified after HPLC analysis in saponified samples were lutein (37-53μg/kg), β-carotene (18-31μg/kg), violaxanthin (9-23μg/kg) and neoxanthin (10-22μg/kg). These carotenoids were all affected by storage and/or heating. The content of carotenoids was best preserved after storage for one day at 4°C. The total phenolic content in the fresh spinach was 2088mg GAE/kg FW. After LC-MS analysis three phenolic acids were identified and quantified. These being ortho-coumaric acid (28-60mg/kg FW), ferulic acid (10-35mg/kg) and para-coumaric acid (1-30mg/kg) depending on the sample type. After storage of spinach at different temperatures (4°C or -18°C) the amount of total phenolic compounds decreased by around 20%, while the amount of individual phenolic acids increased by four times on average.

Pathogen-associated self-medication behavior in the honeybee Apis mellifera

Honeybees, Apis mellifera, have several prophylactic disease defense strategies, including the foraging of antibiotic, antifungal, and antiviral compounds of plant products. Hence, honey and pollen contain many compounds that prevent fungal and bacterial growth and inhibit viral replication. Since these compounds are also fed to the larvae by nurse bees, they play a central role for colony health inside the hive. Here, we show that honeybee nurse bees, infected with the microsporidian gut parasite Nosema ceranae, show different preferences for various types of honeys in a simultaneous choice test. Infected workers preferred honeys with a higher antibiotic activity that reduced the microsporidian infection after the consumption of the honey. Since nurse bees feed not only the larvae but also other colony members, this behavior might be a highly adaptive form of therapeutic medication at both the individual and the colony level.

Predominant and Secondary Pollen Botanical Origins Influence the Carotenoid and Fatty Acid Profile in Fresh Honeybee-Collected Pollen

Total and individual carotenoids, fatty acid composition of total lipids, and main lipid classes of 16 fresh bee-collected pollen samples from Romania were determined by high-performance liquid chromatography with photodiode array detection and capillary gas chromatography with mass detection. Analyzed samples were found rich in lutein, whereas β-criptoxanthin and β-carotene were present in a wide range of amounts correlated with predominant botanical origin of the samples. High amounts of lutein were correlated with the presence of Callendula officinalis, Taraxacum officinale and Anthylis sp. The highest amount of total lipids was found in samples where pollen from Brassica sp. was predominant. Lipid classes were dominated by polyunsaturated fatty acids. Saturated fatty acids were determined in variable amounts. Lipid and carotenoid contents present great variability, explained by the various botanical species present in the samples.

Diversity of honey stores and their impact on pathogenic bacteria of the honeybee, Apis mellifera

Honeybee colonies offer an excellent environment for microbial pathogen development. The highest virulent, colony killing, bacterial agents are Paenibacillus larvae causing American foulbrood (AFB), and European foulbrood (EFB) associated bacteria. Besides the innate immune defense, honeybees evolved behavioral defenses to combat infections. Foraging of antimicrobial plant compounds plays a key role for this “social immunity” behavior. Secondary plant metabolites in floral nectar are known for their antimicrobial effects. Yet, these compounds are highly plant specific, and the effects on bee health will depend on the floral origin of the honey produced. As worker bees not only feed themselves, but also the larvae and other colony members, honey is a prime candidate acting as self-medication agent in honeybee colonies to prevent or decrease infections. Here, we test eight AFB and EFB bacterial strains and the growth inhibitory activity of three honey types. Using a high-throughput cell growth assay, we show that all honeys have high growth inhibitory activity and the two monofloral honeys appeared to be strain specific. The specificity of the monofloral honeys and the strong antimicrobial potential of the polyfloral honey suggest that the diversity of honeys in the honey stores of a colony may be highly adaptive for its “social immunity” against the highly diverse suite of pathogens encountered in nature. This ecological diversity may therefore operate similar to the well-known effects of host genetic variance in the arms race between host and parasite.

Botanical Origin Causes Changes in Nutritional Profile and Antioxidant Activity of Fermented Products Obtained from Honey

Honey as rich source of enzymatic and nonenzymatic antioxidants serves as health-promoting nutrient in the human body. Here, we present the first time a comparative study of nutritional profiles (e.g., acidities, sugar, organic acid profile, total polyphenolic, flavonoid content) for different unifloral, multifloral honeys and their fermented products, in correlation with their antioxidant activity. Additionally, an optimized method for HPLC separation of organic acids from honey was established. The total phenolic content of honey samples varied widely among the honey types compared to fermented products. High amounts of total flavonoids were quantified in heather honey, followed by raspberry, multifloral, black locust, and linden honey. A positive correlation between the content of polyphenols, flavonoids, and antioxidant activity was observed in honey samples. After fermentation, the flavonoid content of dark honey fermented products decreased significantly. Black locust and linden honeys are more suitable for fermentation because the decrease in antioxidant substances is less pronounced.

Important Developments in Romanian Propolis Research

The most important developments in propolis analysis and pharmacological properties are discussed. In order to help in the Romanian propolis standardization, different methodologies for chemical composition analysis (UV-VIS, HP-TLC, and HPLC-DAD) are reviewed using new approaches and software (fuzzy divisive hierarchical clustering approach and ChromQuest software) and compared with international studies made until now in propolis research. Practical applications of Romanian propolis in medicinal therapy and cosmetics are reviewed, and quality criteria for further standardization are proposed.

Food to some, poison to others - honeybee royal jelly and its growth inhibiting effect on European Foulbrood bacteria

Honeybee colonies (Apis mellifera) serve as attractive hosts for a variety of pathogens providing optimal temperatures, humidity, and an abundance of food. Thus, honeybees have to deal with pathogens throughout their lives and, even as larvae they are affected by severe brood diseases like the European Foulbrood caused by Melissococcus plutonius. Accordingly, it is highly adaptive that larval food jelly contains antibiotic compounds. However, although food jelly is primarily consumed by bee larvae, studies investigating the antibiotic effects of this jelly have largely concentrated on bacterial human diseases. In this study, we show that royal jelly fed to queen larvae and added to the jelly of drone and worker larvae, inhibits not only the growth of European Foulbrood‐associated bacteria but also its causative agent M. plutonius. This effect is shown to be caused by the main protein (major royal jelly protein 1) of royal jelly.

Influence of phytochemical profile on antibacterial activity of different medicinal plants against gram-positive and gram-negative bacteria

Nettle (Urtica dioica), basil (Ocimum basilicum), thyme (Thymus serphyllium), costmary (Chrysanthemum balsamita) and yarrow (Achillea millefolium) are used worldwide as aromatic herbs and medicinal plants. The alcoholic macerates of these plants were prepared and their chemical composition was investigated by spectrophotometric methods and HPLC chromatography with photodiode array detection. Alcoholic extracts were tested also in vitro against 5 pathogenic bacterial strains: 2 Gram-positive (Staphyloccocus aureus and Bacillus cereus) and 3 Gram-negative (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium). Minimum inhibitory concentrations for the extracts against all the microorganisms were determined by serial dilutions method. All the extracts demonstrated antibacterial activity against Gram-positive bacteria and partially against Gram-negative bacteria. In addition, nettle extract possessed the highest polyphenolic and flavonoid content. The results obtained indicated that these plants represent a potential source of natural antibacterial substances and can be used for the production of natural antibacterial formulations.

Influence of geographic origin, plant source and polyphenolic substances on antimicrobial properties of propolis against human and honey bee pathogens

Natural honey bee products, especially propolis are well known for their biological properties. However, less well known are the impact of propolis’ single phenolic substances and variation across different landscapes, geographic locations and botanical origins. Here, we determined the chemical composition of propolis samples collected in different geographic areas of Romania with a continental climate. Main groups of polyphenols, as well as individual phenolics (phenolic acids and flavonoids), were identified and quantified. The antimicrobial activity of propolis ethanolic extracts and some of the most important propolis phenolics (caffeic and ferulic acid, pinocembrin, chrysin and galangin) were evaluated against different bacterial species. Analyzing the interaction of bacterial growth inhibition and different chemical parameters, revealed that flavone/flavonol, flavanone/dihydroflavonol, chrysin and galangin are largely responsible for the propolis’ antimicrobial activity against Gram-positive bacteria. Gram-negative bacteria were mostly inhibited by galangin, caffeic acid and naringenin. Chemical composition and antimicrobial activity of the propolis samples might be explained by the botanical sources present in the specific foraging areas. The highest amounts of polyphenols and flavonoids were measured in regions where deciduous forests were dominant to coniferous, or where large areas of willow could be observed.

Nutraceutical properties of Romanian heather honey

Purpose – The main purpose of this study is to create a complete physico‐chemical characterisation of Romanian heather honey.Design/methodology/approach – A total of 30 samples of heather honey were harvested from three different geographical areas (Fântânele, Călăţele, Mărisel) from Transylvania region (Romania). This study contains a complete characterization of heather honey regarding its physico‐chemical composition, total phenols content, flavonoids content, antioxidant activity (expressed as radical scavenging activity – RSA) and micro‐ and macroelements content.Findings – The results obtained for the total phenols content and total flavonoids demonstrate that honey samples have good bioactive properties and the antioxidant activities are similar to those of dark honeys. Heather honeys normally have a high content of minerals, having their origin in soil. All quantified minerals in heather honey presented values higher that those reported for other types of honey.Practical implications – Heather hon...