Honeys from different floral sources as inhibitors of enzymatic browning in fruit and vegetable homogenates

Inhibitory effect of bioactive compounds derived from freeze-dried paraprobiotic of Pediococcus acidilactici against food-borne pathogens: In-vitro and food model studies

It was aimed to assess the antimicrobial potential of lyophilized/freeze-dried paraprobiotic (LP) of P. acidilactici against some food-borne pathogens under in-vitro conditions and food model, and determination of bioactive compounds that contribute to the antimicrobial activity of LP. For this purpose, minimum inhibitory concentration (MIC), inhibition zones were determined against Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7. The MIC value was 6.25 mg/mL and a 20 µL LP displayed 8.78 to 10.0 mm inhibition zones against these pathogens. In the food matrice challenge, two concentrations of LP (3% and 6%) alone or in combination with EDTA (0.02 M) were added to pathogenic bacteria spiked meatballs, and antimicrobial activity of LP was also determined during refrigerated storage. 6% LP + 0.02 M EDTA treatment provided 1.32 to 3.11 log₁₀ CFU/g reductions in the numbers of these pathogens (P < 0.05). Furthermore, this treatment provided significant reductions on psychrotrophs, TVC, LAB, mold-yeast, and Pseudomonas spp. over the storage (P < 0.05). Regarding characterization results, LP contained contained a wide variety of bioactive compounds, including 5 organic acids (2.15 to 30.64 g/100 g), 19 free amino acids (6.97 to 699.15 mg/100 g), free fatty acids (short-, medium-, and long-chain fatty acids), 15 polyphenols (0.03 to 383.78 mg/100 g), and some volatile compounds such as pyrazines, pyranone and pyrrole derivatives. These bioactive compounds are not only involved in antimicrobial activity but also contribute to the free radical scavenging activity according to the DPPH, ABTS and FRAP assays. In conclusion, the result revealed that the LP improved the chemical and microbiological quality of foods due to containing biologically-active metabolites involved in antimicrobial and antioxidant capacity.

Unexpected Value of Honey Color for Prediction of a Non-Enzymatic H2O2 Production and Honey Antibacterial Activity: A Perspective

Hydrogen peroxide is the principal antibacterial compound of honey and its concentration determines honey bacteriostatic (MIC) and bactericidal (MBC) potencies. Levels of H₂O₂ produced are highly relevant to honey therapeutic potential, but they vary extensively among honey with reasons not immediately apparent. According to a traditional view, H₂O₂ is produced as a by-product of glucose oxidation by the honey bee enzyme, glucose oxidase; however, significant levels of H₂O₂ could be produced in a non-enzymatic way via polyphenol autooxidation. The aim of this study was to evaluate the potential for such an alternative pathway by re-examining evidence from many experimental and correlative studies in order to identify factors and compounds required for pro-oxidant activity. Unexpectedly, the color intensity was found to be the main indicator separating honey varieties based on the quantitative differences in the polyphenolic content, antioxidant activity and the content of transition metals, Fe, Cu and Mn, the main factors required for pro-oxidant effects. The color-impeding polyphenolics and their oxidation products (semiquinones and quinones) further contributed to color development through multiple chemical conjugations with proteins, phenolic oxidative polymerization, chelation or the reduction of metal ions. Moreover, quinones, as an intrinsic part of polyphenol redox activity, play an active role in the formation of higher-order structures, melanoidins and colloids in honey. The latter structures are also known to chelate metal ions, potentially contributing to H₂O₂ production. Thus, the color intensity appears as a major parameter that integrates polyphenol-dependent pro-oxidant reactions resulting in H₂O₂ generation.

Determination of the Content of Phenolic Compounds and the Changes of Polyphenol Oxidase and Each Index during Browning of Phyllanthus emblica at Different Storage Temperatures

In order to further study the early browning of P. emblica marker and mechanism, it is necessary for us to measure the changes in the content of some substances to find quality markers during the browning process of P. emblica. So, we simulated the storage conditions under different temperatures, including 5°C, 25°C, and 35°C. And, the contents of some of its phenolic compounds were determined by RP-HPLC. Polyphenol oxidase (PPO) activity was determined by PPO reagent kits, and pH was determined with a pH measuring instrument, etc. The experimental results showed that 1-galloyl-glucose was the smoothest at 5°C among the three storage temperature conditions. It fluctuates and decreases in a curve at 35°C and 25°C. The content changes of gallic acid (GA) fluctuated more obviously at 35°C, and it showed a maximum value on the 7th day. The content changes of 1,3,6-tri-O-galloyl-β-D-glucose (TGG) all showed a peak on the 5th day and then showed a gradual decrease. The content changes of ellagic acid (EA) fluctuated more at 35°C. The peak of the content of rutin at both 35°C and 25°C appeared on the 3rd day, and that showed a gradually decreasing trend. The PPO activity varied more significantly at 25°C and 35°C. The browning index increased with time at both 35°C and 25°C. The complete browning of P. emblica was already observed on the 13th day. Tips for experimental results 5°C are effective in preventing browning of P. emblica. The contents of TGG, 1-galloyl-glucose, and rutin in P. emblica are greatly affected by temperature and time, and its contents had a linear relationship with time and temperature and can be used as one of the indicators of early browning, which provides a reference for the storage and transportation of fresh fruit in Chinese herbals.

Diversity of Monofloral Honey Based on the Antimicrobial and Antioxidant Potential

This study aimed to investigate the antioxidant profile and the antimicrobial activity of four different types of monofloral honey (manuka (MH), brassica rapeseed (BH), acacia (AH), and linden honey (LH)) against some bacterial/fungal ATCC strains and some multidrug-resistant strains isolated from chronic otitis in dogs. For the characterisation of the antioxidant profile of each honey, we extracted the honey samples by hydroalcoholic extraction and analysed them in terms of total polyphenols (TPC), total flavonoids (TFC), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) using the spectrophotometric method. The antimicrobial activity was determined using the microdilution method at concentrations of 10%, 15%, and 20%, with the results expressed in OD (optical density) calculated as BIR% (bacterial inhibition rate)/MIR% (mycelial inhibition rate). The antioxidant characterisation of the analysed honey samples showed the highest antioxidant activity and concentrations of TPC and TFC in MH, followed by LH. MH was proven to be the most effective on most clinical isolates concerning the antimicrobial activity in comparison with BH, AH, and LH. Except for B. cepacia and P. vulgaris, all the clinical isolates were sensitive to the antibacterial activity of honey. Regarding the ATCC strains, MH 10% was the most effective in inhibiting all the strains tested except for P. aeruginosa. In conclusion, the efficacy classification in our study was MH > BH > AH > LH.

Purification of damson plum polyphenol oxidase by affinity chromatography and investigation of metal effects on enzyme activity

Polyphenol oxidase (PPO) was firstly purified from damson plum as a high antioxidant source. PPO was treated by 0-80% ammonium sulfate precipitation and dialysis. Characterization results were determined for catechol, 4-methyl catechol, pyrogallol and caffeic acid as 0.05 M/pH: 7.2/25 °C; 0.2 M/pH: 4.5/10 °C; 0.01 M/pH: 6.8/5 °C, and 0.2 M/pH: 8.5/10 °C, respectively. V_max and K_M values were calculated for same substrates as 17,219.97 U/(mL*min) and 11.67 mM; 7309.72 U/(mL*min) and 5 mM; 12,580.12 U/(mL*min) and 3.74 mM; 12,100.41 U/(mL*min) and 6.25 mM, respectively. Catechol gave the highest V_max value among substrates. Affinity purification was performed by using Sepharose 4B-L-Tyrosine-p-aminobenzoic acid and Sepharose 6B-L-Tyrosine-p-aminobenzoic acid. Single bands were approximately observed at 50 kDa for each affinity sample in SDS-PAGE and Native-PAGE. 93.88 and 10.46 purification-folds were obtained for PPO by reference Sepharose-4B and original Sepharose-6B gels. Metal effects upon PPO activity were also investigated due to the importance of enzymatic browning in foods. Cu⁺² activation and Fe⁺² inhibition were observed with a final metal concentration of 1 mM at 219.66 and 43.18%, respectively. PPO purification from damson plum by affinity chromatography, its characterization, stability evaluation by statistically, and effects of metal ions on damson plum PPO have not been investigated in the literature.

Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography-Electron Spray Ionization-Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the “raw material” to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC–ESI–MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.

Multidimensional Comparative Analysis of Bioactive Phenolic Compounds of Honeys of Various Origin

Honey is a natural product which owes its health benefits to its numerous bioactive compounds. The composition of honey is highly diverse and depends on the type of honey and its origin. Antioxidant capacity arises mainly from the total content of polyphenols and their composition. The aim of this study was to perform a multidimensional comparative analysis of phenolic compounds of honeys of various origins. Honeydew, buckwheat, manuka, Malaysian and goldenrod honeys had the highest antioxidant capacity (above 400 mg Trolox equivalents kg⁻¹). These honeys were also characterized by the highest total polyphenol content (about 2500 mg gallic acid equivalents (GAE) kg⁻¹) and the highest total flavonoid content (1400–1800 mg catechin equivalents (CAE) kg⁻¹). Other honeys had much lower antioxidant properties. A multidimensional analysis of the profiles of phenolic compounds showed that honeys constitute a non-homogeneous data set and manuka honey was in contrast to other samples. Principal component analysis (PCA) (based on 18 phenolic compounds) distinguished honeys into five groups. Manuka, Malaysian and honeydew honeys created their own separate groups and the location of other honeys was variable. Ultra-high-performance liquid chromatography (UHPLC) analysis demonstrated that profiles of polyphenols in honeys were highly varied. Caffeic acid, datiscetin and rhamnetin were characteristic compounds for manuka honey. Quercetin, kaempferol and apigenin were present in all honeys except Malaysian honey. The antioxidant properties and the profiles of bioactive phenolic compounds of honeys were miscellaneous. The richest sources of polyphenols were local buckwheat and honeydew honeys, alongside exotic manuka and Malaysian honeys. These honeys could provide valuable ingredients to the human diet, helping to prevent diseases.

Colloidal structure of honey and its influence on antibacterial activity

Honey colloidal structure emerges as a new trend in research on honey functions since it became recognized as a major factor altering bioactivity of honey compounds. In honey complex matrix, macromolecules self-associate to colloidal particles at the critical concentration, driven by honey viscosity. Sequestration of macromolecules into colloids changes their activities and affects honey antibacterial function. This review fills the 80-year-old gap in research on honey colloidal structure. It summarizes past and current status of the research on honey colloids and describes physicochemical properties and the mechanisms of colloid formation and their dissociation upon honey dilution. The experimental observations are explained in the context of theoretical background of colloidal science. The functional changes and bioactivity of honey macromolecules bound to colloidal particles are illustrated here by the production of H₂ O₂ by glucose oxidase and the effect they have on antibacterial activity of honey. The changes in the production of H₂ O₂ and antibacterial activity of honey were coordinated with the changes in the aggregation-dissociation states of honey colloidal particles upon dilution. In all cases, these changes were nonlinear, assuming an inverted U-shaped dose-response curve. At the curve maximum, the production of H₂ O₂ and antibacterial activity reached the peak. The curve maximum signaled the minimum honey concentration required for the phase separation. With phase transition from two-phase colloidal condense state to dilute state dispersion, the change to opposite effects of dilution on these honey's activities occurred. Thus, the colloidal structure strongly influences bioactivity of honey compounds and affects its antibacterial activity.

Effect of ascorbic acid and citric acid on the quality of salted Chinese cabbage during storage

Changes in color, browning indices, enzyme activity, and physical and chemical quality during the storage period were investigated to assess the effectiveness of storage period extension along with the addition of ascorbic acid (AA) and citric acid (CA) to salted Chinese cabbage. After 16 days of storage, the change in chromaticity value showed treatment with 0.5% CA showed the lowest change in the brown index during the storage period. The control showed the highest residual activity of polyphenol oxidase among control, AA, and CA-treated salted cabbage. AA and CA treatment effectively inhibited the initial populations of microorganisms including total aerobic bacteria, lactic acid bacteria, and yeast and molds in salted Chinese cabbage during storage. Further, the texture, i.e., hardness, chewability, and elasticity, tended to decrease with increasing storage. These results suggest that treatment with AA could help maintain the quality of salted Chinese cabbage during the storage period.

Pesticides and Environmental Contaminants in Organic Honeys According to Their Different Productive Areas toward Food Safety Protection

Monitoring contaminant residues in honey helps to avoid risks to human health, as it is a natural product widely consumed in all population groups, including the most vulnerable, such as children and the elderly. This is important for organic honey production that may be negatively influenced by geographical area pollution. Considering the importance of collecting data on the occurrence of various xenobiotics in different geographical areas, this study aimed to investigate the presence of contaminant residues (persistent organic pollutants (POPs) and pesticides, including glyphosate and metabolites) in organic honey samples from different production areas using different analytical methods, in order to confirm their incidence and possible impact on the food safety traits of organic production. Regarding POPs, traces of benzofluoroanthene and chrysene were detected in honey from intensive orchards and arable lands. Traces of all polychlorobiphenyl (PCB) congeners were detected at different percentages in almost all of the samples, regardless of the origin area. Traces of polybromodiphenylethers (PBDE 28, 33, and 47) were found in different percentages of samples from all of the geographical areas examined. Traces of organochlorines (OCs) and organophosphates (OPs) were identified in honey samples belonging to all of the geographical areas. No glyphosate, glufosinate, and aminomethylphosphonic acid (AMPA) residues were detected.

Determination of antibiotic residues in honey in relation to different potential sources and relevance for food inspection

Honey contaminations could derive from intensive agriculture and industrial activities, but also from beekeeper treatments. In EU no MRLs for antibiotics in honey are set, only a minimum required performance limit for chloramphenicol of 0.3 μg kg^-1 is recommended. Screening tests are available, characterised by their rapidity and simple use. Due to their high rate of false positives and the need to meet zero tolerance levels for antibiotics, their presence in samples was investigated using a liquid chromatography High Resolution Mass Spectrometry (LC-HRMS) multiclass antibiotic residue method, comparing the results with those of previous screening tests. The confirmatory method showed good sensitivity: CCα and CCβ ranging from 0.03 to 4.80 ng g^-1 and from 0.12 to 5.56 ng g^-1, respectively. Ninety-eight honey samples from different geographical areas, analysed by two screening tests, showed a high percentage of false positives. This is fundamental to guarantee honey safety, especially, for organic production.

Modification of Polyacrylonitrile Fibers by Coupling to Thiosemicarbazones

This work reports the modification of Polyacrylonitrile (PAN) fibers by coupling to thiosemicarbazones to achieve the biological activity for the applications in the food product packaging. After modification, seven thiosemicarbazone compounds were synthesized. The as-synthesized thiosemicarbazone compounds were bonded to PAN fibers via covalent coupling, which was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy. The mean graft efficiency of the compounds was about 1.92%, and the antibacterial efficiency was 88.6% and 45.1% against Staphylococcus aureus (S-aureus) bacteria. All the seven thiosemicarbazone compounds exerted excellent tyrosinase activity, low cytotoxicity, excellent metal ion chelation ability, and anti-bacterial behavior against both gram-positive and negative bacteria. The mechanical properties of the fibers have been maintained without significant damage after the chemical modification. The break strength test and elongation at the break test were done to measure the fracture strength of the modified fibers. Overall, the promising properties of the modified PAN fibers show potential applications in food packaging materials for fruits and vegetables, which require long-term anti-browning effects during their transportation and storage.

Physicochemical and Antioxidant Properties of Iranian Commercial Honeys

Background:

All over the world, the quality of commercial honeys varies greatly depending on many factors. Hence, this study was conducted to evaluate the physicochemical and antioxidant properties of Iranian commercial honeys to confirm their nutritional and economical quality.

Methods:

Fifty three honey samples from six different types, including alfalfa, milkvetch, lotus, thyme, coriander and multifloral honeys, were analyzed for pH, free acidity, electrical conductivity, Ash, moisture, hydroxymethylfurfural, reducing sugars, glucose, fructose, proline, color, total phenolic content, ferric reducing antioxidant power and DPPH radical-scavenging activity.

Results:

: In total, physicochemical properties of different honey types were in the range of 4.3 ± 0.49 to 5.2 ± 0.49 for pH, 13.81 ± 2.5 to 26.22 ± 2.8 for free acidity (meq/kg), 15.95 ± 0.45 to 17.98 ± 0.97 for moisture (%), 282.2 ± 50.3 to 578 ± 47 for electrical conductivity (µS/cm), 0.14 ± 0.04 to 0.38 ± 0.03 for ash (g/100 g), 68.66 ± 4.3 to 72.09 ± 6.4 for reducing sugars (g/100 g), 34.67 ± 2.6 to 36.7 ± 2.2 for glucose (g/100 g), 31.9 ± 4.75 to 37.04 ± 4.0 for fructose (g/100 g), 6.1 ± 5.8 to 22.85 ± 10.9 for hydroxymethylfurfural (mg/kg), 426.7 ± 53.91 to 593.9 ± 108.6 for proline (mg/kg), 46.27 ± 4.3 to 96.04 ± 14.4 for color (mm) and 245.4 ± 48.45 to 573.9 ± 69.3 for total phenolic (mg/kg) content. In terms of antioxidant capacity, lotus and thyme honeys were preferable, while the highest level of DPPH radical scavenging activity and ferric reducing antioxidant power were observed in lotus and thyme honeys.

Conclusion:

These results confirmed that the Iranian commercial honeys meet the quality standards established by national and international regulatory agencies.

Honey as a Potential Natural Antioxidant Medicine: An Insight into Its Molecular Mechanisms of Action

Honey clasps several medicinal and health effects as a natural food supplement. It has been established as a potential therapeutic antioxidant agent for various biodiverse ailments. Data report that it exhibits strong wound healing, antibacterial, anti-inflammatory, antifungal, antiviral, and antidiabetic effects. It also retains immunomodulatory, estrogenic regulatory, antimutagenic, anticancer, and numerous other vigor effects. Data also show that honey, as a conventional therapy, might be a novel antioxidant to abate many of the diseases directly or indirectly associated with oxidative stress. In this review, these wholesome effects have been thoroughly reviewed to underscore the mode of action of honey exploring various possible mechanisms. Evidence-based research intends that honey acts through a modulatory road of multiple signaling pathways and molecular targets. This road contemplates through various pathways such as induction of caspases in apoptosis; stimulation of TNF-α, IL-1β, IFN-γ, IFNGR1, and p53; inhibition of cell proliferation and cell cycle arrest; inhibition of lipoprotein oxidation, IL-1, IL-10, COX-2, and LOXs; and modulation of other diverse targets. The review highlights the research done as well as the apertures to be investigated. The literature suggests that honey administered alone or as adjuvant therapy might be a potential natural antioxidant medicinal agent warranting further experimental and clinical research.

Characterization of Physico-Chemical Properties and Antioxidant Capacities of Bioactive Honey Produced from Australian Grown Agastache rugosa and its Correlation with Colour and Poly-Phenol Content

The antioxidant and antimicrobial components of honey vary based on sourced of nectar. Medicinal plants with the therapeutic value have potential to produce honey with greater bioactivity. The aim of the present study was to characterize the physico-chemical and antioxidant capacities of Agastache honey produced from Agastache rugosa and compare them with other popular commercial honeys sold in Australia. The total phenolics, total flavonoids, moisture content, colour, pH, protein content and antioxidant capacity were evaluated for Agastache, Manuka, Jelly bush, Tea tree, Super manuka and Jarrah honeys. The results reveal that the moisture content ranged from 17-21%, pH ranged from 3.8-4.3 and estimated protein content ranged from 900-2200 µg/g. The DPPH•, ABTS•+, ORAC and FRAP methods were used to measure the antioxidant capacity of the honey samples. The DPPH• % inhibition, ABTS•+, ORAC and FRAP values for Agastache honey were 9.85 (±1.98 µmol TE/g), 26.88 (±0.32 µmol TE/g), 19.78 (±1.1 µmol TE/g) and 3.61 (±0.02 µmol TE/g) whereas the highest antioxidant capacity values obtained were 18.69 (±0.9 µmol TE/g), 30.72 (±0.27 µmol TE/g), 26.95 (±0.9 µmol TE/g) and 3.68 (±0.04 µmol TE/g), respectively. There was a positive correlation between colour, total phenolic content and DPPH• scavenging activity for most of the honeys except Tea tree honey. However, there was no clear correlation with ABTS•+, ORAC and FRAP values. The measured antioxidant capacity of samples varied with the assays used. The DPPH• assay clearly indicated that the phenolic compounds contribute to the scavenging activity of the honeys. Nevertheless, all assays confirm that Agastache honey has significant antioxidant capacity. Therefore, Agastache honey can be important to human nutrition and health.

Bioactive Constituents and Antioxidant Activity of Some Carpathian Basin Honeys

Unifloral honeys have a high commercial value and should undergo a strict quality control before marketing. This study aimed at determining floral origin, polyphenolic compounds and antioxidant activity in 7 samples marketed as lavender and thyme honeys. The samples were subjected to pollen analysis to confirm their botanical origin. Coupled chromatographic techniques (HPLC-DAD-ESI-MS) were optimized for the separation and identification of polyphenolic compounds. The antioxidant properties of the samples were determined by spectrophotometric methods. Pollen profile analysis revealed that only 3 out of 5 alleged lavender honeys contained a low percentage (0.6-1.5) of lavender pollen; and there were only traces (0.1–0.6%) of thyme pollen in the alleged thyme honeys. Polyphenolic constituents did not allow for the clear separation of honey samples, revealing no marker compounds previously associated with lavender and thyme honeys. All samples contained large amounts of chlorogenic acid, chrysin, hesperetin, kaempferol and p-coumaric acid; as well as abscisic acid, a plant hormone known to be present in floral nectar and honey. Our results suggest that only one of five alleged lavender honeys and neither of the two alleged thyme honeys are true unifloral honeys. However, they can still provide various health benefits, such as being good sources of antioxidants. There was no relationship between the antioxidant activity and the uni- or multifloral character of the honey samples. Total phenolic content and antioxidant activity was the lowest in the honey sample with lavender and the highest in one of the alleged lavender honeys. Our findings highlight the importance of microscopical and phytochemical analyses of honeys before marketing, to ensure satisfactory quality for customers.

Comparative analysis of bioactive phenolic compounds composition from 26 medicinal plants

Bioactive phenolic compounds are powerful antioxidants in traditionally used medicinal and industrial crop plants and have attracted increased interest in the last years in their application and role in non-destructive methodology for pre-screening analysis of some stress factors. In this study the qualitative target was linked with future possible applications of received data for improving non-destructive methodology as well as for improving existing knowledge regarding antioxidant content in some plant species. Comparative analysis of total phenolics, flavonoid contents, phenolic acid composition, and antioxidant activity in known east central Europe medicinal and industrial crop plants of 26 species of families Asteraceae, Rosaceae and Lamiaceae was done. Among the investigated leaf extracts the highest total phenolic, total flavonoid contents and antioxidant activity have been seen for Stachys byzantine L. (Lamiaceae), Calendula officinalis L. (Asteraceae) and for Potentilla recta L. (Rosaceae). The highest syringic acid content has been found in the leaf extracts of plant family Asteraceae – in the range from 0.782 to 5.078 mg g⁻¹ DW. The representative’s family Rosaceae has a higher content of p-anisic acid in the range 0.334–3.442 mg g⁻¹DW compared to the leaf extracts of families Lamiaceae and Asteraceae. The comparative study showed significant differences of content of phenolic acids in the leaf extracts of different representative’s families Rosaceae, Asteraceae and Lamiaceae. We suggest that the presence of some phenolic acids can be used as a possible marker for family botanical specifications of representative families Asteraceae and Rosaceae. It was supposed that some pharmacological effects can be connected with the analyzed data.

Biomedical Activity and Related Volatile Compounds of Thai Honeys from 3 Different Honeybee Species

This study investigated the effect of 3 factors (floral source, honeybee species, and postcollection processing) that influence the antibacterial activity, free radical reduction, and other biochemical compositions of different honey types typical of Thailand. Honey samples from 3 honeybee species (Apis mellifera, Apis cerana, and Apis dorsata) were obtained from 9 floral sources (longan, wild flower, lychee, coffee, sunflower, sesame, bitter bush, para-rubber, and manuka as a control) in different regions of Thailand. These samples were evaluated for both their total and nonperoxide antibacterial activity against 10 human pathogens by agar incorporation technique. Honey samples were further analyzed to evaluate the capacity for free radical-scavenging activity, total phenolic content, and the total flavonoid contents by the 2,2-diphenyl-1-picrylhydrazyl assay, Folin-Ciocalteu method, and aluminum chloride colorimetric assay, respectively. Furthermore, the volatile organic compounds (VOCs) of Thai honey samples were investigated by headspace solid-phase microextraction and gas chromatography-mass spectrometry analysis. Findings of this study suggest a strong correlation between floral origin and honeybee species on one hand, and differences in %Brix, total acidity, protein content, antimicrobial activities, free radical reduction, phenolic, and flavonoid contents on the other hand. Moreover, VOCs of wild and coffee honey types were remarkably different, depending on the floral source. Both honeys contained characteristics of VOCs, some of which are involved in antibacterial and antioxidant activities.

PRACTICAL APPLICATION

Different origins and processing (floral source, honeybee species, and postcollection processing) of Thai honeys result in different antibacterial activities, physico-chemical properties, and aroma. Based on these findings, consumers of honey could select the type of honey based on their needs and preferred aroma.

Influence of a Nigerian honey on CYP3A4 biotransformation of quinine in healthy volunteers

WHAT IS KNOWN AND OBJECTIVES

Some studies, howbeit with conflicting reports, have suggested that consumption of honey has a potential to modulate drug metabolizing enzymes which may result in a honey-drug interaction. Numerous studies have established that honey varies in composition, influenced by the dominant floral, processing and environmental factors. Thus, variation in honey composition may be a contributing factor to the controversial results obtained. No previous drug interaction study has been carried out with any honey from Africa. CYP 3A4 is an important enzyme in drug metabolism studies as it is involved in the metabolism of over 50% of drugs in clinical use and quinine remains very relevant in malaria treatment in the tropics, and we therefore determined whether there is potential drug interaction between a Nigerian honey and quinine, a drug whose metabolism to 3-hydroxyquinine is mediated majorly by CYP3A4.

METHODS

In a three-phase randomized crossover study with a washout period of 2 weeks between each treatment phase, ten (10) healthy volunteers received quinine sulphate tablet (600 mg single dose) alone (phase 1) or after administration of 10 ml of honey (Phase 2) and 20 mL of honey (Phase 3) twice daily for seven (7) days. Blood samples were collected at the 16th hour post-quinine administration in each phase, and quinine and its major metabolite, 3-hydroxyquinine, were analysed using a validated HPLC method.

RESULTS

After scheduled doses of honey, the mean metabolic ratios of quinine (3-hydroxyquinine/quinine) increased by 24·4% (with 10 mL of honey) and reduced by 23·9% (with 20 mL of honey) when compared to baseline. These magnitudes of alteration in the mean metabolic ratios were not significant (P > 0·05; Friedman test). The geometric mean (95% CI) for the metabolic ratio of quinine before and after honey intake at the two dose levels studied was 0·82 (0·54, 1·23) and 1·29 (0·96, 1·72), respectively, and were also not significant (P = 0·296 and 0·081 respectively; Student's t-test).

WHAT IS NEW AND CONCLUSION

This is a pioneer study on the effect of Nigerian/African honey on quinine metabolism. The findings indicated that low and high doses of honey did not significantly affect metabolism of quinine to 3-hydroxyquinine. This suggests that CYP3A4 activity is not significantly altered following low or high dose of honey, as CYP3A4 has been reported to be responsible for the conversion of quinine to 3-hydroxyquinine. In conclusion, the outcome of this study suggests that there may be no potential significant metabolic interaction between Nigerian honey and quinine administration.

Development and evaluation of honey based mango nectar

Honey enriched mango nectar was prepared by using honey as sweetening agent because of its high fructose and glucose content and medicinal properties. The nectar having 20 % pulp, 15°B TSS and 0.30 % acidity was prepared, filled in pre-sterilized glass bottles, heat processed and stored up to 6 months under ambient (13.3-26.3 °C and 44.5-81.0 % RH) and refrigerated (4-7 °C and 73 % RH) conditions. The honey enriched mango nectar could be stored for 6 months at ambient temperature and low temperature storage conditions and only little changes in the quality parameters viz., TSS, titratable acidity, ascorbic acid, total and reducing sugars, carotenoids and hydroxymethylfurfural (HMF) were recorded as compared to sugar based nectar. These changes were more under ambient conditions than refrigerated and no microbial growth was found in nectars at fresh stage and during storage up to 6 months. The hydroxymethylfurfural (HMF) content in the mango nectars increased with prolonged storage period. The mustard honey based mango nectar had the higher carotenoids content but this decreased (725.60-689.20 mg/100 ml) during storage up to 6 months under ambient storage conditions, whereas the decrease was less under refrigerated storage conditions. Organoleptic quality score was higher in mustard honey based mango nectar (6.8) as compared to sugar based mango nectar under refrigerated conditions after 6 months storage. The results indicated that the mustard honey based mango nectar stored at low temperature was acceptable with respect to colour, taste and overall acceptability without any microbial spoilage and could be marketed as health drink.

Antioxidant and Sensorial Properties of Polyfloral Honey with Dried Apricots after One Year of Storage

Total phenol (TPh) and flavonoid (TFd) contents, antioxidant and sensorial properties of polyfloral (PH), and polyfloral honey after one year of storage (PHs) with dried apricots (20, 30, and 40%) were evaluated. In comparison to honey, TPh increased 1.86 times for PH40. After storage time, TPh of PH40s increased slightly lower (1.77 times), compared to PHs. TFd slightly increased, approximately 3.23-fold, from PH to PH40, while PHs showed increase of 5.15-fold for PH40s. Antioxidant activity increased with increasing concentration of apricots in honey.EC50OHvaried from 3.36 for PH to 2.29 mg/mL for PH40 and from 3.48 for PHs to 2.68 mg/mL for PH40s;EC50DPPHranged from 30.60 for PH to 14.95 mg/mL for PH40 and from 31.22 for PHs to 17.43 mg/mL for PH40s; RP0.5ranged from 66.37 for PH to 31.83 mg/mL for PH40 and from 67.99 for PHs to 35.03 mg/mL for PH40s. Statistical analysis suggested that TPh and TFd were associated with antioxidant activity and colour. Sensory parameters, before and after storage, indicated very good sensory qualities. Phenolic composition, antioxidant capacity, and sensory properties were promoted after addition of dried apricots and these parameters stayed improved, since antioxidant compounds present in dried apricots aided in maintenance of honey properties along one year of storage.

Bark depolymerization during submerged fermentation using monofloral honey, a natural mediator substitute, and integration between laccases vs. bark biopolymers, characterized by Py-GC-MS

This is a new green biochemical approach to edify that how we can replace synthetic, toxic and costly mediators into natural mediator using monofloral honey which accelerates oxidation mechanism with combination of fungal laccases.

Honey in dermatology and skin care: a review

Honey is a bee-derived, supersaturated solution composed mainly of fructose and glucose, and containing proteins and amino acids, vitamins, enzymes, minerals, and other minor components. Historical records of honey skin uses date back to the earliest civilizations, showing that honey has been frequently used as a binder or vehicle, but also for its therapeutic virtues. Antimicrobial properties are pivotal in dermatological applications, owing to enzymatic H2 O2 release or the presence of active components, like methylglyoxal in manuka, while medical-grade honey is also available. Honey is particularly suitable as a dressing for wounds and burns and has also been included in treatments against pityriasis, tinea, seborrhea, dandruff, diaper dermatitis, psoriasis, hemorrhoids, and anal fissure. In cosmetic formulations, it exerts emollient, humectant, soothing, and hair conditioning effects, keeps the skin juvenile and retards wrinkle formation, regulates pH and prevents pathogen infections. Honey-based cosmetic products include lip ointments, cleansing milks, hydrating creams, after sun, tonic lotions, shampoos, and conditioners. The used amounts range between 1 and 10%, but concentrations up to 70% can be reached by mixing with oils, gel, and emulsifiers, or polymer entrapment. Intermediate-moisture, dried, and chemically modified honeys are also used. Mechanisms of action on skin cells are deeply conditioned by the botanical sources and include antioxidant activity, the induction of cytokines and matrix metalloproteinase expression, as well as epithelial-mesenchymal transition in wounded epidermis. Future achievements, throwing light on honey chemistry and pharmacological traits, will open the way to new therapeutic approaches and add considerable market value to the product.

Antioxidant, antibacterial and ACE-inhibitory activity of four monofloral honeys in relation to their chemical composition

Different monofloral honeys from Castilla-La Mancha (Spain) have been studied in order to determine their main functional and biological properties. Thyme honey and chestnut honey possess the highest antioxidant capacity, which is due to their high vitamin C (in thyme honey) and total polyphenolic content (in chestnut honey). On the other hand, chestnut honey showed high antimicrobial activity against Staphylococcus aureus and Escherichia coli, whilst others had no activity against S. aureus and showed very small activity against E. coli. Moreover it was found that the antimicrobial activity measured in chestnut honey was partly due to its lysozyme content. In addition the angiotensin I-converting enzyme (ACE) inhibitory activity was measured, and the ACE inhibition is one mechanism by which antihypertensive activity is exerted in vivo. All the types of honey showed some activity but chestnut honey had the highest ACE inhibitory activity.

Thermosonication as a potential quality enhancement technique of apple juice

Enzymatic browning and microbial growth lead to quality losses in apple products. In the present study, fresh apple juice was thermosonicated using ultrasound in-bath (25 kHz, 30 min, 0.06 W cm(-3)) and ultrasound with-probe sonicator (20 kHz, 5 and 10 min, 0.30 W cm(-3)) at 20, 40 and 60°C for inactivation of enzymes (polyphenolase, peroxidase and pectinmethylesterase) and microflora (total plate count, yeast and mold). Additionally, ascorbic acid, total phenolics, flavonoids, flavonols, pH, titratable acidity, (°)Brix and color values influenced by thermosonication were investigated. The highest inactivation of enzymes was obtained in ultrasound with-probe at 60°C for 10 min, and the microbial population was completely inactivated at 60°C. The retention of ascorbic acid, total phenolics, flavonoids and flavonols were significantly higher in ultrasound with-probe than ultrasound in-bath at 60°C. These results indicated the usefulness of thermosonication for apple juice processing at low temperature, for enhanced inactivation of enzymes and microorganisms.

Effect of jujube honey on Candida albicans growth and biofilm formation

BACKGROUND AND AIMS

Candida species, especially Candida albicans, are major fungal pathogens of humans that are capable of causing superficial mucosal infections and systemic infections in humans. The aim of this study was to evaluate the jujube (Zizyphus spina-christi) honey for its in vitro inhibitory activity against pre-formed biofilm and its interference with the biofilm formation of C. albicans.

METHODS

The XTT reduction assay, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed to determine the inhibitory effect of Jujube honey on C. albicans biofilm. Changes in the infrared spectrum after treatment with honey were also determined by Fourier transform infrared (FTIR) spectroscopy.

RESULTS

Jujube honey affects biofilms by decreasing the size of mature biofilms and by disruption of their structure. At a concentration of 40% w/v, it interferes with formation of C. albicans biofilms and disrupts established biofilms. The SEM and AFM results indicated that this type of honey affected the cellular morphology of C. albicans and decreased biofilm thickness.

CONCLUSIONS

The present findings show that jujube honey has antifungal properties against C. albicans and has the ability to inhibit the formation of C. albicans biofilms and disrupt established biofilms.

The antioxidant effect of the Malaysian Gelam honey on pancreatic hamster cells cultured under hyperglycemic conditions

Type 2 diabetes consists of progressive hyperglycemia, insulin resistance, and pancreatic β-cell failure which could result from glucose toxicity, inflammatory cytokines, and oxidative stress. In the present study, we investigate the effect of pretreatment with Gelam honey (Melaleuca spp.) and the individual flavonoid components chrysin, luteolin, and quercetin, on the production of reactive oxygen species (ROS), cell viability, lipid peroxidation, and insulin content in hamster pancreatic cells (HIT-T15 cells), cultured under normal and hyperglycemic conditions. Phenolic extracts from a local Malaysian species of Gelam honey (Melaleuca spp.) were prepared using the standard extraction methods. HIT-T15 cells were cultured in 5 % CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 μg/ml) as well as some of its flavonoid components chrysin, luteolin, and quercetin (20, 40, 60, and 80 μM), prior to stimulation by 20 and 50 mM of glucose. The antioxidative effects were measured in these cultured cells at different concentrations and time point by DCFH-DA assay. Pretreatment of cells with Gelam honey extract or the flavonoid components prior to culturing in 20 or 50 mM glucose showed a significant decrease in the production of ROS, glucose-induced lipid peroxidation, and a significant increase in insulin content and the viability of cells cultured under hyperglycemic condition. Our results show the in vitro antioxidative property of the Gelam honey and the flavonoids on the β-cells from hamsters and its cytoprotective effect against hyperglycemia.

Determination of the floral origin of some Romanian honeys on the basis of physical and biochemical properties

The aim of this study was to determine the physical and biochemical properties of some Romanian honeys in order to discriminate between their floral origins. The evaluated properties were total phenolic content, total protein content, total free amino acids content, color intensity (ABS(450)), pH, ash content, antioxidant activity. Twenty-six commercial honeys from six types of flowers (acacia, sunflower, forest, polyfloral, lime and Sea Buckthorn) were investigated. All samples showed considerable variations with reference to their properties. The properties values were in the range of approved limits (according to EU legislation). The total phenolic, total protein and total free amino acids contents and color intensity varied considerably. Similarly, forest honey had the highest antioxidant activity while the lowest was found in acacia honey. Correlation between the floral origin of honeys and the physical and biochemical properties, respectively, was observed. Moreover, this study demonstrates remarkable variation in DPPH scavenging activity and content of total phenols in honey, depending on its botanic source.

Fast HPLC-DAD quantification of nine polyphenols in honey by using second-order calibration method based on trilinear decomposition algorithm

This paper describes the use of second-order calibration for development of HPLC-DAD method to quantify nine polyphenols in five kinds of honey samples. The sample treatment procedure was simplified effectively relative to the traditional ways. Baselines drift was also overcome by means of regarding the drift as additional factor(s) as well as the analytes of interest in the mathematical model. The contents of polyphenols obtained by the alternating trilinear decomposition (ATLD) method have been successfully used to distinguish different types of honey. This method shows good linearity (r>0.99), rapidity (t<7.60 min) and accuracy, which may be extremely promising as an excellent routine strategy for identification and quantification of polyphenols in the complex matrices.