Bioactive constituents, in vitro radical scavenging and antibacterial activities of selected Apis mellifera honey from Kenya

Bio-functional properties and phytochemical composition of selected Apis mellifera honey from Africa

Globally, the demand for natural remedies such as honey to manage ailments has increased. Yet, the health benefits and chemical composition of African honeys are not well understood. Therefore, this study aimed to characterise the bio-functional properties and the phytochemical composition of 18 Apis mellifera honeys from Kenya, Uganda, and Cameroon in comparison to the popular and commercially available Manuka 5+ honey from New Zealand. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH-RSA) was used to determine the antioxidant property, whilst the agar well diffusion and broth dilution (Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) assays were used to determine antimicrobial property. Further, colorimetric methods were used for phytochemical analysis. Our results showed that honeys collected from Rift Valley region of Kenya (e.g. Poi, Salabani and Mbechot) and Western region of Cameron (e.g. Bangoulap) had the highest antioxidant (DPPH RSA of 41.52-43.81%) and antimicrobial (MIC (3.125-6.25% w/v) and MBC (6.25-12.5% w/v)) activities. Additionally, the total flavonoid (770-970 mg QE/100 g), phenol (944.79-1047.53 mg GAE/100 g), terpenoid (239.78-320.89 mg LE/100 g) and alkaloid (119.40-266.57 mg CE/100 g) contents reached the highest levels in these bioactive African honeys, which significantly and positively correlated with their bio-functional properties. The functional and phytochemical composition of these bioactive African honeys were similar to or higher than those of the Manuka 5+ honey. Furthermore, gas chromatography-mass spectrometry analysis of African honeys revealed 10 most prominent volatile organic compounds that contribute to their geographical distinction: triacontane, heptacosane, (Z)-9-tricosene, tetracosane, 6-propyl-2,3-dihydropyran-2,4-dione, octacosane, 1,2,4-trimethylcyclohexane, 1,3-bis(1,1-dimethylethyl) benzene, 2-methylheptane and phytol. Overall, our findings suggest that some of the tested African honeys are natural sources of antimicrobial and antioxidant therapies that can be exploited upon further research and commercialized as high value honey.

Geographical Origin Authentication-A Mandatory Step in the Efficient Involvement of Honey in Medical Treatment

Nowadays, in people's perceptions, the return to roots in all aspects of life is an increasing temptation. This tendency has also been observed in the medical field, despite the availability of high-level medical services with many years of research, expertise, and trials. Equilibrium is found in the combination of the two tendencies through the inclusion of the scientific experience with the advantages and benefits provided by nature. It is well accepted that the nutritional and medicinal properties of honey are closely related to the botanical origin of the plants at the base of honey production. Despite this, people perceive honey as a natural and subsequently a simple product from a chemical point of view. In reality, honey is a very complex matrix containing more than 200 compounds having a high degree of compositional variability as function of its origin. Therefore, when discussing the nutritional and medicinal properties of honey, the importance of the geographical origin and its link to the honey's composition, due to potential emerging contaminants such as Rare Earth Elements (REEs), should also be considered. This work offers a critical view on the use of honey as a natural superfood, in a direct relationship with its botanical and geographical origin.

Composition, functional properties and safety of honey: a review

Honey has been used not only as a food source but also for medicinal purposes. Recent studies have indicated that honey exhibits antioxidant, hepatoprotective, hypolipidemic, hypoglycemic and anti-obesity properties, as well as anticancer, anti-atherosclerotic, hypotensive, neuroprotective and immunomodulatory activities. These health benefits of honey could be attributed to its wide range of nutritional components, including polysaccharides and polyphenols, which have been proven to possess various beneficial properties. It is notable that the composition of honey can also be affected by nectar, season, geography and storage condition. Moreover, the safety of honey requires caution to avoid any potential safety incidents. Therefore, this review aims to provide recent research regarding the chemical composition, biological activities and safety of honey, which might be attributed to comprehensive utilization of honey. © 2023 Society of Chemical Industry.

Characterisation of physicochemical parameters and antibacterial properties of New Caledonian honeys

Honey is an attractive natural product with various health benefits. A few honey-based commercial products have successfully been adopted in clinics to improve wound healing. However, screening of other potential sources of medical-grade honey, in particular, honeys from territories with high floral species diversity and high endemicity, is highly needed. The goal of this study was to characterise the physicochemical and antibacterial properties of New Caledonian honey samples (n = 33) and to elucidate the major mechanism of their antibacterial action. Inhibitory antibacterial activity of honeys against Staphylococcus aureus and Pseudomonas aeruginosa was determined with a minimum inhibitory concentration (MIC) assay. Enzymatic activity of glucose oxidase and the content of hydrogen peroxide (H2O2) in honey samples were analysed. Furthermore, total protein content of honeys together with their electrophoretic protein profiles were also determined in the study. The antibacterial efficacy of 24% of the tested honey samples was slightly superior to that of manuka honey with unique manuka factor 15+. The antibacterial activity of catalase-treated honey sample solutions was significantly reduced, suggesting that H2O2 is a key antibacterial compound of diluted honeys. However, the kinetic profiles of H2O2 production in most potent honeys at a MIC value of 6% was not uniform. Under the experimental conditions, we found that a H2O2 concentration of 150 μM in diluted honeys is a critical concentration for inhibiting the growth of S. aureus. In contrast, 150 μM H2O2 in artificial honey solution was not able to inhibit bacterial growth, suggesting a role of phytochemicals in the antibacterial activity of natural honey. In addition, the continuous generation of H2O2 in diluted honey demonstrated an ability to counteract additional bacteria in re-inoculation experiments. In conclusion, the tested New Caledonian honey samples showed strong antibacterial activity, primarily based on H2O2 action, and therefore represent a suitable source for medical-grade honey.

Enhancement of the Antioxidant Capacity of Thyme and Chestnut Honey by Addition of Bee Products

Honey consumption and imports have increased in recent years, and it is considered by consumers to be a healthy alternative to more commonly used sweeteners. Honey contains a mixture of polyphenols and antioxidant compounds, and the botanical origin and geographical area of collection play an important role on its chemical composition. The present study investigated the physicochemical properties, total phenolic content and antioxidant capacity of Spanish thyme honey and chestnut honey, and their mixtures with royal jelly (2% and 10%) and propolis (2% and 10%). The analysis of the physicochemical parameters of both honey samples showed values within the established limits. Propolis showed the highest value of total phenolic content (17.21–266.83 mg GAE/100 g) and antioxidant capacity (DPPH, ORAC and ABTS assays; 0.63–24.10 µg eq. Tx/g, 1.61–40.82 µg eq. Tx/g and 1.89–68.54 µg eq. Tx/g, respectively), and significantly reduced ROS production in human hepatoma cells. In addition, mixtures of honey with 10% of propolis improved the results obtained with natural honey, increasing the value of total phenolic content and antioxidant capacity. A significant positive correlation was observed between total phenolic compounds and antioxidant capacity. Therefore, the antioxidant capacity could be attributed to the phenolic compounds present in the samples, at least partially. In conclusion, our results indicated that thyme and chestnut honey supplemented with propolis can be an excellent natural source of antioxidants and could be incorporated as a potential food ingredient with biological properties of technological interest, added as a preservative. Moreover, these mixtures could be used as natural sweeteners enriched in antioxidants and other bioactive compounds.

The role of microencapsulation in maintaining biological activity of royal jelly: comparison with biological activity and bioaccessibility of microencapsulated, fresh and lyophilized forms during storage

BACKGROUND

Royal jelly (RJ) is a unique beehive product and has been recommended for human health since ancient times because of its antioxidant, antimicrobial, antiproliferative, neuroprotective, anti-lipidemic and anti-aging features. However, the biggest obstacle in the use of RJ is the need for cold storage and the instability of bioactive components over time. In the present study, 10-hydroxy-2-decenoic acid (10-HDA) content, as well as antioxidant [using 1,1-diphenyl-2-picrylhydrazy and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) methods] and antimicrobial activity (five Gram-positive, five Gram-negative and three yeasts), were comparatively evaluated for three RJ forms, two of which can be stored at 24 ± 1 °C during storage.

RESULTS

Microencapsulated royal jelly (MRJ) stored at room temperature succeeded in preserving its 10-HDA content, a major bioactive compound, during the 6 months, with respect to lyophilized royal jelly (LRJ) and fresh RJ stored at 4 °C. The initial 10-HDA contents of RJ, LRJ and MRJ were determined as 1.90%, 5.26% and 2.75%, respectively. Moreover, the total phenolic content, antioxidant capacity and antimicrobial activity mostly remained constant throughout the storage period (P ≥ 0.05). Gram-positive strains were generally more sensitive than Gram-negative strains. In the present study, the in vitro simulated digestion analysis showed that MRJ can tolerate the digestion process.

CONCLUSION

Overall, the encapsulation process was considered as one preservative technique for RJ. The microencapsulation of RJ as shown in the results of the present study are encouraging in terms of enabling the local beekeeping sector to achieve ease of production and increased product diversity. MRJ shows promise as a commercial product with a high export value for producers. © 2022 Society of Chemical Industry.

A Review of Commonly Used Methodologies for Assessing the Antibacterial Activity of Honey and Honey Products

Honey, a naturally sweet and viscous substance is mainly produced by honeybees (Apis mellifera) from flower nectar. Honey exerts a plethora of biological and pharmacological activities, namely, antioxidant, antimicrobial and anti-inflammatory activity, because of the presence of an extensive variety of bioactive compounds. The antibacterial activity is one of the most reported biological properties, with many studies demonstrating that honey is active against clinically important pathogens. As a result, beside honey’s widespread utilization as a common food and flavouring agent, honey is an attractive natural antimicrobial agent. However, the use of neat honey for therapeutic purposes poses some problems, for instance, its stickiness may hamper its appeal to consumers and health care professionals, and the maintenance of an adequate therapeutic concentration over a sufficient timeframe may be challenging due to honey liquidity and leakage. It has motivated researchers to integrate honey into diverse formulations, for example, hydrogels, dressings, ointments, pastes and lozenges. The antibacterial activity of these formulations should be scientifically determined to underscore claims of effectiveness. Some researchers have made efforts to adapt the disc carrier and suspension test to assess the antimicrobial activity of topical products (e.g., silver-based wound dressings). However, there is currently no established and validated method for determining the in vitro antimicrobial potential of natural product-based formulations, including those containing honey as the active principle. Against the backdrop of a brief discussion of the parameters that contribute to its antibacterial activity, this review provides an outline of the methods currently used for investigating the antibacterial activity of neat honey and discusses their limitations for application to honey-based formulations.

Metabolites From Trypanosome-Infected Cattle as Sensitive Biomarkers for Animal Trypanosomosis

Trypanosomes are important global livestock and human pathogens of public health importance. Elucidating the chemical mechanisms of trypanosome-relevant host interactions can enhance the design and development of a novel, next-generation trypanosomosis diagnostics. However, it is unknown how trypanosome infection affects livestock volatile odors. Here, we show that Trypanosoma congolense and Trypanosoma vivax infections induced dihydro-β- ionone and junenol, while abundance of dihydro-α-ionone, phenolics, p-cresol, and 3-propylphenol significantly elevated in cow urine. These biomarkers of trypanosome infection are conserved in cow breath and the urine metabolites of naturally infected cows, regardless of population, diet, or environment differences. Furthermore, treating trypanosome-infected cows reduced the levels of these indicators back to the pre-infection levels. Finally, we demonstrated that the potential of some specific biomarkers of phenolic origin may be used to detect active trypanosome infections, including low-level infections that are not detectable by microscopy. The sensitivity and specificity of biomarkers detection are suited for rapid, robust, and non-invasive trypanosomosis diagnosis under field conditions.

Phenolic Compounds in Honey and Their Relationship with Antioxidant Activity, Botanical Origin, and Color

Honey has been employed since antiquity due to its sensory, nutritional, and therapeutic properties. These characteristics are related to its physical and chemical composition. For example, phenolic compounds are substances that can determine antioxidant activity, as well as sensory characteristics, and can be employed as biomarkers of floral and geographical origin. This has generated a growing interest in the study of phenolic compounds and their influence in the intrinsic properties of this beekeeping product. This review aims to summarize, analyze, and update the status of the research that demonstrates the role of phenolic compounds in antioxidant activity, botanical-geographical origin, and the sensory characteristics of honey. These phenolic compounds, according to various results reported, have great relevance in honey's biological and functional activity. This leads to research that will link phenolic compounds to their floral, geographical, productive, and territorial origin, as well as some sensory and functional characteristics.

Characterization of honeys produced by sympatric species of Afrotropical stingless bees (Hymenoptera, Meliponini)

We investigated the effect of bee species identity and harvesting methods on the chemical composition and antiradical activity of 53 honey samples, produced by six stingless bee species in western Kenya (Kakamega forest). Our results illustrate that none of the assayed parameters significantly varied between the honey samples harvested by "punching holes" (n = 25) and "squeezing" (n = 28) methods. By contrast, species identity drove significant differences in the assayed parameters. Positive correlations between the antiradical activity and the phytochemicals (phenols and flavonoids) were observed, and honeys from Liotrigona sp. exhibited the highest amounts of phenols (214 mg GAE/100 g), flavonoids (73.0 mg QE/100 g) and antiradical activity (76.2%). The physicochemical analyses confirm the need to establish separate stingless bee honey standards for moisture, free acidity, invertase, electrical conductivity, and HMF, as these parameters significantly diverged from the set limits for Apis mellifera honey.

Beehive Products as Antibacterial Agents: A Review

Honeybees are one of the most marvelous and economically beneficial insects. As pollinators, they play a vital role in every aspect of the ecosystem. Beehive products have been used for thousands of years in many cultures for the treatment of various diseases. Their healing properties have been documented in many religious texts like the Noble Quran and the Holy Bible. Honey, bee venom, propolis, pollen and royal jelly all demonstrated a richness in their bioactive compounds which make them effective against a variety of bacterial strains. Furthermore, many studies showed that honey and bee venom work as powerful antibacterial agents against a wide range of bacteria including life-threatening bacteria. Several reports documented the biological activities of honeybee products but none of them emphasized on the antibacterial activity of all beehive products. Therefore, this review aims to highlight the antibacterial activity of honey, bee venom, propolis, pollen and royal jelly, that are produced by honeybees.