Characterization of a non-glycosylated fraction from honey proteins of Melipona beecheii with antimicrobial activity against Escherichia coli O157:H7

Effect of conA-unbound proteins from Melipona beecheii honey on the formation of Pseudomonas aeruginosa ATCC 27853 biofilm

Pseudomonas aeruginosa is an opportunistic bacterium that can form a biofilm with the ability to colonize different surfaces and for increasing resistance to antibiotics. An alternative to solve this problem may be the use of non-glucose/mannose glycosylated proteins from Melipona beecheii honey, which are capable of inhibiting the growth of this pathogen. In this work, the antibiofilm activity of the conA-unbound protein fraction (F1) from M. beecheii was evaluated. The crude protein extract (CPE) and the F1 fraction inhibited the P. aeruginosa biofilm growth above 80% at 4 and 1.3 µg/mL, respectively. These proteins affected the structure of the biofilm, as well as fleQ and fleR gene expressions involved in the formation and regulation of the P. aeruginosa biofilm. The results demonstrated that the F1 fraction proteins of M. beecheii honey inhibit and affect the formation of the P. aeruginosa biofilm.

Antimicrobial and antioxidant activity of proteins isolated from Melipona beecheii honey

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Melipona honey proteins had antibacterial activity against foodborne pathogens.

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The non-glycosylated fraction possessed the highest antimicrobial activity.

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The least-glycosylated Melipona honey Proteins had highest antioxidant activity.

Proteins from Melipona beecheii honey were purified by concanavalin A (conA) affinity chromatography and eluted with a stepwise glucose gradient into fractions named F2-F5. The conA-unbound fraction (F1) was further separated by molecular exclusion into fractions named MbF1-1,2 and MbF1-3. All fractions were evaluated for antibacterial activity against foodborne pathogens and antioxidant capacity. F1 fraction possessed highest antimicrobial activity against S. aureus, L. monocytogenes, S. Typhimurium, E. coli and P. aeruginosa with MIC’s 1.4 ± 0.2, 15 ± 1, 39 ± 2, 1 ± 0.1, and 75 ± 2 µg/mL, respectively. F1, MbF1-1,2 and MbF1-3 had bactericidal effect except against P. aeruginosa. When the antioxidant capacity of the fractions was determined, F2 had the highest antioxidant activity measured by DPPH radical scavenging activity (IC₅₀ = 2.4 ± 0.4 µg/µL) and reducing power of Fe(III) (IC₅₀ = 1.8 ± 0.2 µg/µL). We provide evidence that M. beecheii honey proteins possess broad spectrum antibacterial and antioxidant activity, the latter probably through their reducing agent and free radical scavenger properties.

Stingless bee honey: An overview of health benefits and main market challenges

This review aimed to evaluate the nutraceutical and medicinal effects of stingless bee honey (SBH) by bringing a discussion focused on the main known in vitro/in vivo health-promoting effects. SBH has a high-water content, slight sweetness, acidic flavor, fluid texture, and slow crystallization. The type and concentration of phenolic compounds and consequent antioxidant activity were mainly associated with the floral sources, geographical location, bee species, and processing steps. SBH has anti-inflammatory, antimicrobial (against spoilage and pathogenic microorganisms), anti-diabetic, and skin aging delay activities in in vitro tests. It has also shown antioxidant and hypolipidemic effects, can protect from injuries caused by dyslipidemia, possess anti-inflammatory activity against chronic subclinical systemic inflammation and anti-diabetic properties, and can control and prevent Staphylococcus aureus infection on infected wound healings in in vivo tests (rats). However, clinical trials are crucial for the probation of the medicinal and nutraceutical properties of SBH. Despite this, there are still no general norms and/or quality standards for this type of honey. The information summarized in this review is important to add value to this little-consumed food, providing helpful information to spread knowledge about its benefits, assisting future studies, and raising perspectives for its recognition as a functional food. Furthermore, it may encourage the creation of standard quality for the production and marketing of SBH. PRACTICAL APPLICATIONS: Previous studies have already summarized the chemical profile and physicochemical properties of stingless bee honey (SBH) and its potential health properties. However, no study has performed an overview of the potential nutraceutical and medicinal effects of SBH, presenting results from in vitro and in vivo investigations. Therefore, this review is the first study to overview the potential nutraceutical and medicinal effects of SBH, showing results of in vitro/in vivo health-promoting effects. The bioactivity of SBH is related to bee species and floral sources. The SBH has anti-inflammatory, antimicrobial, anti-diabetic, and antioxidant in vitro activity. It has also shown hypolipidemic effects and protection from injuries caused by dyslipidemia in rats.

Promising Antimicrobial Properties of Bioactive Compounds from Different Honeybee Products

Bee products have been known for centuries for their versatile healing properties. In recent decades they have become the subject of documented scientific research. This review aims to present and compare the impact of bee products and their components as antimicrobial agents. Honey, propolis, royal jelly and bee venom are bee products that have antibacterial properties. Sensitivity of bacteria to these products varies considerably between products and varieties of the same product depending on their origin. According to the type of bee product, different degrees of activity were observed against Gram-positive and Gram-negative bacteria, yeasts, molds and dermatophytes, as well as biofilm-forming microorganisms. Pseudomonas aeruginosa turned out to be the most resistant to bee products. An analysis of average minimum inhibitory concentration values for bee products showed that bee venom has the strongest bacterial effectiveness, while royal jelly showed the weakest antibacterial activity. The most challenging problems associated with using bee products for medical purposes are dosage and safety. The complexity and variability in composition of these products raise the need for their standardization before safe and predictable clinical uses can be achieved.