Characterization of Bioactive Constituents from Honey Produced by Costa Rican Stingless Bees

Abstract

Antimicrobial resistance created the need for innovations in topical treatments for wound healing. This thesis comprises a series of investigations that allowed Costa Rican Tetragonisca angustula honeys to pass from being a highly regarded traditional medicine to becoming a novel candidate for wound dressing developments. This series of investigations started with an antimicrobial activity screening of Costa Rican stingless bee honeys. This included a comparison between the inhibitory activity of Meliponini honeys and Apis mellifera honeys. Stingless bee honeys reported higher antimicrobial activity than Apis mellifera honeys from the same region. Next, the health risk associated with the use of Meliponini honey as a wound dressing, and the determination of the honey’s botanical origin were assessed. In addition, minimum inhibitory concentration (MIC) assays for Costa Rican stingless bee honeys against type culture collection microorganisms of relevance for the wound healing practice were performed. For this analysis, MedihoneyTM, a medical grade honey-based wound dressing was used as reference. The results demonstrated the low health risk associated with the practice of using Meliponini honey as a wound dressing agent; given the low microbiological counts, absence of Clostridium botulinum spores by polymerase chain reaction tests, and consequently, the compliance with the European Pharmacopoeia’s acceptance criteria for microbiological quality of non-sterile substances for pharmaceutical use. Furthermore, all the stingless bee honeys under study reported a homogenous (monofloral) botanical composition, which provides foundation to the standardization of a desired antimicrobial effect. Over 90 % of T. angustula and Melipona beecheii honeys inhibited Pseudomonas aeruginosa and Staphylococcus aureus at MICs lower than MedihoneyTM. Under the conditions tested, MedihoneyTM was not active against Candida albicans, whereas 53 % of T. angustula honeys rendered inhibition. All of these results, provided evidence supporting the ethnopharmacological application of Costa Rican Meliponini honeys as a wound dressing. A practice that unveils the application of a proficient antiseptic agent with low health risks associated. The interference of the signal transduction pathways of inflammation is the cornerstone of antioxidant therapy for wound healing. MedihoneyTM is up to the present, the only antioxidant therapy specifically approved by the United States Food and Drug Administration for wound healing. An evaluation of the potential of Costa Rican stingless bee honeys as an antioxidant wound dressing agent was performed. T. angustula honeys reported antioxidant capacities not statistically different from MedihoneyTM. Infections with antibiotic-resistant microorganisms are major obstacles for wound healing. MIC assays of stingless bee honeys against clinical isolates of antibiotic-resistant S. aureus and P. aeruginosa were performed. T. angustula honeys possess broad-spectrum inhibitory action against microorganisms of clinical relevance, regardless of their resistance to antibiotics.