ANTIBACTERIAL EFFECT AND CLINICAL POTENTIAL OF HONEY COLLECTED FROM Scaptotrigona bipunctata LEPELETIER (1836) AND AFRICANIZED BEES APIS MELLIFERA LATREILLE AND THEIR MIXTURE

Honey, used since Antiquity as a folk medicine, has had its clinical use reduced after the discovery of antibacterial agents such as penicillin. However, studies of its many medical uses have resumed due to many reasons, among which is the demand of constant search of new therapies against bacterial infections given the rise of bacterial resistant strains. The antibacterial effect of honey is based on its physico-chemical proprieties, glucose oxidase`s peroxide production and antibacterial proteins derived from both its animal as its floral origin. Thus, its antibacterial effect varies according to its origin, we have studied the antibacterial potential of honey samples collected from two different bees species: the Scaptotrigona bipunctata stingless bee (HSB), a native Brazilian stingless bee; and the africanized Apis mellifera honeybee (HAM), a honeybee species responsible for the majority of the honey commercialized worldwide. The antibacterial proprieties of the two kinds of honey were analyzed both separately and combined against Gram positive and Gram negative bacterial strains using five assays: 1) Minimal inhibitory concentration (MIC) assay; 2) Checkerboard assay; 3) Time-kill curve; 4) Oxygen superoxide production assay; 5) Scanning electron microscopy (SEM). HSB, which is an expensive honey but has a more potent antibacterial effect showed a higher oxygen peroxide production than HAM. HSB MIC varied between 1.25 and 5% (v/v) and HSB presented a bactericidal effect against Staphylococcus aureus and a bacteriostatic effect against Escherichia coli. Meanwhile HAM, the cheapest and most commercialized type of honey, was able to reduce E. coli cell viability and demonstrated a bacteriostatic activity against S. aureus and HAM MIC varied between 20% and 25% (v/v). The combination between honeys exhibited an additive effect, which reduced MIC values by half and increased significantly oxygen peroxide production. Lastly, images of S. aureus obtained by SEM showed bleb formation following HSB treatment, furrows after HAM treatment; and both structures when S. aureus was exposed to the honey mixture. These results indicate differences in HSB and HAM antibacterial effects (and their correlation to peroxide production); the existence of multiple antibacterial mechanisms in the HSB/HAM combination and the clinical potential of honey usage against bacterial infections.