Buckwheat Honey has Effective Antimicrobial Activity:
A large number of in vitro and fewer clinical studies have confirmed the broad spectrum antimicrobial (antibacterial, antifungal, antiviral and antimycobacterial) properties of honey (reviewed by Israili, 20131), including antibiotic resistant bacteria45-48 and biofilm.49, 50 Honey has been shown to contain multiple antimicrobial mechanisms, including its low pH, high osmolarity, hydrogen peroxide, polyphenols, methylglyoxal and bee peptides.43, 47
In the current clinical environment, antibiotic resistant strains of bacteria are increasingly widespread so alternative therapeutic agents are urgently needed.51 Honey demonstrates strong antibacterial activity against clinically important pathogens, such that its use is increasing in modern medicine.47 Not all honey varieties, however, have high antimicrobial activities. Some, but not all, manuka honey has been found to have high non-peroxide antibacterial activity, and has been widely studied. However, it has been found that other honeys from different floral sources exhibit equivalent inhibitory activity.22, 52
In a study where 27 honey samples from different floral sources were evaluated for their ability to inhibit the growth of seven food spoilage organisms and five foodborne pathogens, Mundo et al., (2004)22 demonstrated that buckwheat honey had a high peroxide-dependent antimicrobial activity. Against Staphylococcus aureus, a common bacteria of chronic wounds, buckwheat honey had the highest antibacterial activity of all 27 varieties of honey, including manuka honey, although the antibacterial activity of buckwheat honey was peroxide-dependent, whereas the manuka honey was mostly non-peroxide dependent.22 The peroxide antibacterial activity is due to hydrogen peroxide generation by the enzyme glucose oxidase in honey as it converts glucose into gluconic acid. The enzyme remains inactive until honey is diluted, as the high sugar concentration prevents the enzyme from functioning. Against Bacillus stearothermophilus, buckwheat honey was again one of the two most active antibacterial honeys, having nearly 2.25-times more antibacterial activity than manuka honey, and where most of the antibacterial activity of buckwheat honey was, this time, non-peroxide activity.22
Huttunen et al., (2013)23 confirmed the high antibacterial activity of buckwheat honey, this time in a study of five Finnish honeys tested against the four important human pathogens of Streptococcus pneumoniae, Streptococcus pyogenes, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA), which all colonize the nasopharyngeal niche. The antimicrobial growth inhibition results of the five Finnish honeys against the four bacterial species are shown in Fig. 4.
Figure 41. Superior Antimicrobial Activity of Buckwheat Honey Compared to Four Other Honey Varieties in Killing Four Important Human Bacterial Pathogens.
1Data from Huttunen et al., 2013.23
As can be seen in Panel A of Fig. 4, Buckwheat honey was the most effective honey varietal at killing Staphylococcus aureus, where at buckwheat honey concentrations of 60% and 40%, less than 10% of the bacteria survived. This result was also seen against the antibiotic-resistant strain of Staphylococus aureus, known as MRSA (methicillin-resistant Staphylococcus aureus), as demonstrated in Panel B of Fig. 4. Here again, the antimicrobial effect of buckwheat honey was the highest of the five different honey varieties tested, where its application at either 60% or 40% resulted in killing of more than 87% of the antibiotic-resistant MRSA bacteria. Staphylococcus aureus, in both its native and antibiotic-resistant forms, is a major human pathogen, contributing to infections of many types, including superficial skin lesions (boils, styes); abscesses; osteomyelitis; endocarditis; chronic wounds; hospital-acquired infection of surgical wounds; toxic shock syndrome by releasing superantigens into the bloodstream; and food poisoning by releasing enterotoxins. Staphylococcus aureus is particularly hard to treat when it forms biofilm communities. Due to its effective killing of Staphylococcus aureus, buckwheat honey could be an effective therapeutic agent for many of these disorders. Buckwheat honey is also seen to be an effective antibacterial agent against Streptococcus pneumonia (Fig. 4, Panel C) and Streptococcus pyogenes (Fig. 4, Panel D), two further important human pathogens.
Honey is a natural, nontoxic, and inexpensive product for the need of new therapies against bacterial infections. The clinical use of honey has enormous potential, especially in the fight against antibiotic-resistant strains. Of particular interest, is the recent finding that honey can impede biofilm formation.49, 50 One group, interested in dental biofilm, demonstrated that natural honey purchased from a Saudi Arabian supermarket, inhibited biofilm formation by the dental carie-producing bacterium Streptococcus mutans.49 A second research group, interested in honey as a therapeutic for chronic dermal wounds, demonstrated that manuka honey permeated 24-hour established biofilms of Streptococcus pyogenes, resulting in significant bacterial cell death and dissociation of cells from the biofilm.50 Constant pressure from the therapeutic use of antibiotics over the last half-century has pushed bacteria to grow more often in biofilm colonies where they are much harder to kill. Another beneficial effect of honey that has been found from its use in chronic wound treatment is that of autolytic debridement where it painlessly lifts of slough (containing biofilm) and necrotic tissue, making surgical debridement unnecessary,8, 10, 11, 13 developing a clean granulating wound bed,8, 10 and deodorizing wounds.8, 10