Breakthrough Discovery Reveals Secret Antibacterial Factor in Manuka Honey

New research on Manuka Honey from New Zealand has unveiled another reason for its antibacterial activity.

Findings of a research laboratory in Singapore shows that a special molecule in Manuka honey acts to augment the antibacterial activity of methylglyoxal in the honey – a process known as synergy. The unique type of antibacterial activity in Manuka honey was originally discovered at the University of Waikato in New Zealand during the 1980s. Evidence shows Manuka honey's special antibacterial properties are effective at healing wounds and other skin conditions. Research also shows that this activity is only present in some Manuka honey.

Research indicates that methylglyoxal is responsible for the antibacterial activity in Manuka honey. However, researchers also feel there is another synergistic factor contributing to its antibacterial properties. Research has proven the existence of a special molecule that combines with the methylglyoxal molecule and other fractions in Manuka honey to create the powerful antibacterial activity that it is known for. This discovery is also the key to understanding why the clinically proven antibacterial activity is so effective and why research to date has shown that bacteria fail to develop the resistance that is inevitable with conventional antibiotics.

Research is now underway to confirm the mode of action of the synergist and to further understand its interaction with other fractions, including methylglyoxal. This latest research will provide the medical industry with a full scientific understanding of the antibacterial properties of Manuka honey.

The Manuka honey industry is now worth in excess of $100 million in export earnings. However, not all Manuka honeys are equal and the way to test potency has been an issue for some time. The original testing standard uses a simple method of comparing the bacterial kill-zone of a honey sample to the kill-zone of a standard antiseptic. For a variety of reasons this can't be perfect and is open to interpretation and a margin of error. The ideal objective is to have a simple analytical chemical test that can be carried out by any lab anywhere in the world. But such a test isn't possible until we know what we're trying to measure. Discovering the synergist was the key. Analysis now includes developing an algorithm to find the strength of a honey's antibacterial activity by measuring the level of the synergist and the level of methylglyoxal present. It will then be possible to very precisely determine the non-peroxide activity of Manuka honey.

Methylglyoxal in Manuka Honey – Correlation with Antibacterial Properties

Abstract

A perfect linear correlation was found for methylglyoxal levels in 61 samples of Manuka honey, ranging from 189 to 835 mg/kg, and the corresponding antibacterial activities of the samples, which were between 12.4% and 30.9% equivalent phenol concentration. This clearly underlines that methylglyoxal is the dominant bioactive compound in Manuka honey and above concentrations of around 150 mg/kg directly responsible for the characteristic antibacterial properties of Manuka honey. Methylglyoxal can be a suitable tool for labeling the unique bioactivity of Manuka honey.

Introduction

Manuka honey, derived from the Manuka tree (Leptospermum scoparium) in New Zealand, is well-known for a pronounced antibacterial activity which cannot be found in any other honey. Manuka honey has been reported to exhibit antimicrobial activity against pathogenic bacteria such as Staphylococcus aureus and Helicobacter pylori, making this honey to a promising functional food for the treatment of wounds, stomach ulcers, etc. Besides hydrogen peroxide, which is produced in most conventional honeys by the endogenous enzyme glucoseoxidase, several other non-peroxide factors were discussed to be responsible for the unique antibacterial activity of Manuka honey.

The Unique Manuka Factor (UMF) was introduced years ago, leading to a classification of premium products based on microbiological assays. A UMF of 10, for instance, has the same antibacterial activity to a 10% solution of phenol. Recently, researchers were able to demonstrate that the surprisingly high amounts of the 1,2-dicarbonyl compound methylglyoxal are present in Manuka honey. Methylglyoxal, at the levels at which were found it in Manuka honey, proved to be another non-peroxide antibacterial constituent. This observation was confirmed by scientists. The purpose of the present study was to investigate to which extent methylglyoxal is responsible for the non-peroxide antibacterial activity of Manuka honey, in order to check whether it is possible to back-reference from the methylglyoxal content to the antibacterial properties of a honey sample.

Materials and Methods

The source of the 61 samples of Manuka honey from New Zealand came from drums of honey selected on a spread of non-peroxide contents and of varying ages. The amount of methylglyoxal was measured as the corresponding quinoxaline after pre-column derivatisation with o-phenylendiamine using RP-HPLC with UV detection. The data for non-peroxide antibacterial activity were analyzed by a specially appointed laboratory for testing for antibacterial activity using criteria laid down by the Honey Research Unit at Waikato University, New Zealand. Antibacterial activity was expressed as equivalent phenol concentration (% w/v). This value is used commercially as the Unique Manuka Factor (UMF).

Results and Discussion

Methylglyoxal levels in 61 samples of Manuka honey ranged from 189 to 835 mg/kg honey. Corresponding antibacterial activities were between 12.4 and 30.9% equivalent phenol concentration. A good linear correlation (y = 8.388 + 0.0263x; r2 = 0.905) between methylglyoxal and the antibacterial activity was found. This indicates that methylglyoxal is directly responsible for the characteristic antibacterial properties of Manuka honey. Our data is in perfect agreement with results published by Adams who had reported data for 49 samples of Manuka honey. In their study, concentrations of methylglyoxal as measured according to Mavric ranged from 25 to 709 mg/kg.

Corresponding antibacterial activity was between “not detectable” and 27.5% equivalent phenol concentration. Among the samples analyzed by Adams, 30 samples had antibacterial activities higher or equal 10% equivalent phenol concentration. Plotting these 30 samples together with data obtained in our study, a perfect match of the data sets can be obtained. This remarkable agreement of results obtained in two independent studies clearly underlines the final statement that methylglyoxal is the dominant bioactive compound in Manuka honey and starting from concentrations of approximately 150 mg/kg is exclusively responsible for the pronounced antibacterial activity. Due to limited sensitivity and inaccuracy of the used test system, data obtained for antibacterial activities below 10% equivalent phenol concentration must be handled with care. This may explain the fact that the corresponding regression lines in Figure 1 do not pass through the origin (parameter a = 8.388 or 7.783, respectively). Furthermore, for such low antibacterial activities, other factors such as polyphenols, organic acids or currently unknown compounds may additionally contribute to non-peroxide antibacterial properties.

In conclusion, methylglyoxal is a unique antibacterial compound found in high concentrations in Manuka honeys from New Zealand and directly responsible for the specific antibacterial activity of these samples. Methylglyoxal can serve as a suitable tool for the labeling of the bioactivity of commercial products.



Figure 1. (A) correlation between methylglyoxal and antibacterial activity for 61 samples of Manuka honey analyzed in this study, (B) data analyzed in this study plus data from Allen shown as filled triangles

Manuka Honey Benefits

Derived from a floral source indigenous to New Zealand, this special type of honey is effective in destroying microorganisms responsible for many negative health conditions.

Honey was originally used for medical purposes due to its antibacterial properties. However, it was replaced by antibiotics and other forms of traditional medicine in the 1940s and 1950s. Due to recent studies, there is now an increasing interest in honey as a topical antibacterial agent for the treatment of infected wounds, burns, eczema, ringworm and other bacterial and fungal infections.

The antibacterial properties of honey are a result of its high levels of sugar, acidity, osmolarity and hydrogen peroxide content. Manuka Honey is different in that its antibacterial activity is not only attributed to hydrogen peroxide, but also plant-derived components, such as methylglyoxal and what some experts refer to as the Unique Manuka Factor or UMF.

Wounds in laboratory studies were healed more rapidly by wound dressings containing Manuka Honey than by using standard types of honey. The bacterium Staphylococcus aureus is also very susceptible to the antibacterial activity of Manuka Honey, making it a valuable resource in treating MRSA and other antibiotic-resistant strains of bacteria.

The antimicrobial activity of Manuka Honey has been observed in many studies around the world. It has been discovered that Manuka Honey is effective in destroying the following bacterial and fungal microorganisms:

• Escherichia coli
  
• Staphylococcus aureus
  
• Citrobacter freundii
  
• Proteus mirabilis
  
• Pseudomonas aeruginosa
  
• Salmonella typhimurium
  
• Streptococcus faecalis
  
• Streptococcus pyogenes
  
• Helicobacter Pylori
  

Research also indicates that Manuka Honey inhibits enzymes called cysteine proteases, which have been implicated in muscle-wasting diseases such as muscular dystrophy, viral replication, tumor invasion and metastasis.

"Manuka Honey is the best thing to happen to the medical industry in decades," says Frank Buonanotte, CEO of Honeymark International, which is manufacturer of skin care products containing Active Manuka Honey as a healing agent. "At a time when consumers are losing faith in pharmaceuticals and gaining faith in natural alternatives, Manuka Honey is gaining its well-deserved recognition."

For more information or to purchase Manuka Honey products, call 1-866-427-7329 or visit www.HoneymarkProducts.com.