Manuka honey

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Manuka honey
Manuka honey from various New Zealand manufacturers

Manuka honey is a by honey bees from the nectar of Leptospermum scoparium ( Manuka generated) honey , the traditionally known as a natural remedy is used. In vitro could antibacterial properties of honey are detected. The South Sea myrtle (Latin: Leptospermum scoparium ), a relative of the Australian tea tree , has its home in the remote, mountainous regions of New Zealand and Southeast Australia .

history

The indigenous people of New Zealand, the Maori , traditionally use leaves and bark or extracts from them as well as the honey of the Manuka tree externally to disinfect and support the healing of wounds and inflammations , and internally for colds , bladder infections and other infections . New Zealand farmers are said to have fed manuka honey to their cows as early as the 1930s to make them more resistant to disease.

With increasing international demand, the price rose from 37 NZD for a kilo in 2010 to over 100 NZD in 2015. The number of beekeepers grew by leaps and bounds and the amount of honey produced reached 20,000 tons in 2015. With the growing competition for the limited number of fodder crops, there were numerous conflicts and increasing crime in the Manuka beekeeping community. Hundreds of bee colonies were poisoned or stolen in 2015 alone.

ingredients

Native bee on a flowering branch of a Manuka tree in New Zealand
Structural formula of methylglyoxal (MGO)

The essential ingredients of Manuka honey are, in addition to the sugars in honey, in varying amounts, the non-peroxidic antibacterial sugar breakdown product methylglyoxal (MGO). Methylglyoxal is produced in the honeycomb by dehydration of the substance dihydroxyacetone contained in the nectar of the flowers of the Manuka bush (see below). There is still no methylglyoxal in the nectar itself. Apparently this substance only develops after the bees have absorbed the nectar and transported it to the beehive.

In the work of the Institute for Food Chemistry at the Technical University of Dresden , the concentration of the metabolite methylglyoxal in certain Manuka honeys from New Zealand was measured and its antibacterial influence was quantitatively demonstrated in vitro . Particularly bactericidal properties were found against the pathogens Staphylococcus aureus and Escherichia coli . For methylglyoxal, the minimum inhibitory concentration against both germs was found to be 1.1 millimoles per liter (corresponding to 0.075 grams of methylglyoxal per kilogram). The methylglyoxal content in Manuka honey, determined using an HPLC method, was up to 100 times higher than in conventional types of honey.

Due to its molecular properties and in contrast to hydrogen peroxide, methylglyoxal has a high stability. You can even heat the honey without reducing the methylglyoxal content.

Researchers at the University of Waikato (New Zealand) found that methylglyoxal is mainly produced by a catalytic effect. Various anions apparently trigger dehydration of the ingredient dihydroxyacetone (DHA) to methylglyoxal in the “young” Manuka honey. This process takes place after the honey is placed in the beehive. The MGO concentration in the “ripe” honey correlates with the DHA concentration in the nectar, which in turn varies from bush to bush. The TU Dresden has developed a measuring method with which the MGO concentration in honey that can be achieved through storage can be predicted. In the medium term, this could lead to the targeted breeding and cultivation of Manuka bushes and thus enable the production of a highly effective honey.

The honey from the nectar of the directly related Leptospermum species Kanuka cannot develop an MGO; it lacks DHA as a starting material for the MGO synthesis. However, since the pollen of Manuka and Kanuka are practically indistinguishable, Kanuka honey is also often designated as Manuka honey. In the great outdoors in New Zealand, Kanuka and Manuka often grow in close proximity, but bloom one after the other. The beekeepers sometimes leave the beehives close to this mixed vegetation, so that the natural mixture of the traditional costumes creates honeys with different MGO levels.

The phenol carboxylic acids (such as caffeic acid , ferulic acid , syringic acid ) and flavonoids ( quercetin , isorhamnetin , luteolin ) also contained in Manuka honey occur in low concentrations without developing an antibacterial effect.

Non-peroxidic antibacterial potency

In terms of their non-peroxidic antibacterial activity, commercial manuka honeys are labeled with a so-called Unique Manuka Factor = UMF, which the New Zealand Active Manuka Honey Association Inc. (AMHA) awards to licensees for appropriate honey qualities . To determine this factor, the antibacterial effect of Manuka honey is compared with that of a phenol solution: for example, a Manuka honey UMF ®  20+ has the same non-peroxidic antibacterial effectiveness in vitro as a 20 percent phenolic solution. In contrast to the MGO measurement, this is a measurement of the effectiveness without taking a special ingredient as a basis. For reference measurement, requires at least two petri dishes with the same bacterial cultures and measures after treatment with honey or phenol, the size of the resulting court . The method is still used by some companies in New Zealand today, but has the disadvantage that the results can vary greatly due to the physical conditions (deviations in the bacterial cultures, inaccuracies in the circle formation of the respective farm), so that only several measurements provide an approximately reliable mean value surrender.

In 2006, the Technical University of Dresden identified methylglyoxal (MGO) as an antibacterially active component in Manuka honey. The concentrations measured using a specially developed HPLC method were around 20 to 800 milligrams per kilogram, depending on the type of Manuka honey. It was also possible to establish a correlation between the values ​​determined using the UMF method and the measured methylglyoxal content. The company Manuka Health New Zealand Ltd. characterizes the methylglyoxal content of the Manuka honeys it sells with the trademark MGO ® , followed by a number indicating the minimum methylglyoxal content in milligrams per kilogram of honey. Other providers are now following this methodology by also specifying an MGO value (methylglyoxal content) to characterize the non-peroxidic antibacterial potency. Furthermore, the methylglyoxal content is also used as the basis for the mathematical determination of the UMF value instead of its experimental determination by means of the inhibition area test.

Relationship between Unique Manuka Factor UMF and
Methylglyoxal Concentration MGO (mg / kg) in Manuka Honey
UMF 5+ 10+ 15+ 20+ 25+
MGO ≥ 83 ≥ 263 ≥ 514 ≥ 829 ≥ 1200

The importance of the methylglyoxal content in Manuka honey has been discussed controversially both in terms of antibacterial effectiveness and toxicological harmlessness. The food chemist Thomas Henle from the TU Dresden considers the 300 to 700 mg per kilogram found in Manuka honeys "possibly no longer harmless for the human organism (...)". In addition, it could be "that the Manuka tree produces the methylglyoxal itself - as a pest defense or through stress". Microorganisms from bees or even synthetic production and subsequent admixture could also explain the high MGO levels.

finished products

In August 2005, a ready-to-use preparation for the treatment of wounds was approved throughout Europe as a medical product under the name Medihoney . Medihoney is obtained from the flower nectar of various types of Leptospermum and contains, as an additional component, flower honey with a high proportion of the enzyme glucose oxidase . Medihoney is a registered trademark of Derma Sciences and is marketed for the treatment of burn wounds and general wound management.

The mixture is made sterile by irradiation. In the previous certification process, the manufacturer claimed that the effect was based on the osmotic effect, i.e. that it came about purely physically. According to the current knowledge about the antibacterial properties of the ingredient methylglyoxal and its high analytically proven concentrations in the commercial product, this is questionable.

There are no approved finished medicinal products for the medicinal use of Manuka honey , so that it can only be obtained as a prescription or as an extended prescription in the pharmacy.

Manuka honey is also offered health-related as a food and used cosmetically in skin care products.

application areas

In the meantime, manuka honey is being researched in clinical studies and some of it is being used. The children's clinic at the Rheinische Friedrich-Wilhelms-Universität Bonn uses the medical product Medihoney , which is based on Manuka honey, for wound care in children. In the diabetology department of a Berlin clinic for anthroposophic medicine , Manuka honey is used as a complement to conventional methods in the treatment of diabetic foot syndrome and other wounds that are difficult to heal.

By using honey as a wound pad, a moist wound environment should be created. This should be able to constantly disinfect itself, close the wound from the outside and supply it with important nutrients. These properties are particularly important in burn wounds, where secondary infections are a common and dreaded complication. Secondary infections can arise quickly due to the large attack surface for germs. The honey is said to cause wounds to heal faster and fewer scars to form.

Evidence base

A systematic review by the Cochrane Collaboration from 2015 found that, due to the differences in wound types and comparative treatments, no general conclusions can be drawn about the effect of honey on wound healing . The evidence for most comparisons is low or very low quality. However, there is high quality evidence that partial layer burns with honey heal around four to five days faster than with conventional bandages . There is moderate-quality evidence that honey is more effective at healing infected wounds after surgery than antiseptics followed by a gauze bandage. It is unclear whether the treatment with honey for burns, mixed acute and chronic wounds, pressure ulcers , Fournier's gangrene , venous leg ulcers, small acute wounds, diabetic foot ulcers and leishmaniasis is better or worse than other treatments, as the existing evidence is usually lower or very low quality.

Heuer et al. in 2011 advocated the use of manuka honey only on non-chronic wounds, such as those caused by injury, surgery or after radiation therapy . At the time of the assessment, only a few animal or clinical studies were available on this variant of moist wound treatment.

The German Society for Wound Healing and Wound Treatment e. V. advises against its use in its S3 guideline on local therapy for chronic wounds. The main problem in the treatment with Manuka honey is the development of pain, which can be attributed to the methylglyoxal .

Manuka honey varieties with a high content of methylglyoxal have an in vitro antibacterial effect on Porphyromonas gingivalis , which is responsible for severe and aggressive forms of periodontitis and thus for the loss of teeth .

Counterfeit products

According to New Zealand law, any honey that has been produced by a colony of bees that is set up near Manuka plants can be marketed by beekeepers as “Manuka”, even if the manuka components in the honey are hardly detectable. According to a report by the Guardian , in 2016, due to increased competition from the bee colonies for the few Manuka plants, it was common for sugar syrup to be fed as well. The Deutsche Apothekerzeitung reported in June 2011 that "some New Zealand honey" was mixed with MGO, which is available as an inexpensive laboratory chemical, "in order to transform a low-priced food into a high-quality 'natural medicine'". A patent application has been filed for the corresponding process.

The UK Food Standards Agency warns consumers of increasing scams with fake Manuka honey. Analysis results would show “that obviously in England in particular, but of course also in the rest of Europe, a lot of Manuka honey is sold that is not Manuka honey at all. Specifically, it was found that these honeys did not contain any methylglyoxal at all, i.e. no actual valuable ingredient at all. ”New Zealand producers reported an annual production of only 1700 tons in 2013, but 10,000 tons of alleged Manuka honey are sold worldwide every year. According to this, only every fifth to sixth “Manuka honey” sold is authentic. The rest are actually other honeys. A group of Dresden food chemists led by Thomas Henle was able to identify a number of the “Manuka honeys” offered in Germany that do not contain methylglyoxal. These honeys would be sold with corresponding “fantasy claims” such as active plus or active 10 . On the other hand , the test seals on the packaging for the methylglyoxal content, labeled MGO or UMF , are an indication of real Manuka honeys. In 2013, stretching with syrup was found in 14 of 55 Manuka honeys tested in Hong Kong .

The New Zealand Department of Basic Industries is working on a specification that will define the authenticity of New Zealand Manuka honey. In April 2017, there was a first draft with five parameters (minimum concentrations for four typically occurring substances and for the DNA of manuka pollen), which, however, does not meet with recognition within the New Zealand honey industry. On the one hand, the leading manuka honey exporter Comvita has already patented its own definition, and on the other hand, the specification would also be met by honey qualities from neighboring Australia.

literature

  • Detlef Mix: The healing power of honey. 2nd Edition. Herbig, Munich 2006, ISBN 3-7766-2498-1 .
  • Andreas Ende: Natural remedies. Manuka. Southwest, 1998, ISBN 3-517-08032-2 .
  • E. Mavric, S. Wittmann, G. Barth, T. Henle: Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka honeys from New Zealand. PMID 18210383 .
  • E. Mavric: Arginine derivatization and 1,2-dicarbonyl compounds in foods. Dissertation 2006. Full text (PDF, 2.51 MByte) .
  • University of Waikato - Waikato Honey Research Unit: Link Collection (online) .

Individual evidence

  1. ↑ M. Doerler, S. Reich-Schupke, P. Altmeyer, M. Stücker: Impact on wound healing and efficacy of various leg ulcer debridement techniques. In: Journal of the German Dermatological Society . Volume 10, Number 9, 2012, pp. 624-632, ISSN  1610-0387 . doi : 10.1111 / j.1610-0387.2012.07952.x . PMID 22591415 .
  2. ^ A b Eleanor Ainge Roy: "Honey wars: crime and killings in New Zealand's booming manuka industry" The Guardian of November 4, 2016
  3. ↑ Kilty SJ, Duval M, Chan FT, Ferris W, Slinger R .: Methylglyoxal: (active agent of manuka honey) in vitro activity against bacterial biofilms. , Int Forum Allergy Rhinol. 2011 Sep-Oct; 1 (5): 348-350., PMID 22287464 .
  4. ↑ a b c Christopher J. Adams, Merilyn Manley-Harrisa, Peter C. Molan: The origin of methylglyoxal in New Zealand manuka (Leptospermum scoparium) honey. In: Carbohydrate Research . 344 (8), 2009, 1050-3. doi : 10.1016 / j.carres.2009.03.020 , PMID 19368902 , full text (PDF; 275 kB) ( Memento from August 9, 2017 in the Internet Archive ).
  5. ↑ a b c d Elvira Mavric et al .: Identification and quantification of methylglyoxal as the dominant antibacterial constituent of Manuka (Leptospermum scoparium) honeys from New Zealand . In: Wiley Molecular Nutrition & Food Research . tape 52 , no. 4 , 2008, p. 483-489 ( PDF - in English). PDF ( Memento from October 16, 2011 in the Internet Archive )
  6. ↑ http://www.umf.org.nz/ .
  7. ↑ Detlef Mix: The healing power of honey. 2nd edition, Herbig, Munich 2006, ISBN 3-7766-2498-1 , p. 70 ff.
  8. ↑ E. Mavric: Arginine derivatization and 1,2-dicarbonyl compounds in foods. Dissertation 2006, p. 75.
  9. ^ J. Atrott, T. Henle: Methylglyoxal in Manuka Honey - Correlation with Antibacterial Properties. In: Czech J. Food Sci. Vol. 27, 2009. (full text)  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (PDF; 584 kB).@1@ 2Template: Dead Link / manukahonig.org  
  10. ↑ Unique Manuka Honey Association: UMF Honey Association .
  11. ↑ Peter Molan: MGO Level Not Good Indicator of Honey's Antibacterial Activity , January 30, 2008.
  12. ↑ Pharmacy Today, press release: Experts agree on robust test for manuka honey ( Memento from February 15, 2017 in the Internet Archive ), March 5, 2012.
  13. ↑ With golden-yellow bee sap against bacteria In: KONTAKT - online, the graduate magazine of the TU Dresden , issue 2/2006.
  14. ^ About Derma Sciences Inc.
  15. ^ S. Windsor, M. Pappalardo, P. Brooks et al .: A convenient new analysis of dihydroxyacetone and methylglyoxal applied to Australian Leptospermum honeys. In: Journal of Pharmacognosy and Phytotherapy. Vol. 4 (1), 2012, pp. 6-11.
  16. ↑ a b c D. Heuer, L. Heuer, V. Saalfrank: Manuka honey. In: Deutsche Apothekerzeitung . 25/2011, p. 2981 ff.
  17. ↑ Honey helps with problem wounds: "Medihoney" is often even better than antibiotics. Press release from the University of Bonn on July 27, 2006.
  18. ↑ Acute diabetic foot syndrome - Havelhöhe Hospital. Retrieved April 8, 2020 .
  19. ^ PE Lusby, A. Coombes, JM Wilkinson: Honey: a potent agent for wound healing? In: J. Wound Ostomy Continence Nurs. 29 (6), 2002, pp. 295-300, PMID 12439453 .
  20. ↑ Andrew B. Jull, Nicky Cullum, Jo C. Dumville, Maggie J. Westby, Sohan Deshpande, Natalie Walker: Honey as a topical treatment for wounds In: Cochrane Database of Systematic Reviews. 3, 2015, John Wiley & Sons, Ltd. DOI: 10.1002 / 14651858.CD005083.pub4 , PMID 25742878 .
  21. ↑ German Society for Wound Healing and Wound Treatment eV: Local therapy of chronic wounds in patients with the risks of peripheral arterial disease, diabetes mellitus, chronic venous insufficiency ( Memento of the original from July 10, 2012 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 9.3 MB), as of June 12, 2012, version 1, pages 117–119. @1@ 2Template: Webachiv / IABot / www.awmf.org
  22. ↑ Gesine Schäfer: Antibacterial Effects of Honey on Porphyromonas gingivalis Dissertation, University of Tübingen, 2013. Accessed October 24, 2017.
  23. ↑ Volker Mrasek : Expensive and allegedly germicidal - increasing consumer deception with New Zealand manuka honey In: Deutschlandfunk - Forschung aktuell , October 10, 2013.
  24. ↑ Jonathan Leake: Food fraud buzz over fake manuka honey ( Memento of the original from May 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: The Australian Times. August 26, 2013. @1@ 2Template: Webachiv / IABot / urbansweethoney.com
  25. ↑ Gerard Hutching: Government releases manuka honey definition to deal with fraud claims on nz.farmer.co.nz, April 11, 2017.
  26. ↑ Those trying to define what makes NZ's manuka honey special struggle to agree on nz.farmer.co.nz, August 4, 2017