The antibacterial belongingss of the undermentioned honeys were studied against a scope of bacteriums capable of doing timeserving infections: criterion commercially available honeys, Manuka honey ( Unique Manuka factor ( UMF ) , 10, 15, 20 ) and Sedr honeys from Saudi Arabia All honeys surveies showed antibacterial activity which varied depending on the honey and the bacteria under trial. Manuka 15 and 20 honeys were by and large more antibacterial than the standard honeys, although the latter were by and large every bit active as Manuka 10 honey.
Of the honeys tested, Sedr varieties by and large exhibited the most pronounced antibacterial activities. The activity of all honeys was reduced by heating and by intervention with catalase, the latter demonstrating that much of their antibacterial activity is due to hydrogen peroxide ; residuary activity in the presence of catalase demonstrated the likely presence of complex antibacterial phytochemicals. There appear to hold been no old studies on the antibacterial activity of Sedr honeys ; the comparatively pronounced antibacterial activity of Sedr honeys, which was merely partly reduced by catalase and heat intervention suggests that these honeys should be to the full evaluated for usage in would intervention.Infective bacteriums are progressively demoing opposition to antecedently effectual antibiotics, a fact which led to the hunt for alternate attacks to the direction of bacterial infections ( Lione,1998, Wainwright,1994 ) , including, for illustration bacteriophage ( Stone,2002 ) and maggot therapy ( Bonn,2000 ) and the usage of antibacterial honeys ( Molan,1999 ) . In their natural signifier, all honeys exhibit some grade of antibiotic activity. This is mostly due to the sourness and high osmolarity nowadays which is typical of any concentrated sugar solution, which sequester free environmental H2O, thereby forestalling bacterial growing.
Honey besides retains some activity when it is diluted and the osmolarity is reduced. Hydrogen peroxide is a 2nd antibacterial constituent which is universally present in honey ; this denatures bacterial DNA and interrupts membrane possible thereby doing cell lysis ( Molan,1992, Molan,2001 ) . Honeys may besides incorporate antibacterial phytochemicals, which are a major constituent of, alleged, Manuka honey ; these are produced ( chiefly in New Zealand ) by bees feeding on Leptospermum scoparium. Manuka honey ( MH ) has proved successful as a topical application for the intervention of ulcers, sphacelus ( Molan and Betts,2004 ) and Burnss ( Cooper et al. , 2002 ) .
Although an active compound particular to Manuka honey has net yet been isolated, a scope of benzoic and cinammic acid derivates have been isolated from MH, every bit good as flavonoids ; such compounds frequently act synergy, thereby doing it hard to insulate the single active compounds ( Western et Al. 1999 ) . Manuka honeys are graded by their comparative ability to suppress the growing of Staphylococcus aureus. The alleged UMF ( Unique Manuka Factor ) graduated table compares the antibacterial action to that of phenol, with a honey graded ‘Factor 10 ‘ suppressing S.
aureus growing every bit successfully as a 10 % phenol solution ( Bell, 2008 ) . .Here, the comparative antibacterial activity of commercial or “ standard “ honeys were compared with Manuka and Sedr honeys as MH. A scope of common bacteriums, which have been shown to be timeserving pathogens in worlds and animate beings, were used as trial being. The consequence of heat and catalase intervention on the antimicrobic activity of the honeys was besides determined One of our chief purposes was to compare the antibacterial effects of honeys ( i.e.
” criterion ” and Sedr honeys ) for which no claims for antibacterial activity is made by the manufacturers with that of MH, for which comparatively marked antibacterial activity is claimed.The five trial bacterium chosen for usage in this the survey were the gm positive species, Staphylococcus epidermidis and Bacillus sphaericus, Bacillus subtilis. and the gm negative species, Serratia marcescens, and Escherichia coli. These bacteriums are all timeserving pathogens, which normally cause relentless wound infections peculiarly in immunocompromised patients.
MATERIALS AND METHODS
Types of honey tested
The undermentioned honeys were trials: a ) commercially available UK- monofloral honeys ( i.
e. from one works beginning: grazing land, chestnut and lavender ) ; b ) New Zealand Manuka honeys ( Unique Manuka factor ( UMF 10,15 and 20 ) and Sedr and Sedr Mountain honey signifier Saudi ArabiaBacterial strains and growing mediumA civilization ( 0.2ml ) of the trial bacteria was spread on the surface of Nutrient Agar ( Oxoid ) in petri dishes and three Wellss ( 1cm ) was cut from the Centre of the medium utilizing a flame-sterilized cork bore bit ) . The honey under trial was added to the Wellss, utilizing a wide-tip pipette and the home bases were incubated at 37A°C for 48 H.
Some samples of honey were diluted to 50 % and 10 % weight/volume with unfertile distilled H2O, and assorted exhaustively. Diluted samples settled over clip, and were resuspended prior to utilize.
The honey samples ( diluted to 50 % ) were treated with lyophilized bovine liver catalase ( Sigma ) ( 1 milliliter of a 10 % w/v solution ) , so that the concluding catalase concentration of 50 % w/v was achieved.
Heat intervention of honey
The honeys were heated utilizing direct heat to make boiling point, so instantly removed from the heat beginning. The boiling point of honeys sampled varied. All samples were allowed to chill in air-tight vass for 24hrs to 25A°C before usage and farther dilution to 50 % and 10 % w/v ( as above ) .
RESULTS AND DISCUSSION
Antibacterial effects of “ standard ” and Manuka honeys
All of the honeys tested inhibited the growing of all of the bacteriums used as trial being. ( Table1 ) , demoing that n honey wide spectrum antibacterial activity against timeserving infective bacteriums. Each single honey showed changing repressive consequence on bacteriums ; for illustration the assorted grazing land honey markedly inhibited B.subtilis, but had less repressive consequence on B.sphearicus.
This makes it hard to generalise sing the overall antibacterial belongingss of a given honey Similarly, the Chestnut and Lavender monofloral honeys inhibited B.subtilis but less so S.marcescens. As a generalisation, the three grazing land honeys showed loosely similar inhibitory effects as shown by the Manuka 10 honeys. The Manuka 15 and 20 honeys on the other manus by and large inhibited bacterial growing more efficaciously than did the “ standard “ honeys.
The largest suppression zone seen in Table 1 was produced by Manuka 20 when tested against B.sphaericus. Manuka 20 did non overall outperform Manuka 15 and Manuka 20, unlike Manuka 15, did non suppress the growing of E.coli. Table I shows that although Manuka 15 and 20 honeys by and large have greater antibacterial activity than Manuka 10 and the “ standard ” honeys, bacterial suppression is dependent on the bacteriums in inquiry.Table 1.
The antibacterial consequence of “ standard ” and Manuka honeys.PastureChestnutLavenderManuka 10+Manuka 15+Manuka 20+B.subtilis7.5 A± 2.57.5 A± 26.5 A± 15.5 A± 0.
511A± 18.5B.sphaericus2.5 A± 13 A± 0.54.5 A± 13.
5 A± 3.55.5 A± 1.59.
5A± 1E.coli3 A± 1.54 A± 14 A± 13.5 A± 0.
570S.epidermidis3.4A± 15 A± 0,57 A± 34 A± 28 A± 210 A± 1.5S.marcescens2.5 A± 1.53 A± 122 A± 26 A± 1.58.
5Therefore, Manuka 20 would likely be less effectual than any of the “ standard ” honey and the other Manuka honeys for handling surface infections caused by E.coli, but would be the honey of pick for using to infections caused by S.epidermidis and B.sphearicus.
Table 1 besides shows that there is by and large small point in puting in comparatively expensive Manuka 10 honeys when cheaper, more readily available “ standard ” honeys have similar antibacterial effects. Clearly, honeys have differing antibacterial belongingss and there is no honey which can be expected to be utile in the intervention of all timeserving infections ; even using comparatively expensive Manuka 20 honey would non needfully be the most effectual pick, both in footings of pathogen suppression and cost effectivity. The consequences shown in Table 1 suggests that in every instance, the bacteria responsible for an timeserving infection demands to insulate and so tested against a scope of honeys in order to find which is the likely T be the most effectual honey type.
Although by and large more effectual than standard honeys, and Manuka 10 honey, Manuka,15 and 20 honeys can non be used as a cosmopolitan honey antibiotic for usage in the intervention of all timeserving infections. On the positive side, the consequence show that “ standard “ honeys, obtained commercially in retail mercantile establishments are effectual antibacterial agents, a fact that is peculiarly importance in developing states, where local honeys are likely to be effectual in handling timeserving infections ; in short, there is no a priori ground why inexpensive, local honeys ( after sterilisation ) should non be evaluated in the intervention of timeserving infections caused by the bacteriums used here, and presumptively other, similar infections.Manuka honeys for median usage are supplied pre-sterilized ( by filtration or by the usage of ionising radiation in order to avoid the possibility of potentially infective autochthonal bacteriums and Fungis being transferred to the infection site. If cheaper, and more readily available a “ standard ” honeys are to be used as antibacterial agents it would be desirable to be able to sterilise them utilizing a readily available method, i.
e. warming. Table 2 nevertheless, shows that heat intervention by and large markedly reduces the antibacterial consequence of “ standard “ honeys although some activity is retained by Manuka 15 honey.Table 2. The consequence of warming and catalase intervention on diluted grazing land and manuka honeysgrazing land honeyUMF “ 10+ ” Manuka honeyUMF “ 15+ ” Manuka honey50 %50 % heated50 % Catalase50 %50 % heated50 % Catalase50 %50 % heated50 % CatalaseB.subtilis21.
524.5 A± 1.53.5 A± 2.
504.5 A± 1.52 A± 12 A± 1B.sphaericus3.0 A± 0.
21.5 A± 1.5000.5 A±0.504 A± 12 A± 13E.
coli1010.5 A± 0.5011 A± 13 A± 14S.epidermidis2.5 A± 0.5113 A± 1116 A± 13 A± 13.5 A±1S.
marcescens00000003 A± 11.5 A± 1The consequences shown in Table 2 support claims made by manufacturers of Manuka honey, that the antibacterial consequence of these honeys is due to a factor other than H peroxide, since activity is retained ( although diminished ) by the application of catalase ; the antibacterial effects of “ standard ” honeys in contrast is markedly cut down by catalase intervention demoing that there effectiveness against bacterium is due chiefly to hydrogen peroxide an non complex phytochemicals.
Evaluation of Sedr Honeys
The two Sedr honeys tested here by and large showed pronounced antibacterial activity ; for illustration both Sedr honey and the mountain assortment showed pronounced activity against S.marcescens ( Table 3 ) . As a generalisation, the Sedr honeys we showed greater antibacterial activity than the both the “ standard ” and Manuka honeys ( Table 1 ad 3 ) .Table 3.
The antibacterial effects of het and non-heated Sedr honeysMountain Sedr honeySedr honeyNon heatedHeatedNon heatedHeatedB.subtilis11 A± 0. 52.3 A± 0.711.6 A± 1.77 A± 0.
6B.sphaericus12 A± 0.69.2 A± 0.812.3 A± 0.39.
2 A± 0.8E.coli22.7 A± 0.66.
6 A± 0.87.3 A± 1.35.3 A± 0.6S.
epidermidis7.7 A± 0.35.
3 A± 0.27.7 A± 0.36.
1 A± 0.6S.marcescens19 A± 0.66.
6 A± 0.821.3 A± 1.910.5 A± 0.2Heat intervention cut down the activity of both types of Sedr honeys, but did non destruct them it ; proposing that heat intervention could be used as agencies of cheaply and efficaciously sterilising these honeys prior to utilize on lesions ; a characteristic which would do these honeys peculiarly utile for usage in handling lesion sin low engineering infirmaries and field intervention centres.
When diluted ( 50 % w/v ) , the Sedr honeys retained considerable activity ( increased in the instance of B.subtilis for both Sedr honey types following heat intervention ( Table 4 ) .Table 4. The consequence of heat and catalase intervention on diluted Sedr honeysMountain Sedr honeySedr honey50 %50 % heated50 % Catalase50 %50 % heated50 % CatalaseB.subtilis9 A± 114 A± 0.512.
3A±0.67.4 A± 2.311.3A±0.
810B.sphaericus107.3 A± 0.210.
6A±0.611 A± 0.37.12A±0.310.7A±0.3E.
coli18 A± 1.54.2 A± 0.810.3A±0.
3A±0.3S.epidermidis1.7 A± 0.956A±0.
11.7 A± 0.94.6A±0.37.3A±0.6S.
marcescens12.7 A± 0.74.2 A± 0.
85.8A±0.416.7 A± 2.37.
3A±0.35 A±0.5The ability of a honey to retain activity following dilution is utile as a diluted honey is likely to break perforate lesions and make hidden bacterium than is a full strength honey. Catalase reduced the antibacterial effects of Sedr honeys, but once more activity remained high ; a consequence which shows that the antibacterial activity of Sedr honeys is non due entirely to hydrogen peroxide, but besides to complex phytochemicals ( Table 4 ) .There appear to hold been no old published studies on the antibacterial effects of Sedr honeys.
The comparatively pronounced antibacterial activity of the two Sedr honeys tested here nevertheless, suggests that these merchandises could happen a topographic point in would intervention and replace the Manuka honeys which presently the chief honey-type used in medical specialty ; as a consequence, we suggest that it would be worthwhile to further, to the full, assess the medical potency of Sedr honeys.
The authour thanks Professor M. Wainwright and H.Seaton of the Department of Molecular Biology and Biotechnology, University of Sheffield, UK, for their parts to this survey.