Manuka essential oil bibliography

Manuka Biblio.

Leptospermum scoparium J.R. Forst & G. Forst.

Anti-Microbial Activity.

Christolph F., Kaulfers P.M. & Stahl-Biskup E. (2000). "A comparitive study of the in vitro anti-microbial activity of tea tree oils s.l. with special reference to the activity of b-triketones". Planta Med. 66(6), 556-60. Abstract. The in vitro antibacterial and antifungal activities of Australian tea tree oil, cajuput oil, niaouli oil, kanuka oil and manuka oil as well as of a b-triketone complex isolated from manuka oil were investigated in a constituent-oriented study. The compositions of the oils were analysed by capillary GLC and GLC-MS. The MICs for sixteen different microorganisms were determined applying the broth dilution method. Australian tea tree oil showed the best overall antimicrobial effect. The best inhibitory effects on Gram-positive bacteria and dermatophytes were achieved with manuka oil due to its b-triketone content.

Christolph F., Kaulfers P.M. & Stahl-Biskup E. (2001). “In vitro evaluation of the antibactericidal activity of b-triketones admixed to Melaleuca oils.” Planta Med. 67(8), 768-771. Abstract. The in vitro antibacterial properties of mixtures of Australian tea tree oil and niaouli oil after adding the b-triketone complex isolated from manuka oil were tested. MIC and MBC values for four different bacteria were determined applying the broth dilution method. Both Melaleuca oil mixtures showed good antimicrobial effects against Staphylococcus aureus and Moraxella catarrhalis, exceeding the effectiveness of myrtol, which is well established in the treatment of acute and chronic bronchitis and sinusitis. The death kinetics of S. aureus were determined to draw subtle comparisons between the mixtures. The kill rate data indicated that both Melaleuca oil mixtures achieved a complete kill within 240 min.

Christolph F. & Stahl-Biskup E. (2001) “Death kinetics of Staphlococcus aureus exposed to commercial tea tree oils s.l.” J. Essen. Oil Res. 13, 98-102. Abstract. Staphyloccus aureus cells were exposed to increasing concentrations of Australian tea-tree oil, cajuput oil, niaouli oil, Lema oil, kanuka oil, and manuka oil as well as of a b-triketone complex isolated from manuka oil. The death kinetics were determined by calculation of log₁₀ reduction factors after increasing exposure periods. Niaouli oil turned out to be highly active, followed by Lema (this is a registered trademark), tea tree & cajuput oils. Kill rate data indicated that 1.0% (v/v) were lethal to the stationary phase cells in the assay conditions used. At 2.0% (v/v) niaouli oil and Lema oil yielded a complete 6.8 log₁₀ reduction of cell numbers in suspensions within 60 min, whereas cells treated with tea tree & cajuput oils were inactivated more slowly within 120 & 240 min. respectively. Kanuka & manuka oils as well as the b-triketone complex, the active principle of manuka oil, lacked any bactericidal properties. Their high effectiveness against Gram-positive bacteria can be explained by bacteriostatic effects. The results obtained with Lema oil, a blend of tea tree and a polar fraction of manuka oil (mainly b-triketones), gave cause to discuss synergistic effects.

Cooke & Cooke M.D. (1994) "An investigation into the antimicrobial properties of manuka & kanuka oils" Cawthron Report No 263, New Zealand.

Harkenthal M., Reichling J., Geiss H.K. & Saller R. (1999) "Comparative study on the in vitro antibacterial activity of Australian tea tree oil, cajuput oil, niaouli oil, manuka oil, kanuka oil, and eucalyptus oil." Pharmazie 54(6), 460-463. Abstract.  To compare the antibacterial activity of the Australian tea tree oil (TTO) with various other medicinally and commercially important essential myrtaceous oils (cajuput oil, niaouli oil, kanuka oil, manuka oil, and eucalyptus oil) the essential oils were first analysed by GC-MS and then tested against various bacteria using a broth microdilution method. The highest activity was obtained by TTO, with MIC values of 0.25% for Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella choleraesuis, Shigella flexneri, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus, S. saprophyticus, and S. xylosus. It is noteworthy that manuka oil exhibited a higher activity than TTO against gram-positive bacteria, with MIC values of 0.12%. Both TTO and manuka oil also demonstrated a very good antimicrobial efficacy against various antibiotic-resistant Staphylococcus species. Pseudomonas aeruginosa was resistant to all essential oils tested, even at the highest concentration of 4%.

Kim, E. H. & Rhee G.J. (1999). “Activities of ketonic fraction from Leptospermum scoparium alone and synergism in combination with some antibiotics against various bacterial strains and fungi.” Yakhak Hoeji (J. - Pharmaceutical Society of Korea). 43(6), 716-728.

Malone M.A., Gatehouse H.S. & Treqidqa E.L. (2001) “Effects of time, temperature & honey on Nosema apis (Microsporidia: Nosematidae), a parasite of the honeybee Apis mellifera (Hymenoptera: Apidae). J. Invertebrate Pathol 77(4), 258-68. Abstract. Newly emerged adult bees were fed with Nosema apis spores subjected to various treatments, and their longevity, proportions of bees infected, and spores per bee recorded. Spores lost viability after 1, 3, or 6 months in active manuka or multifloral honey, after 3 days in multifloral honey, and after 21 days in water or sugar syrup at 33 degrees C. Air-dried spores lost viability after 3 or 5 days at 40 degrees, 45 degrees, or 49 degrees C. Increasing numbers of bees became infected with increasing doses of spores, regardless of their subsequent food (active manuka honey, thyme honey, or sugar syrup). Final spore loads were similar among bees receiving the same food, regardless of dose. Bees fed with either honey had lighter infections than those fed with syrup, but this may have been due to reductions in their longevity. Bees fed with manuka honey were significantly shorter lived, whether infected or not.