Manuka Oil

Scientific Name(s): Leptospermum scoparium J.R. Forst. et G. Forst. Family: Myrtaceae 1

Common Name(s): Red manuka , tea tree , manuka oil 1 , 2

Uses

Manuka oil has selective antibacterial activity against Gram-positive organisms, 3 particularly S. aureus .

Dosing

There are no reported clinical studies of manuka oil on which dosage recommendations can be based.

Contraindications

Avoid use during pregnancy because of spasmolytic activity. 4 , 5

Pregnancy/Lactation

Documented adverse effects. Avoid use during pregnancy because of spasmolytic activity. 4 , 5

Interactions

There is potential synergistic effect with bacitracin, cefadroxil, cephradin, and meropenem but an antagonist effect with ofloxacin, enoxacin, and sparfloxacin. 6

Adverse Reactions

L. scoparium contains a lipophilic flavonoid that specifically interacts with benzodiazepine receptors (GABA-A receptor-chloride channel complex). 7 , 8

Toxicology

There are limited clinical toxicological data on manuka oil in the scientific literature.

Botany

L. scoparium is the only Leptospermum species native to New Zealand. Its size ranges from a creeping plant to a small tree (of 8 m in height) and it is widely distributed in various climatic and altitudinal zones in New Zealand. The physical characteristics, such as flower and leaf color, leaf size and shape, branching habit, and foliage density vary considerably among populations. 1 , 9 , 10

History

Early New Zealand records indicate that the plant's bark, leaves, sap, and seed capsules were used in beverages and medicinal preparations. 10 The plant was valued for its medicinal properties and wood by the indigenous Maori people; the wood was utilized for gardening tools, fishing, housing structures, and weapons. 1 , 2

Captain James Cook used the leaves of the plant as a tea to combat scurvy during long explorations of the southern hemisphere; early European settlers of New Zealand adopted Captain Cook's use of the plant as a tea. 1

Commercial development of the essential oils has led to a range of OTC products marketed in New Zealand and exported to European and Asian markets. These products are used for topical treatment of various conditions including the following: Fungal and bacterial skin infections; inflammation from sunburn, insect bites, or joint pain; eczema or psoriasis. The oils also are used in perfumes and soaps. 1

Chemistry

The L. scoparium populations of New Zealand are highly variable in oil chemical composition and activity. 11 , 12 Standardized steam distillation and gas chromatography-mass spectrometry of the essential oils of 15 New Zealand L. scoparium populations identified the following in various quantities per species: α-pinene, β-pinene, myrcene, ρ-cymene, 1,8-cineole, linalol, methylcinnamate, α-farnesine, isoleptospermone, leptospermone, sesquiterpenes such as cadina-3,5-diene and δ-amorphene, and triketones. 9 , 10 , 11

Triterpenoids and flavonoids (including methylated and methoxylated flavonoids such as 5,7-dimethoxyflavone, 5-hydroxy-7-methoxy-6-methylflavone, and 5-hydroxy-7-methoxy-6,8-dimethylflavan-3-one) have been identified in a dichloromethane extract of L. scoparium . 13 , 14 Oligosaccharide components include maltose (the major component), isomaltose (or maltulose), kojibiose, turanose (or gentiobiose), and nigerose. 15

The average content of total flavonoids in New Zealand manuka ( L. scoparium ) honey was 3.06 mg/100 g honey; the main flavonoids consisted of quercetin, isorhamnetin, chrysin, and luteolin. 16

Uses and Pharmacology

The antimicrobial activity of manuka oil against 10 microorganisms was determined by both 2-fold dilution method and agar plate 2-fold dilution method. Manuka oil has selective antibacterial activity against gram positive organisms, 17 such as Staphylococcus aureus and Micrococcus luteus . Enhanced antibacterial activity against the Staphylococcus was higher when manuka oil ointment was used in combination with other drugs (ie, gentamicin sulfate, clotrimazol and hydrocortisone acetate, diphenhydramine HCl, hydrocortisone acetate). 3 Manuka oil has little to no activity against gram negative organisms such as Pseudomonas aeruginosa , Escherichia coli , Klebsiella pneumoniae , and Proteus vulgaris . 3 , 6 , 17 A ketonic fraction of L. scoparium showed a synergistic effect with bacitracin, cefadroxil, cephradin, and meropenem but an antagonist effect with ofloxacin, enoxacin, and sparfloxacin. 6

Some studies document the activity of L. scoparium against fungi and yeast; 6 , 17 however, there are limited data to support these claims for L. scoparium as compared with other species of Myrtaceae (eg, kanuka or Kunzea ericoides ). 4

The pharmacological action of manuka oil for treating diarrhea, colds, and inflammation was studied on a field-stimulated guinea pig ileum. Manuka oil induced a spasmolytic effect; 4 , 5 the mechanism of action is likely to be the result of a postsynaptic mechanism and associated with cAMP. 5

L. scoparium contains a lipophilic flavonoid that specifically interacts with benzodiazepine receptors in the GABA-A receptor-chloride channel complex. A sedating and potentially anxiolytic effect was recorded in a locomotion study with rats. 7 , 8

Dosage

There are no reported clinical studies of manuka oil on which dosage recommendations can be based.

Pregnancy/Lactation

Documented adverse effects. Avoid use during pregnancy because of spasmolytic activity. 4 , 5

Interactions

There is potential synergistic effect with bacitracin, cefadroxil, cephradin, and meropenem but an antagonist effect with ofloxacin, enoxacin, and sparfloxacin. 6

Adverse Reactions

L. scoparium contains a lipophilic flavonoid that specifically interacts with benzodiazepine receptors (GABA-A receptor-chloride channel complex). 7 , 8

Toxicology

There are limited clinical toxicological data on manuka oil in the scientific literature. Anecdotal information from OTC use of topical manuka oil products suggests good potential for its future use as an antimicrobial agent. 1 Avoid use during pregnancy because of spasmolytic activity. 4 , 5

Bibliography

1. Porter N. Manuka: The good oil from New Zealand. HerbalGram . 2001;53:26-30.
2. Riley M. Maori Healing and Herbal: New Zealand Ethnobotanical Sourcebook . Paraparaumu, NZ: Viking Sevenseas NZ; 1994.
3. Rhee GJ, Chung KS, Kim EH, Suh HJ, Hong ND. Antimicrobial activities of a steam distillate of Leptospermum scoparium . Yakhakhoe Chi . 1997;41:132-138.
4. Lis-Balchin M, Hart SL, Deans SG. Pharmacological and antimicrobial studies on different tea-tree oils ( Melaleuca alternifolia , Leptospermum scoparium or Manuka and Kunzea ericoides or Kanuka), originating in Australia and New Zealand. J Phytother Res . 2000;14:623-629.
5. Lis-Balchin M, Hart SL. An investigation of the actions of the essential oils of Manuka ( Leptospermum scoparium ) and Kanuka ( Kunzea ericoides ), Myrtaceae on guinea-pig smooth muscle. Pharm Pharmacol . 1998;50:809-811.
6. Kim EH, Rhee GJ. Activities of ketonic fraction from Leptospermum scoparium alone and synergism in combination with some antibiotics against various bacterial strains and fungi. Yakhakhoe Chi . 1999;43:716-728.
7. Häberlein H, Tschiersch KP. 2,5-Dihydroxy-7-methoxy-6,8-dimethylflavan-3-one a novel flavonoid from Leptospermum scoparium : in vitro affinity to the benzodiazepine binding site of the GABA-A receptor-chloride channel complex. Pharmazie . 1994;49:860.
8. Häberlein H, Tschiersch KP, Schafer HL. Flavonoids from Leptospermum scoparium with affinity to the benzodiazepine receptor characterized by structure activity relationships and in vivo studies of a plant extract. Pharmazie . 1994;49:912-922.
9. Melching S, Bülow N, Wihstutz K, Jung S, König WA. Natural occurrence of both enantiomers of cadina-3,5-diene and δ-amorphene. Phytochemistry . 1997;44:1291-1296.
10. Porter NG, Wilkins AL. Chemical, physical and antimicrobial properties of essential oils of Leptospermum scoparium and Kunzea ericoides . Phytochemistry . 1999;50:407-415.
11. Perry NB, Brennan NJ, Van Klink JW, et al. Essential oils from New Zealand manuka and kanuka: Chemotaxonomy of Leptospermum . Phytochemistry . 1997;44:1485-1494.
12. Priest D. Natural antimicrobials for personal care. Chimicaoggi . 2002;20:43-46.
13. Häberlein H, Tschiersch KP. Triterpenoids and flavonoids from Leptospermum scoparium . Phytochemistry . 1994;35:765-768.
14. Häberlein H, Tschiersch KP. On the occurrence of methylated and methoxylated flavonoids in Leptospermum scoparium . Biochem Syst Ecol . 1998;26:97-103.
15. Weston RJ, Brocklebank LK. The oligosaccharide composition of some New Zealand honeys. Food Chem . 1999;64:33-37.
16. Yao L, Datta N, Tomas-Barberan FA, Ferreres F, Martos I, Singanusong R. Flavonoids, phenolic acids and abscisic acid in Australian and New Zealand Leptospermum honeys. Food Chem . 2003;81:159-168.
17. Harkenthal M, Reichling J, Geiss HK, Saller R. 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 . 1999;54:460-463.

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