FAMILY: Myrtaceae
SYNONYMS: New Zealand tea tree, kahikatoa, red manuka, manex.
GENERAL DESCRIPTION: The Manuka plant is an elegant, bushy evergreen shrub with deep green small spiky leaves that bears small flowers of white to pink in colour. The blossom is produced from September to February and most profusely in the later months. Its size ranges from a creeping plant to a small tree – trees can reach heights of up to 8 metres, especially when found within dense woodland. The leaves and flowers are strongly aromatic.
DISTRIBUTION: Manuka is the only Leptospermum species native to New Zealand, where it is widely distributed in various climatic and altitudinal zones. The physical characteristics, such as flower and leaf colour, leaf size and shape, branching habit, and foliage density vary considerably among populations. The plant can now be found in Australia where it seems to acclimatize well to varied terrain from marshland to dry mountain slopes. The essential oil is generally harvested from wild plants, as little farming of Manuka is currently undertaken.
OTHER SPECIES: The family Myrtaceae yields many valuable essential oils including eucalyptus, myrtle and tea tree. Another native tree of New Zealand called kanuka (Kunzea ericoides), sometimes called white or tree manuka, although superficially similar to L. scoparium in that both are collectively known as ‘tea trees’, is actually genetically a very distinct species. Kanuka in its typical form can grow into a tree up to 30 metres tall. It is also used to produce an essential oil.
HERBAL/FOLK TRADITION: For centuries, New Zealand Maori have used manuka to treat a wide range of complaints. Early New Zealand records indicate that the plant’s bark, leaves, sap and seed capsules were used in beverages and medicinal preparations. A decoction of the leaves was drunk for urinary complaints and as a febrifuge. The steam from leaves boiled in water was inhaled for head colds. A decoction was prepared from the leaves and bark and the warm liquid was rubbed on stiff muscles and aching joints. The emollient white gum, called ‘pai manuka’, was given to nursing babies and also used to treat scalds and burns. Chewing the bark is said to have a relaxing effect and enhance sleep. It is said that Captain James Cook used the leaves of the plant as a tea to combat scurvy during long explorations of the southern hemisphere; later, early European settlers of New Zealand adopted Captain Cook’s use of the plant as a tea.
Recently, scientists have confirmed that manuka oil is up to 33 times stronger than tea tree essential oil for protecting against specific strains of bacteria; it is also effective against the MRSA (Methicillin-Resistant Staph. Aureus) bacteria, which is resistant to normal antibiotics.
ACTIONS: Analgesic, antibacterial, antibiotic, antifungal, antihistamine, anti-inflammatory, anti-infectious, antimicrobial, antiseptic, astringent, deodorant, digestive, expectorant, immune stimulant, insecticide, sedative, vulnerary.
EXTRACTION: Steam distilled from the leaves, twigs and branches.
CHARACTERISTICS: A mobile liquid with a distinctive fresh, spicy, herbaceous aroma with a honey-like sweetness. It blends well with bay leaf, bergamot, black pepper, cajuput, cedarwood atlas, cinnamon, clove bud, elemi, ginger, juniper, lavender, nutmeg, peppermint, rose, rosemary, sandalwood, thyme, vetiver and ylang ylang.
PRINCIPAL CONSTITUENTS: The main active constituents of manuka oil are isoleptospermone, ?-pinene, ?-pinene, myrcene, ?-cymene, 1,8-cineole, linalol, methylcinnamate, ?-farnesine, isoleptospermone, leptospermone, sesquiterpenes such as cadina-3, 5-diene and ?-amorphene, and triketones. However, within the species of manuka there are at least nine different chemotypes: oil which contains high levels of triketones, found in the East Cape area of North Island in New Zealand appears to possess the greatest antimicrobial potential. Other chemotypes however are thought to reveal greater anti-inflammatory and analgesic tendencies. It is important to be aware of these various chemotypes when selecting an oil for therapeutic purposes.
SAFETY DATA: Generally it is thought to be non-sensitizing, non-toxic, and non-irritant. It can in some individuals, produce mild irritation but has a low irritancy compared to Australian tea tree oil. Avoid use during pregnancy because of spasmolytic activity.
AROMATHERAPY/HOME: USE
Skin care: Acne, abscesses, athlete’s foot skin, bed sores, blisters, boils, burns, carbuncles, cold sores, cracked skin, dandruff, dermatitis, eczema, fungal infections, insect bites and stings, lice, nail infections, oily skin, pimples, ringworm, sores, sunburn, tinea and ulcers.
Circulation, muscles and joints: Aches and pains, muscular tension, sprains and stiffness in joints, rheumatism.
Respiratory system: Coughs, cold, ’flu congestion, as well as asthma and hayfever.
Immune system: Tonic
Nervous system: Nervous debility.
OTHER USES: The essential oil is much used in phyto-cosmetic and pharmaceutical preparations mainly for its potent antimicrobial properties. Commercial development of the essential oil has led to a range of products for the topical treatment of various conditions including joint pain, eczema and psoriasis. The oil is also used in perfumes and soaps. The scented flowers of the shrub attract bees, which are used for making the popular manuka honey.
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