Agathosma betulina

Buchu

ALSO CALLED:

Bergboegoe (a), Buchu (e), Rondblaarboegoe (a), Round Leaf Buchu (e), Round-leaved Buchu (e), ibuchu (xhosa), Buchu (khoi)

Photos

Derivation of name and historical aspects

Indigenous to the Cape region of South Africa, Buchu is an aromatic plant known for its essential-oil producing ability and its multiple healing properties. Known taxonomically as Agathosma betulina and Agathosma crenulata, its traditional benefits have made their way from Africa to the Western world.

Agathosma derived from the Greek meaning agathos, pleasant and osme, smell. Agathosma crenulata and A. betulina (see below) belong to the Rutaceae, commonly known as the citrus family. There are 150 species in the genus Agathosma and they are mainly found in the Western Cape. Barosma is an old name for Agathosma.

The word “Buchu” originated from the Khoi-San people of southern Africa, and was a word used in reference to any plant that could be dried or powdered.

Nowadays, the name Buchu refers to the Agathosma species. Previously known as Barosma betulia, the name originates from the word Barosma (Greek) meaning “heavy smell” and the word betulina (Latin) which means “birch-like”, a word used in reference to the serrated birch-like appearance of the leaves.

Plant parts used

dried leaves used

Medicinal Uses / Ethnopharmacological uses

Cultural heritage of San and Khoi people. Mix dried and powdered leaves with animal fat, to anoint the body, for cosmetic and antibacterial reasons. Leaves chewed for stomach complaints. The Dutch settlers steeped it in brandy, the tincure, Boegoebrandewyn, was an everyday remedy for stomach problems. Buch vinegar, boegoe-asy, was highly regarded for washing and cleaning of wounds. Buchu is still widely used household medicine in SA., great reputation for treating kidney and urinirary tract diseases, for syptomatic relief of rheumatism and external application on wounds and bruises.

Agathosma crenulata and A. betulina are commercially grown for their oil. The oil is extracted and used in the manufacture of cosmetics, soaps, food colorants and medicinally for the treatment of renal disorders and chest complaints. Isomenthone and disphenol are the major oil compounds in the essential oils of A. betulina. The essential oils are used for their antiseptic and diuretic properties. Used in the food industry, the sulphur-containing compounds are responsible for the characteristic blackcurrant smell and flavour of buchu oil (Scott and Springfield 2004). The indigenous Khoi-San people of the Western Cape have used Agathosma betulina, (better known as buchu) the focus of this study, for many years (Jodamus 2003). It has been well documented that the Khoi people used it for almost everything, from stomach ailments to moisturizing their skins). More recently, due to its commercialization, buchu has become so sought after that it is being treated as a protected species, is highly vulnerable to extinction, and is being cited as the abalone of the land. Internationally, there is a huge demand for it, since its major uses are in the pharmaceutical and food industry (Coetzee et al. 1999). Locally, it is being distilled by large companies at profitable rate. According to the Western Cape Nature Conservation Board (WCNCB), the buchu industry generates approximately R150 million per year. Until 1995, the only sources of buchu were wild plantations in the mountains of the Western Cape. This put the resource at risk.

Buchu first was exported to Britain in 1790. In 1821, it was listed in the British Pharmacopoeia as a medicine for “cystitis, urethritis, nephritis and catarrh of the bladder.”

The drug had been included in the US National Formulary and was described as a diuretic and antiseptic. Its use since has been abandoned in favor of more effective diuretics and antibacterials. Buchu remains a popular ingredient in over-the-counter herbal diuretic preparations.

Health benefits

Distribution

Endemic to South Africa. Found in the Western Cape, from Cederberg to Groot Winterhoek Mountains including the Piketberg. Sandy mountain slopes of 300-700m above sea level.

Population

Conservation

Botanical Description

The plant is a resprouting shrub of up to 1,5m in height. The leaves are about 20mm long, characteristically very broad, less than twice as long as wide (and widest in the upper half), with a rounded apex which curves backwards. Conspicous oil gland are present along the margins and lower surfaces of the leaves (under high magnification, visible as round glands on the mesophyll). The flowers are solitary, star shaped and have five white or pale purple petals. This species is sometimes confused with A.crenulata, but in the latter the leaves are more than twice as long as they are wide (and widest in the lower half).

Preparation and Dosage

A number of Buchu preparations are used to deliver it to the body. It may be prepared as a brandy, a tincture (an alcohol or aqueous solution), a tea, or soaked in vinegar. The vinegar can be used for external applications to treat bruises, contusions, sprains and fractures, to clean wounds and to treat rheumatism.

The Khoi-San used the plant as an ‘antibiotic repellent’ to repel insects and mixed it with oil to use as a moisturiser, which was essential in their natural environment and desert climate surroundings. Topical application allowed entry of the active ingredients of Buchu oil through the skin and provided antibacterial and antifungal properties, and also acted as an insect repellent and deodorant.

Buchu has a long-standing traditional use, but it has made its way into the fragrance and flavour industries due to its sulphur-containing compounds and sensory properties. It is used to enhance fruit flavours and fragrances, and boost blackcurrant-like flavours. It has a naturally minty, sweet berry, apricot, peach and green herbal taste, and its oils are used in perfumes and colognes.

Active Ingredients

Fractionation of Buchu by distillation, crystallisation and chromatography releases an oil with many constituents. Agathosma betulina contains the major volatile compounds limonene, menthone, diosphenol and one of its isomers (ψ)-diosphenol, and l-pulegone. Aganthosma crenulata contains the same main constistuents, but has trace amounts of diosphenol and larger amounts of l-pulegone. These are responsible for the odour, flavour and medicinal properties of Buchu oil. Two monoterpene thiols are accountable for the distinguishing odour of Buchu oil, one being 9-mercapto-p-menthan-3-one. This sulphur-containing terpene is essential to the aroma and flavour of the plant

The plant contains essential oil components (about 1,8% on a dry weight basis). The presence of two isomers of diosphenol (=buchu camphor) at about 40% of the total oil is highly chareacteristic for A.betulina (more or less absent in the A.crenulata and hybrids). The level of pulegone is low, <5%, in A.betulina but high, 50%, in A crenulate. Sulphur containing minor compounds are responsible for the characteristic blackcurrent smell and flavour of buchu oil. Also reported are flavonoids, especially diosmin (based on early reports; also claimed to have diosmetin, quercetin-3, 7-diglucoside and rutin). The presence of diosmin as the main compound are responsible for the diuretic effects. Also present are mucilages and resins.

Pharmacological Effects

Diuretic activity
Diospenol is responsible for the diuretic action of Buchu. There is no explanation of the mechanism of action, but the available literature states that diosphenol acts by irritating the gallbladder, causing the production of urine [18]. Buchu also contains flavonoids that induce urine production.

Antimicrobial activity
Buchu essential oils and extracts were analysed to assess the antimicrobial activity of the plant. The essential oils and extracts were found to be active against the selected pathogens, namely Staphylococcus aureus, Bacillus cereus, Klebsiella pneumonia and Candida albicans. Buchu extracts have a good antibacterial activity, and has been found to be more active against gram positive than gram negative bacteria. Buchu was found to affect the development of biofilms by preventing attachment of bacteria to the polyvinyl chloride surface. This was, however, not the case with the fungus (C. albicans), as exposure to the extracts improved the attachment to the surface, allowing the formation of a biofilm. The more well-known Buchu species are thus effective against bacteria, but not against fungi. There is, however, a less extensively researched member of the Agathosma family called A. arida that is effective against Candida albicans. Agathosma species have been found to contain coumarins, phenolic substances with benzene and α-pyrone rings. A number of these compounds have been found to be active against microbials by stimulating macrophages, allowing the plant to have an indirect ability to eliminate infection.

Anti-oxidant activity
Free radicals are molecules with one or more unpaired electron(s) that are highly reactive, attacking nearby stable molecules to gain an electron. The two forms of free radicals are reactive oxygen species (ROS) and reactive nitrogen species (RNS). Free radical scavengers are known as antioxidants, and these assist in keeping free radicals at physiologically homeostatic levels. Polyphenolics in plants are scavengers of free radicals, allowing them to act as anti-oxidants. These compounds act via several mechanisms to reduce free radicals, and make wonderful antioxidants due to the hydrogen donating ability of the phenolic groups. Members of the Agathosma specie have been found to contain flavonoids such as diosmin, hesperidin, rutin, quercitin, mucilage and resins which have extensive anti-oxidant properties. These are some of the compounds that give the Buchu plant its anti-oxidant ability, allowing it to be effective against many ailments that result from an increase in oxidative stress.

Anti-inflammatory
Buchu oil contains limonene, a monoterpene hydrocarbon with anti-inflammatory properties. Essential oils found in Agathosma have been found to inhibit the synthesis of leukotrienes by blocking synthesis of the key enzyme 5-lypoxygenase. By doing so, it reduces inflammation by preventing the initiation and maintenance of the inflammatory process, thereby limiting an infection and preventing its progression. Limonene has also shown to be effective in reducing cyclooxygenase 1 and 2 biosynthesis, reducing the proinflammatory agents prostaglandins and leukotrienes from being synthesised, reducing inflammation.

Status

Least concern

Threats

Heavily impacted throughout its range by harvesting for essential oils, prices between 1998 and 2004 were very high due to demand from overseas markets. Although local declines in some subpopulations have been reported, the population is not suspected to have lost more than 10% of individuals. This species is a resprouter and is able to recover from moderate levels of harvesting. Only severe repeat harvesting of the same individuals in some areas has caused declines. Current provincial legislation managing the trade has resulted in cultivated material being promoted, most wild subpopulations are therefore no longer targeted.

References

https://www.health24.com/Natural/Herbs/Is-buchu-South-Africas-miracle-herb-20150811
https://redlist.sanbi.org/species.php?species=3359-22
https://www.drugs.com/npc/buchu.html
https://www.intechopen.com/books/antioxidant-antidiabetic-agents-and-human-health/buchu-the-multi-purpose-ethnomedicinally-important-specie-and-its-benefits-in-the-reproductive-syste
https://www.daff.gov.za/Daffweb3/Portals/0/Brochures%20and%20Production%20guidelines/Brochure%20Buchu.pdf
https://pza.sanbi.org/sites/default/files/info_library/agathosmabetulina%20%281%29.pdf
https://open.uct.ac.za/bitstream/handle/11427/19985/thesis_sci_2015_muller_claudette.pdf?sequence=1&isAllowed=y

Medicinal Plants of Southern Africa. Ben-Eric van Wyk, Bosch van Oudtshoorn, Nigel Gericke.

African Herbal Pharmacopoeia. AAMPS (Association for African Medicinal Plants Standard). Brendler,T; Eloff J.N.; Gurib-Fakim, A; Phillips,L.D

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