IngredientsLongleaf Buchu (Agathosma serratifolia (Curtis) Spreeth) is a shrub species belonging to the family Rutaceae. From a systematic standpoint, it belongs to the Eukaryota Domain, Plantae Kingdom, Magnoliophyta Division, Magnoliopsida Class, Rosidae Subclass, Sapindales Order, Rutaceae Family, and to the genus Agathosma.
Accepted synonyms include Barosma serratifolia (Curtis) Willd. and Diosma serratifolia Curtis. The genus name Agathosma comes from the Greek agathós ("good") and osmé ("odor"), referring to the plant's pleasant aromatic scent. The specific epithet serratifolia derives from serratus ("saw-shaped") and folium ("leaf"), describing the serrated leaf margins.
Common names for buchu species include boegoe, boechoe, boekoe, boggoa, bookoo, bouchou, bugu, buccho, bucchuu, bucco, buchu, bucku, and buku. In the commercial trade, B. serratifolia is known in commerce as "longs," in distinction from B. betulina ("shorts") and B. crenulata ("ovals" or "shortbroads").
The term "buchu" today primarily refers to the two species most prevalent in commerce: Agathosma betulina (P.J.Bergius) Pillans and Agathosma crenulata (L.) Pillans (Rutaceae). A. serratifolia (longleaf buchu) has historically been considered one of the three standard commercial buchu species, and its leaves share many phytochemical and traditional-use characteristics with these two, though it is generally considered of lesser commercial importance than A. betulina. The leaves of A. betulina are considered the most valued and constitute the Folia buchu of the British Pharmacopoeia. These plants should not be confused with "Indian buchu" (Myrtus communis), which is native to Mediterranean regions.
Agathosma serratifolia, known as longleaf buchu or long buchu, is an erect South African shrub belonging to the citrus family Rutaceae. It is an erect shrub that reaches 30–100 cm in height but is slow growing. The leaves are opposite, often crowded, simple, ovoid, and slightly serrated, 0.5–3.5 cm long. The flowers are produced in terminal clusters 0.7–2 cm in diameter with five white–pink petals.
Agathosma serratifolia is one of about 135 species mainly occurring in the south-western Cape Province of South Africa, where it is found on mountain slopes, wooded ravines, and valleys. It is endemic to the Western Cape of South Africa—it grows here and nowhere else in the world. Its habitat is the fynbos, the particular shrubby vegetation that populates a small area of the south-western Cape Province.
Buchu leaves are collected while the plant is flowering and fruiting, and are then dried and exported from Cape Town. The bulk of the buchu exported to London from South Africa eventually finds its way to America, where it is used in certain proprietary medicines. Buchu is commercially marketed as fresh or dried leaves, tinctures, herbal water, and essential oils. There are numerous buchu products on the market, including teas, capsules, and herbal water, which claim to have a medicinal effect because of non-volatile components. Recent commercial focus is on the essential oil for use in the perfume and food-flavoring industry.
Buchu has been utilized in southern Africa for millennia by the Khoi-San people indigenous to the region for a multitude of daily uses and a plethora of ailments. Agathosma is a fragrant-smelling South African fynbos shrub widely known and marketed as a traditional remedy of southern Africa's Khoisan herders and hunter-gatherers.
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. Buchu is an important part of the Khoi-San culture and is still used in the Cape as a general tonic and medicine throughout South Africa.
The fragrant herb of buchu has been used for centuries in South Africa by the San and Khoi people. Many Khoi and San people thought the herb to be a tonic for youth, but they also chewed it for stomach ailments, anti-inflammatory properties, and mixed it with animal fat for various cosmetic applications. Long used as an antiseptic and anti-inflammatory, buchu was employed for urinary problems including haematuria, calculi, kidney disease, and infections of the bladder, prostate, and urethra.
The Khoisan place great emphasis on the sense of smell. Buchu's strong scent is associated with physical and mental transformation. According to traditional San folklore, buchu's fragrance carries the herb's medicinal powers to the body through the ears, nose, mouth, and skin pores, encouraging one's interior body to be in the "right place."
The indigenous people first introduced buchu in the 1650s as a medicinal plant to the European settlers in the Cape. The use of the plant subsequently spread to Europe and America, where it was extensively used as a medicine. Buchu was first 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 earliest pharmacopoeia entries for buchu appeared in chronological order in the Dublin Pharmacopoeia (1826), the Edinburgh Dispensatory (1830), the Schleswig-Holstein Pharmacopoeia (1831), and the US Dispensatory (1833). In 1828, Nees von Esenbeck included D. crenata and D. serratifolia in his Plantae Officinalis. A dissertation of 1838 summarized advancements in research hitherto and promoted the use of buchu as a diuretic, diaphoretic, and stimulant. Publications of 1847 and 1848 suggested buchu for oedema (anasarca, dropsy).
The drug had been included in the US National Formulary and was described as a diuretic and antiseptic. Its traditional use in urinary tract infections and related ailments made it a popular remedy, specifically in the US in the 19th century, but with the advent of antibiotics it became largely obsolete.
Traditionally, buchu is used to treat cholera, indigestion, constipation, prostatitis, rheumatism, fever, respiratory and urinary tract infections, as well as for disinfecting wounds and relieving menstrual cramps. The Hottentots (Khoikhoi) used several species, all under the common name of "bucku." The leaves have a rue-like smell and were used by the natives to perfume their bodies.
The essential oils and extracts of the leaves are used as flavoring for teas, candy, and a liquor known as buchu brandy in South Africa. Dutch settlers in early times used Agathosma betulina, commonly called buchu, to make a brandy tincture.
More than 120 compounds have been identified in buchu, including volatile oils, diosphenol, menthone, isomenthone, limonene, and pulegone. Buchu leaves contain from 1.5% to 3.5% volatile oil.
Lamparsky and Schudel isolated 8-mercapto-p-menthan-3-one, a sulfur-containing terpene responsible for the flavor and aroma of the oil. Kaiser and colleagues identified more than 120 components, including the already known pulegone, diosphenol, and 8-mercapto-p-menthan-3-one.
The major volatile components of the related commercial buchu species provide the chemical profile most relevant to understanding longleaf buchu. In A. betulina, the oil is characterized by 31% isomenthone, 41% diosphenol, and 3% of the olfactory important cis- and trans-8-mercapto-p-menthane-3-ones. The A. crenulata oil (which A. serratifolia was historically grouped with and sometimes confused with) contains very high quantities of pulegone (54%) and considerable quantities of trans-acetylthio-p-menthan-3-one (7%).
Known components of buchu oils include pulegone, diosphenol, and 8-mercapto-p-menthan-3-one. Buchu leaf oil has also been shown to contain α-thujone, β-thujone, menthofuran, and methyleugenol.
Two A. betulina chemotypes have been identified. The diosphenol chemotype is characterized by high ψ-diosphenol (>10%) and diosphenol (>12%), and low isomenthone (<29%) concentrations. The principal active ingredient of the oil is considered to be diosphenol, described as a potent diuretic and antiseptic.
Flavonoids in buchu include diosmetin, quercetin, diosmin, quercetin-3,7-diglucoside, and rutin. Other constituents include mucilage, resin, thiamine, and sulfur compounds. Members of the Agathosma species have been found to contain flavonoids such as diosmin, hesperidin, rutin, and quercetin, which have extensive antioxidant properties—some of the compounds that give buchu its antioxidant ability, allowing it to be effective against ailments resulting from increased oxidative stress.
The only extract shown to suppress the oxidation of linoleic acid in one study was an acetone extract containing four lipophilic flavonoids: 3 and 3,3′-dimethyl ethers of quercetin and the 3 and 3,4′ dimethyl ethers of kaempferol. The 80% methanol extract contained hyperoside, rutin, and a novel compound designated agathosin, shown to be a quercetin glucoside esterified with oleuropeic acid. The main antioxidative compound in the aqueous extract was rutin.
The marker compounds in the non-volatile fraction have been identified as diosmin, hesperidin, and rutin, based on both HPTLC and UPLC–MS analysis. Coumarins have been reported from other Agathosma species.
No definitive scientific evidence is available to justify buchu's herbal uses, but its diuretic and anti-inflammatory effects may be attributed to the volatile oil and flavonoids' irritant nature. Diosphenol, the flavonoids, and terpinen-4-ol may contribute to the plant's diuretic activity, but this action of buchu teas is probably no greater than that of the xanthine alkaloids in coffee or tea.
The mode of action of buchu essential oils has been studied on smooth muscle in vitro using guinea-pig ileum. At high concentration, the oils had an initial spasmogenic activity followed by spasmolysis. The spasmolytic action was post-synaptic, not atropine-like, and did not involve adrenoceptor or guanylyl cyclase activation. In the presence of the phosphodiesterase inhibitor rolipram, the spasmolytic action of A. betulina was significantly increased, suggesting a mode of action involving cyclic adenosine monophosphate. In addition, A. betulina appeared to block calcium channels.
In the 5-lipoxygenase (5-LO) assay, the essential oil of A. betulina and A. crenulata revealed IC50 values of 50.37 ± 1.87 μg/ml and 59.15 ± 7.44 μg/ml, respectively. Recent in vitro studies with a commercial aqueous extract of buchu revealed increased uptake of glucose added to 3T3-L1 cell line, significant inhibition of the respiratory burst of neutrophils and monocytes, reduction in the expression of adhesion molecules, and inhibition of the release of IL-6 and TNF-α.
Several studies have revealed quercetin's significant anti-inflammatory activity due to direct inhibition of initial processes of inflammation. Various promising antioxidant pharmacological activities and health benefits have been reported for citrus flavonoids like hesperidin and diosmin, which are present in Agathosma species.
In 1821, buchu was listed in the British Pharmacopoeia as a medicine for "cystitis, urethritis, nephritis and catarrh of the bladder." The drug was included in the US National Formulary and described as a diuretic and antiseptic. Its use was subsequently abandoned in favor of more effective diuretics and antibacterials.
Based on the traditional use of buchu in urinary tract infections, several assays have been utilized to study the antimicrobial activity of hydro-distilled essential oils and methanol-dichloromethane extracts of A. betulina and A. crenulata. It is noteworthy that these extracts do not correspond with traditional extraction methods (infusion in water or a tincture in ethanol). Applying the microtiter plate dilution method in the minimum inhibitory concentration (MIC) assay, the methanol-dichloromethane extracts of both species revealed moderate antimicrobial activity with a MIC in the range of 2 mg/ml–4 mg/ml against the tested pathogens Bacillus cereus, Staphylococcus aureus, Klebsiella pneumoniae, and Candida albicans.
A review of the scarce pharmacological research revealed moderate antimicrobial activity for a leaf extract but not the essential oil of both species in the MIC assay. The efficacy of buchu has not been proven in prospective clinical trials for any of these conditions. The evidence base for urinary-tract applications is therefore limited to in vitro and animal studies; no controlled human clinical trials have been published to substantiate efficacy.
Buchu contains bioactive compounds such as diosphenol, menthone, and pulegone, which have demonstrated antibacterial, anti-inflammatory, and antioxidant properties in preclinical studies. The 5-lipoxygenase inhibition data described above (IC50 values in the range of 50–59 μg/ml for the essential oil) represent in vitro findings only. Most studies have been conducted in vitro or on animals, and there is a lack of substantial scientific evidence supporting anti-inflammatory claims from human trials.
An aqueous extract of A. betulina showed a Trolox equivalent antioxidant capacity (TEAC) of 11.8 µM Trolox in one in vitro assessment. These findings are based on in vitro assays and have not been evaluated in human clinical studies.
In diabetic rats, ingestion of aqueous buchu extract completely normalized the glucose level; in rats receiving a high-fat diet, consumption of aqueous buchu extract resulted in less weight gain, less intraperitoneal fat gain, a reduction of elevated blood pressure to normal, and associated cardioprotective effects. Limitations in these studies lie in the undisclosed composition of the buchu extracts used and the difficulty in extrapolating data from animal studies to humans. No human clinical data are available for these endpoints.
Dried buchu leaves have been used for medicinal purposes in tonics and as tablets or powders to treat musculoskeletal pain, chronic arthritis, dyspepsia, edema, fever, the common cold, ulcers, irritable bowel syndrome, gout, prostatitis, prostatic hypertrophy, and sexually transmitted diseases. These applications are rooted in traditional use and historical pharmacopoeial listing; however, the efficacy of buchu has not been proven in prospective clinical trials for any of these conditions.
Buchu is applied to the skin as an insect repellent, as a deodorant, and for skin infections. These applications are based on traditional use and in vitro/animal data; no human clinical trial evidence has been identified.
Buchu is listed in the German Commission E Monographs to treat inflammation, kidney and urinary tract infections, and is also used as a diuretic, but the monograph explains that the plant's activity in these claimed uses has not been substantiated. Buchu has been compendial since 1826 for its diuretic effects and use in the treatment of genitourinary tract infections; however, it became obsolete in the 20th century due to the sparsity of scientific evidence for its efficacy and the advent of antibiotics. All existing pharmacological evidence is preclinical (in vitro and animal models); no robust randomized controlled trials in humans have been conducted or published.
There is no recent clinical evidence to guide dosage of buchu. Classical doses were from 1 to 2 g of the leaves daily.
Historical pharmacopoeial preparations, as recorded in A Modern Herbal (based on the British Pharmacopoeia), include: an infusion of 1 oz of leaves to 1 pint of boiling water, taken in wineglassful doses three or four times a day; fluid extract in doses of ½ to 1 drachm; and tincture (B.P.) in doses of ½ to 1 drachm. Solid extract was given in doses of 5 to 15 grains; Barosmin in doses of 2 to 3 grains.
Additional reported preparation formats include: powder at 1–2 grams; infusion at 1–2 teaspoonfuls per cup; tincture (1:5 in 60% alcohol) at 2–4 mL three times daily; and fluid extract (1:1 in 90% alcohol) at 0.5–1.5 mL.
Dosage as a dietary supplement typically involves 1 to 2 grams of dried leaves taken three times a day.
It should be noted that none of these dosages derive from modern randomized controlled clinical trials; they reflect historical pharmacopoeial convention and herbal medicine tradition only.
Buchu contains many compounds, including pulegone, which causes liver injury in rodent models and induces cytotoxicity in cell culture systems. The concentration of pulegone is higher in leaves from Agathosma crenulata than in those of Agathosma betulina. Large oral doses of pulegone have been found to deplete glutathione, which may be the mechanism of its toxic effects. Essential oils at high doses were found to be hepatotoxic in rats, affecting liver and uterine functions. This was attributed to R-(+)-pulegone, known to be a hepatotoxic compound causing depletion of glutathione at high doses.
Hepatotoxicity from buchu must be quite rare if it occurs at all in humans. Buchu preparations have not been linked to instances of serum enzyme elevations or clinically apparent liver injury with jaundice in formal surveillance. The NIH LiverTox database does note a single case report: a 52-year-old man developed jaundice one month after starting buchu and rooibos herbal tea.
Analysis of buchu oil batches showed detectable concentrations of pulegone (2.13–7.81%) in all batches. Buchu leaf oil also contains α-thujone, β-thujone, menthofuran, and methyleugenol. Pulegone, α- and β-thujone, menthofuran, and methyleugenol are included in the list of substances which shall not be added as such to food according to Annex III of Regulation (EC) No 1334/2008, and for which maximum levels in food are set by that regulation.
Buchu can cause stomach and kidney irritation, is hepatotoxic, and can be an abortifacient. It can also induce increased menstrual flow. Buchu is not recommended during pregnancy. The volatile oil of buchu contains the compound pulegone, which stimulates the uterus to contract and is potentially toxic to the kidneys and liver in excess or over prolonged doses.
Caution is advised during use with a kidney infection, as the volatile oil may irritate the kidney. Due to its diosmin and essential oils (diosphenol and pulegone), buchu is a potential kidney and liver irritant in high or prolonged doses.
Buchu might have an effect like a water pill or "diuretic." Taking buchu might decrease how well the body gets rid of lithium. Stopping buchu use at least 2 weeks before a scheduled surgery has been recommended. No other well-documented drug interactions have been identified in the literature.
The commercial term "buchu" primarily refers to A. betulina and A. crenulata. Because A. serratifolia (longleaf buchu) is historically one of the three commercial species and shares common names with its relatives, the two primary commercial species can be mainly distinguished by their leaf form, and the cultivation of both outside their natural habitat has resulted in the formation of hybrid plants. Misidentification or substitution of one species for another carries practical safety implications given the significant difference in pulegone content between species.
Buchu may cause mild gastrointestinal discomfort if taken on an empty stomach.
Health conditions that Longleaf buchu may help support.
Body systems that Longleaf buchu may help support.
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