Catechu

Other Names

Acacia catechuAcacia catechu subsp. sumaAcacia catechu subsp. sundraAcacia catechu var. catechuoidesAcacia catechu var. sundraAcacia catechu var. wallichianaAcacia catechuoidesAcacia chundraAcacia polyacanthaAcacia SumaAcacie au cachouBalapatraBlack catechuBlack cutchCachouCachou de PeguCachou NoirCachou pâleCachuCatechu nigrumCatechu pallidumCatechu treeCube gambirCutchCutch treeDantadhavanDark catechuEr ChaGambierGambirGambir catechuGayatriGum catechuKaatKachuKadaraKadiramKalippakkuKaluKamuguKantakiKarinnaliKarukaliKarungaliKathKathaKatthaKhadiraKhadirahKhairKhairaKhayer gumKherKhersalKoirMimosa catechuMimosa sumaNauclea gambirOurouparia gambirPakuPale catechuPegu cutchPinangPodalianuRaktasaraSenegalia catechuShaSomavalkaSundraSupariTallatumaTerra JaponicaUncaria gambirYajniya

Synopsis

Catechu: A Comprehensive Reference Article

1. Identity, Botanical Classification, and Common Forms

1.1 Nomenclature and Taxonomy

Catechu, also known as black catechu or cutch, is a hard, reddish-brown extract obtained from the heartwood of the deciduous tree Senegalia catechu (synonym Acacia catechu), a species in the family Fabaceae, native to tropical regions of South and Southeast Asia, including India, Pakistan, Myanmar, and Thailand. The plant is called kachu in Malay; this Malay name was Latinized to "catechu" in Linnaean taxonomy, as the species from which the extracts cutch and catechu are derived. Other common names include kher, catechu, cachou, cutchtree, black cutch, and black catechu.

It is called the Cutch tree in English, Kahir in Hindi, and Khadira in Sanskrit. The heartwood of this plant is a medicinally potent product known as Katha, which is made up of concentrated extracts from 10–20-year-old A. catechu trees and is used as an ingredient in paan (betel leaf masticatory), imparting a red colour to saliva.

Through derivatives of the flavanols in its extracts, the species has lent its name to the important catechins, catechols, and catecholamines of chemistry and biology. Indeed, the name of the catechin family of chemicals is derived from "catechu," which refers to the juice or boiled extract of Mimosa catechu (Acacia catechu L.f.).

1.2 The Black Catechu / Pale Catechu Distinction

Pharmacognosy recognizes two principal types of catechu, which are botanically and chemically distinct and must not be confused with each other.

Black catechu (cutch): Cutch or black catechu is an extract prepared from the heartwood of Acacia catechu (Leguminosae) and occurs in black, somewhat porous masses. It contains 2–12% catechins, 25–33% phlobatannin, 20–30% gummy matter, quercitrin, quercitin, and moisture; it yields 2–3% of ash.

Pale catechu (gambir): Gambir, or pale catechu of the British Pharmacopoeia, is a dried aqueous extract prepared from the leaves and young twigs of the climbing shrub Uncaria gambir (Rubiaceae), and must be carefully distinguished from black catechu or cutch. The plant is native to Malaya and is largely cultivated for the production of the drug in Indonesia and Malaya for marketing through Singapore. Pale catechu contains from about 7 to 30% of the pseudotannin catechin and 22 to 55% of the phlobatannin catechutannic acid; both components together constitute over 60% of the drug. It also contains catechu red, gambier fluorescin, quercetin, and an indole alkaloid (up to 0.05%) known as gambirtannin.

A third source: A third product to which the name catechu is also applied is obtained from the fruits of the areca or betel palm, Areca catechu. However, this areca-derived product is entirely distinct and has different chemical and safety characteristics from the acacia-derived extracts discussed in this article.

Historically, the catechu described by Barbosa in 1514 was black catechu or cutch, and the first account of gambir appears to be that of a Dutch trader in 1780.

1.3 Botanical Description of the Source Plant

Senegalia catechu, previously known as Acacia catechu, is a deciduous, thorny tree which grows up to 15 m (50 ft) in height. The tree thrives in well-drained, sandy or rocky soils at elevations from sea level to 1,500 metres and is valued for its nitrogen-fixing properties through symbiosis with soil bacteria. The leaves are bipinnate, glabrous, with small rounded leaflets that fold at night; the flowers are white to pale yellow, fragrant, and arranged in globose heads; the seed pods are flat, brown, and dehiscent, carrying 3–6 seeds each.

1.4 Preparation and Common Forms

Catechu is extracted by boiling the wood in water and evaporating the resulting brew. Ordinary black catechu is usually imported in three forms: the first and best quality, known as Pegu catechu, is obtained in blocks externally covered with large leaves; the second and less pure variety is in masses moulded in sand; and the third consists of large cubes packed in coarse bags.

Modern commercial preparations include standardized heartwood extracts in capsule and tablet form, often in combination with other botanical ingredients. Catechu is used variously as a food additive, astringent, tannin, and dye. As an astringent, it has been used since ancient times in Ayurvedic medicine as well as in breath-freshening spice mixtures — for example, in France and Italy it is used in some liquorice pastilles. Catechu black extract has been approved by the US FDA for food use as a natural flavouring substance and/or natural substance used in conjunction with flavours.

2. Traditional and Historical Use

2.1 Ayurvedic Tradition

The use of Acacia catechu dates back to at least the 7th century CE, as mentioned in classical Ayurvedic texts such as the Ashtanga Hridaya and Charaka Samhita, where it is listed under the category of kashaya dravyas — astringent substances employed to bind and tone bodily tissues.

In the Caraka Saṃhitā, Khadira is listed under the Sthāvara Varga of astringent herbs to pacify pitta dosha and reduce haemorrhages. Traditional Ayurvedic practitioners prized Khadira's ability to staunch bleeding, tone mucous membranes, and treat ulcers. It was commonly used in a formulation called Khadirarishta, as well as in guggulu-based pastes for joint inflammation.

Its heartwood extract was used in Ayurveda for asthma, cough, bronchitis, colic, diarrhoea, dysentery, boils, skin afflictions, sores, and for stomatitis. In Ayurveda, Khadira is considered a "rasayana" herb, meaning it is believed to promote longevity and rejuvenation.

2.2 Regional and Folk Traditions

Khadira has been used for centuries in traditional medicine systems such as Ayurveda and traditional Chinese medicine, with a long history of use in treating various ailments, including gastrointestinal disorders, skin diseases, respiratory infections, and oral health problems.

Tribal healers in central India used khair bark decoction for wound healing and to staunch bleeding. The decoction of heartwood has been used for drinking purposes in the southern part of India, especially in Kerala. Over centuries, its status evolved from a local folk remedy to a mainstream Ayurvedic ingredient, appearing in popular preparations like Dasmoola Kashayam and Khadirarishta.

2.3 Trade and Global Spread

By the 19th century, British colonial botanists documented it for export as "catechu" tannin, primarily for leather tanning, though many Ayurvedic households always regarded its medicinal value as paramount.

Catechu is also an important ingredient in South Asian paan mixtures, such as ready-made paan masala and gutka. Kattha (catechu), an extract of its heartwood, gives a characteristic flavour and red colour to paan, a traditional Indian and Southeast Asian method for chewing betel leaf (Piper betle) with areca nut and slaked lime paste.

2.4 Traditional Preparations and Dosage Forms

Traditionally, catechu was and continues to be used in multiple forms depending on the indication. It is typically used as a powder, paste, or decoction depending on the condition being treated; for digestion it is often taken as a powder, while for external use or oral care, a paste may be applied.

3. Key Constituents and Active Compounds

3.1 Primary Polyphenols

The extract is rich in tannins (25–33%), catechins (such as catechin and epicatechin), flavonoids (including quercetin), and other polyphenols that contribute to its therapeutic and industrial applications.

On chemical analysis, different parts of A. catechu contain very high amounts of flavonoids, tannins, and phenolic compounds, especially catechin/epicatechin, epigallocatechin, taxifolin, procyanidin, quercetin, and related compounds. Catechin itself is a 3,3′,4′,5,7-pentahydroxyflavan with two steric forms of (+)-catechin and its enantiomer.

Using UHPLC analysis, A. catechu extract was found to contain ellagic acid, rutin, quercetin, gallic acid, catechin, chlorogenic acid, umbelliferone, kaempferol, epicatechin, coumaric acid, and caffeic acid.

A more detailed phytochemical analysis identified twelve compounds, including 4-hydroxybenzoic acid, kaempferol, quercetin, catechin, epicatechin, afzelechin, epiafzelechin, mesquitol, ophioglonin, aromadendrin, and phenol.

3.2 Tannins

Active compounds such as catechin and epicatechin perform significant functions as anti-inflammatory and antioxidant agents; likewise, tannins are responsible for astringent action in the human body and have been considered as having good potential for curing wounds. The catechin (acacatechin) found in black catechu is not identical to that in gambir.

3.3 Minor Constituents

Phenolic compounds including 5-hydroxy-2-[2-(4-hydroxyphenyl)acetyl]-3-methoxylbenzoic acid, (2S,3S)-3,7,8,3′,4′-pentahydroxyflavane, rhamnetin, 4-hydroxyphenyl ethanol, 3,3′,5,5′,7-pentahydroxyflavane, and fisetinidol have been isolated from aqueous extract of A. catechu. Additionally, camphor, phytol, hexadecane, and vitamin E acetate have been identified from leaf extract of the plant.

4. Established Mechanisms of Action

4.1 Anti-Inflammatory Mechanisms

The anti-inflammatory activity of catechu is the most extensively studied and mechanistically characterised property of the extract. Catechin modulates the inflammatory response by inhibiting the activity of cyclooxygenase-2 (COX-2) and lipoxygenase (5-LOX), lowering the activity level of platelet phospholipase A2, and significantly reducing platelet cyclooxygenase levels possibly by suppression of nuclear factor Kappa B (NF-κB), inhibiting the production of inflammatory cytokines tumour necrosis factor-alpha (TNF-α), interleukin-1, interleukin-2, interleukin-6, interleukin-8, and interleukin-12, and migration inhibitory protein through a number of mechanisms.

A standardised bioflavonoid composition containing catechin from A. catechu (known as UP446 in combination with baicalin) reduces production of eicosanoids through inhibition of cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzymes, and also decreases expressions of inducible nitric oxide synthase (iNOS), nuclear factor-kappaB (NF-κB), and tumour necrosis factor-alpha (TNF-α).

4.2 Antioxidant Mechanisms

Extracts of A. catechu heartwood have been shown to enhance various antioxidant enzymes, increase cellular content of reduced glutathione — one of the primary endogenous antioxidants — and inhibit lipid peroxidation and DNA damage. Furthermore, these effects may be mediated by a normalising effect on the pro-inflammatory genes responsible for the production of inflammatory cytokines, and the downregulation of NF-κB, the central controlling factor for these genes.

4.3 Immunomodulatory Mechanisms

Catechin can block the activity of NF-κB, a major transcription factor that regulates genes involved in inflammation; in animal studies, extract treatment increased IL-10 levels, and the extracts stimulated splenocyte proliferation both in the presence and absence of mitogens.

4.4 Antidiabetic Mechanisms

An ethyl acetate extract of black catechu at doses of 250 and 500 mg/kg was shown to significantly reduce glucose absorption when given orally to rats; the presence of tannins and flavonoids was believed to be responsible for this action, representing a mechanism whereby A. catechu extract can control blood sugar levels.

5. Scientific Evidence by Health Area

5.1 Musculoskeletal Health — Osteoarthritis

The area with the greatest volume of human clinical evidence for catechu is joint health, particularly osteoarthritis of the knee. However, it is critical to note that virtually all human trials to date have used catechu in combination with other botanical ingredients rather than as a standalone agent.

UP446 (Flavocoxid) — Scutellaria baicalensis and Acacia catechu: One group of investigators (Arjmandi et al., 2014) conducted a 1-week randomised, double-blind clinical trial in 79 moderately osteoarthritic subjects (ages 40–90 years) to examine the efficacy of UP446, a proprietary blend of A. catechu and S. baicalensis extracts (500 mg/day), to ameliorate knee joint pain and mobility as well as selected biomarkers of inflammation in comparison to naproxen (440 mg/day). The combination product exhibited significant efficacy in perceived pain, stiffness, and knee range of motion, indicating that this combination product is efficacious in ameliorating the symptoms of knee osteoarthritis.

UP1306 (AmLexin) — Acacia catechu and Morus alba: In a randomised, double-blinded, placebo-controlled parallel-design trial, 135 subjects received UP1306, a standardised proprietary extract of Morus alba and Acacia catechu, glucosamine chondroitin, or placebo for 12 weeks; discomfort, stiffness, and activities of daily living measured by the WOMAC questionnaire and VAS (pain/discomfort) were improved within all groups, and range of motion and distance walked were improved. There was a significant difference in urinary C-telopeptides of type II collagen (CTX-II), a marker of cartilage degradation, between UP1306 and placebo after 12 weeks (p = 0.029). However, all efficacy measurements were improved from baseline for UP1306, the comparator, and placebo without a significant association between the products — meaning the advantage over placebo for many outcomes was modest.

Evidence strength: The human clinical evidence for catechu in osteoarthritis is preliminary and limited. Despite the fact that Acacia products have been used for many years and the general safety of catechins and epicatechins is well documented, few human studies have ever been conducted on the efficacy or safety of A. catechu heartwood extracts. Several studies involving a two-ingredient combination product exhibited no adverse effects when administered daily for up to 12 weeks while exhibiting significant anti-inflammatory activity in subjects with osteoarthritis of the knee; however, there is a need for additional human clinical studies with regard to efficacy and safety.

5.2 Musculoskeletal Health — Delayed Onset Muscle Soreness (DOMS)

In a randomised, double-blind, placebo-controlled trial, subjects were supplemented with 400 mg of AmLexin (a standardised blend of Acacia catechu heartwood and Morus alba root bark) per day or a look-alike placebo during an 8-week training program and for one week following a 13.1-mile half-marathon; 26 subjects completed the 9-week supplementation trial.

Results showed the AmLexin group experienced significantly lower levels of post-exercise pain on days 1–3 following the half-marathon compared to the placebo group; the AmLexin group also showed lower post-exercise oxidative stress and higher antioxidant capacity on days 1 and 6 following the half-marathon.

Evidence strength: Preliminary. The trial was small (26 completers), conducted in a single centre, and used a combination product rather than A. catechu alone. Results are directionally promising but not sufficient to establish a definitive effect.

5.3 Antidiabetic and Glycaemic Effects

Rahmatullah et al. (2013) evaluated the dose-dependent antidiabetic and antinociceptive efficacy of an aqueous extract of the heartwood of A. catechu in mice at doses up to 400 mg/kg body weight. A reduction of 37% in serum glucose levels was observed in an oral glucose tolerance test at a dose of 200 mg/kg body weight of the extract, with a similar result at 400 mg/kg. In a parallel experiment, the antihyperglycemic drug glibenclamide (10 mg/kg body weight) lowered serum glucose level by 48.6%.

Evidence strength: Evidence for antidiabetic effects is limited to animal models and in-vitro enzyme inhibition studies. Antihyperglycaemic, antidiarrhoeal, antinociceptive, and antipyretic activities have been demonstrated in animal studies, but no published human clinical trials specifically addressing glycaemic outcomes were identified in available literature.

5.4 Antimicrobial Activity

Various parts of A. catechu extract show antimicrobial properties against a number of pathogens including Salmonella typhi, Pseudomonas aeruginosa, Candida albicans, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, and Shigella spp.

Evidence strength: Antimicrobial evidence is entirely in-vitro. No controlled human clinical trials evaluating catechu for antimicrobial indications were identified.

5.5 Antioxidant Activity

Potent antioxidant activity has been well established in both in-vitro and in-vivo studies. This antioxidant activity is believed to be responsible for the anti-inflammatory, tissue protectant, antineoplastic, and analgesic activities that have been demonstrated and established in animal and cell culture systems.

Evidence strength: Antioxidant properties are well documented in laboratory models, but robust human clinical trials are lacking.

5.6 Chemoprotective and Antiproliferative Activity

Various extracts of A. catechu have a chemo-protective role in chemically induced hepatocytic damage, breast cancer, and squamous cell cancers in preclinical models. Most studies involving A. catechu heartwood extract have been conducted in rats, mice, and cell culture systems. Monga et al. (2011, 2012, 2013) conducted a series of studies demonstrating the chemoprotective and cancer-preventive activities of A. catechu extracts.

Evidence strength: Purely preclinical (animal and cell-based). No human clinical evidence for anticancer effects exists in the available literature.

5.7 Immunomodulation

In a study evaluating immunomodulatory effects of heartwood extracts of A. catechu in Swiss albino mice, in-vivo immunomodulatory activity was analysed by haemagglutinating antibody (HA) titer, plaque forming cell assay, and delayed-type hypersensitivity (DTH), while in-vitro immunomodulatory potential was studied using peritoneal macrophages and splenocytes. A. catechu inhibited the production of TNF-α in these models. Evidence remains confined to animal models.

5.8 Hepatoprotective Effects

Supplementation with catechin in rat models ameliorated alcohol-induced liver injury by downregulating the endotoxin-mediated activation of the initial signalling molecule NF-κB and further downstream signalling cascade including TNF-α, nitric oxide, and reactive oxygen species, while enhancing the antioxidant profile. However, catechin did not significantly improve alcoholic liver diseases in limited human clinical trials done in the 1980s, and extensive evaluation of catechin effects at higher doses in long-term trials has not been carried out.

6. Body Systems and Health Areas Associated with Catechu

Musculoskeletal system: Joints, cartilage protection, reduction of inflammation in osteoarthritis; exercise-induced muscle soreness.
Digestive system: A. catechu has demonstrated antidiarrheal, antiulcer, and antihyperlipidaemic activities in pharmacological studies.
Oral cavity: As an astringent it has been used since ancient times in Ayurvedic medicine in breath-freshening spice mixtures. Traditionally used for gum disease, toothache, mouth ulcers, and bad breath.
Skin: Traditionally applied for wound healing, skin disorders, and external sores, attributable to its tannin-rich astringent composition.
Respiratory system: The heartwood extract has been used in Ayurveda for asthma, cough, and bronchitis.
Metabolic health: Preclinical evidence for antidiabetic and antihyperlipidaemic effects linked to its flavonoid and tannin content.
Immune system: Immunomodulatory effects demonstrated in animal models, including stimulation of immune cell proliferation and modulation of cytokine profiles.

7. Dosage Forms and Dosages Reported in Studies

The following dosages are reported precisely as stated in the referenced scientific studies and should not be interpreted as therapeutic recommendations.

UP446 (combination of S. baicalensis and A. catechu) for osteoarthritis: 500 mg/day in a 1-week double-blind randomised controlled trial in 79 subjects with mild to moderate osteoarthritis.
UP1306 (AmLexin; A. catechu and Morus alba) for osteoarthritis: 135 subjects received UP1306, a standardised proprietary extract, for 12 weeks — the exact per-capsule dosage was not separately specified from the combined formulation in the available abstract.
AmLexin for DOMS: 400 mg of AmLexin/day during an 8-week training program and for one week following a half-marathon.
Flavocoxid (Limbrel) — the recalled combination product: Available in two dosages (250 mg and 500 mg), both containing a blend of baicalin (from Scutellaria baicalensis) and catechin (from Acacia catechu).
Preclinical (animal) antidiabetic dose: Doses up to 400 mg/kg body weight were evaluated in mice; a reduction of 37% in serum glucose levels was observed at 200 mg/kg in an oral glucose tolerance test. These are animal-model dosages and do not translate directly to human use.

The standardised extract of A. catechu used in AmLexin contains not less than 65% catechins from the heartwood, mixed at a 1:2 weight ratio with Morus alba root bark extract.

8. Safety Considerations and Notable Interactions

8.1 General Safety Profile

No adverse effects have been observed in animal or human studies or in cell culture systems for A. catechu heartwood extracts evaluated in research to date. Catechu black extract has been approved by the US FDA for food use as a natural flavouring substance. A two-ingredient combination product containing A. catechu extract exhibited no adverse effects when administered daily for up to 12 weeks.

8.2 Flavocoxid (Limbrel) — Liver Injury and FDA Recall

The most clinically significant safety signal associated with catechu-containing products arises from the prescription medical food flavocoxid (marketed as Limbrel), which contained catechin from Acacia catechu combined with baicalin from Scutellaria baicalensis.

Limbrel (flavocoxid) has been linked to a total of 194 adverse events, including two "serious and potentially life-threatening" medical conditions — drug-induced liver injury and hypersensitivity pneumonitis. The US FDA requested a Limbrel recall in December 2017 after the product had been linked to cases of drug-induced liver injury and a lung condition called hypersensitivity pneumonitis.

A published case series from the Drug-Induced Liver Injury Network (DILIN) described the clinical findings: among 877 patients enrolled in the DILIN Prospective Study, 4 were attributed to flavocoxid; all 4 were women with a mean age of 61 years; the time to onset averaged 11.2 weeks (range 5–16) after initiating therapy; liver injury was characterised by marked elevations in alanine aminotransferase (mean peak ALT 1268 U/L, range 741 to 1540 U/L), with moderate elevations in other liver markers.

The mixture includes extracts from Scutellaria baicalensis (containing baicalin) and Acacia catechu (containing catechin), both of which have been implicated in causing rare instances of idiosyncratic acute liver injury, but the mechanism is unknown. No instances of acute liver failure or chronic liver injury have been linked to flavocoxid use, and all cases have been self-limited, without subsequent chronic hepatitis or vanishing bile duct syndrome. Recurrence upon re-exposure has been reported and rechallenge should be avoided.

Concerns exist that this combination product might cause liver problems in some people; this side effect does not appear to be common and might only occur in people who have a type of allergic reaction to it. It should be noted that it has not been definitively established whether the hepatotoxic signal is attributable to the catechu component, the baicalin component, or the combination.

8.3 Drug Interactions

Catechu might decrease how quickly the liver breaks down theophylline; taking catechu with theophylline might increase the side effects from theophylline.

Catechu might lower blood pressure; taking catechu along with medications that lower blood pressure might cause blood pressure to go too low.

At the level of whole-plant preparations (betel nut chewing), a distinct interaction has been documented: extrapyramidal effects precipitated by betel nuts (Areca catechu) in patients taking neuroleptic drugs represent a clinically significant herb-drug interaction, though this concerns the areca palm rather than Senegalia catechu.

8.4 Gaps and Limitations of Safety Evidence

Although the plant's metabolites are reported to have many different pharmacological uses, there is limited information about their toxicity or clinical trials; further research on diverse metabolites of A. catechu should be carried out to ensure safety. Although the metabolites from the plant are reported with diverse pharmacological applications, there is little information in regards to toxicity and clinical trials on bioactive compounds of this plant.

References

Health Conditions

Health conditions that Catechu may help support.

No conditions available.

Body Systems

Body systems that Catechu may help support.

No body systems available.