Blackbrush

Blackbrush: A Comprehensive Reference Article

Nomenclature and the "Blackbrush" Name Disambiguation

The common name blackbrush is shared by two botanically unrelated shrubs that appear in the dietary supplement and ethnobotanical literature, and careful distinction between them is essential. The first is Coleogyne ramosissima Torr. (family Rosaceae), a monotypic desert shrub of the American Southwest. The second is Vachellia rigidula (Benth.) Seigler & Ebinger — also known under its older and still widely used synonym Acacia rigidula Benth. (family Fabaceae) — a shrub native to south Texas and northern Mexico commonly called blackbrush acacia, blackbush, or chaparro prieto. In the modern dietary supplement trade, it is almost exclusively Acacia rigidula / Vachellia rigidula that is marketed under the abbreviated label "blackbrush." This article addresses both taxa, presenting their distinct botanical identities, phytochemistries, traditional uses, and documented safety profiles in separate sections before comparing their regulatory and scientific status.

Part I — Coleogyne ramosissima (Blackbrush, Rosaceae)

Identity and Botanical Description

Coleogyne ramosissima, known as blackbrush, is a low-lying, dark grayish-green, aromatic, spiny, perennial, soft-wooded shrub native to the deserts of the southwestern United States. It is called blackbrush because the gray branches darken when wet by rains. It belongs to the rose family (Rosaceae) and is monotypic — the only species in its genus. The genus name Coleogyne is Greek for "sheathed fruit," while the species epithet ramosissima is Latin for "many branched."

Blackbrush is a native aromatic shrub with soft wood, growing from 1 to 6 feet (0.3–2 m) tall, with compact, erect growth and a symmetrically round form. The terminal branches grow for a few years and then die, drying back several centimeters from the tip and resulting in the characteristically tangled spinescence of blackbrush. The leaves are aromatic, opposite, small (3 to 12 millimeters long), and hairy with a small point on the tip. Flowers lack petals, but the thick sepals remain when the flowers open; the sepals are yellow on the inside and reddish on the outside. Flowers are bisexual, cup-like, and have 20 to 40 stamens.

Blackbrush occurs primarily in the transition zone between the Mojave and Great Basin deserts and on the western border of the Sonoran Desert, forming a band from southeastern California to southwestern Colorado. It is found on mesas, open plains, and foothills at an elevation between 2,500 to 7,000 feet, and is most abundant in sandy, gravelly, and rocky soils. Blackbrush is drought-deciduous, avoiding water stress during the dry season by becoming temporarily dormant and shedding old leaves.

Traditional and Historical Use

Documented ethnobotanical use of Coleogyne ramosissima among Indigenous peoples of the Great Basin and Mojave region is limited in the peer-reviewed literature. The plant's primary historical roles were ecological — as a dominant scrub-community shrub — rather than as a major medicinal plant. Some accounts reference its use by Indigenous communities of the region.

Traditionally, blackbrush has played a role in the medicinal practices of Indigenous peoples, particularly the Paiute and Shoshone tribes, who recognized it for its therapeutic properties, utilizing it in remedies aimed at promoting overall wellness and treating various ailments. Historically, blackbrush stems and leaves were brewed into teas or decoctions to address digestive concerns, soothe sore throats, and ease symptoms of colds and respiratory discomforts.

Note on evidence quality: The ethnobotanical claims attributed specifically to Coleogyne ramosissima in the supplement literature are not robustly sourced in peer-reviewed ethnobotanical monographs. The USDA Fire Effects Information System profile for the species, which is among the most comprehensive scientific reviews, focuses on ecological data and does not substantiate detailed medicinal uses. Claims of widespread traditional medicinal use for this species should be treated with caution absent primary ethnobotanical documentation.

Key Constituents and Phytochemistry of Coleogyne ramosissima

Coleogyne ramosissima produces stenophyllanin A, an ellagitannin. This is one of the most biochemically significant documented compounds from this plant. Beyond stenophyllanin A, scientific investigation has identified a broader polyphenol profile.

Chemical investigation of polyphenol-rich fractions of Coleogyne ramosissima (Rosaceae) led to the characterization of 17 polyphenols, including flavonoid glycosides. Among the constituents from C. ramosissima, two flavonoid glycosides — isorhamnetin 3-O-β-D-glucoside and narcissin — were revealed to possess strong inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation. These compounds are structurally related to isorhamnetin, a well-characterized flavonoid with known antioxidant properties.

Scientific Evidence: Anti-Tumor Promotion Activity

The most substantive laboratory research on Coleogyne ramosissima comes from a single peer-reviewed study published in Cancer Letters (1999) by Ito and colleagues.

The study investigated polyphenol-rich fractions of Coleogyne ramosissima that showed significant inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), and evaluated the effects of individual components on TPA-induced EBV-EA activation. EBV-EA induction by TPA is a standard in vitro short-term screening assay for tumor-promoting activity.

Evidence strength: This research is entirely preclinical and in vitro. No human or animal intervention studies have been conducted on Coleogyne ramosissima extracts or its isolated polyphenols for any health condition. The finding that isorhamnetin 3-O-β-D-glucoside and narcissin inhibit EBV-EA activation in cell culture is preliminary and cannot be extrapolated to clinical efficacy.

Body Systems Associated with Coleogyne ramosissima

• Gastrointestinal system: Traditional use as a digestive remedy (tea/decoction), not scientifically validated.
• Respiratory system: Traditional use for coughs, sore throats, and cold symptoms, not scientifically validated.
• Integumentary system: Traditional topical application for wounds and skin irritations, not scientifically validated.
• Antioxidant/anti-tumor promotion: Preliminary in vitro evidence only (EBV-EA inhibition assay).

Dosage Forms of Coleogyne ramosissima

No standardized dosage forms, dose ranges, or clinical dosing recommendations appear in the peer-reviewed literature for Coleogyne ramosissima. Traditional preparations reportedly involved brewing leaves and stems as a tea or decoction, but no quantitative parameters have been documented in verified sources. Most available research on blackbrush is preclinical, involving in vitro or animal models rather than human clinical trials, and comprehensive human studies are lacking. The NIH Dietary Supplement Label Database (DSLD) lists "blackbrush" as an ingredient in some products, but no specific dosage data is provided by that resource for this species.

Safety Considerations for Coleogyne ramosissima

No formal toxicological studies or safety evaluations of Coleogyne ramosissima as a dietary supplement appear in the peer-reviewed literature. The plant has a long history of use as rangeland forage for wildlife and some livestock, suggesting acute toxicity is not a major concern at ordinary exposure levels. While blackbrush shows potential as a source of natural antioxidants, more rigorous clinical research is needed to confirm its efficacy and safety in humans. No drug interaction data exists for this species.

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Part II — Vachellia rigidula / Acacia rigidula (Blackbrush Acacia, Fabaceae)

Identity, Nomenclature, and Botanical Description

Vachellia rigidula, commonly known as blackbrush acacia or chaparro prieto, and also known under the synonym Acacia rigidula, is a species of shrub or small tree in the legume family, Fabaceae. Its native range stretches from Texas in the United States south to central Mexico. This perennial is not listed as being threatened. It reaches a height of 5–15 feet (1.5–4.6 m) and grows on limestone hillsides and canyons.

Acacia rigidula is also known by the names: Vachellia rigidula, Chaparro Prieto, and Blackbrush. Older field guides and most experts in Texas continue using Acacia, so the plant is likely to be found designated either as Acacia rigidula or Vachellia rigidula. The common name "blackbrush" is used interchangeably with "blackbush," "blackbrush acacia," "blackbush acacia," and "chaparro prieto."

Blackbrush (Acacia rigidula Benth.) is a shrub found growing on rocky ridges in west and southwest Texas and northern Mexico. Consumption of blackbrush and a related species, guajillo (Acacia berlandieri Benth.), has been associated with a locomotor ataxia known as limber leg. Its distribution spans regions of south and east Texas, to northern regions of Mexico including Nuevo León and further south to Tamaulipas and San Luis Potosí. It is common on rocky limestone hillsides at elevations between 350–550 m (1,100–1,800 ft).

Traditional and Historical Use

Native to the semi-arid regions of southern Texas and northern Mexico, Acacia rigidula has been traditionally utilized by indigenous communities for various medicinal purposes. In recent years, it has gained popularity as a dietary supplement due to its purported health benefits, particularly in weight management and energy enhancement.

Indigenous communities in southern Texas and northern Mexico have long utilized various parts of Acacia rigidula for medicinal purposes. Traditional uses include the treatment of conditions such as coughs, colds, gastrointestinal disorders, and skin ailments. Additionally, it has been employed as a natural energy booster and appetite suppressant.

Leaves ground into powder are used to stop bleeding, relieve chafed skin, or diluted in water and used as an antimicrobial wash.

Seeds and fruits of at least three acacia species, including Acacia rigidula, have been observed in collections from Fate Bell Shelter and from 5,000 to 6,000-year-old deposits in Hinds Cave. These species have little mention in the ethnographies, primarily because they did not grow in the areas where the studies were conducted. Although these archaeological finds demonstrate that the native peoples of the Lower Pecos Canyonlands made use of acacia for thousands of years, the exact uses have not been discerned.

Like many acacias, all parts of this species have a long history of medicinal use and are used by many people as medicine. This species is used in weight loss dietary supplements because of the presence of chemical compounds claimed to stimulate beta-receptors to increase lipolysis and metabolic rate and decrease appetite. This modern supplement use arose after laboratory analysis of the plant's alkaloid content was publicized beginning in the late 1990s.

Key Constituents and Active Compounds

The phytochemistry of Acacia rigidula has been subjected to systematic analysis and is the most scientifically documented aspect of this plant. A landmark study published in Phytochemistry (1998) by Clement, Goff, and Forbes at Texas A&M University is the primary chemical reference.

In an effort to identify the mechanism of limber leg toxicity, blackbrush was subjected to rigorous chemical analysis. In addition to four previously detected amines — N-methyl-β-phenethylamine, tyramine, N-methyltyramine, and hordenine — 40 other alkaloids and amines were isolated and identified by GC-MS. These alkaloids and amines included nicotine, N,N-dimethyltryptamine, mescaline, several tetrahydroisoquinoline alkaloids, and four amphetamines.

A phytochemical study of V. rigidula by workers at the Texas A&M University Agricultural Research and Extension Center at Uvalde, TX, reported the presence of over forty alkaloids, including low amounts (up to around 15 ppm) of several phenolic amines that had previously been found by the same research group in the related species Senegalia berlandieri, but which otherwise are known only as products of laboratory synthesis.

Compounds found in the highest concentrations (ranging from a few hundred to a few thousand ppm) were phenethylamine, tryptamine, tyramine, and β-methylphenethylamine (which can be misidentified as amphetamine). Tryptamine, N-methyltryptamine, and N,N-dimethyltryptamine were also isolated from blackbrush. Other noteworthy alkaloids found in blackbrush include nicotine, nornicotine, and four tetrahydroisoquinoline alkaloids — anhalamine, anhalidine, anhalonidine, and peyophorine.

The bioactive constituents of Acacia rigidula include alkaloids, phenethylamines, flavonoids, and terpenoids. Among these, phenylethylamine alkaloids such as β-methylphenylethylamine (BMPEA) and N-methylphenylethylamine (NMPEA) have received significant attention due to their potential pharmacological effects.

A significant increase in the number and relative quantities of these compounds was observed in late-season foliage. This seasonal variation is relevant to both grazing livestock toxicity and to the alkaloid concentrations in plant material harvested for supplements.

Controversy Over the Amphetamine Content of the Plant

The Clement et al. (1998) report of amphetamines in A. rigidula became the basis for its incorporation into stimulant supplements; however, the findings have been subjected to significant methodological scrutiny. The report of DMT, NMT, tryptamine, amphetamines, mescaline, nicotine and others is in serious question due to reference standards problems. Subsequent analyses by FDA scientists found that BMPEA specifically was not naturally present in the plant.

Many supplements listing Acacia rigidula have been found to contain an amphetamine-like chemical called beta-methylphenethylamine (BMPEA). It is not found naturally in Acacia rigidula or any other known plants. While phenethylamine is found in Acacia rigidula leaves naturally, the amounts found in supplements is often greater than would be expected from the plant parts alone.

Mechanisms of Action (Proposed)

This species is used in weight loss dietary supplements because of the presence of chemical compounds claimed to stimulate beta-receptors to increase lipolysis and metabolic rate and decrease appetite.

Studies have suggested that the phenylethylamine alkaloids present in Acacia rigidula may exert stimulant effects on the central nervous system, leading to increased energy expenditure and appetite suppression. Phenethylamine and its derivatives act as trace amine-associated receptor (TAAR) agonists and may promote monoamine release (dopamine, norepinephrine, serotonin), consistent with their structural similarities to amphetamine class compounds.

Research has also documented cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants found in dietary supplements containing Acacia rigidula (Drug Testing and Analysis, 2016, Vol. 8(3-4):307-10). This is a drug-interaction-relevant mechanism, as CYP2D6 and CYP3A4 are responsible for the metabolism of a large proportion of clinically used pharmaceuticals.

Ranchers have noted that livestock grazing on blackbrush leaves in the fall sometimes show erratic behavior such as "limber leg." Researchers at Texas A&M University analyzed blackbrush and found it to contain toxic substances such as amphetamines. The limber leg syndrome in livestock further supports the pharmacological activity of the plant's alkaloid content in mammals, though animal toxicity is distinct from intended therapeutic action in humans.

Scientific Evidence by Area of Use

Weight Loss and Metabolic Effects

Acacia rigidula is used for athletic performance, obesity, and many other conditions, but there is no good scientific evidence to support these uses. Extracts of Acacia rigidula leaves are used in weight-loss products sold in vitamin shops and over the internet with little or no published data about their potential biological effects.

No randomized controlled trials, cohort studies, or any other clinical study design have examined the effect of authenticated Acacia rigidula extract in human subjects for weight loss or any other health endpoint. The weight-loss claims in the marketplace are inferred from the known pharmacology of phenethylamine-class compounds generally, not from clinical data specific to this plant or its extracts.

Studies have suggested that phenylethylamine alkaloids may exert stimulant effects on the central nervous system leading to increased energy expenditure and appetite suppression, but further research — particularly clinical trials — is warranted to elucidate efficacy, safety profile, and optimal dosage regimens.

Evidence strength: No clinical evidence. Mechanistic rationale is plausible based on known pharmacology of structural analogs, but is unvalidated for this specific plant extract in humans.

Athletic Performance

People use Acacia rigidula for athletic performance and many other conditions, but there is no good scientific evidence to support these uses. The stimulant alkaloid profile has led to its marketing as an ergogenic agent, but no controlled trials have been conducted. The World Anti-Doping Agency (WADA) prohibited list has included relevant stimulant compounds.

Evidence strength: No clinical evidence. Use in athletes is further complicated by the risk of inadvertent exposure to BMPEA, a prohibited amphetamine isomer.

Antimicrobial Activity

Research from Cavazos, Lanorio, and Ynalvez (2020), published in The FASEB Journal, evaluated the antimicrobial activity and phytochemical composition of leaf extracts of Acacia rigidula and Acacia berlandieri. This represents one of the more recent in vitro investigations, but findings from conference abstracts and in vitro assays cannot be extrapolated to clinical applications.

Evidence strength: Preliminary in vitro only.

Body Systems Associated with Acacia rigidula

• Central nervous system: Stimulant alkaloids (phenethylamine, tyramine, N,N-dimethyltryptamine) act on monoamine systems; effects on energy, mood, and appetite proposed but not clinically validated.
• Cardiovascular system: Stimulant alkaloids and BMPEA (when present as an adulterant) may increase blood pressure and heart rate — a documented safety concern rather than a therapeutic target.
• Metabolic/adipose system: Beta-receptor stimulation claimed to increase lipolysis; not clinically validated for this plant.
• Integumentary system: Traditional use as a hemostatic and antimicrobial topical agent (powdered leaves).
• Gastrointestinal system: Traditional use for coughs, colds, and gastrointestinal disorders.

Dosage Forms and Reported Doses

Acacia rigidula is commonly consumed in the form of dietary supplements, including capsules, powders, and extracts. There is not enough reliable information to know what an appropriate dose of Acacia rigidula might be.

The only quantitative dosage data that appears in the scientific literature concerns not the intended plant dose but the amount of the adulterant BMPEA that consumers have been inadvertently exposed to: More than half (11 out of 21; 52.4%) of Acacia rigidula supplement brands contained BMPEA. The stimulant was present at quantities such that consumers following recommended maximum daily servings would consume a maximum of 93.7 mg of BMPEA per day. Consumers of Acacia rigidula supplements may be exposed to pharmacological dosages of an amphetamine isomer that lacks evidence of safety in humans.

Naturally occurring levels of β-phenethylamine (β-PEA) in authenticated plant material have been reported: Pawar et al. reported levels of β-PEA in A. rigidula in the range of <0.03–1.5 mg/g, and Clement et al. detected levels of 0.9–1.1 mg/g. In dietary supplements, the levels of β-PEA detected ranged from 1.4–122.0 mg/g (units consistent with source). The dramatic discrepancy between plant and supplement concentrations is evidence of adulteration or synthetic addition.

Safety Considerations, Adverse Events, and Drug Interactions

Cardiovascular Adverse Events

When taken by mouth, Acacia rigidula is possibly unsafe. There have been several reports of increased heart rate and heart palpitations in people taking products containing Acacia rigidula. There is one reported case of cardiac arrest. It is unclear if these side effects were caused by Acacia rigidula or other stimulants in these products.

BMPEA was first made in the 1930s as a possible replacement for amphetamine, but it never became a drug because no studies were performed on its safety in humans. More recent studies have shown that BMPEA can raise blood pressure and increase the risk of a cardiovascular event.

The efficacy and safety of BMPEA have not been studied in people. In general, stimulants can increase blood pressure, heart rate, and body temperature, and decrease sleep and appetite. At high doses, they can lead to serious cardiovascular complications, including stroke. Addiction to stimulants is also a concern for anyone taking them without medical supervision.

Cardiovascular Risk Populations

Some chemicals in Acacia rigidula have stimulant effects. Many products that list Acacia rigidula as an ingredient have been found to contain BMPEA. BMPEA and other stimulants can increase blood pressure and heart rate. Taking Acacia rigidula supplements might make high blood pressure worse.

Perioperative Concerns

Some chemicals in Acacia rigidula have stimulant effects. BMPEA and other stimulants can increase blood pressure and heart rate. Taking Acacia rigidula supplements might interfere with surgery by increasing blood pressure and heart rate. It is recommended to stop taking Acacia rigidula supplements at least 2 weeks before surgery.

Drug–Drug Interactions: CYP Enzyme Inhibition

A study by Liu and Santillo examined cytochrome P450 2D6 and 3A4 enzyme inhibition by amine stimulants found in dietary supplements, published in Drug Testing and Analysis (2016, Vol. 8(3-4):307–10). CYP2D6 is responsible for metabolizing a wide range of pharmaceuticals including many antidepressants, antipsychotics, opioids, and cardiovascular drugs; CYP3A4 metabolizes the largest fraction of currently used drugs. Inhibition of these enzymes by amine stimulants could theoretically elevate plasma concentrations of co-administered medications, potentially to toxic levels, though the clinical significance specifically for Acacia rigidula constituents at supplement doses has not been quantified in human pharmacokinetic studies.

Livestock Toxicity

Consumption of blackbrush and a related species, guajillo (Acacia berlandieri), has been associated with a locomotor ataxia known as limber leg. Extended consumption of A. berlandieri has been reported to lead to ataxia of the hindquarters in grazing sheep and goats. Over-consumption of both A. rigidula and A. berlandieri has been related to poor reproductive performance in cattle. These animal toxicity data underscore the pharmacological activity of the alkaloid constituents and provide a basis for concern about chronic human exposure, though direct human toxicity data are not available.

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Regulatory Status

U.S. Food and Drug Administration (FDA)

Acacia rigidula is declared as a dietary ingredient on the labeling of some dietary supplements. Under existing law, a "new dietary ingredient" is a dietary ingredient that was not marketed in the United States before October 15, 1994. The FDA is not aware of any information demonstrating that A. rigidula was lawfully marketed as a dietary ingredient in the United States before this date.

Because neither of the required conditions has been met by those marketing products that contain A. rigidula as a dietary ingredient, these products are deemed to be adulterated. On March 15, 2016, the FDA issued warning letters to six companies regarding a total of six products for which the product labeling lists A. rigidula as a dietary ingredient. The FDA considers these products to be adulterated because they contain a new dietary ingredient, A. rigidula, and because they have not satisfied the required conditions regarding the use of A. rigidula as a new dietary ingredient.

The FDA has issued a warning stating that "BMPEA does not meet the statutory definition of a dietary ingredient." Therefore, dietary supplement products with BMPEA are misbranded and cannot be sold as dietary supplements. However, BMPEA continues to be found as an ingredient in dietary supplement products, including ones with "Acacia rigidula" on their labels.

A 2013 study carried out by FDA scientists found BMPEA in 9 of 21 tested supplements listing Acacia rigidula on their labels. That study also found that real Acacia rigidula leaves, twigs, and bark do not contain any trace of BMPEA.

BMPEA was synthesized in the 1930s as a potential replacement for amphetamine; however, for unknown reasons, studies of efficacy and safety in humans were never performed, and BMPEA was never introduced as a pharmaceutical drug. BMPEA remained known only as a research chemical until early 2013, when the FDA identified BMPEA in multiple supplements labelled as containing "Acacia rigidula," even though the stimulant has never been identified or extracted from the plant.

U.S. Department of Defense

Products that contain Acacia rigidula are considered "adulterated" and cannot be marketed legally. In 2016, FDA sent warning letters to 6 companies marketing supplements that listed Acacia rigidula on the label. As a result, Acacia rigidula is on the DoD Prohibited Dietary Supplement Ingredients list.

Research Integrity Concerns

A 2014 study by FDA scientists (published in the Journal of Pharmaceutical and Biomedical Analysis, Vol. 88, pp. 457–466) concluded: "Given the low natural abundance of PEA in the plant materials, it appears nearly impossible to achieve the amounts of [BM]PEA found in the dietary supplements by formulating them with plant material or extracts of A. rigidula." BMPEA, a positional isomer of amphetamine, was found in 9 of 21 dietary supplements analyzed at levels ranging from 963 to 60,500 micrograms per gram. The FDA study found no safety data on the biological effects of this isomer in humans.

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Comparative Summary

The two plants sharing the common name "blackbrush" present entirely different risk-benefit profiles. Coleogyne ramosissima (Rosaceae) is a legitimate botanical entity with a modest but real phytochemical profile (ellagitannins, flavonoid glycosides) and a limited body of preliminary in vitro evidence suggesting antioxidant and potential anti-tumor-promoting properties; it carries no established clinical evidence and no documented serious safety concerns. By contrast, Vachellia rigidula (Acacia rigidula, Fabaceae) — the plant most commonly sold in dietary supplements as "blackbrush" — has a complex and contested alkaloid profile, no clinical evidence of benefit, documented cardiovascular adverse events in supplement users, a regulatory finding of adulteration with a synthetic amphetamine isomer (BMPEA), and a classification as a prohibited ingredient for members of the U.S. military. Research cited in the literature highlights that blackbrush contains unique flavonoids which may contribute to health-promoting effects; however, most available research is preclinical, involving in vitro or animal models rather than human clinical trials. Consumers and clinicians should be aware of the systematic naming ambiguity and that supplement labels reading "blackbrush" in the context of weight loss, energy, or athletic performance products almost invariably refer to Acacia rigidula, a legally adulterated ingredient under current FDA rulings.

References

• Wikipedia — Coleogyne (Coleogyne ramosissima)
• Wikipedia — Vachellia rigidula (Blackbrush Acacia)
• USDA Forest Service Fire Effects Information System — Coleogyne ramosissima
• USA National Phenology Network — Coleogyne ramosissima
• FloraFinder — Coleogyne ramosissima (Blackbrush)
• U.S. FDA — Acacia rigidula in Dietary Supplements
• U.S. FDA — Recent FDA Action on Products Labeled as Containing Acacia rigidula (2016)
• U.S. Department of Defense / OPSS — Acacia rigidula: Is It Legal?
• U.S. Department of Defense / OPSS — BMPEA: A Prohibited Ingredient
• NIH/NCCIH — Recent Study Finds Amphetamine-Like Stimulant BMPEA in Supplements
• NIH Dietary Supplement Label Database (DSLD) — Blackbrush Ingredient Listing
• Cohen PA, Bloszies C, Yee C, Gerona R. "An amphetamine isomer whose efficacy and safety in humans has never been studied, β-methylphenylethylamine (BMPEA), is found in multiple dietary supplements." Drug Testing and Analysis 2016;8(3-4):328–333
• Clement BA, Goff CM, Forbes TDA. "Toxic amines and alkaloids from Acacia rigidula." Phytochemistry 1998;49(5):1377–1380
• Ito H et al. "Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissima." Cancer Letters 1999;143:5–13 (PubMed)
• Pawar RS, Grundel E, Fardin-Kia AR, Rader JI. "Determination of selected biogenic amines in Acacia rigidula plant materials and dietary supplements using LC-MS/MS methods." J Pharm Biomed Anal 2014;88:457–466
• WebMD Natural Medicines — Acacia rigidula (Blackbrush)
• NutraIngredients — FDA Warns Companies with Products Listing Acacia rigidula as a Dietary Ingredient (2016)
• University of Arizona Campus Arboretum — Acacia rigidula
• Texas Beyond History — Ethnobotany of Acacia (Lower Pecos Canyonlands)
• Encyclopedia of Life — Blackbrush Acacia (Vachellia rigidula) Articles
• Caring Sunshine — Ingredient: Blackbrush (Coleogyne ramosissima)
• ResearchGate — Anti-tumor promoting activity of polyphenols from Cowania mexicana and Coleogyne ramosissima