Guazuma ulmifolia

Guazuma ulmifolia Lam. (Mutamba / West Indian Elm)

1. Identity and Botanical Description

Accepted scientific name: Guazuma ulmifolia Lam. Family: Malvaceae (formerly placed in Sterculiaceae), commonly called Bastard Cedar. Other widely used vernacular names include mutamba, West Indian elm, and bay cedar; the species is native to tropical America. In Spanish-speaking Latin America it is also known as guácimo or cuaulote.

The tree grows to 30 m in height and 30–40 cm in diameter with a round-shaped crown. The alternate, ovate to lance-shaped leaves are 5–7 cm long and 2–5 cm wide, with finely saw-toothed margins. The flowers are brownish-yellow and form in clusters at the base of the leaves. The seeds are black, round to elliptic, 1.5–3 cm long, and hard. Seed capsules contain 5 cells which open at the apex and contain many seeds, 3–5 mm in diameter. Young twigs are covered with rust-brown or light-gray star-shaped hairs.

Distribution: The species is also found in the Caribbean, Mexico, Central America and Colombia, Ecuador, Peru, Bolivia, Paraguay, Argentina, and Brazil. It has been cultivated in India for over 100 years.

Plant parts used: Ethnobotanical uses of G. ulmifolia involving the leaves, bark, fruit, root, and stem bark are widely reported. The bark is the most intensively studied part in modern phytochemical and pharmacological research. Most of the research work carried out on this plant has focused on the bark because of its high concentration of antioxidant proanthocyanidins.

Common preparations and dosage forms: In the popular medicine of several Latin-American countries, the plant is used for the treatment of burns, diarrhea, inflammations, and alopecia. Preparations reported in the literature include aqueous infusions and decoctions of the bark, leaves, and fruit; hydroalcoholic and ethanolic bark extracts; and dried standardized bark extracts. The preparation as an antihypertensive agent is not described in detail in traditional sources; it is only mentioned that the entire plant infusion is orally ingested. In contrast, the doses recommended for respiratory and gastrointestinal affections are more fully detailed, at 2–3 g three times per day in infusion. A TRAMIL network preliminary clinical trial used a senescent leaf decoction at 12 g/L, administered at 240 mL every 8 hours.

2. Traditional and Historical Use

Guazuma ulmifolia has a well-documented record of traditional use spanning the Americas, and more recently Asia, across multiple ethnobotanical traditions. It is a favorite natural remedy among central and South American health practitioners and the indigenous peoples of the Amazon, often turned to first for upper respiratory infections, as it can quiet coughs, reduce fever, as well as provide antiviral and antibacterial action.

Mesoamerica and Central America

An ethnobotanical study on Guatemala's traditional medicine showed that the mutamba stem bark and fruit are used for diarrhea and gastrointestinal disorders. The leaf and stem bark are used in Honduras to treat physical discomforts, such as dental, digestive, and urinary tract aches. In Mexico, the tea from the leaves is used in diabetes mellitus control, and an aqueous extract from stem without bark is used for the treatment of stomachache and diarrhea.

South America

The aqueous infusion of mutamba fruit is used by Ecuadoreans to treat influenza. Guazuma ulmifolia has been used in Latin America for the treatment of a variety of diseases, particularly for gastrointestinal disorders; stomach aches; diabetes mellitus; malaria and syphilis; and as a uterine contraction stimulant.

Brazil

Guazuma ulmifolia Lam. is well known in India for more than 2000 years as one of the most versatile medicinal plants having a wide spectrum of biological activity, and its traditional application in Brazil is similarly extensive. Brazilian traditional medicine uses the bark primarily for diarrhea, gastrointestinal disorders, and alopecia.

Broader Ethnobotanical Summary

Ethnobotanical uses reported for the leaves, bark, fruit, root, and stem bark include antidysenteric, antibacterial, anti-inflammatory, antimicrobial, antifungal, astringent, depurative, diaphoretic, febrifuge, emollient, hepatoprotective, pectoral, stomachic, styptic, sudorific, refrigerant, and vulnerary properties. The flowers and leaves of Guazuma ulmifolia are also used as a remedy for different conditions, such as kidney and gastrointestinal diseases, fever, and diabetes.

3. Key Phytochemical Constituents

The medicinal properties are associated with the presence of alkaloids, tannins, saponins, flavonoids, terpenoids, glycosides, and steroids, as well as octacosanol, taraxeroloac, friedelin-3-áoac, β-sitosterol, friedelinol-3-acetate, kaempferol, epicatechin oligomers, and procyanidins, such as procyanidin B2, procyanidin B5, and procyanidin C1, in different parts of G. ulmifolia.

Condensed Tannins (Proanthocyanidins) — the Principal Active Class

Previous investigations of the chemical composition of G. ulmifolia have indicated the occurrence of flavan-3-ols, procyanidins, and the nitrile glucoside menisdaurin. The anti-diabetic properties, hypotensive and vasorelaxant activity, antiulcer, anti-bacterial activities, and antiviral activity of the bark, aerial parts, fruits, crude extract, and fractions were attributed to the presence of proanthocyanidins.

Detailed phytochemical analysis of the bark has isolated a rich array of flavan-3-ol monomers and oligomers. From the bark of Guazuma ulmifolia, nine compounds were isolated and identified: ent-catechin, epicatechin, ent-gallocatechin, epigallocatechin, epiafzelechin-(4β→8)-epicatechin, epicatechin-(4β→8)-catechin (procyanidin B1), epicatechin-(4β→8)-epicatechin (procyanidin B2), epicatechin-(4β→8)-epigallocatechin, and the new compound 4'-O-methyl-epiafzelechin.

Polysaccharides, epicatechin (EP), and procyanidin oligomers, such as procyanidins B2 and B5, three trimers (procyanidin C1; epicatechin-(4β→6)-epicatechin-(4β→8)-epicatechin; epicatechin-(4β→8)-epicatechin-(4β→6)-epicatechin), and one tetramer have been isolated and identified from its bark extract.

A 2024 PMC study confirmed that chemical analyses corroborate those obtained in the literature, which reported gallocatechin, epigallocatechin, and epigallocatechin gallate.

Flavonoids and Other Phenolics

Phytochemical analysis of the leaves revealed the presence of kaempferol, ethyl ferulate, ethyl coumarate, flavonol, luteolin, ferulic acid, luteolin rhamnoside, apigenin rutinoside, coumaric acid derivative, luteolin glucoside, and quercetin glucoside. The fruit has been shown to contain flavonoids as well: mutamba fruit is composed mainly of soluble flavonoids (1385.9 µg/g dry weight), namely proanthocyanidins, and aglycones and glycosylated flavonoids. Procyanidin trimer C1 (972.8 µg/g dry weight), followed by procyanidin dimer B2, rutin, epicatechin, and hyperoside, were the main soluble phenolics.

Terpenoids, Steroids, and Other Isolates

The plant contains alkaloids, tannins, saponins, flavonoids, terpenoids, cardiac glycosides, and steroids. Isolation of octacosanol, taraxeroloac, friedelin-3-áoac, β-sitosterol, and friedelinol-3-acetate in the leaves are reported. Heartwood contains kaempferol and fruit contains the sweet edible mucilage. Its essential oil contains the major compound eugenol (10.13%).

Notably, phytochemical investigation of the methanol extract of G. ulmifolia bark led to the isolation of (−)-epicatechin, the flavanocoumarin epiphyllocoumarin, and two proanthocyanidin derivatives related to epiphyllocoumarin — epiphyllocoumarin-[4β→8]-(−)-epicatechin and epiphyllocoumarin-[4β→8]-(−)-epicatechin-[4β→8]-(−)-epicatechin — never previously reported.

Leaf Phenolic Acids

Guazuma ulmifolia leaves contain secondary metabolites such as phenolic acids (chlorogenic acid and caffeic acid) and some flavonoids such as catechin, quercetin, and luteolin.

Chemical Markers for Quality Control

Selective HPLC has been used for determination of the stability of characteristic constituents (chemical markers), namely procyanidin B2 (PB2) and epicatechin (EP). The results showed that PB2 is an appropriate compound to be used as a chemical marker in the quality control of dried extracts of G. ulmifolia. The procyanidins are the pharmacologically active constituents of G. ulmifolia; however, they are unstable condensed tannins.

4. Established Mechanisms of Action

Antisecretory / Antidiarrheal Mechanism

The antisecretory activity of Guazuma ulmifolia bark was examined in rabbit distal colon mounted in an Ussing chamber. Chloride secretion was stimulated by cholera toxin and prostaglandin E2 (PGE2). Guazuma ulmifolia extract completely inhibited cholera toxin-induced secretion if the extract was added to the mucosal bath prior to the toxin. Adding the extract after administration of the toxin had no effect on secretion. The extract did not inhibit PGE2-induced chloride secretion. These results indicate an indirect antisecretory mechanism. SDS-PAGE analysis of cholera toxin treated with the extract confirmed this presumption; the extract specifically interacted with the A subunit of the toxin. Preliminary phytochemical examinations showed that the most active fraction contains procyanidins with a degree of polymerization higher than 8.

Antidiabetic Mechanisms

Research in cell models concluded that Guazuma ulmifolia exerts its anti-diabetic effects by stimulating glucose uptake in both insulin-sensitive and insulin-resistant adipocytes without inducing adipogenesis. A complementary mechanism involves enzyme inhibition: inhibition of α-glucosidase enzymes and prevention of oxidative stress in postprandial hyperglycemia are possible mechanisms by which antidiabetic properties are exerted, which would imply potential for reducing postprandial glucose. An in-vitro study demonstrated a highly potent α-glucosidase inhibitory effect: the lyophilized aqueous extract of Guazuma ulmifolia showed a significant inhibitory effect (IC₅₀: 13.49 ± 3.65 µg/mL) compared with the control drug acarbose (IC₅₀: 858.67 ± 29.73 µg/mL).

Antihypertensive and Vasorelaxant Mechanism

The in vivo and in vitro cardiovascular activity of a procyanidin fraction (PCF) obtained from the acetone extract of Guazuma ulmifolia bark was investigated. At 10 mg/kg, PCF doses orally administered to sugar-fed hypertensive rats decreased both the systolic arterial pressure and the heart rate; the same doses intravenously administered induced arterial hypotension, which was attenuated by NG-nitro-L-arginine methylester (L-NAME) pretreatment. The PCF reduced the contraction induced by norepinephrine in isolated aortic rings of normotensive (IC₅₀ = 35.3 ± 12.4 ng/mL) and sugar-fed hypertensive (IC₅₀ = 101.3 ± 57.2 ng/mL) rats. This relaxant activity was inhibited by either vascular endothelium removal or L-NAME pretreatment, while indomethacin or atropine had no effect. These findings strongly implicate a nitric oxide/endothelium-dependent pathway in the vasorelaxant effect. In vitro studies also indicate that the extract can inhibit angiotensin II.

Antioxidant Mechanism

A number of studies have confirmed the antioxidant, antibacterial, antiviral, antisecretory, and antihypertensive properties of Guazuma ulmifolia bark, mainly attributable to its content in polymeric proanthocyanidins, which consist of epicatechin units. Compared with the ethanolic extract, the aqueous extract showed greater antioxidant capacity.

Anti-inflammatory Mechanism

Preparations of G. ulmifolia have shown a gastroprotective effect against the injurious effect of NSAIDs mainly by anti-inflammatory and radical-scavenging mechanisms.

Hair-Growth Mechanism

The hair-growing activity of certain procyanidins is attributed to their ability to inhibit protein kinase C. Procyanidin B-2 and procyanidin C-1 are able to selectively inhibit protein kinase C.

5. Scientific Evidence by Health Area

5.1 Gastrointestinal Health (Diarrhea, Gastric Ulcer)

Preclinical / in vitro evidence: The most mechanistically rigorous work concerns the antidiarrheal property. The antisecretory activity of Guazuma ulmifolia bark was examined in rabbit distal colon mounted in an Ussing chamber. Chloride secretion was stimulated by cholera toxin and prostaglandin E2 (PGE2). The extract completely inhibited cholera toxin-induced secretion when added prior to the toxin. Adding the extract after administration of the toxin had no effect. The extract did not inhibit PGE2-induced chloride secretion. These results indicate an indirect antisecretory mechanism. SDS-PAGE analysis confirmed the extract specifically interacted with the A subunit of the toxin. This work was published in Planta Medica (1995) and represents reproducible ex-vivo organ-level evidence.

For gastroprotection, a study reported in Journal of Ethnopharmacology (2007) investigated the aerial parts: the aerial parts of Guazuma ulmifolia Lam. protect against NSAID-induced gastric lesions. The gastroprotective effect is mediated primarily by anti-inflammatory and radical-scavenging mechanisms of procyanidins. The evidence from gastrointestinal studies is largely preclinical (in vitro, ex vivo, and rodent models); there are no published randomized controlled trials in humans specifically for this indication.

The traditional uses of G. ulmifolia have been experimentally supported by in vitro and in vivo studies, in which its bioactivities were associated with its phytochemical composition, mainly proanthocyanidins dimer B and trimer C (condensed tannins).

Clinical evidence: The TRAMIL network conducted a small preliminary study: a preliminary double-blind trial used senescent leaf decoction (12 g/L) administered to 15 patients affected by the common cold (240 mL every 8 hours), controlled with two groups of ten patients who received Cymbopogon citratus leaf syrup or simple syrup (placebo). This study was extremely small, and its primary endpoint was respiratory rather than gastrointestinal. Overall, the human clinical evidence for gastrointestinal indications is sparse and preliminary.

5.2 Diabetes and Blood Glucose Regulation

In vitro / cell-culture evidence: In vitro results show that Guazuma ulmifolia exerts its anti-diabetic properties by stimulating glucose uptake in insulin-sensitive and insulin-resistant 3T3 adipocytes without inducing adipogenesis. The α-glucosidase inhibitory data cited above (IC₅₀: 13.49 µg/mL vs. acarbose IC₅₀: 858.67 µg/mL) further document potent enzyme inhibition in cell-free systems.

Animal model evidence: A 2024 study published in the International Journal of Molecular Sciences (PMC) evaluated bark extracts in C57BL/6 mice receiving a high-fat diet. Both extracts resulted in lower feed consumption in the animals, but they did not influence weight gain or visceral adiposity and resulted in varied changes in the lipid profile. In addition, they did not influence glucose tolerance, insulin sensitivity, or fasting blood glucose. Furthermore, leptin levels increased, which may have contributed to satiety, but this was shown to have a negative impact on other inflammatory and hormonal parameters. Therefore, under the conditions of this study, the biologically active compounds present in Guazuma ulmifolia were not able to contribute to the treatment of metabolic changes related to the consumption of a high-fat diet.

Human / clinical evidence: The most rigorous human trial was a randomized, double-blind, placebo-controlled study. The aim was to evaluate the effect of oral administration of a herbarium mixture (Guazuma ulmifolia/Tecoma stans) on metabolic profile in patients with type 2 diabetes mellitus (T2DM). The trial was carried out in 40 patients with T2DM between 40 and 65 years of age, with BMI between 25.0 and 34.9 kg/m² and HbA1c >7.0%. BMI, waist circumference, fasting glucose, HbA1c, lipids, kidney, and liver function were measured. The patients were randomly assigned to receive the herbarium mixture 400 mg before each meal, or placebo for 90 days. The herbarium mixture group showed decreased waist circumference (99 ± 14 vs. 98 ± 15 cm; P = .019) and decreased fasting glucose. Importantly, this trial tested a combination formula (G. ulmifolia + T. stans), making it impossible to attribute the effects solely to G. ulmifolia. The trial was small (40 subjects) and of short duration (90 days). Although a large number of studies have been carried out on various biological activities of mutamba extracts, a few reports are available on clinical studies with the extracts or the compounds and their medicinal applications. Overall, the evidence for antidiabetic effects in humans is preliminary and methodologically limited.

5.3 Cardiovascular Effects (Hypertension)

Preclinical evidence: The most detailed mechanistic work on blood pressure was conducted by Magos et al. (2008), published in Journal of Ethnopharmacology. This study investigated the in vivo and in vitro cardiovascular activity of a procyanidin fraction (PCF) obtained from the acetone extract of Guazuma ulmifolia bark, which had traditionally been used as an antihypertensive agent. PCF doses of 10 mg/kg orally administered to sugar-fed hypertensive rats decreased both the systolic arterial pressure and the heart rate, whereas the same doses intravenously administered induced arterial hypotension, which was attenuated by L-NAME pretreatment. The PCF reduced the contraction induced by norepinephrine in isolated aortic rings of normotensive (IC₅₀ = 35.3 ± 12.4 ng/mL) and sugar-fed hypertensive (IC₅₀ = 101.3 ± 57.2 ng/mL) rats. The relaxant activity was inhibited by either vascular endothelium removal or L-NAME pretreatment, while indomethacin or atropine had no effect. These results are consistent with an endothelium-dependent, nitric oxide-mediated vasodilatory mechanism, but remain confined to animal models. No human RCTs have been published specifically targeting hypertension.

5.4 Antimicrobial Activity

Antibacterial (in vitro): The extracts and metabolites of Guazuma ulmifolia, particularly those from leaves and bark, possess several useful bioactive compounds, and recently additional data are available on exploitation of these compounds in various biological activities including antibacterial, antiviral, antifungal, anti-inflammatory, antisecretory, antitumor, antioxidant, and cytotoxicity. Multiple in vitro studies have confirmed antibacterial activity; however, the evidence base remains preclinical.

Antiviral (in vitro): A study published in PubMed (PMID 16754999) tested crude extract and fractions against poliovirus 1 and bovine herpesvirus 1. The therapeutic protocol demonstrated statistically significant positive results with both plants and for both virus strains. The highest percentages of viral inhibition were found for G. ulmifolia ethyl acetate fraction, which inhibited BHV-1 and P-1 replication by 100% and 99%, respectively. In the virucidal protocol, G. ulmifolia crude extract inhibited the replication of BHV-1 and P-1 by 60% and 26%, respectively. These are cell-culture results only. Research projects have discussed using tannins extracted from Guazuma ulmifolia to inhibit HIV reverse transcriptase, aiming to identify the molecular weight of tannin that most effectively inhibits HIV replication with lowest toxicity, but this work is at an early investigational stage and has not been validated in clinical trials.

5.5 Anthelmintic Activity

In vitro anthelmintic studies demonstrated that a hydroalcoholic extract displayed the highest ovicidal activity (100% egg hatch inhibition at 10 mg/mL). Fractionation of the extract allowed increasing the nematicidal effect in the ethyl acetate fraction (100% egg hatch inhibition at 0.62 mg/mL and 85.35% mortality at 25 mg/mL). These results suggest that G. ulmifolia leaves could be potential candidates for the control of Haemonchus contortus or other gastrointestinal parasitic nematodes. This evidence is entirely in vitro / ex vivo.

5.6 Hair Growth

The hair-growing activity of certain procyanidins in mutamba is attributed to their ability to inhibit protein kinase C. Procyanidin B-2 and procyanidin C-1 are able to selectively inhibit protein kinase C, and a 1% procyanidin B-2 extract resulted in enhanced hair growth. This property was reported in a preclinical context; no clinical trials specifically testing G. ulmifolia extracts for alopecia were identified in the peer-reviewed literature.

5.7 Antioxidant Activity

Chemical analyses corroborate literature reports of gallocatechin, epigallocatechin, and epigallocatechin gallate as key antioxidant constituents. Compared with the ethanolic extract, the aqueous extract showed greater antioxidant capacity. Antioxidant properties are well-characterized in vitro but have not been investigated in human clinical trials.

5.8 Cytotoxicity / Antitumor Activity

Procyanidin B-2 has shown in vitro antitumor activity. In one study, it showed activity towards melanoma cells PRMI-7951 with an ED₅₀ of 1–4 mcg/mL. No activity was seen towards lung carcinoma, ileocecal adenocarcinoma, epidermoid carcinoma of the nasopharynx, or medulloblastoma. This evidence is limited to cell-culture assays; there are no clinical data.

6. Body Systems and Health Areas of Association

Based on the cumulative published literature, G. ulmifolia is associated with the following body systems and health areas:

• Gastrointestinal system: Antidiarrheal, antisecretory, gastroprotective, anti-ulcerogenic, and antidysenteric effects are the most consistently documented properties across multiple research groups and model systems.
• Cardiovascular / metabolic system: Antihypertensive and vasorelaxant activity via nitric oxide pathways; hypocholesterolemic effects in animal models; blood glucose regulation.
• Endocrine system (diabetes): α-glucosidase inhibition, stimulation of glucose uptake in adipocytes.
• Immunological / antimicrobial: Antibacterial, antifungal, antiviral (poliovirus, herpesvirus, preliminary HIV tannin studies), and antiprotozoal activity documented in vitro.
• Integumentary / dermatological: Traditional use for burns and wound healing (vulnerary); hair-growth potential via procyanidin B2 and C1 kinase C inhibition.
• Respiratory system: Traditional use for coughs, asthma, and bronchitis; limited clinical data.
• Urinary system: Traditional use for kidney and urinary tract complaints.

In pharmacological evaluations, antioxidant, antihypertensive, vasodilatory, antidiabetic, antiviral, antibacterial, antifungal, gastroprotective, hepatoprotective, and cytotoxic activities were demonstrated.

7. Dosage Forms and Reported Dosages

The following dosages have been reported in source literature and should not be interpreted as clinical recommendations:

• For respiratory and gastrointestinal affections, 2–3 g three times per day in infusion.
• In the randomized clinical trial (herbarium mixture of G. ulmifolia/T. stans), patients received 1 g before each meal for 90 days. An earlier publication from the same trial cites the dose as 400 mg per meal.
• In the TRAMIL preliminary double-blind study, a senescent leaf decoction at 12 g/L was administered as 240 mL every 8 hours.
• In a rat gastroprotection study, the aqueous suspension of ethanolic extract was administered twice orally to three groups at doses of 500, 250, and 125 mg/kg.
• In the rodent antihypertensive study, 10 mg/kg of the procyanidin fraction was administered orally.
• Ethanol extraction in the metabolic disorder study was carried out with 100 mL of ethanol–water solution (80:20 v/v) to which 5 g of fine powder from the stem bark was added.

For stability purposes, the physical and chemical properties of dried extracts were evaluated for 21 days of storage under stress conditions of temperature (45 ± 2°C) and humidity (75 ± 5%). HPLC was used for determination of stability of the chemical markers procyanidin B2 and epicatechin. Data suggest that colloidal silicon dioxide increases the stability of the dried extract of G. ulmifolia. Preparations must never be stored for more than 24 hours, even if refrigerated, according to TRAMIL network guidelines.

8. Safety Considerations

Acute Toxicity

Formal acute toxicity studies have been conducted in murine models. Oral administration of ethanolic extracts at the limit dose of 5000 mg/kg body weight did not show any toxic symptoms or death of mice. Observation of pathological and histological examination of vital organs also did not show any significant changes. The LD₅₀ value in mice was therefore classified as greater than 5000 mg/kg, equivalent to a dose of approximately 38.79 g in a 70-kg human. Based on the acute toxicity classification, this value was classified as "practically non-toxic."

Similarly, in a 2024 PMC study, there were no signs of systemic toxicity, with no significant differences in body weight among control, ethanolic extract, and aqueous extract groups; in addition, there were no changes in water intake or urine and feces excretion. No motor, sensory, or neurological changes were observed in the Hippocratic screening test, nor were there any deaths of animals over the 14-day observation period.

Drug Interactions

People with low blood pressure should use mutamba with caution while monitoring their blood pressure accordingly. No drug interactions have been formally published; however, mutamba bark may potentiate the action of certain antihypertensive drugs. This interaction is biologically plausible given the endothelium-dependent vasorelaxant mechanism demonstrated in preclinical studies.

Leptin and Hormonal Effects

In a 2024 animal study, leptin levels increased, which may have contributed to satiety, but this was shown to have a negative impact on other inflammatory and hormonal parameters. The implications of this for human use are not established.

Evidence Gaps

Less information is available regarding clinical and toxicity properties of this plant. Gaps include: evaluating the mutamba fruit nutritional value; quantitative and qualitative phytochemical composition of different botanical parts, especially the fruits, roots, and flowers; the study of mutamba's biological activities and toxicity by using randomized and controlled clinical trials; and the development of products. The biological and toxicological properties of G. ulmifolia should be proved by clinical trials to confirm its health effects as well as to assure the safety and well-being of consumers.

Overall Evidence Characterization

Extensive literature survey reveals that Guazuma ulmifolia Lam. is an important medicinal plant with diverse pharmacological spectrum. However, very little work has been done on the biological activity and plausible medicinal applications of these compounds, and hence extensive investigation is needed to exploit their therapeutic utility. Although mutamba has medicinal applications from time immemorial, modern drugs can be developed only after extensive investigation of its bioactivity, mechanism of action, pharmacotherapeutics, and toxicity, and after proper standardization and clinical trials. The existing human clinical evidence is sparse, consisting primarily of one small combination-product RCT, one small preliminary TRAMIL double-blind study, and preclinical in vitro and animal model data that, while mechanistically informative, cannot be extrapolated to clinical efficacy with confidence.

References

• Sousa et al. (2024). Use of Guazuma ulmifolia Lam. Stem Bark Extracts to Prevent High-Fat Diet Induced Metabolic Disorders in Mice. International Journal of Molecular Sciences, 25(16), 8889. PMC11354271.
• Solano-Aguilar et al. (2020). Administration of Herbarium Mixture (Guazuma ulmifolia/Tecoma stans) on Metabolic Profile in Type 2 Diabetes Mellitus Patients: A Randomized, Double-Blind, Placebo-Controlled Trial. PubMed PMID 32955964.
• ClinicalTrials.gov. Effect of Oral Administration of a Herbarium Mixture (Guazuma ulmifolia and Tecoma stans) on Metabolic Profile in Type 2 Diabetic Patients. NCT03313856.
• Alarcón-Aguilara et al. (2008). The anti-diabetic properties of Guazuma ulmifolia Lam are mediated by the stimulation of glucose uptake in normal and diabetic adipocytes without inducing adipogenesis. Journal of Ethnopharmacology. PMID 18487028.
• Magos GA, et al. (2008). Hypotensive and vasorelaxant effects of the procyanidin fraction from Guazuma ulmifolia bark in normotensive and hypertensive rats. Journal of Ethnopharmacology, 117(1), 58–68. PMID 18314282.
• Hör M, Rimpler H, Heinrich M. (1995). Inhibition of intestinal chloride secretion by proanthocyanidins from Guazuma ulmifolia. Planta Medica, 61(3), 208–212. PMID 7617760.
• Felipe et al. (2006). Antiviral effect of Guazuma ulmifolia and Stryphnodendron adstringens on poliovirus and bovine herpesvirus. PMID 16754999.
• Lopes GC, et al. (2012). Preliminary Assessment of the Chemical Stability of Dried Extracts from Guazuma ulmifolia Lam. (Sterculiaceae). International Journal of Analytical Chemistry. PMC3265066.
• Lopes GC, et al. Condensed Tannins from the Bark of Guazuma ulmifolia Lam. (Sterculiaceae). Journal of the Brazilian Chemical Society.
• Flavanocoumarins from Guazuma ulmifolia bark and evaluation of their affinity for STAT1. ScienceDirect (Phytochemistry, 2012).
• In Vitro Anthelmintic Activity of a Hydroalcoholic Extract from Guazuma ulmifolia Leaves against Haemonchus contortus. PMC9607474.
• Shekhawat N. (2021). Guazuma ulmifolia: A Review on its Traditional uses, Phytochemistry and Pharmacology. Gynecol Obstet Med Aromat Plants, 10: 374. DOI: 10.35248/2167-0412.21.10.374.
• Guazuma ulmifolia — Overview. ScienceDirect Topics (aggregated peer-reviewed literature).
• Phytochemicals and biological activities of mutamba (Guazuma ulmifolia Lam.): A review. ScienceDirect (Food Chemistry, 2019).
• TRAMIL Network. Guazuma ulmifolia — Ethnopharmacological and Toxicological Monograph.
• Guazuma ulmifolia LAM: A Review for Future View. Journal of Pharmacognosy and Phytochemistry, 2019; 7(2).