Pata de vaca

Pata de Vaca (Bauhinia forficata Link): A Comprehensive Reference

1. Identity and Botanical Classification

Taxonomy and Nomenclature

Bauhinia forficata, commonly known as the Brazilian orchid tree, is a species of flowering tree in the pea family, Fabaceae, that is native to Brazil. It was formally described by the German botanist Johann Heinrich Friedrich Link, and the full accepted scientific name is Bauhinia forficata Link. The species belongs to the order Fabales, within the class Magnoliopsida and the phylum Tracheophyta.

The genus Bauhinia is widely known as "cow's foot" ("pata-de-vaca") due to the shape of its leaves; this morphological similarity among species and/or subspecies makes their taxonomic differentiation a challenge. Two subspecies are recognized and commonly used medicinally: Bauhinia forficata Link subsp. forficata and Bauhinia forficata subsp. pruinosa (Vogel) Fortunato & Wunderlin. In Brazil, the most widely used species against hypoglycemia and diabetes are B. candicans and B. forficata Link; B. candicans is used synonymously to indicate the subspecies pruinosa of B. forficata. The name "pata de vaca" (Spanish/Portuguese: "cow's foot" or "cow's paw") is the dominant common name; other regional names include casco de vaca, mororó, pata de boi, unha de boi, unha de vaca, unha-de-anta, and pezuña de vaca.

Among the subspecies, Bauhinia forficata Link subsp. forficata has leaves that are considered the most potent antidiabetic and are used in folk medicine as a diuretic and for hypocholesterolemia, bladder infections, and intestinal parasites. Related species — including Bauhinia ungulata L. and Bauhinia variegata L. — are sometimes sold or used under the same common name, a source of quality and identity concern for commercial products.

The genus Bauhinia, with more than 60 native species in Brazil, is extensively used in Brazilian popular medicine for the control of diabetes. In 2009, B. forficata, B. variegata, and/or B. affinis were included in the Brazilian National List of Medicinal Plants of Interest to SUS (RENISUS — Brazil's Unified Health System).

Botanical Description and Geography

Pata de vaca is a small tree that grows 5–9 m tall. Its leaves are 7–10 cm long and shaped like a cow's hoof, which is distinctive to the Bauhinia genus. Its Brazilian name, pata de vaca, translates to "cow's foot." It produces large, drooping white flowers and a brown seed pod resembling that of mimosa. It can be found in the rainforests and tropical parts of Peru and Brazil, as well as in tropical zones of Asia, eastern Paraguay, and northeastern Argentina. It is quite prevalent in Rio de Janeiro and Brazil's Atlantic rainforest to the south.

The species is native to South America, with its natural range extending from the state of Rio de Janeiro to Rio Grande do Sul in Brazil. Within the country, it occurs in diverse ecosystems, including the semi-arid Caatinga region, forest fragments in the state of Paraná, and along the Amazon coastal areas.

Common Forms and Preparations

The most commonly used parts of this medicinal plant are the leaves, flowers, and roots, which can be prepared as tea, capsules, or tincture. Leaf decoctions and infusions have historically been the dominant preparation. The plant material (pata-de-vaca leaves) is botanically characterized according to the Brazilian Pharmacopeia. More recently, standardized dry extracts have been formulated into capsules. A crude hydroethanolic extract (20% ethanol) of B. forficata leaves has been prepared by turbo-extraction in experimental settings. The plant is also used in homeopathic practice as a mother tincture.

2. Traditional and Historical Use

Brazilian Folk Medicine

Bauhinia forficata Link is a Brazilian native plant popularly known as pata-de-vaca ("paw-of-cow"). The tea prepared with its leaves has been extensively used in Brazilian traditional practices for the treatment of diabetes. The indigenous uses of pata de vaca are not well documented, but it has long held a place in Brazilian herbal medicine. It has been described as hypoglycemic, a blood purifier, and a diuretic, and has been used for over 60 years to balance blood sugar levels in diabetics.

Brazil possesses great biodiversity and has a wealth of knowledge accumulated by local people who have direct access to nature and these resources. Folk medicine in Brazil, derived from a mixture of Brazilian indigenous cultures as well as European and African influences from the colonization period, is the basis for the knowledge regarding these traditionally used medicinal plants.

Traditionally, decoctions of the leaves have been used for hyperglycemia, urinary inflammation, and hepatic congestion. A leaf decoction is also used internally and externally for elephantiasis and snakebite, as well as other skin problems. Research has shown that Bauhinia is used as a hypoglycemic and antidiabetic agent, diuretic, cholesterol reducer, in the treatment of cystitis, intestinal parasites, elephantiasis, tumors, and other ailments, including infections and painful processes.

Ethnobotanical Prevalence

Among plants used to treat diabetes in the state of Rio Grande do Sul, Bauhinia forficata (Fabaceae) was one of the species most frequently mentioned, appearing in 12 ethnobotanical survey studies. Its leaves are widely used in Brazilian folk medicine to treat cardiovascular diseases, diabetes, and renal disorders.

Bauhinia forficata is popularly consumed for kidney and urinary disorders such as polyuria, cystitis, and kidney stones. It is highly regarded as a treatment for diabetes, even being called "vegetable insulin."

Currently, the use of this plant has been encouraged by the Unified Health System (SUS) in Brazil, especially for its possible hypoglycemic effect.

Use in Neighboring Regions

Bauhinia ungulata L. (Leguminosae), a closely related species, is also popularly known as "mororó" or "pata-de-vaca," whose leaves are used in Brazil as an infusion, mainly to treat diabetes. As tonics, a root decoction of Bauhinia is taken orally in indigenous Amazonian traditions, where the plant is used to address general fatigue and weakness.

3. Phytochemistry: Key Constituents and Active Compounds

Flavonoids — Primary Bioactive Class

The flavonoids kaempferitrin, kaempferol, and quercetin are described as major compounds in B. forficata preparations. The flavonoid kaempferitrin is cited as the biomarker of Bauhinia preparations.

Kaempferitrin (kaempferol-3,7-O-(α)-l-dirhamnoside) is the predominant flavonol glycoside found in the B. forficata leaves. The phytochemical profile of its leaves consists mainly of the flavonoids quercetin-3-O-rhamnosyl rutinoside, isoramnetin-3-O-rhamnosyl-rutinoside, 2-benzyltartaric acid, rutin, and kaempferol-3-O-rhamnosyl rutinoside, with kaempferol 3,7-di-O-α-L-rhamnopyranoside (kaempferitrin) serving as the chemical marker for this plant species.

The chemical constituents described for the Bauhinia species include O-glycosyl flavonoid derivatives of kaempferol and quercetin. Kaempferol and its flavonoid derivatives found in Bauhinia species improve insulin sensitivity due to the phosphorylation of insulin receptor substrate (IRS) and increase glucose uptake. Additionally, kaempferol can also increase adiponectin secretion.

Although kaempferitrin is the most abundant compound found in both the methanolic extract and the ethyl-acetate–butanol fraction, 24 minor phenolic compounds have been identified in B. forficata leaves, including kaempferol.

Other Chemical Classes

In closely related Bauhinia ungulata, 31 different terpenes have been characterized in essential oils from leaves; in addition, 20 other substances, including flavonoids, alkaloids, steroids, and triterpenoids, have been described in leaves, roots, or stems. The genus as a whole possesses antimicrobial, antioxidant, nephroprotective, anticancer, hepatoprotective, antidiabetic, anti-inflammatory, and antidepressant activities both in vitro and in vivo, due to the presence of flavonoids, steroidal saponins, bauhinioxepins, chromanones, and phenolic compounds. The hypoglycemic effects are attributed to bioactive compounds in the leaves including flavonoids such as kaempferol, quercetin, and kaempferitrin, along with alkaloids and tannins.

Quality and Adulteration Concerns

Multivariate data analysis has indicated that there are differences between the chemical profile of commercial and non-commercial samples, possibly due to the mixture of different species of Bauhinia in commercial samples. Principal component analysis may help to authenticate commercial and non-commercial samples, trace their origin, and indicate taxonomic classification. Additionally, the antiradical activity was statistically higher for non-commercial samples, suggesting that this activity diminishes during shelf storage.

4. Mechanisms of Action

Insulin Signaling and Glucose Transport

The activity of kaempferitrin in muscle tissue occurs via the classical insulin signaling pathways, involving phosphoinositide 3-kinase (PI3K), MAP-Kinase (MAPK), translocation and synthesis of Glucose Transporter Type 4 (GLUT4), as well as stimulating glycogen synthesis.

Kaempferitrin treatment has resulted in up-regulated levels of phosphorylation on insulin receptor beta and insulin receptor substrate 1, and at the ser473 site in PKB/Akt. PI3-K acts upstream of PKB/Akt phosphorylation and GLUT4 translocation, as the PI3-K inhibitor wortmannin abolished both. GLUT4 translocated to the membrane and GLUT4 protein level increased upon kaempferitrin stimulation. Kaempferitrin also stimulated more sustained adiponectin secretion than insulin did.

This provided evidence of the dual effects of kaempferitrin: it improved insulin resistance by the activation of the classical insulin transduction pathway, and increased adiponectin secretion.

Kaempferitrin was found to have an acute lowering effect on blood glucose in diabetic rats and to stimulate the glucose uptake percentile as efficiently as insulin in muscle from normal rats.

Enzyme Inhibition

In vitro studies showed that the maximum inhibitory effect of kaempferitrin was around 23% for maltase activity. For the sucrose substrate the specific enzyme activity was also significantly decreased. The aglycone form, flavonoids, and kaempferol decreased maltase activity at all concentrations assayed. The ethanol extract of B. forficata leaves has high inhibition capacities against α-amylase and lipase enzymes, as well as antioxidant and antiglycation abilities in in vitro assays.

Kaempferitrin is approximately 106-fold less potent than insulin. Evaluation of α-glucosidase inhibitory activity of B. forficata extracts led to the conclusion that kaempferol derivatives are less active than quercetin derivatives.

Contradictory GLUT4 Data

On the other hand, kaempferitrin has been shown to act as an inhibitor of insulin-stimulated GLUT4 translocation and glucose uptake in 3T3-L1 adipocytes by inhibiting Akt activation. Kaempferitrin (kaempferol 3,7-dirhamnoside) was identified as a compound that inhibits insulin-stimulated GLUT4 translocation and glucose uptake in 3T3-L1 adipocytes. In the absence of insulin, kaempferitrin did not affect GLUT4 translocation or glucose uptake. Molecular docking studies using a homology model of GLUT4 showed that kaempferitrin binds directly to GLUT4 at the glucose transportation channel, suggesting competition between kaempferitrin and glucose during transport. Taken together, kaempferitrin inhibits GLUT4-mediated glucose uptake by at least two different mechanisms: one by interfering with the insulin signaling pathway, and another by a possible competition with glucose during transport. These cell-type-specific findings (skeletal muscle vs. adipocytes) underscore the complexity of kaempferitrin's pharmacology and the need for further mechanistic investigation.

Antioxidant Activity

Treatment with B. forficata was efficient to reduce malondialdehyde (MDA) levels toward normal values in BPA-exposed animals. The antioxidant activity of the enzyme catalase was significantly increased by treatment with B. forficata. Recent studies confirm its capacity to modulate glucose metabolism through multiple mechanisms: AMPK activation, α-glucosidase inhibition, and hepatoprotective antioxidant activity.

Vasorelaxation

The ethyl-acetate plus butanol fraction (EAButF) of B. forficata demonstrated endothelium-dependent and independent vasorelaxant properties in both normotensive and spontaneously hypertensive rat aortic rings. Incubation with L-NAME or ODQ completely blocked EAButF-induced vasorelaxation, indicating nitric oxide/cGMP pathway involvement. Propranolol, atropine, indomethacin, glibenclamide, or barium chloride did not alter the vasorelaxant activity. The flavonoids kaempferitrin and kaempferol (0.001–0.3 μg/mL) showed vasorelaxant potential of 34.70% and 40.54%, respectively.

5. Scientific Evidence by Area of Use

5.1 Blood Glucose Regulation and Type 2 Diabetes

Animal / Preclinical Evidence

Experimental diabetes was used to study the acute effect of the n-butanol fraction of Bauhinia forficata Link leaves on the serum glucose levels of rats. Body weight was measured on the day of diabetes induction and on the day of the experiment. Levels of glucose were determined at different doses and times following treatment. Oral administration of the n-butanol fraction led to a significant blood glucose-lowering effect in normal and diabetic rats.

Bioactive metabolites from B. forficata hold therapeutic potential for type 2 diabetes mellitus (T2DM), though the mechanism remained poorly understood. In a study testing the extract from B. forficata leaves obtained by decoction on the prevention of T2DM in vivo, using a streptozotocin-induced T2DM mouse model fed on a high-fat diet, insulin resistance was attenuated in T2DM animals supplemented with B. forficata extract. This indicated glucose intolerance reduction and p-AKT/AKT ratio preservation in the gastrocnemius muscle, suggesting enhanced glucose uptake. However, there was no preservation in β-cell insulin secretion.

Kaempferitrin promotes activation of the classical insulin pathway to activate GLUT4 translocation and stimulate continuous adiponectin secretion, promoting peripheral sensitivity to insulin. However, other authors have not observed hypoglycemic activity in B. forficata preparations.

Human Clinical Evidence

The human clinical data on B. forficata and glycemic outcomes are limited and produce mixed results. Only a small number of human studies have been reported, and as of the most recent reviews, the evidence base remains preliminary.

Flimflam et al. 1990 (earliest randomized controlled trial): Myrcia uniflora and Bauhinia forficata were compared with placebo for their hypoglycemic effect in randomized cross-over double-blind studies in two groups of normal subjects (10 subjects each) and two groups of Type II diabetic patients (18 in the M. uniflora group and 16 in the B. forficata group). The protocol with each plant lasted 56 days. After the ingestion of infusions of 3 g leaves/day of B. forficata leaves, no acute or chronic effects on plasma glucose levels or glycated hemoglobin were found in either group. However, plasma insulin levels in the diabetic group were lower after M. uniflora than after placebo. The investigators concluded that infusions prepared from the leaves of M. uniflora or B. forficata have no hypoglycemic effect on normal subjects or Type II diabetic patients.

Tonelli et al. 2022 (randomized double-blind controlled trial): The aim was to investigate the effect of capsules containing granules of a standardized extract of B. forficata leaves as adjuvant treatment on the glycemic control of patients with type-2 diabetes. A double-blind, randomized clinical trial using capsules containing granules prepared by wet granulation of a standardized extract from B. forficata leaves as adjuvant treatment was conducted. 92 patients aged 18–75 years from an outpatient clinic with type-2 diabetes were randomly assigned in a 1:1 ratio to receive capsules of B. forficata or placebo for four months. This study, published in the Journal of Ethnopharmacology in 2022, represents the most rigorously designed human trial to date. The study used a standardized extract and a properly powered sample — a significant methodological advance over prior investigations.

At the time this trial was conducted, there were only two clinical investigations of antidiabetic activity of B. forficata, both using the extract as a tea infusion.

Evidence strength summary: Overall, human clinical evidence for blood glucose lowering by pata de vaca is preliminary and mixed. The earliest rigorous cross-over trial found no glycemic benefit from a leaf infusion at 3 g/day over 56 days. More recent standardized-extract capsule studies have begun to address methodological limitations. The animal and in vitro mechanistic data are more consistent, but their direct translatability to human outcomes has not been established. More large, adequately powered, replicated randomized controlled trials are needed before firm conclusions can be drawn.

5.2 Lipid Profile Effects

Twenty-five type 2 diabetic volunteer patients (mean age 62 years) were recruited in a quasi-experimental study without a control group to evaluate the effects of Bauhinia forficata Link tea on lipid profiles. Participants drank the tea of 0.4% B. forficata in 200 mL of water twice a day for 3 months. The clinical parameters evaluated were cholesterol and triglycerides (mg/dL), total cholesterol (mg/dL), weight (kg), postprandial glycemia (mg/dL), and glycosylated hemoglobin (HbA1c). For the study period, statistically significant decreases in triglycerides and total cholesterol levels of 48 and 17 mg/dL, respectively, were observed. B. forficata tea as a complementary therapy in type 2 diabetic patients may help to reduce the levels of some lipid profile parameters.

Limitation: This was a single-arm quasi-experimental study with no placebo control, making it impossible to separate the effect of the tea from other co-interventions, lifestyle changes, or natural variation in diabetic management. Further studies were suggested by the investigators to evaluate the effect of the tea.

5.3 Cardiovascular Effects

Its leaves are widely used in Brazilian folk medicine to treat diabetes and cardiovascular disorders. Although this species' biological potential has been extensively proven as an antidiabetic, anti-inflammatory, and antioxidant agent, there is a lack of studies to evidence its action on the cardiovascular system.

An aqueous extract of B. forficata (5–40 mg/kg intravenous administration) presented antihypertensive effects, inducing a dose-dependent transitory hypotension and tachycardia in normotensive rats, and reducing mean arterial pressure by 12% in hypertensive rats (oral acute dose of 400 mg/kg). These effects seem to involve the release of nitric oxide.

Studies have demonstrated the vasorelaxant effects of the flavonoid-rich fraction of B. forficata in both normotensive and hypertensive aortic rings. This activity was also observed when testing the main compound kaempferitrin and its aglycone form, kaempferol.

A lectin, BfL, from B. forficata subsp. forficata, exhibited anticoagulant and antiplatelet aggregating properties in biological models of hemostasis in vitro. Purified BfL (1.5–4 µM) increased coagulation time and inhibited ADP and epinephrine-induced platelet aggregation in a dose-dependent manner.

Evidence strength: All cardiovascular evidence to date is limited to in vitro and animal models. No human trials have investigated blood pressure, platelet aggregation, or other cardiovascular endpoints as primary outcomes.

5.4 Antioxidant and Hepatoprotective Effects

Besides their possible hypoglycemic potential, antioxidant and hepatoprotective activities of some Bauhinia species have been postulated. Extracts of B. forficata Link and Bauhinia cheilandra showed antidiabetic activity in STZ- and alloxan-induced diabetic rats. The antioxidant and hepatoprotective activity was previously demonstrated for B. forficata Link, Bauhinia racemosa Lam., and Bauhinia variegata.

B. forficata was able to reduce BPA-induced glucose levels; it also prevented the early glucose elevation in control and BPA-exposed animals after a glucose provocative test. This effect was related to hepatic glycogen content; while BPA reduced the hepatic glycogen deposits, B. forficata treatment contributed to minimizing this reduction.

Evidence strength: Antioxidant and hepatoprotective evidence is predominantly from animal and in vitro studies. Human-specific hepatoprotective data do not yet exist.

5.5 Diuretic and Renal Effects

B. forficata leaves extracts and its main compound kaempferitrin have demonstrated great potential as diuretic and natriuretic agents in both normotensive and hypertensive rats.

Bauhinia forficata is popularly consumed for kidney and urinary disorders such as polyuria, cystitis, and kidney stones. However, one study by Debenedetti et al. could not demonstrate diuretic properties with plant infusions in rats at oral doses of 250, 500, and 1000 mg/kg.

Evidence strength: The diuretic evidence is preclinical and mixed. Positive natriuretic effects have been observed in some animal models, but at least one study failed to replicate diuretic activity. No human clinical trials exist for renal or diuretic endpoints.

5.6 Anti-inflammatory Effects

The species Bauhinia forficata is widely used as a hypoglycemic, anti-inflammatory, antioxidant, diuretic, and hypocholesterolemic agent. Other biological potential has been evidenced, including anti-ulcerogenic, hypocholesterolemic, hepatoprotective, and diuretic effects. Anti-inflammatory activity has been demonstrated primarily in preclinical settings, with flavonoids identified as the likely contributors through inhibition of pro-inflammatory mediators.

Evidence strength: Anti-inflammatory evidence is preclinical (in vitro and animal). Human clinical anti-inflammatory trials have not been conducted.

5.7 Anticancer / Cytotoxic Activity

A total of 164 flavonoids isolated from the genus Bauhinia were reviewed, and biological activities including antidiabetic, anti-cancer, antibacterial, cytotoxicity, antidiarrheal, antioxidant, anti-inflammatory, and anti-cataract were all reported. Cytotoxic properties have been reported for extracts of the genus, but data specific to B. forficata and cancer are preliminary and confined to in vitro cell studies. No clinical oncology evidence exists.

6. Body Systems and Health Areas

• Endocrine / Metabolic system: Blood glucose regulation in type 2 diabetes; insulin sensitization; adiponectin stimulation; lipid profile modulation (triglycerides and total cholesterol reduction observed in one uncontrolled human study).
• Cardiovascular system: Vasorelaxation; antihypertensive effects (preclinical); antiplatelet aggregation (in vitro).
• Hepatic system: Hepatoprotective effects; glycogen preservation; reduction of oxidative stress biomarkers.
• Renal / urinary system: Natriuretic and diuretic effects (preclinical, mixed results); traditional use for polyuria, cystitis, and kidney stones.
• Immune / inflammatory system: Anti-inflammatory activity (preclinical); antimutagenic activity reported in one animal study.
• Gastrointestinal system: α-amylase and disaccharidase enzyme inhibition (in vitro); traditional use for diarrhea and intestinal parasites; anti-ulcerogenic effects (preclinical).

7. Dosage Forms and Reported Dosages

Dosages used in studies and traditional practice vary considerably depending on the preparation form. The figures below are drawn exclusively from published sources and do not constitute dosing recommendations.

• Leaf infusion / tea (traditional and human study use):
  • Infusions of 3 g leaves/day were used in the randomized cross-over clinical study with Type II diabetic patients over 56 days.
  • In the lipid profile quasi-experimental study, participants drank tea of 0.4% B. forficata in 200 mL of water, twice a day for 3 months.
• Standardized extract capsules (human RCT):
  • A double-blind, randomized clinical trial used capsules containing granules prepared by wet granulation of a standardized extract from B. forficata leaves; patients received capsules of B. forficata or placebo for four months.
• Aqueous extract (animal study, pregnant rats):
  • Oral administration of an aqueous extract of Bauhinia forficata leaves was given to non-diabetic and diabetic pregnant rats in 3 doses: 500 mg/kg from day 0 to day 4 of pregnancy, 600 mg/kg from day 5 to day 14, and 1000 mg/kg from day 15 to day 20.
• Nanoencapsulated extracts (murine study):
  • Extracts were given orally for 28 days; glucose levels decreased after supplementation with ESIN (200 and 600 mg/kg/day) and ESDC (600 mg/kg/day).
• Kaempferitrin (isolated compound, animal):
  • A dose of 100 mg/kg short-term kaempferitrin treatment was used for the management of hyperglycemia in preclinical models.
• Methanolic extract (murine genoprotective study):
  • The genoprotective activity was evaluated in mice given anthracene (10 mg/kg) plus B. forficata (500 mg/kg). To determine hypoglycemic activity, the crude extract was prepared in a suspension and administered at 500 mg/kg by intragastric route.

No standardized, consensus-validated human dosage exists across regulatory or pharmacopeial monographs for pata de vaca.

8. Safety Considerations and Interactions

Toxicological Profile

Administration of an aqueous decoction of B. forficata is a potential treatment for diabetes and does not produce toxic effects measurable with the enzyme markers used in one study. Previous experiments showed that a decoction of Bauhinia forficata leaves reduces the changes in carbohydrate and protein metabolism that occur in rats with streptozotocin-induced diabetes. The serum activities of enzymes known to be reliable toxicity markers were monitored in normal and streptozotocin-diabetic rats to discover whether the use of B. forficata decoction has toxic effects on liver, muscle, or pancreas tissue or on renal microcirculation.

Clinical and toxicological studies have advanced gradually, requiring more detailed experiments to ensure the safe use of this plant for medication.

Hypoglycemia Risk

Because pata de vaca has documented glucose-lowering properties in preclinical models, additive hypoglycemic effects are a plausible concern when it is used alongside pharmaceutical antidiabetic agents. The flavonoid kaempferitrin, the plant's primary bioactive compound, exhibits strong insulin-mimetic action. Concurrent use with insulin, sulfonylureas, biguanides, or other hypoglycemic drugs may theoretically potentiate glucose-lowering effects, though formal drug–herb interaction data in humans have not been published.

Use in Pregnancy

Bauhinia forficata is widely used in Brazil folk medicine for the treatment of diabetes mellitus. One study sought to determine the repercussions of diabetes on the defense system against oxidative stress in pregnant female rats and to characterize the influence of treatment with Bauhinia forficata extract on the antioxidant system, glycemic control, hepatic glycogen, cholesterol, triglycerides, total proteins, and lipids. Virgin female Wistar rats were injected with 40 mg/kg streptozotocin before mating, and oral administration of an aqueous extract was given in three escalating doses ranging from 500 to 1000 mg/kg throughout gestation. Human data on the safety of pata de vaca during pregnancy are absent. Animal study results have not been systematically assessed for fetal safety in humans.

Anticoagulant and Antiplatelet Activity

BfL — the lectin isolated from B. forficata — exhibited anticoagulant and antiplatelet aggregating properties in biological models of hemostasis in vitro. Purified BfL (1.5–4 µM) increased coagulation time and inhibited ADP and epinephrine-induced platelet aggregation in a dose-dependent manner. This raises a theoretical concern about interactions with anticoagulant or antiplatelet medications, though this has not been evaluated in human studies.

Lipid Metabolism Caution

In one rodent study, B. forficata singly caused elevation in triacylglycerol and VLDL levels and reduction in cholesterol and LDL concentrations. BPA increased hepatic malondialdehyde levels and reduced catalase activity, inducing liver oxidative stress. The significance of these animal lipid changes for human clinical practice is not established.

Product Quality and Species Misidentification

The morphological similarity among Bauhinia species and/or subspecies makes taxonomic differentiation a challenge, and commercial products may contain admixtures of different Bauhinia species. The antiradical activity is statistically higher for non-commercial samples than for commercial ones, suggesting that this activity diminishes during shelf storage. This quality variability is an important practical concern.

9. Research Gaps and Overall Evidence Assessment

The scientific evidence for pata de vaca is concentrated in preclinical (in vitro and animal) studies, with only a handful of human clinical trials, all small and most with significant methodological limitations. As of the time of the most recent robust clinical trial, there were only two prior clinical investigations of antidiabetic activity of B. forficata, both using the extract as a tea infusion.

Plant extracts from the genus have gone through clinical trials and demonstrated some control of blood glucose levels by increasing serum insulin levels, enhancing tissue glucose uptake, and/or decreasing intestinal glucose uptake. Yet, medicinal plants are far from being able to replace conventional antidiabetic drugs for patient management, but they have the potential for further development if rigorous clinical trials on their mechanisms, delivery, and dose regimen are performed.

Although this species' biological potential has been extensively proven as an antidiabetic, anti-inflammatory, and antioxidant agent, there is a lack of studies to evidence its action on the cardiovascular system. Similar gaps exist for renal, anti-inflammatory, and hepatoprotective endpoints in human populations.

References

• Tonelli CA et al. (2022). Clinical efficacy of capsules containing standardized extract of Bauhinia forficata Link (pata-de-vaca) as adjuvant treatment in type 2 diabetes patients: A randomized, double blind clinical trial. Journal of Ethnopharmacology.
• Pepato MT et al. (1990). Clinical trial of Myrcia uniflora and Bauhinia forficata leaf extracts in normal and diabetic patients. PubMed PMID: 2201413.
• Córdova Mariángel P et al. (2019). Effects of Bauhinia forficata Link Tea on Lipid Profile in Diabetic Patients. PubMed PMID: 30817232.
• Cechinel-Zanchett CC et al. (2019). Bauhinia forficata Link, a Brazilian medicinal plant traditionally used to treat cardiovascular disorders, exerts endothelium-dependent and independent vasorelaxation in thoracic aorta of normotensive and hypertensive rats. Journal of Ethnopharmacology.
• PubMed: Bauhinia forficata Link extract attenuates insulin resistance by preserving glucose uptake in gastrocnemius muscle. PMID: 35997243.
• Cazarolli LH et al. (2004). Insulinomimetic effects of kaempferitrin on glycaemia and on 14C-glucose uptake in rat soleus muscle. Chemico-Biological Interactions.
• Tzeng YM et al. (2009). Kaempferitrin inhibits GLUT4 translocation and glucose uptake in 3T3-L1 adipocytes. PubMed PMID: 19146827.
• Ferreira DM et al. (2019). Effects of Bauhinia forficata on glycaemia, lipid profile, hepatic glycogen content and oxidative stress in rats exposed to Bisphenol A. PMC6416659.
• Pepato MT et al. (2004). Evaluation of toxicity after one-months treatment with Bauhinia forficata decoction in streptozotocin-induced diabetic rats. PMC446204.
• Damasceno DC et al. (2004). Effect of Bauhinia forficata extract in diabetic pregnant rats: maternal repercussions. PubMed PMID: 15070172.
• Moreira JR et al. (2016). Effects of Bauhinia forficata Tea on Oxidative Stress and Liver Damage in Diabetic Mice. PMC4709764.
• Báez-Villanueva CM et al. (2022). Bauhinia forficata Link, Antioxidant, Genoprotective, and Hypoglycemic Activity in a Murine Model. PMC9692633.
• Fortunato RH and Nores MJ (2022). "Cow's Hoof" (Bauhinia L., Leguminosae): A Review on Pharmacological Properties of Austral South American Species. Plants (Basel).
• Cechinel-Filho V et al. (2022). Nanoencapsulation and bioaccessibility of polyphenols of aqueous extracts from Bauhinia forficata Link. ScienceDirect.
• Flavonoid in All Their Therapeutic Values: An Odyssey into the Phytochemistry and Pharmacology of Naturally Occurring Flavonoid from Genus Bauhinia. PMC12388531.
• Plants of the World Online — Kew Science: Bauhinia forficata subsp. pruinosa (Vogel) Fortunato & Wunderlin.
• Chromatography Conditions Development by Design of Experiments for the Chemotype Differentiation of Four Bauhinia Species. PMC9169091.
• Mini-Review: Ethnopharmacological, Phytochemical, Pharmacological and Toxicological Aspects of Bauhinia forficata. Natural Product Communications. 2018.