Trumpet vine

Trumpet Vine (Campsis radicans): A Comprehensive Reference

1. Identity and Botanical Description

1.1 Nomenclature and Taxonomy

Trumpet vine — scientifically known as Campsis radicans — is a species of flowering plant in the trumpet vine family Bignoniaceae, native to eastern North America, and naturalized elsewhere. The species carries a substantial list of synonyms accumulated across its taxonomic history: it has been formally recorded under the synonyms Bignonia radicans L. and Tecoma radicans (L.) Juss. The authority citation for the currently accepted name is Campsis radicans (L.) Seem. ex Bureau. Common names in circulation include trumpet creeper, trumpet climber, cow-itch vine, hummingbird vine, foxglove vine, hellvine, devil's shoestring, and cow vine.

The genus name Campsis is derived from the Greek word for "curved," indicative of the flower's unique shape, while radicans comes from the Latin word meaning "to root," referencing the plant's ability to root from its stem nodes. In Chinese herbal medicine, both C. radicans and its East Asian relative Campsis grandiflora (Thunb.) K. Schum are collectively designated Lingxiaohua (凌霄花) when their flowers are used medicinally.

1.2 Botanical Description

Campsis radicans is a perennial, deciduous vine belonging to the Bignoniaceae family. Growing to 10 metres (33 feet), it is a vigorous, deciduous woody vine, notable for its showy trumpet-shaped flowers. It inhabits woodlands and riverbanks, and is also a popular garden plant. The vine climbs using aerial rootlets, similar to English ivy, which allow it to cling tightly to surfaces.

The leaves are pinnately compound, usually consisting of 7 to 11 leaflets, which create a lush, green backdrop to its stunning flowers. Clusters (terminal cymes) of red trumpet-shaped flowers (to 3 inches long) appear throughout the summer (June to September). Flowers are followed by long, bean-like seed pods (3–5 inches long) which split open when ripe releasing numerous 2-winged seeds for dispersal by the wind.

1.3 Native Range and Distribution

Trumpet vine is native to much of eastern North America, from New Jersey and Indiana down to Florida and west to Texas. In these regions, it naturally grows in forest edges, thickets, streambanks, and disturbed soils. It is native to the eastern United States and extreme southern Ontario in Canada. Beyond its native range, it has been cultivated and naturalized widely, including in parts of South Asia, China, and Europe. C. radicans is widely distributed in the USA, Canada, China, and South Asia.

1.4 Common Preparations and Forms

As a dietary supplement or herbal preparation, Campsis radicans is most frequently encountered in the following forms:

• Dried flowers (Lingxiaohua): The dried flowers are the official medicinal part in Chinese pharmacopeial practice, used alone or in multi-herb decoctions.
• Flower/leaf decoctions and teas: Historically, trumpet vine was prepared as decoctions or teas, often combined with other botanicals like safflower and angelica root to enhance effectiveness.
• Methanolic and solvent extracts: Contemporary laboratory research has used methanol-extracted leaf fractions, subsequently partitioned into petroleum ether, dichloromethane, and ethyl acetate fractions, for pharmacological testing.
• Topical preparations: Plant parts — particularly the root — have been applied externally for skin and wound conditions in some traditions. The root is documented as diaphoretic and vulnerary.
• Antifungal douche/external application: Traditionally, trumpet vine has been used as a douche for treating candida or externally for fungal skin infections.

2. Traditional and Historical Use

2.1 Native American Traditions

In traditional medicine, Native American tribes utilized various parts of the plant for their potential health benefits. The plant's historical use across indigenous North American communities included applications for skin ailments, wounds, and infections, though specific tribal ethnobotanical records vary. Traditional medicinal uses include the healing of wounds, treatment of infections caused by Candida, Haemophilus, and other organisms, as well as anti-itching medication.

2.2 Traditional Chinese Medicine (TCM)

In traditional Chinese herbal medicine, Lingxiaohua — derived from Campsis grandiflora or Campsis radicans — has long been used as a herbal medicine for treating blood-stasis-related disorders. Lingxiaohua is a medicinal herb used for promoting diuresis and treating blood-related disorders by the promotion of blood circulation. It also possesses anti-inflammatory and antioxidative properties.

In traditional Chinese herbal medicine, the dried flowers — referred to as Shan Teng Hua — have been used for centuries to support women's health and promote healthy blood circulation. Practitioners have traditionally used trumpet vine to "invigorate the blood," dispel wind, and alleviate symptoms such as joint pain, skin irritations, and swelling caused by injuries. In China, the plant is well known for its anticoagulant property, which is traditionally used for the treatment of abnormal menstruation and dysmenorrhea. It is also used to treat gynecological and dermatological disorders.

Lingxiaohua contains various valuable compounds, including triterpenes, phenethyl glycosides, flavonoids, phenolic acids, sterols, sterol glycosides, and volatile oils, as acknowledged by the State Pharmacopoeia Commission of China.

2.3 South Asian and Bangladeshi Ethnomedicine

In Bangladesh, the plant — locally known as Kolkephul — has been traditionally used for the treatment of several human diseases. As a folkloric medicine, it has been used for the treatment of wounds and infections caused by Candida and Haemophilus.

2.4 Historical Introduction to Europe

The flamboyant flowering of Campsis radicans made it obvious to even the least botanically-minded of the first English colonists in Virginia. Consequently, the plant quickly made its way to England early in the 17th century. Its botanical parentage, as a hardy member of a mostly subtropical group, made its naming problematic: according to John Parkinson, the Virginia settlers were at first calling it a jasmine or a honeysuckle, and then a bellflower; he classed it in the genus Apocynum (dogbane).

3. Key Phytochemical Constituents

3.1 Coumarins

Chemical investigation of the aerial parts of Tecoma radicans (a synonym for C. radicans) indicates the presence of four coumarins: 2′,3′-epoxide alloimperatorin (an 8-methoxy furanocoumarin), pabulenone (a 5-alkoxy-furanocoumarin), pereflorin B, and 17-methylbothrioclinin. One chromone was also isolated: peucenin-7-methyl ether (a 7,5-dioxygenated chromone). These coumarins have been identified as possessing antioxidant activity. Biological screening of this fraction showed no antitumoral effects but demonstrated antioxidant activity.

3.2 Flavonoids

Flavonoids isolated from C. radicans include luteolin, quercetin 3-methyl ether, apigenin, and chrysoeriol. The flowers of Campsis radicans contain apigenin, ferulic acid, and β-sitosterol, which are known as anti-inflammatory agents, as cognition enhancers, and for treatment of skin disorders and control of infectious bacterial and fungal diseases. The common anthocyanin cyanidin 3-rutinoside has also been found in Campsis radicans petals.

3.3 Triterpenes

A total of five triterpene compounds — corosolic acid methyl ester, β-amyrin, arjunolic acid, maslinic acid, and a glucopyranosyl-substituted ursolic acid derivative — were isolated from the dichloromethane fractions of crude methanolic extract of the leaves of C. radicans, and their structures were characterized by ¹H NMR spectroscopy.

3.4 Iridoids and Other Phenolic Compounds

The plant's sap contains irritant compounds, including iridoids like stansioside and phenolic substances. The full iridoid profile of C. radicans has not been as comprehensively characterized as that of the closely related C. grandiflora; however, iridoid glycosides are considered characteristic of the Bignoniaceae family broadly.

3.5 General Phenolic Content

All the organic soluble fractions of C. radicans contained phenolic compounds varying from 6.38 to 60.13 mg of gallic acid equivalents (GAE) per gram of extractive, while in DPPH assay, the ethyl acetate soluble fraction (EASF) showed the highest free radical scavenging activity with IC₅₀ of 4.69 μg/ml.

4. Scientific Evidence by Area of Use

Important caveat on evidence quality: The overwhelming majority of pharmacological research on C. radicans is preclinical — conducted in laboratory cell culture (in vitro) or in rodent models (in vivo). A 2024 review published in Phytochemistry Reviews summarized therapeutic applications of C. radicans in wound healing, anti-inflammatory interventions, cancer management, and potential prospects in neurology and cardiology. No controlled human clinical trials of C. radicans as an isolated therapeutic agent have been identified in the peer-reviewed literature. All findings described below should be understood as preliminary, mechanistic, or animal-based unless otherwise stated.

4.1 Antioxidant Activity

In vitro antioxidant activity of organic soluble fractions of crude methanol extract of C. radicans leaf was investigated using appropriate experimental models. In the DPPH free radical scavenging assay, the ethyl acetate soluble fraction showed the highest free radical scavenging activity with an IC₅₀ of 4.69 μg/ml. While this IC₅₀ value indicates potent in vitro scavenging, it has not been translated to human studies. The antioxidant activity is attributed primarily to the high phenolic and flavonoid content of the plant's extracts.

4.2 Analgesic (Pain-Reducing) Activity

Tail immersion procedure and acetic acid-induced writhing model were used to measure the analgesic activity of C. radicans in an animal (mouse) study. In both tail immersion and acetic acid-induced writhing models, the PESF, DMSF, and EASF fractions at the doses of 200 and 400 mg/kg body weight induced a significant (P < 0.001) decrease in painful sensation in mice. The result shows that the tested soluble fractions (200 and 400 mg/kg body weight) and the standard drug diclofenac sodium (2 mg/kg body weight) significantly (P < 0.001) reduced abdominal writhing in mice when compared to the negative control group, reducing the mean number of writhing from 17.66 in the negative group to 5.0 by the dichloromethane fraction at the dose of 400 mg/kg body weight. Evidence is entirely preclinical (mouse models); no human analgesic trials exist.

4.3 Thrombolytic (Clot-Dissolving) Activity

The thrombolytic activity was assessed by measuring clot lysis ability. The petroleum ether soluble fraction (PESF) exhibited the highest thrombolytic activity at 57.14% clot lysis. This in vitro thrombolytic finding is consistent with the plant's traditional use as an anticoagulant and for menstrual disorders. The plant has a reported anticoagulant property and is reported to be useful for treatment of gynecological disorders. These results remain in vitro; clinical translation has not been established.

4.4 Hypoglycemic Activity

Hypoglycemic activity was determined by oral glucose tolerance test in mice. The study by Islam et al. (2019) demonstrated that soluble fractions of C. radicans leaf extract exhibited hypoglycemic effects in this animal model. All findings revealed that C. radicans possesses significant antioxidant, thrombolytic, membrane stabilizing, analgesic, hypoglycemic, anti-diarrheal, and CNS antidepressant activities in preclinical models. The hypoglycemic effect has not been studied in human subjects.

4.5 Anti-Diarrheal Activity

Anti-diarrheal activity was determined by a castor oil-induced diarrheal model in mice. The anti-diarrheal activity of the experimental plant samples could be mediated by phytoconstituents like alkaloids, terpenes, glycosides, tannins, and flavonoids present in C. radicans. This represents mouse model data only.

4.6 CNS Antidepressant Activity

The CNS antidepressant activity was evaluated by thiopental sodium-induced sleeping time test. This test evaluated whether the experimental soluble fractions of C. radicans extract would be able to reduce the duration of sleep caused by thiopental sodium administration in mice. All soluble fractions showed statistically significant (p < 0.01) antidepressant activity. The study demonstrated that administration of 200 and 400 mg/kg body weight doses of organic soluble fractions of C. radicans leaves showed significant antidepressant properties. The proposed mechanism involves the flavonoid content: phytochemical constituents such as flavonoids have been reported to exhibit antidepressant action on the CNS. All findings are from rodent models; no human data exists.

4.7 Membrane Stabilizing Activity

The dichloromethane soluble fraction (DMSF) showed maximum 53.95% inhibition of heat-induced hemolysis of human red blood cells. Membrane stabilization is considered a proxy marker for anti-inflammatory potential, as it suggests the ability of an extract to protect cell membranes from damage — a property associated with several of the plant's flavonoid constituents.

4.8 Antibacterial and Antifungal Activity

Human infections such as Haemophillus and Candida have been treated using the plant as a medicine. In a laboratory study examining silver nanoparticles synthesized from C. radicans petal extracts, prominent zones of inhibition were observed against all tested bacterial strains by both nanoparticle preparations. CrAg nanoparticles showed 77.3% lipase inhibition and 75.1 ± 0.65% urease inhibition. These antimicrobial results relate to biogenically synthesized nanoparticles derived from the plant — not to crude plant extracts consumed directly — and remain in vitro findings.

4.9 Antiproliferative / Anticancer Activity

A 2024 review provided an overview of the therapeutic applications of C. radicans in cancer management. A separate study investigated antiapoptotic effects of C. radicans in the human colon adenocarcinoma cell line (HT-29), performing cytotoxic activity experiments on this cell line. Research on apigenin — one of the principal flavonoids isolated from the plant — has documented anti-inflammatory and potentially anticancer properties; however, these findings pertain to the isolated compound across many plant sources and are not specific to C. radicans-derived preparations. Evidence for anticancer activity of C. radicans itself is at an early in vitro stage.

4.10 Anti-Inflammatory Activity

Intraperitoneal administration of acetic acid elicits an inflammatory response via the production of prostaglandins PGE₂ and PGF₂α and histamine in the peritoneal fluid of experimental animals. These endogenous products induce pain and inflammation in mice. The soluble fractions at doses of 200 and 400 mg/kg body weight significantly inhibited the number of abdominal constrictions induced by the injection of acetic acid, indicative of analgesic activity of C. radicans through inhibition of pain mediators. The plant possesses antioxidative and anti-inflammatory properties as demonstrated in preclinical and in vitro models. Clinical evidence for anti-inflammatory efficacy in humans is absent.

4.11 Wound Healing

Data and information synthesized from original research articles, meta-analyses, systematic reviews, and pertinent animal studies provide an overview of the therapeutic applications of C. radicans in wound healing and anti-inflammatory interventions. The wound healing application is historically supported by the plant's vulnerary (wound-healing) designation in traditional medicine systems, and preclinical data suggest antioxidant and membrane-stabilizing properties that could contribute to this effect. No human wound-healing trials have been published.

4.12 Neurological and Cardiovascular Prospects

A 2024 review by Killi et al. dedicated to revealing the biomedical potential of C. radicans presented an overview of the therapeutic use of this plant in inflammatory processes, in the treatment of cancer, and prospects for use in neurology and cardiology. These neurological and cardiovascular applications remain prospective and exploratory, supported by mechanistic rationale from phytochemical data rather than clinical evidence.

A related species, Campsis grandiflora, has been studied by network pharmacology for its principal active ingredient apigenin: through ingredient–target–pathway network analysis, apigenin was identified as the main active ingredient of Lingxiaohua — a flavonoid natural compound found in C. grandiflora. Research on C. grandiflora may inform understanding of C. radicans given their overlapping phytochemistry, but species-specific findings should not be conflated.

5. Body Systems and Health Areas Associated with Trumpet Vine

• Cardiovascular / Hematological system: Anticoagulant and thrombolytic properties; traditional use for blood stasis and improving circulation.
• Reproductive / Gynecological system: Traditional use in China for the treatment of abnormal menstruation and dysmenorrhea.
• Dermatological system: Used to treat dermatological disorders. Topical wound healing, anti-itch, and antifungal skin applications in traditional practice.
• Metabolic / Endocrine system: Preclinical hypoglycemic activity demonstrated in mouse oral glucose tolerance testing.
• Gastrointestinal system: Preclinical anti-diarrheal activity in mouse models; traditional use for digestive complaints.
• Central nervous system: Preclinical antidepressant-like activity in rodent sleeping-time tests.
• Immune / Antimicrobial system: In vitro antibacterial and antifungal activity; traditional use against Candida and bacterial infections.
• Musculoskeletal system: Traditional use to alleviate symptoms such as joint pain and swelling caused by injuries.

6. Dosage Forms and Dosages Reported in Studies

There are no established human clinical dosage guidelines for Campsis radicans as an isolated supplement. The following dosages appear in the preclinical literature only:

• Animal model dosages (mice): Administration of 200 and 400 mg/kg body weight doses of organic soluble fractions of C. radicans leaves showed significant antidepressant properties in mice using thiopental-sodium induced sleeping time tests.
• Animal model dosages for analgesia: The PESF, DMSF, and EASF fractions at the doses of 200 and 400 mg/kg body weight induced a significant (P < 0.001) decrease in painful sensation in mice in both tail immersion and acetic acid induced writhing models.
• Extraction methodology reported: The leaves of C. radicans were collected, authenticated, dried and extracted with methanol at room temperature for 30 days. The concentrated methanol extract was partitioned to petroleum-ether (PESF), dichloromethane (DMSF), and ethyl acetate (EASF) soluble fractions.
• Nanoparticle preparation (research context): The size of silver nanoparticles synthesized from C. radicans petal extracts (CrAg) was 8.58 nm, used in antimicrobial testing — this represents a laboratory research preparation, not a consumer dosage form.

No standardized extract, defined daily dose, or pharmacopeial dosage specification for oral or topical use in humans has been identified in the reviewed sources.

7. Safety Considerations and Known Interactions

7.1 Contact Dermatitis

Campsis radicans is known to cause contact dermatitis when its leaves, stems, or flowers are handled, leading to skin redness, swelling, and intense itching that can last from minutes to several days depending on individual sensitivity. This irritant effect on mammalian skin, including that of livestock such as cattle, contributes to one of its common names, "cow-itch vine." The plant can cause contact dermatitis. The skin-irritant mechanism involves iridoid compounds and phenolic substances present in the plant's sap.

7.2 Oral Ingestion Toxicity

Ingestion of any part of the plant except the fruit can result in mild gastrointestinal upset in humans and other mammals, with symptoms including nausea, vomiting, and diarrhea. In more pronounced cases, ingestion may cause additional effects such as gastric irritation, dilated pupils, and numbness in the extremities. The plant is slightly toxic if ingested, and contact with flowers and leaves can result in swelling and skin redness.

7.3 Risk of Confusion with Toxic Lookalikes

Lingxiaohua is frequently confused with poisonous Yangjinhua (Daturae Metelis Flos, Datura metel Linnaeus) in the Chinese herbal medicine market, resulting in serious anticholinergic poisoning. The confusion of these two herbs is due to the similarity in their appearances. This is a documented safety concern in traditional Chinese medicine contexts, and correct botanical identification is critical.

7.4 Overall Toxicity Classification

Trumpet vine has low severity poison characteristics according to the North Carolina Cooperative Extension Service. Lingxiaohua (the dried flower preparation) is classified as non-poisonous; however, misuse of similar-looking herbs has caused adverse cases.

7.5 Livestock Concerns

The foliage is typically unpalatable to livestock like cattle but remains toxic if consumed, potentially exacerbating digestive issues in grazing animals.

7.6 Anticoagulant Activity and Drug Interactions

Given the documented in vitro thrombolytic and anticoagulant properties of C. radicans preparations, the plant has great anticoagulant property and is reported to be useful for treatment of gynecological disorders. Theoretically, this property could interact with pharmaceutical anticoagulants or antiplatelet medications. No formal drug interaction studies in humans have been published. This interaction concern is extrapolated from preclinical pharmacological data and is not yet supported by clinical evidence.

7.7 Evidence Gaps and Research Limitations

Extensive literature search indicates that there is no significant body of controlled clinical trial data for C. radicans in human populations. The available pharmacological studies are largely limited to mouse and rat models and in vitro cell culture systems. Doses used in animal studies (200–400 mg/kg body weight) cannot be directly extrapolated to human equivalents without additional pharmacokinetic and safety data. The overall evidence base for any therapeutic application of trumpet vine in humans must therefore be characterized as preliminary and insufficient to support health claims.

References

• Islam M, Jannat T, Kuddus MR, Rashid MA. "In vitro and in vivo evaluation of pharmacological potentials of Campsis radicans L." Clinical Phytoscience 5, 42 (2019). Springer Nature / SpringerOpen.
• Killi UK et al. "Exploring the biomedical applications of Campsis radicans (woody vine): integrating traditional wisdom and contemporary insights." Phytochemistry Reviews. Springer Nature, 2024.
• Islam M, Kuddus MR, Rashid MA, Haque MR. "Phytochemical investigations of Campsis radicans L." Journal of Applied Pharmaceutical Research 8(3), 55–59. 2020.
• Hashem FA. "Investigation of Free Radical Scavenging Activity by ESR for Coumarins Isolated from Tecoma radicans." Journal of Medical Sciences 7, 1027–1032. 2007.
• Iltaf S et al. "Synthesis and morphological & biological characterization of Campsis radicans and Cascabela thevetia petals derived silver nanoparticles." Biocatalysis and Agricultural Biotechnology. ScienceDirect, 2022.
• Wang X et al. "Differentiation of Lingxiaohua and Yangjinhua by chloroplast genome sequencing and DNA barcoding markers." Genome. Canadian Science Publishing, 2022.
• PMC11463827. "Network pharmacology combined with experimental validation show that apigenin as the active ingredient of Campsis grandiflora flower against Parkinson's disease by inhibiting the PI3K/AKT/NF-κB pathway." PMC / PubMed Central, 2024.
• Wikipedia contributors. "Campsis radicans." Wikipedia, The Free Encyclopedia. (Used for taxonomic history and common names; cross-referenced with primary sources.)
• North Carolina Cooperative Extension Service. "Campsis radicans (Trumpet Vine)." NC State Extension Gardener Plant Toolbox.
• Missouri Botanical Garden Plant Finder. "Campsis radicans." Missouri Botanical Garden.
• Native Plant Trust. "Campsis radicans (trumpet-creeper)." Go Botany.
• ResearchGate. "Bioactive Compounds from Campsis radicans L.: Antioxidant and Antiproliferative Effects on Colon Cancer Cells." 2024.
• Grokipedia. "Campsis radicans." (Cited for toxicity summary cross-referenced with primary botanical sources.)