Gua Lou Pi
StarTrichosanthes kirilowii Maxim.
Traditionally used for
- Cough & breathing
- Heart & circulation
Cautions & contraindications
- Pregnancy
☯ TCM Properties
Clears Heat and Transforms Phlegm; Opens the Chest and Disperses Stagnation; Clears Lung Heat and Stops Cough; Dissipates Nodules and Softens Hardness
Traditional Chinese Uses
Gua Lou Pi (trichosanthes fruit peel) is a cool, sweet-bitter herb used to clear Phlegm-Heat from the Lungs and relieve chest tightness. It addresses coughs with thick, yellow, difficult-to-expectorate phlegm associated with Lung Heat, and its Qi-regulating action relieves the constricting chest fullness and pain of Phlegm-Heat obstructing the thorax. It is a key ingredient in classical formulas for both Lung Heat cough and chest pain related to cardiac conditions.
Relationships
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Botanical Description
Trichosanthes kirilowii is a perennial dioecious climbing vine in the Cucurbitaceae, native to northern and central China, Korea, and Japan. From a large fleshy tuberous root system, slender ridged stems climb by branched tendrils to 5 metres or more. The alternate leaves are deeply palmately three- to seven-lobed with coarsely toothed margins. White flowers, the corolla lobes fringed with long thread-like segments, open at dusk; male flowers are borne in racemes, female flowers solitary. The fruit is a smooth ovoid to globose pepo about 8-10 cm in diameter, ripening from green to orange-yellow, with a thin leathery rind enclosing yellow pulp and flat ovate seeds. The dried mature rind, separated from pulp and seed, constitutes Gua Lou Pi.
Active Constituents
Cynaroside (luteolin-7-O-beta-D-glucoside)
Flavone glycosideConcentration: One of the principal flavonoid glycosides of the dried ripe pericarp; a marker compound of Trichosanthis Pericarpium extracts
Identified by network pharmacology plus experimental verification as one of the antithrombotic active compounds of the pericarp, acting on platelet function and oxidative-stress pathways in a rat coronary heart disease model. It is also one of the flavonoid glycosides in the total-flavonoid fraction shown to blunt inflammation and mucus hypersecretion in COPD models.
Isoquercitrin (quercetin-3-O-beta-D-glucoside)
Flavonol glycosideConcentration: Minor flavonoid glycoside of the pericarp
One of five constituents identified as antithrombotic actives of Trichosanthis Pericarpium in a 2024 network-pharmacology and rat study. Contributes antioxidant and platelet-modulating activity rather than any direct expectorant action.
Rutin (quercetin-3-O-rutinoside)
Flavonol glycosideConcentration: Minor flavonoid glycoside of the pericarp
Reported among the antithrombotic actives of the pericarp and among the flavonoid glycosides of the total-flavonoid fraction active in COPD models. Widely distributed and not specific to this drug.
Apigenin-7-O-glucoside
Flavone glycosideConcentration: Component of the total flavonoid fraction of Trichosanthis Pericarpium
One of the flavonoid glycosides credited, with luteolin-7-O-glucoside and rutin, with reducing airway inflammation and mucus hypersecretion via EGFR/PI3K/AKT and EGFR/STAT3 signalling in cell and rodent COPD models.
Diosmetin-7-O-beta-D-glucopyranoside
Flavone glycosideConcentration: Constituent of the pericarp; used as one of three components of a reconstituted active combination
With paeonol and 5-hydroxymethylfurfural, one of three pericarp constituents whose combination reduced arachidonic-acid-induced thrombosis in a zebrafish model, supporting the traditional chest-opening use.
5-Hydroxymethylfurfural
Furan aldehyde (Maillard-type sugar degradation product)Concentration: Present in the aqueous extract; content rises with heating and processing of the sugar-rich peel
Part of the three-component combination active against arachidonic-acid-induced thrombosis in zebrafish. It is a processing artefact of a sugar-rich drug rather than a biosynthetic secondary metabolite, so its level is a marker of how the peel was dried and stored.
Paeonol
Phenolic ketone (acetophenone)Concentration: Reported constituent of Trichosanthis Pericarpium
Reported from the pericarp and used as one of the three components of the antithrombotic combination tested in zebrafish. Better known from Moutan Cortex, so its presence here should be read as a shared minor constituent, not a marker of identity.
Citrulline
Non-protein amino acidConcentration: About 40 percent of the total free amino acids of the pericarp; total amino acids in the pericarp about 7.6 mg/g
The dominant free amino acid of the peel and one of the antithrombotic actives identified in the 2024 rat study. As a nitric-oxide precursor it is a plausible contributor to the vasorelaxant and endothelium-protective effects attributed to the drug.
Arginine
Amino acidConcentration: Present among the free amino acids of the pericarp
Listed with citrulline among the antithrombotic active compounds of the pericarp; both feed the nitric-oxide pathway implicated in the cardioprotective activity of Trichosanthis Pericarpium aqueous extract.
Fructose
MonosaccharideConcentration: About 21 percent of the dried pericarp by comparative HPLC-ELSD analysis of nine plant parts
Sugars dominate the mass of the peel and account for its sweet taste and syrupy decoction. They are not the pharmacologically interesting fraction, but they explain the drug's high caloric load and its tendency to generate 5-hydroxymethylfurfural on heating.
⚠ Drug Interactions
Trichosanthis Radix (Tian Hua Fen, the root of the same plant; source of trichosanthin)
Trichosanthin, the type-1 ribosome-inactivating protein responsible for the abortifacient, anaphylactogenic and hepatorenal toxicity attributed to Tian Hua Fen, is a protein of the root tuber. Gua Lou Pi is the dried ripe pericarp of the fruit; the peel's characterised chemistry is flavonoid glycosides, free amino acids and sugars, and trichosanthin is not among its reported constituents. The two drugs come from one plant and share the pinyin root, which is exactly the circumstance in which a dispensing substitution goes unnoticed.
Clinical note: Do not carry Tian Hua Fen's pregnancy contraindication or its RIP toxicity onto the fruit peel. Conversely, confirm on the packing slip that what was supplied is Trichosanthis Pericarpium and not Trichosanthis Radix, particularly for a pregnant patient.
Aconitum species (Chuan Wu, Cao Wu, Fu Zi)
Trichosanthes (lou) is one of the five drugs set against Wu Tou in the eighteen incompatibilities couplet (ban lou bei lian ji gong wu), and the prohibition is normally read as covering all the Trichosanthes drugs including the pericarp. Modern experimental work on the aconite incompatible pairs has concentrated on Fritillaria and Pinellia, where P-glycoprotein inhibition raising the intestinal permeability of the aconite alkaloid benzoylmesaconine has been demonstrated. Comparable data for a Trichosanthis Pericarpium and aconite pair are sparse, so the interaction rests on classical authority and on the general finding that co-prescribed drugs can raise aconite alkaloid exposure.
Clinical note: Most pharmacopoeial and regulatory prescribing conventions treat the combination as prohibited. Given that aconite's therapeutic index is narrow and the modern mechanism found in sibling pairs increases alkaloid absorption, do not combine them outside a controlled setting.
Antiplatelet and anticoagulant drugs (aspirin, clopidogrel, warfarin, direct oral anticoagulants)
Pericarp flavonoid glycosides and amino acids reduce platelet activation and thrombosis in a rat coronary heart disease model, and a three-constituent combination from the peel reduced arachidonic-acid-induced thrombus formation in zebrafish. Both are preclinical; no human pharmacodynamic or bleeding data exist for Trichosanthis Pericarpium.
Clinical note: No dose change is required on present evidence. If the patient is already anticoagulated or is approaching surgery, note the herb in the record and ask about bruising and gum bleeding at follow-up.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6–10 g | Daily | — | — | 中国药典 2020 【用法与用量】6～10g。 【注意】不宜与川乌、制川乌、草乌、制草乌、附子同用。 【性味与归经】甘，寒。归肺、胃经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Moderate evidence · 5 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
5
1 verified · 4 unverified
Show 5 studies
- Network pharmacology analysis and experimental verification of the antithrombotic active compounds of trichosanthis pericarpium (Gualoupi) in treating coronary heart disease
- Unraveling the pharmacodynamic substances and possible mechanism of Trichosanthis Pericarpium in the treatment of coronary heart disease based on plasma pharmacochemistry, network pharmacology and experimental validation
- Study on the mechanism of Trichosanthes kirilowii Maxim. against COPD based on serum chemical composition analysis, network pharmacology, and experimental study
- The combination of paeonol, diosmetin-7-O-β-D-glucopyranoside, and 5-hydroxymethylfurfural from Trichosanthis pericarpium alleviates arachidonic acid-induced thrombosis in a zebrafish model
- Trichosanthis Pericarpium Aqueous Extract Protects H9c2 Cardiomyocytes from Hypoxia/Reoxygenation Injury by Regulating PI3K/Akt/NO Pathway
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Network pharmacology analysis and experimental verification of the antithrombotic active compounds of trichosanthis pericarpium (Gualoupi) in treating coronary heart disease
Network pharmacology combined with experimental verification in a rat coronary heart disease model identified cynaroside, isoquercitrin, rutin, citrulline and arginine as the antithrombotic active compounds of the pericarp, acting through oxidative stress injury and platelet function. This is preclinical work on the peel specifically, not on the whole fruit or the root.
Unraveling the pharmacodynamic substances and possible mechanism of Trichosanthis Pericarpium in the treatment of coronary heart disease based on plasma pharmacochemistry, network pharmacology and experimental validation
Plasma pharmacochemistry was used to establish which pericarp constituents are actually absorbed after dosing, and the resulting candidates were tested in a rodent coronary heart disease model. The design addresses the usual weakness of network-pharmacology papers, which model compounds that may never reach the circulation.
Study on the mechanism of Trichosanthes kirilowii Maxim. against COPD based on serum chemical composition analysis, network pharmacology, and experimental study
Serum chemical composition analysis predicted the absorbed constituents of the pericarp, and the total flavonoid fraction was then tested in vivo and in vitro. The fraction reduced airway inflammation and mucus hypersecretion, attributed to luteolin-7-O-glucoside, rutin and apigenin-7-O-glucoside acting on EGFR/PI3K/AKT and EGFR/STAT3 signalling. This is animal and cell work supporting, but not establishing, the traditional phlegm-transforming indication.
The combination of paeonol, diosmetin-7-O-β-D-glucopyranoside, and 5-hydroxymethylfurfural from Trichosanthis pericarpium alleviates arachidonic acid-induced thrombosis in a zebrafish model
A defined three-component combination drawn from the pericarp reduced arachidonic-acid-induced thrombus formation in zebrafish. A reconstitution design of this kind is stronger evidence that the named compounds carry the activity than a whole-extract experiment, but zebrafish thrombosis is a screening model and the result does not transfer to human dosing.
Trichosanthis Pericarpium Aqueous Extract Protects H9c2 Cardiomyocytes from Hypoxia/Reoxygenation Injury by Regulating PI3K/Akt/NO Pathway
An aqueous extract of the pericarp protected rat H9c2 cardiomyocytes against hypoxia and reoxygenation injury, with the effect traced to PI3K/Akt signalling and nitric oxide production. A single cell-line study; it is consistent with the high citrulline and arginine content of the peel but does not by itself support a clinical cardioprotective claim.
Historical Texts
Jin Gui Yao Lue (Essential Prescriptions of the Golden Cabinet), Zhang Zhongjing
Eastern Han dynasty, c. 200-220 CEShen Nong Ben Cao Jing (Divine Husbandman's Classic of the Materia Medica)
Han dynasty, c. 200 CERu Men Shi Qin (Confucians' Duties to Their Parents), Zhang Congzheng (Zhang Zihe)
Jin dynasty, 13th centuryReferences
- Yu X, Tang L, Wu H, Zhang X, Luo H, Guo R, et al.. Trichosanthis Fructus: botany, traditional uses, phytochemistry and pharmacology . Journal of Ethnopharmacology (2018) [DOI]
- Zhang HQ, Liu P, Duan JA, Dong L, Shang EX, Qian DW, et al.. Comparative Analysis of Carbohydrates, Nucleosides and Amino Acids in Different Parts of Trichosanthes kirilowii Maxim. by (Ultra) High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry and Evaporative Light Scattering Detector Methods . Molecules (2019) [DOI]
- Wang Y, Wang H, Wu M, Gao X, Gao Y, Zhao P, et al.. Rapid Identification of Chemical Components and Screening of Beta–Klotho Agonists From Trichosanthes pericarpium Aqueous Extract Based on Affinity Ultrafiltration and Liquid Chromatography–Tandem Mass Spectrometry . Journal of Separation Science (2026) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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