Huang Pi Ye

Huang Pi Ye (Clausena lansium leaf, also known as wampee leaf) is the dried leaf of Clausena lansium (Lour.) Skeels, a small evergreen tree or shrub in the family Rutaceae. In the traditional TCM classification system, Huang Pi Ye is considered pungent and bitter in flavor with a slightly warm nature. It enters the Lung, Liver, and Spleen meridians, giving it a traditional role in formulas that address Qi stagnation, Wind-Cold invasion, and phlegm accumulation. Huang Pi Ye is primarily a regional folk herb widely used in southern Chinese provinces including Guangdong, Guangxi, and Hainan, where the wampee tree is commonly cultivated for both its fruit and medicinal leaves.

Botanical description: Clausena lansium is a small evergreen tree or large shrub reaching 6-12 meters in height. The tree is characterized by odd-pinnately compound leaves, 15-30 cm long, bearing 5-13 leaflets. The leaflets are ovate to elliptic-lanceolate, 4-13 cm long and 2-6 cm wide, with a dark green upper surface and a paler, pubescent lower surface. The leaf margins are entire to shallowly undulate, slightly revolute. A distinctive feature of the leaves is the presence of numerous small, translucent oil gland dots visible when the leaf is held against light. The leaves have a strong, characteristic aromatic odor when crushed, and the taste is slightly bitter and pungent. The tree produces small, white, fragrant flowers in terminal or axillary panicles, followed by globose to 扁球形 berries (wampee fruit), 1.2-3 cm in diameter, pale yellow to dark yellow when ripe, with a sweet-sour flavor and a thin, edible peel.

Habitat and cultivation: Clausena lansium is native to southern China, particularly the provinces of Guangdong, Guangxi, Fujian, and Hainan, and is also found in Vietnam, Laos, Thailand, and other parts of Southeast Asia. The tree prefers warm, humid subtropical and tropical climates and is widely cultivated in home gardens and orchards for its fruit, which is eaten fresh or processed into preserves, beverages, and traditional food products. The tree is relatively hardy and can be grown in a range of soil types, though it prefers well-drained, slightly acidic soils. In traditional medicinal practice, the leaves are harvested from cultivated trees, typically during the growing season, and dried in the shade for later use. The leaves used for medicinal purposes are usually collected from mature trees that are at least 3-5 years old.

Quality markers: Although Huang Pi Ye is not included in the Chinese Pharmacopoeia as a standalone monograph, traditional quality assessment criteria from folk medicine describe high-quality material as being dark green in color, intact leaves with visible oil gland dots, strong aromatic odor, and a distinctly bitter-pungent taste. The leaves should be free from mold, insect damage, and excessive stem material. The dried leaf material is brittle and easily crumbles when handled. The characteristic aroma is attributed to the essential oil content, which is considered a marker of quality and potency in traditional practice.

In the traditional Chinese medicine and folk medicine framework, Huang Pi Ye is understood in terms of its effects on specific patterns of disharmony (zheng). Because Huang Pi Ye enters the Lung, Liver, and Spleen meridians and has a pungent, bitter, and slightly warm quality, it is traditionally indicated for a range of patterns involving Qi stagnation, Wind-Cold invasion, and phlegm accumulation.

Regulating Qi and relieving pain: Huang Pi Ye is traditionally considered a Qi-regulating herb, meaning it is used in TCM theory to address patterns of Qi stagnation, which may manifest as abdominal distension, epigastric fullness, chest tightness, and wandering pain. The pungent and warm properties of the leaf are believed to promote the smooth flow of Qi through the Liver and Spleen meridians, thereby alleviating pain and discomfort. In traditional folk practice, a decoction of Huang Pi Ye is used for abdominal pain, gastric discomfort, and bloating. It is traditionally combined with Chen Pi (aged tangerine peel) and Mu Xiang (costus root) for Qi-regulating and pain-relieving purposes.

Dispelling Wind-Cold: In traditional folk medicine, Huang Pi Ye is used for common colds with Wind-Cold predominance. The pungent and warm nature of the herb is believed to dispel exterior Wind-Cold pathogens, releasing the exterior and relieving symptoms such as chills, fever, headache, nasal congestion, and body aches. In southern China, a hot decoction of fresh or dried Huang Pi Ye is a traditional home remedy for the early stages of the common cold. It may be combined with other Wind-Cold-dispelling herbs such as Zi Su Ye (perilla leaf) or Jing Jie (schizonepeta) to enhance the diaphoretic effect.

Resolving phlegm and stopping cough: Huang Pi Ye enters the Lung meridian and is traditionally used to resolve phlegm and relieve cough. In TCM theory, when the Lung's descending and dispersing functions are impaired by phlegm or external pathogens, symptoms such as cough, wheezing, and copious sputum may arise. Huang Pi Ye is believed to help transform phlegm and restore the Lung's normal descending function. It is traditionally used for cough with excessive phlegm, particularly in the context of Wind-Cold or phlegm-damp patterns.

Folk medicine uses: Beyond its TCM applications, Huang Pi Ye has a range of traditional folk uses in southern China. Fresh crushed leaves are applied externally for rheumatic pain, insect bites, and skin inflammation. A decoction of the leaves has been used in folk tradition for digestive disorders, including diarrhea, dysentery, and indigestion. Some traditional sources also describe the use of Huang Pi Ye for malaria, influenza, and as a preventive measure during epidemics. The leaf essential oil has been used in traditional aromatherapy for its aromatic and antimicrobial properties. These folk uses are based on generations of empirical observation and are not supported by robust clinical evidence.

Classical literature references: Huang Pi Ye is recorded in the Lingnan Cai Yao Lu (Guangdong Herbal Collection), a regional materia medica from southern China, which describes its traditional use for colds, coughs, abdominal pain, and rheumatic conditions. The herb is also mentioned in the Zhong Hua Ben Cao (Chinese Materia Medica) and various regional medicinal compilations from Guangdong and Guangxi. Unlike many classical TCM herbs, Huang Pi Ye does not have extensive references in the earliest TCM classics such as the Shen Nong Ben Cao Jing or theBen Cao Gang Mu, reflecting its status as a regional folk herb rather than a centrally prescribed classical TCM medicinal.

Huang Pi Ye contains a range of bioactive compounds that have been the subject of phytochemical and pharmacological investigation. The following overview summarizes the major chemical constituents identified in the leaves of Clausena lansium and what is currently known about them from published research.

Clausenamide and related amide alkaloids: Clausenamide is a gamma-lactam alkaloid and one of the most extensively studied constituents of Huang Pi Ye. It belongs to a family of structurally related amide alkaloids that are relatively specific to the Clausena genus. Related compounds include neoclausenamide, isoneoclausenamide, cycloclausenamide, and homoclausenamide. Pre-clinical studies have reported that clausenamide may exhibit hepatoprotective activity (reducing ALT elevation in CCl4-induced liver injury models), anti-amnesic effects in animal models, and potential neuroplasticity-promoting properties. A 2026 study published in ACS Chemical Neuroscience reported that synthetic clausenamide isomers promoted cortical neuron branching and synaptogenesis in vitro, suggesting potential relevance to cognitive function research. However, human clinical data for clausenamide are essentially absent.

Carbazole alkaloids: Huang Pi Ye contains a diverse array of carbazole alkaloids, including mukonal, clausenalansine A, clausenalansine B, and various geranylated carbazole derivatives. These compounds have been studied in pre-clinical research for potential neuroprotective, antimicrobial, and cytotoxic activities. Some geranylated carbazole alkaloids from Clausena lansium have been reported to exhibit potential neuroprotective effects in cell-based assays. The carbazole alkaloid CZK (a novel derivative from Clausena lansium) was reported in a 2023 study to alleviate ischemic stroke injury through Nrf2-mediated antioxidant effects in an animal model. Most of this research is at the pre-clinical stage, and the clinical relevance of these findings is not established.

Coumarins: Huang Pi Ye contains various coumarin compounds, including furanocoumarins such as imperatorin and 8-hydroxyfuranocoumarin derivatives. These compounds have been identified in phytochemical studies of Clausena lansium leaves and stems. Coumarins are widely distributed in the Rutaceae family and have been studied for anti-inflammatory, antimicrobial, and vasodilatory effects in pre-clinical models. Their specific contribution to the pharmacological profile of whole-herb Huang Pi Ye preparations has not been well characterized.

Essential oils: The leaves of Clausena lansium produce a volatile essential oil rich in sesquiterpenes and monoterpenes. Gas chromatography-mass spectrometry (GC-MS) analysis has identified beta-caryophyllene as the predominant constituent in leaf essential oil (up to 112 mg/mL), along with sabinene, 4-terpineol, beta-phellandrene, and alpha-phellandrene. A 2025 study published in Frontiers in Microbiology reported that the essential oil from Clausena lansium leaves exhibited antimicrobial and anti-biofilm activity against Streptococcus mutans, with a minimum inhibitory concentration of 0.12 mg/mL. The essential oil components are also responsible for the characteristic aromatic odor of the leaves.

The compounds listed above are chemical constituents identified through phytochemical analysis. Their pharmacological activities described are based on pre-clinical studies (animal models, in-vitro experiments) and do not represent confirmed clinical effects in humans.

Huang Pi Ye is primarily a folk herb rather than a core ingredient in classical TCM formulas. It is most commonly used in simple decoctions or as a single-herb preparation in southern Chinese folk medicine. However, several traditional combinations and preparation methods are described in regional medicinal literature.

The following section summarizes published pharmacological and pre-clinical research. Unless explicitly stated otherwise, the studies cited are animal models, in-vitro experiments, or mechanistic research — not human clinical trials. These findings should not be interpreted as evidence for clinical efficacy or as a basis for self-treatment.

Neuroplasticity and cognitive effects of clausenamide: Clausenamide, a prominent amide alkaloid from Clausena lansium leaves, has attracted research interest for its potential neuroplasticity-promoting properties. A 2026 study by Ou et al. published in ACS Chemical Neuroscience (PMID: 42089448) reported the synthesis of clausenamide isomers and evaluated their potential as cortical neuroplastogens. The study found that specific clausenamide isomers promoted cortical neuron branching and synaptogenesis in vitro, suggesting potential relevance to cognitive function and neuroregeneration research. These findings are preliminary and represent in-vitro observations; human clinical data are needed to determine any translational relevance.

Antimicrobial and anti-biofilm activity of essential oils: The essential oil extracted from Clausena lansium leaves has been investigated for antimicrobial properties. A 2025 study by Wu et al. published in Frontiers in Microbiology (PMID: 40950592) comprehensively evaluated the antimicrobial and anti-biofilm activity of essential oils from Clausena lansium leaves (EOL), seeds, and peels against Streptococcus mutans, a key pathogen in dental caries. The leaf essential oil, with beta-caryophyllene as the predominant constituent, demonstrated the strongest activity with a minimum inhibitory concentration of 0.12 mg/mL. The essential oil also significantly inhibited biofilm formation and downregulated the expression of virulence genes (brpA, gtfB, gtfC, gtfD, luxS). These findings are promising but represent in-vitro data that require further investigation in clinical settings.

CZK alkaloid and neuroprotection: A novel carbazole alkaloid derivative from Clausena lansium, designated CZK, was investigated for its potential neuroprotective effects against ischemic stroke injury. A study by Chen et al. (PMID: 37055457) reported that CZK alleviated cerebral ischemia-reperfusion injury in an animal model through Nrf2-mediated antioxidant mechanisms. The study found that CZK treatment reduced infarct volume, improved neurological function, and attenuated oxidative stress in the brain tissue of experimental animals. While these findings are scientifically interesting, they represent animal model data, and the translational relevance to human ischemic stroke has not been established.

L-Clausenamide and acute lung injury: A 2025 study by Fu et al. published in Biology (PMID: 40723395) investigated the potential therapeutic effects of L-clausenamide in acute lung injury using network pharmacology, molecular docking, and in-vitro validation. The study identified multiple potential molecular targets of L-clausenamide and suggested that it may exert anti-inflammatory effects through modulation of relevant signaling pathways. These findings are based on computational and in-vitro approaches and require validation in animal models and human studies.

Hepatoprotective effects: Pre-clinical studies have reported that clausenamide and related compounds from Clausena lansium may exhibit hepatoprotective activity. Early research demonstrated that oral administration of clausenamide, neoclausenamide, and cycloclausenamide reduced alanine aminotransferase (ALT) activity in CCl4-induced liver injury models in mice. A 2009 study by Adebajo et al. published in Journal of Ethnopharmacology (PMID: 19095054) investigated the pharmacological properties of Clausena lansium stem bark extract and reported hepatoprotective, antioxidant, anti-inflammatory, and antidiabetic effects in pre-clinical models. These hepatoprotective findings are based on animal studies and do not constitute evidence of clinical efficacy for liver disease in humans.

What the research does NOT show: Despite promising pre-clinical signals, the research on Huang Pi Ye and its active compounds does NOT demonstrate conclusive clinical efficacy for any specific disease in humans. There is no robust evidence from large-scale, randomized, placebo-controlled clinical trials that Huang Pi Ye can treat, cure, or prevent cardiovascular disease, cognitive disorders, infections, liver disease, or any other medical condition. The translation from in-vitro and animal models to human clinical relevance is uncertain. This page does not endorse Huang Pi Ye as a treatment for any condition.

Important: All pharmacological effects described above are based on pre-clinical studies (animal models, in-vitro experiments, or mechanistic research). They do not constitute evidence of clinical efficacy in humans. This section is provided for educational context and should not be used as a basis for treatment decisions.

General safety profile: Huang Pi Ye is a folk herb with a limited formal safety assessment. Published safety data specific to Huang Pi Ye are scarce, and the herb is not included in the Chinese Pharmacopoeia as a standalone monograph. The information below reflects what is currently known from published literature, traditional folk experience, and general principles of herbal safety. The overall safety profile of Huang Pi Ye is not well characterized, and caution is warranted when considering its use.

Yin deficiency with Heat: In traditional TCM theory, Huang Pi Ye is pungent and slightly warm in nature. Individuals with Yin deficiency patterns presenting with Heat signs — such as dry mouth and throat, a red tongue with scanty or no coating, night sweats, and irritability — should generally avoid Huang Pi Ye. Its warm, drying nature may theoretically aggravate deficiency Heat and further damage Yin fluids. Such individuals should only use Huang Pi Ye under professional guidance with appropriate Yin-nourishing or Heat-clearing herbs if at all.

Excessive Heat patterns: In TCM theory, Huang Pi Ye's warm nature makes it less suitable for conditions involving excessive Heat, such as high fever, severe sore throat, red and swollen gums, or constipation with abdominal pain. For such presentations, the herb's warm, dispersing properties are considered theoretically inappropriate. Huang Pi Ye is traditionally reserved for Cold-pattern conditions or Qi stagnation patterns rather than Heat-pattern presentations.

Pregnancy and lactation: Huang Pi Ye does not have well-documented traditional safety data regarding use during pregnancy. Because of its pungent, warm, and Qi-regulating properties, it is traditionally considered that pregnant women should use it with caution, particularly in the early stages of pregnancy. Modern pre-clinical data on Huang Pi Ye constituents in pregnancy are insufficient to fully establish safety. Do not use Huang Pi Ye during pregnancy without direct supervision from a qualified healthcare professional.

Drug interactions: Pre-clinical data on Huang Pi Ye's potential for drug interactions are very limited. Given that some of its constituents, including carbazole alkaloids and essential oil components, may affect hepatic metabolizing enzymes, there is theoretical potential for interactions with drugs processed through these pathways. The essential oil components may also have theoretical additive effects when combined with sedatives or central nervous system depressants. However, clinical interaction data for whole-herb Huang Pi Ye in humans are essentially absent. Consult a qualified healthcare professional before combining Huang Pi Ye with any prescription medications.

Allergic reactions: Individuals with known allergies to plants in the Rutaceae family (which includes citrus plants, Zanthoxylum, and related genera) should exercise caution when using Huang Pi Ye. The essential oil content and alkaloid constituents may act as potential allergens in sensitive individuals. Symptoms of allergic reaction may include skin rash, itching, swelling, or respiratory discomfort. Any suspected adverse effects should be reported to a healthcare professional immediately.

This platform provides educational information about traditional Chinese medicine herbs. It does not recommend, endorse, or prescribe the use of Huang Pi Ye or any other herbal product for the treatment of any medical condition. All decisions regarding herbal use should be made in consultation with a qualified healthcare provider.