Pang Da Hai
StarSterculia lychnophora Hance
☯ TCM Properties
Clears Heat and Moistens the Lungs; Benefits the Throat and Restores the Voice; Moistens the Intestines and Unblocks the Bowels; Diffuses Lung Qi; Clears Heat and Resolves Toxicity
Traditional Chinese Uses
Pang Da Hai (sterculia seed, boat-fruited sterculia) is a cold, sweet herb that expands dramatically in water. It clears Lung Heat to moisten and soothe the throat, addressing sore throat, hoarseness, and loss of voice caused by heat. It also gently lubricates the intestines to relieve constipation and resolves heat patterns involving the eyes. Commonly steeped as a single-herb tea, it is among the most popular herbs for voice care in East Asia.
Western Herbalism Properties
Botanical Description
Sterculia lychnophora Hance, now widely accepted as a synonym of Scaphium affine or Scaphium scaphigerum, is a large tropical deciduous tree in the family Malvaceae (formerly Sterculiaceae), reaching 30 to 40 meters tall with a straight, columnar trunk and a high, spreading crown. The leaves are alternate, simple, ovate, 10 to 20 cm long, leathery, with entire margins and a tapering tip; juvenile leaves are often deeply lobed. Small, greenish-yellow, bell-shaped flowers are borne in axillary or terminal panicles. The fruits are leaf-like, boat-shaped follicles 10 to 20 cm long that split open while still on the tree to expose one or two ellipsoid seeds about 2 to 3 cm long. The dried seeds, dark brown and wrinkled when collected, swell several times their original volume into a soft, gelatinous, sponge-like mass when soaked in water, due to a thick polysaccharide-rich seed coat. These swollen seeds constitute Pang Da Hai in Chinese medicine.
Active Constituents
Mucilage polysaccharides (bassorin-type)
Heteropolysaccharide / mucilageConcentration: Dominant fraction of the seed coat; responsible for swelling to several times its volume in water
Highly hydrophilic mucilage that swells markedly in water to form a jelly; underlies the demulcent, bulk-laxative and throat-soothing actions of the seed.
Acidic polysaccharide (galacturonic-acid rich)
Pectic acidic polysaccharideConcentration: Water-soluble acidic fraction alongside neutral polysaccharides
Composed largely of galacturonic acid; contributes to the mucilaginous, intestine-moistening and anti-inflammatory properties.
Sterculic acid
Cyclopropene fatty acidConcentration: ~55% of the seed fatty-acid fraction
A characteristic cyclopropenoid fatty acid of the seed oil; a chemical marker of the genus Sterculia.
Linoleic acid
Polyunsaturated fatty acidConcentration: Major fatty acid of the seed oil alongside sterculic acid
An essential fatty acid component of the seed oil.
Phenolic compounds and glycosides
Phenolics / glycosidesConcentration: Present in ethanol extracts
Contribute to reported antibacterial and anti-inflammatory activity of the seed.
Alkaloids
AlkaloidConcentration: Minor constituents isolated from the seeds
A group of nitrogenous constituents identified in the seeds; part of the overall phytochemical profile.
⚠ Drug Interactions
Oral medications taken concurrently (general absorption interaction)
The seed's abundant swelling mucilage can form a viscous gel in the gut that may, like other bulk-forming mucilages, slow or reduce absorption of drugs taken at the same time.
Clinical note: Separate ingestion of Pang Da Hai from critical oral medications by about 1-2 hours; ensure adequate fluid intake.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6-15g | Daily | — | — | — |
Preparation Methods
Infusion (steeped whole seed)
Parts: Seed
2-4 seeds steeped whole in hot or boiling water; the seed swells into a soft jelly and the mucilaginous infusion is sipped for sore throat, hoarseness and dry cough. Commonly taken as a herbal tea rather than heavily boiled.
Decoction
Parts: Seed
Included in decoctions (roughly 2-3 seeds per dose) to clear Lung heat, benefit the throat and moisten the intestines to relieve constipation. Best used short-term because of its cold nature.
Clinical Studies
Composition Analysis and Inhibitory Effect of Sterculia lychnophora against Biofilm Formation by Streptococcus mutans
Ethanol extract of S. lychnophora seeds showed dose-dependent antibacterial activity against Streptococcus mutans and inhibited biofilm formation, supporting anticariogenic and antibacterial potential.
Historical Texts
Ben Cao Gang Mu Shi Yi (Supplement to the Compendium of Materia Medica), Zhao Xuemin
Qing dynasty (1765)References
- Oppong MB, Li Y, Banahene PO, Fang SM, Qiu F. Ethnopharmacology, phytochemistry, and pharmacology of Sterculia lychnophora Hance (Pangdahai) . Chinese Journal of Natural Medicines (2018) [DOI]
- Yang Y, Park BI, Hwang EH, You YO. Composition Analysis and Inhibitory Effect of Sterculia lychnophora against Biofilm Formation by Streptococcus mutans . Evidence-Based Complementary and Alternative Medicine (2016) [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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