Sang Bai Pi
StarMorus alba L.
Traditionally used for
- Cough & breathing
- Colds & fever
- Bowel health
- Urinary & fluids
- Skin
☯ TCM Properties
Clears Lung Heat; Stops Cough and Calms Wheezing; Promotes Urination and Reduces Edema; Descends Lung Qi and Stops Cough
Traditional Chinese Uses
Sang Bai Pi (white mulberry root bark) is a cold, sweet herb that descends and clears Lung Qi. Its primary use is for cough and wheezing caused by Lung Heat — the respiratory presentation with fever, yellow phlegm, and difficulty breathing. It also drains fluid accumulation from the Lungs and promotes urination to relieve facial and skin edema, particularly when swelling is associated with Lung dysfunction. Its gentle downward-directing action makes it broadly applicable in Lung Heat and fluid retention patterns.
Western Herbalism Properties
Traditional Uses
The Cherokee used an infusion of the bark for several purposes: taken internally for worms, taken to check dysentery, used as a purgative, and taken as a laxative. The fruit was also used as food (Hamel and Chiltoskey, 1975).
Pharmacological Effects
- Diuretic and cathartic: Decoction (rabbits) and aqueous/butanolic extracts (rats) increased urine and Na/K/Cl excretion; oral aqueous extract caused watery stools in mice.
- Hypotensive: Various extracts lowered blood pressure in dogs, rabbits and rats; kuwanons G and H, sanggenones C and D and moracenins A–D were hypotensive i.v.
- Smooth muscle: Butanolic extract i.v. increased GI motility but relaxed isolated guinea pig ileum; extract stimulated isolated rabbit intestine and uterus.
- CNS: I.p. extracts sedated mice, reduced pain/touch sensitivity, caused mydriasis and reduced electroshock mortality; oral aqueous extract 2 g/kg analgesic comparable to aspirin 0.5 g/kg.
- Antibacterial: Mulberrofuran A and kuwanons I and L active against gram-positive bacteria (MIC in low µg/ml range).
- Hypoglycemic: Glycoprotein moran A (i.p.) lowered blood glucose in normal and alloxan-diabetic mice.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 505.
Relationships
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Botanical Description
Morus alba is a fast-growing deciduous tree in the Moraceae, native to northern and central China and now cultivated and naturalised across temperate and subtropical regions worldwide as the food plant of the silkworm. Trees commonly reach 10-20 m tall with a short, often crooked trunk, smooth grey-brown bark becoming rough and fissured with age, and a broad, spreading, rounded crown. The alternate leaves are highly variable in shape, from ovate and unlobed to deeply three- or five-lobed, 5-20 cm long, with serrate margins, glossy bright green upper surfaces and paler undersides. The species is usually dioecious; small greenish flowers are borne in short pendulous catkins, the male catkins slender and the female catkins shorter and denser. The aggregate fruit is a multiple drupe 1.5-3 cm long, ripening from white through pink to deep purple-black, sweet and juicy when ripe.
Active Constituents
Sanggenon C
Diels-Alder type adduct (chalcone plus dehydroprenylflavanone)Concentration: Isolated from the root bark of Morus alba; no pharmacopoeial assay limit assigned to it
Characterised in 1981 as a hypotensive Diels-Alder adduct from the crude drug Sang Bai Pi itself, so it is genuinely root-bark chemistry rather than a constituent borrowed from another part of the mulberry. Its blood-pressure-lowering activity is the best chemical explanation for the hypotensive effect of root-bark fractions in animals.
Kuwanon G
Diels-Alder type adduct (prenylated flavonoid dimer)Concentration: Root bark of cultivated Morus alba; not routinely quantified in commerce
The first hypotensive principle isolated from mulberry root bark, and with sanggenon C one of the two adducts that mark the root bark chemically. Also reported as antibacterial. Absent from the leaf drug, which makes the adduct class useful for distinguishing genuine root bark from leaf material.
Morusin
Prenylated flavone (isoprenylated flavonoid)Concentration: A principal isoprenylated flavonoid of Morus alba root bark
Bears an isoprenoid group at C-3 and a 2',4'-dioxygenated B ring. Shows stronger inhibition of nitric oxide production and inducible nitric oxide synthase than quercetin in cell assays, consistent with the anti-inflammatory and Lung-heat-clearing use of the drug. Cell-level evidence only.
Mulberrofuran G
2-Arylbenzofuran Diels-Alder type adductConcentration: Root bark of Morus alba; one of three Diels-Alder adducts routinely reported from this part
Together with sanggenon G and mulberrofuran C it forms the arylbenzofuran adduct group specific to the root bark. Contributes to the antibacterial and antioxidant activity attributed to the crude drug.
1-Deoxynojirimycin (moranoline)
Polyhydroxylated piperidine iminosugar alkaloidConcentration: Originally isolated from mulberry root bark, but present at far lower levels than in the leaf and twig; leaf material is reported around 0.10 to 0.12 percent, and no root-bark content limit exists
An intestinal alpha-glucosidase inhibitor that blunts postprandial glucose rise, and the compound on which the modern antidiabetic use of the genus rests. Critically for this record, it is far more concentrated in the leaf and twig than in the root bark, so the human hypoglycaemic trial data belong to those drugs and not to Sang Bai Pi.
Umbelliferone and scopoletin
Simple coumarins (7-hydroxycoumarin and its 6-methoxy derivative)Concentration: Minor constituents of Morus alba root bark; not quantified for quality control
Simple hydroxycoumarins reported alongside mucilage and tannins in the root bark. They are not 4-hydroxycoumarins and carry no intrinsic anticoagulant activity, a distinction worth keeping when patients ask whether a coumarin-containing herb thins the blood.
⚠ Drug Interactions
Commercial mulberry leaf extract supplements (Folium Mori, standardised to 1-deoxynojirimycin)
Morus alba supplies four separate drugs in this corpus: root bark (Sang Bai Pi, this record), leaf (Sang Ye), twig (Sang Zhi) and fruit (Sang Shen). Products sold in the West as mulberry extract or white mulberry are almost always leaf, standardised for 1-deoxynojirimycin, which the leaf carries at around 0.10 to 0.12 percent, far above root-bark levels. Every published human hypoglycaemic trial on this species used leaf or twig material, not root bark: the alpha-glucosidase and postprandial glucose trials used a standardised leaf extract, and the Ramulus Mori alkaloid tablet approved in China in 2020 is a twig preparation. A patient told to take Sang Bai Pi who buys mulberry extract will therefore be taking a different drug with a different constituent profile and a real glucose-lowering effect.
Clinical note: State on the prescription that Sang Bai Pi is root bark, and check what a patient is actually taking if they report buying mulberry extract. Do not counsel patients that root-bark decoction will reproduce the glucose-lowering seen in the leaf and twig trials; that evidence does not transfer.
Insulin and oral hypoglycaemic agents (sulfonylureas, metformin, alpha-glucosidase inhibitors)
Root-bark extracts and root-bark phenolics have both lowered blood glucose in streptozotocin-diabetic rats, and the root bark carries 1-deoxynojirimycin, an alpha-glucosidase inhibitor, albeit at lower concentration than the leaf. The relevant human trials used leaf and twig preparations, so the human-scale magnitude for root bark is unknown; the direction of effect, however, is consistent across the animal work.
Clinical note: Ask diabetic patients to monitor capillary glucose more frequently for the first two weeks. The likely effect size from root bark is modest, and dose reduction of conventional therapy should not be made pre-emptively.
Antihypertensive drugs
Both n-butanol- and water-soluble fractions of mulberry root bark produced hypotensive as well as diuretic, sedative, antitussive and anticonvulsant effects in mice, rats, guinea pigs and dogs, and two of the drug's characteristic Diels-Alder adducts, sanggenon C and kuwanon G, were isolated specifically as hypotensive principles from this part. No human blood-pressure study of the root bark exists.
Clinical note: Reasonable to check blood pressure at the next visit in patients already on antihypertensives, particularly where Sang Bai Pi is combined with other diuretic herbs. Evidence is animal-level, so this is vigilance rather than a contraindication.
Loop and thiazide diuretics
Diuretic and antioedema activity is one of the reproducible actions of root-bark fractions in the 1976 animal series, and matches the traditional indication of promoting urination and reducing oedema. Additive fluid loss with a pharmaceutical diuretic is plausible; no human data quantify it and no electrolyte disturbance has been reported.
Clinical note: For courses beyond a few weeks in patients on diuretics, check urea, electrolytes and creatinine as you normally would. Not a reason to withhold the herb.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 6–12 g | Daily | — | — | 中国药典 2020 【用法与用量】6～12g。 【性味与归经】甘，寒。归肺经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Dui Yao — Herb Pairs
The classical two-herb combinations this herb appears in, each with an action neither herb has alone.
Together they drain lurking heat from the Lung and calm wheezing and cough without injuring the yin.
Classic indication: cough and wheezing from Lung heat with skin that feels hot, worse in the afternoon.
Core pair of a classical formula — Xie Bai San, Xiao Er Yao Zheng Zhi Jue (Qian Yi, 1119)
Lightly clears and disperses heat from the lung exterior while draining heat and fluids from the lung interior.
Named pairing — Lü Jingshan, Shi Jinmo Dui Yao
Evidence Tier
Moderate evidence · 4 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
1
1 verified · 0 unverified
Observational / case report
0
In vitro / animal
3
3 verified · 0 unverified
Show 3 studies
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
PHARMACOLOGICAL STUDIES ON ROOT BARK OF MULBERRY TREE (Morus alba L.)
Systematic screen of n-butanol- and water-soluble fractions of mulberry root bark in mice, rats, guinea pigs and dogs, explicitly set against the classical clinical uses of Sohakuhi (Sang Bai Pi). Both fractions produced cathartic, analgesic, diuretic, antitussive, antioedema, sedative, anticonvulsant and hypotensive actions, differing only in cardiovascular effect. Still the broadest root-bark-specific pharmacology available, and the origin of the modern claim that the antitussive and diuretic traditional indications have an experimental correlate.
Hypoglycemic effect of Egyptian Morus alba root bark extract: Effect on diabetes and lipid peroxidation of streptozotocin-induced diabetic rats
Root-bark extract lowered blood glucose and reduced lipid peroxidation in streptozotocin-diabetic rats. One of the few glucose studies that used root bark rather than leaf, which is why it belongs in this record; it is nonetheless a rodent study and does not license a human antidiabetic claim for Sang Bai Pi.
In vivo hypoglycemic effects of phenolics from the root bark of Morus alba
Attributes the glucose-lowering activity of Sang Bai Pi to its phenolic fraction rather than to its iminosugar content, in a rodent model. Confirms the direction of effect for root bark specifically and supports the additive-hypoglycaemia caution, without providing any human dosing guidance.
Efficacy and Safety of Mulberry Twig Alkaloids Tablet for the Treatment of Type 2 Diabetes: A Multicenter, Randomized, Double-Blind, Double-Dummy, and Parallel Controlled Clinical Trial
Cited here to mark a boundary, not to support the root bark. This multicentre trial tested Ramulus Mori (Sang Zhi, mulberry TWIG) alkaloid tablets, an alkaloid fraction of 1-deoxynojirimycin, 1,4-dideoxy-1,4-imino-D-arabinitol and fagomine, approved by China's National Medical Products Administration in 2020. It found effective glycaemic lowering with few adverse events. It is the strongest human evidence in the species and it does not apply to Sang Bai Pi, which is a different plant part with a different constituent profile.
⚠ Safety & Contraindications
Side Effects
- No adverse reactions in animals given a single large dose or repeated small doses.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 505.
Historical Texts
Shen Nong Ben Cao Jing
Han dynasty, compiled c. 200 CEMing Yi Bie Lu
Six Dynasties, c. 500 CE, attributed to Tao HongjingBen Cao Gang Mu (Li Shizhen)
Ming dynasty, 1596References
- Wei H, Zhu JJ, Liu XQ, Feng WH, Wang ZM, Yan LH. Review of bioactive compounds from root barks of Morus plants (Sang-Bai-Pi) and their pharmacological effects . Cogent Chemistry (2016) [DOI]
- Nomura T, Fukai T, Hano Y, Uzawa J. Structure of Sanggenon C, a Natural Hypotensive Diels-Alder Adduct from Chinese Crude Drug “Sang-bái-pí” (Morus Root Bark) . Heterocycles (1981) [DOI]
- Jung JW, Park JH, Lee YG, Seo KH, Oh EJ, Lee DY, Lim DW, Han D, Baek NI. Three New Isoprenylated Flavonoids from the Root Bark of Morus alba . Molecules (2016) [DOI]
- Batiha GES, Al-Snafi AE, Thuwaini MM, Teibo JO, Shaheen HM, Akomolafe AP, Teibo TKA, Al-kuraishy HM, Al-Garbeeb AI, Alexiou A, Papadakis M. Morus alba: a comprehensive phytochemical and pharmacological review . Naunyn-Schmiedeberg's Archives of Pharmacology (2023) [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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