Bu Zha Ye
StarMicrocos paniculata L.
Traditionally used for
- Cough & breathing
- Digestion
- Urinary & fluids
- Liver & jaundice
☯ TCM Properties
Promotes Digestion and Resolves Food Stagnation; Clears Heat and Drains Dampness; Clears Summer-Heat; Resolves Phlegm; Promotes urination and relieves jaundice
Traditional Chinese Uses
Bu Zha Ye (vitex negundo leaf, five-leaved chaste tree leaf) is a cool, slightly bitter herb used in traditional Lingnan (southern Chinese) herbal medicine to clear Heat and Dampness, relieve indigestion, and reduce bloating and food stagnation. It is a key ingredient in classical cooling herbal teas popular in southern China and Hong Kong for addressing the effects of hot, damp seasonal conditions — including summer-heat indigestion, heavy digestion, and internal Damp-Heat accumulation.
Western Herbalism Properties
Relationships
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Botanical Description
Microcos paniculata is a medium-sized evergreen tree or large shrub in the Malvaceae (formerly Tiliaceae), native to southern China, the Indian subcontinent and tropical Southeast Asia where it grows in lowland and hill forests and along forest margins. The plant reaches 3 to 12 meters in height, with greyish-brown bark and young branchlets covered in stellate hairs. The alternate leaves are simple, oblong-elliptic to ovate-lanceolate, 8 to 18 cm long, with a finely serrate margin, an acuminate tip and three prominent veins arising from the slightly oblique base. The inflorescence is a large terminal panicle of small, yellowish-white, fragrant, five-parted flowers borne in dense cymose clusters. The fruit is a globose to obovoid drupe, 8 to 12 mm across, turning purplish-black on ripening and containing one to three seeds. In southern Chinese folk medicine and as the dried leaf Bu Zha Ye, it is used to clear summer heat, harmonize the stomach and dispel food stagnation.
Active Constituents
Isovitexin
Apigenin C-glycoside (flavone C-glucoside)Concentration: 1.17-5.65 mg per gram of dried leaf across eleven samples from different sites in Guangdong
Usually the most abundant of the three official markers and, with vitexin, the compound class that carries the anti-inflammatory action attributed to the leaf. Apigenin C-glycosides purified from this species reduced pulmonary oedema, microvascular permeability and cytokine levels in lipopolysaccharide-induced acute lung injury in mice, acting through TLR4 signalling. Isovitexin also inhibits alpha-glucosidase, with an IC50 of 266.2 micromolar.
Vitexin
Apigenin C-glycoside (flavone C-glucoside)Concentration: 0.10-2.31 mg per gram of dried leaf, a more than twentyfold range across sites
The reference marker used in the quantitative analysis of Microctis Folium and the compound against which the other flavone glycosides are quantified. It inhibits alpha-glucosidase with an IC50 of 244.0 micromolar. Its enormous batch-to-batch variation is the practical point: the range across eleven Guangdong samples is wide enough that two batches of the same drug are not the same product.
Isorhamnetin 3-O-beta-D-rutinoside
Flavonol glycosideConcentration: 1.66-5.16 mg per gram of dried leaf
The third of the three official quality markers, inhibiting alpha-glucosidase with an IC50 of 275.4 micromolar. Together the three markers total 4.23 to 11.55 mg per gram depending on batch.
Microgrewiapine A
2,6-disubstituted piperidin-3-ol alkaloid (piperidine alkaloid)The alkaloid that defines the toxicological character of this plant. Isolated from the stem bark, it is cytotoxic to HT-29 human colon cancer cells with an IC50 of 6.8 micromolar against 30.4 micromolar in normal CCD-112CoN colon cells, and it is a nicotinic acetylcholine receptor antagonist, inhibiting human alpha3beta4 receptors by 58.2 plus or minus 9.2 percent and alpha4beta2 by 74.0 plus or minus 14.2 percent at 10 micromolar. Nicotinic antagonism is the reason to take the alkaloid fraction of this plant seriously rather than treat it as a bland herbal-tea leaf.
Microgrewiapines B and C
Piperidine alkaloidsIsolated with microgrewiapine A from cytotoxic chloroform-soluble fractions of the stem bark, branches and leaves. Both showed cytotoxicity against HT-29 cells and nicotinic acetylcholine receptor antagonist activity in the same screen, though less selectively than microgrewiapine A.
Microcosamines A and C
Piperidine alkaloidsPiperidine alkaloids of the leaves. Microcosamine A and its congener were only weakly cytotoxic against four tumour cell lines, showing activity only against RAW 264.7 cells. Microcosamines A and B were reported to have significant larvicidal activity against Culex quinquefasciatus, consistent with the insecticidal role of this alkaloid class in the plant.
2,6-Disubstituted piperidin-3-ol alkaloids with a C10 unsaturated side chain
Piperidine alkaloidsEight new alkaloids of this type, plus three known analogues, were isolated from the leaves and characterised by NMR, Mosher's and Snatzke's methods, ECD calculation and X-ray crystallography. One of them concentration-dependently inhibited tube formation by human umbilical vein endothelial cells, making the class antiangiogenic as well as nicotinic-antagonist and insecticidal. This is a chemically coherent, biologically active alkaloid family present in the medicinal part of the plant.
Liriodenine
Oxoaporphine alkaloidIsolated from the branches. It was weakly cytotoxic and gave less than 20 percent inhibition of nicotinic receptors in the same screen, so it is a marker of the plant's alkaloid diversity rather than a contributor to its activity.
Epicatechin
Flavan-3-olConcentration: 23.01 mg per 100 g of dried extract of leaf and stem
One of six polyphenols quantified in leaf and stem extracts by UPLC and a contributor to the antioxidant activity of the drug, which was measurable as raised superoxide dismutase, catalase and reduced glutathione and lowered thiobarbituric acid reactive substances in mouse brain homogenate.
Quercetin
FlavonolConcentration: 32.23 mg per 100 g of dried extract of leaf and stem
The most abundant of the six polyphenols identified in leaf and stem extracts, contributing to the antioxidant profile that correlated with the anticonvulsant effect seen in mice.
MFP-I, an acidic heteropolysaccharide
Acidic heteropolysaccharideConcentration: 8.38 kDa; composed of glucuronic acid 33.6 percent, D-galactose 25.9 percent, L-rhamnose 18.2 percent and galacturonic acid 11.3 percent
A structurally characterised polysaccharide from the aqueous extract, the fraction most relevant to a water decoction or a herbal tea, with an established backbone and side chains and reported oxidative-stress-modulating activity. It is a reminder that the water extract of the leaf is chemically not the alkaloid-rich chloroform fraction that most of the pharmacology was done on.
⚠ Drug Interactions
Nicotinic acetylcholine receptor drugs (varenicline, nicotine replacement, cytisinicline) and neuromuscular blocking agents
The characteristic piperidine alkaloids of this plant are nicotinic acetylcholine receptor antagonists. Microgrewiapine A inhibited human alpha3beta4 receptors by 58.2 percent and alpha4beta2 by 74.0 percent at 10 micromolar, and several of the co-isolated alkaloids were active in the same assay. Alpha3beta4 is the ganglionic subtype and alpha4beta2 the principal central nicotinic subtype targeted by smoking cessation drugs. No pharmacokinetic data exist, so whether an oral decoction of the leaf delivers a receptor-relevant alkaloid concentration is unknown; the alkaloids were also isolated in greatest quantity from stem bark and branches rather than from the leaf that constitutes the drug.
Clinical note: Not a reason to avoid ordinary use of the leaf. Do consider it if a patient consuming large or sustained quantities of Buzhaye, including as a cooling tea, reports unexplained autonomic symptoms or a loss of effect from varenicline or nicotine replacement, and avoid concentrated alkaloid-rich extracts of stem or bark altogether.
Alpha-glucosidase inhibitors (acarbose, miglitol, voglibose) and other antidiabetic drugs
The methanol extract of the leaf inhibits alpha-glucosidase with an IC50 of 61.30 micrograms per millilitre, and its three marker glycosides do so individually, vitexin at 244.0 micromolar, isovitexin at 266.2 and isorhamnetin 3-O-beta-D-rutinoside at 275.4. The mechanism is identical to that of acarbose. This is enzyme-assay data on a methanol extract, not a demonstration of glycaemic effect in an animal, let alone a person.
Clinical note: If a diabetic patient drinks Buzhaye-containing cooling tea regularly and is on acarbose or a sulfonylurea, ask about flatulence, loose stool and hypoglycaemia, and check home glucose readings around any change in intake. Do not treat the herb as a glucose-lowering agent.
Concentrated Buzhaye tea products (Wanglaoji, Jiaduobao, Huoqizheng and similar cooling teas)
Buzhaye is not only a prescribed herb but a bulk ingredient of commercial Chinese cooling-tea beverages, with an annual demand around 250 tons. A patient may therefore be taking substantial quantities without describing it as medicine at all, on top of anything prescribed. Because the leaf carries an alkaloid family with nicotinic antagonist, antiangiogenic and larvicidal activity, and because flavone glycoside content varies more than twentyfold between batches and between prepared slices from different pharmacies, the actual exposure is neither small nor uniform.
Clinical note: Ask specifically about cooling teas when taking a herbal history in a patient from southern China or Southeast Asia, and add that intake to any prescribed Buzhaye rather than treating it as diet. There is no human safety or toxicology study of this drug at any dose, so no reassurance can be offered beyond long customary food use.
Antiepileptic drugs and other GABAergic agents (benzodiazepines, gabapentinoids)
Seven days of oral Microcos paniculata leaf and stem extract at 100, 200 and 400 mg/kg reduced convulsions and mortality in chemically induced seizure mice, and whole-brain GABA levels rose significantly in the leaf- and stem-treated groups alongside improved antioxidant markers. The proposed mechanism is modulation of the GABAergic system. This is one rodent study with an unstandardised extract and no receptor-level work, so the interaction is mechanistic speculation.
Clinical note: No practical action at customary doses. Consider it only if a patient on a sedating antiepileptic reports unexpected drowsiness after starting a concentrated extract.
Leaf versus stem bark, branch or bark material
The drug Folium Microctis is defined as the leaf, but the most pharmacologically active piperidine alkaloids were isolated from other parts: microgrewiapine A from the stem bark, liriodenine from the branches, and the insecticidal N-methyl-6-(deca-1,3,5-trienyl)-3-methoxy-2-methylpiperidine from the stem bark. Bark extracts also show antinociceptive and antidiarrhoeal activity in their own right. Material adulterated with stem, bark or branch is therefore not merely diluted but chemically shifted toward the alkaloid fraction.
Clinical note: Accept leaf only. Inspect for stem and twig fragments, and be aware that quality-control work on prepared Microctis Folium slices from hospital pharmacies found wide variation in flavone glycoside content between batches, which is the accessible proxy for how carefully a batch was prepared.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 15–30 g | Daily | — | — | 中国药典 2020 【用法与用量】15～30g。 【性味与归经】微酸，凉。归脾、胃经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Moderate evidence · 6 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
6
1 verified · 5 unverified
Show 6 studies
- Alkaloids from Microcos paniculata with Cytotoxic and Nicotinic Receptor Antagonistic Activities
- Angiogenesis-Inhibitory Piperidine Alkaloids from the Leaves of Microcos paniculata
- Apigenin C-glycosides of Microcos paniculata protects lipopolysaccharide induced apoptosis and inflammation in acute lung injury through TLR4 signaling pathway
- GABA content and an antioxidant profile positively correlated with the anticonvulsive activity of Microcos paniculata in acute seizure mice
- α-Glucosidase Inhibitory Effect and Simultaneous Quantification of Three Major Flavonoid Glycosides in Microctis folium
- Variations of Flavone Glycosides Profile Underscore the Necessity of Quality Control of Prepared Microctis Folium Slices
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
Alkaloids from Microcos paniculata with Cytotoxic and Nicotinic Receptor Antagonistic Activities
Three new piperidine alkaloids, microgrewiapines A to C, plus microcosamine A, a propenamide and liriodenine were isolated from cytotoxic chloroform-soluble extracts of the stem bark, branches and leaves. All showed a range of cytotoxicity against HT-29 human colon cancer cells, and several were active as antagonists at human alpha3beta4 or alpha4beta2 nicotinic acetylcholine receptors. Microgrewiapine A was selectively cytotoxic to colon cancer over normal colon cells, IC50 6.8 against 30.4 micromolar, and inhibited alpha3beta4 by 58.2 percent and alpha4beta2 by 74.0 percent at 10 micromolar. This is the study that establishes the nicotinic pharmacology of the genus.
Angiogenesis-Inhibitory Piperidine Alkaloids from the Leaves of Microcos paniculata
Eight new 2,6-disubstituted piperidin-3-ol alkaloids bearing a C10 unsaturated alkyl side chain, with three previously reported analogues, were isolated from the leaves of Microcos paniculata and their absolute configurations settled by NMR, modified Mosher's and Snatzke's methods, ECD calculation and single-crystal X-ray crystallography. Screened for antiangiogenic effects on human umbilical vein endothelial cells, one compound inhibited tube formation concentration-dependently. Confirms that the leaf, the medicinal part, carries this alkaloid family and not only the flavone glycosides.
Apigenin C-glycosides of Microcos paniculata protects lipopolysaccharide induced apoptosis and inflammation in acute lung injury through TLR4 signaling pathway
Purified apigenin C-glycosides from Microcos paniculata leaves were tested in lipopolysaccharide-induced acute lung injury in BALB/c mice. They inhibited lung inflammation, reduced pulmonary oedema and microvascular permeability and dose-dependently downregulated the lipopolysaccharide response, with the effect attributed to TLR4 signalling. This is the strongest mechanistic support for the traditional use of the leaf in upper airway infection.
GABA content and an antioxidant profile positively correlated with the anticonvulsive activity of Microcos paniculata in acute seizure mice
Six polyphenols were quantified in leaf and stem extracts by UPLC, epicatechin at 23.01 and quercetin at 32.23 mg per 100 g of dried extract being the highest. Seven days of oral dosing at 100, 200 and 400 mg/kg significantly reduced convulsions and mortality in seizure-induced mice, with raised superoxide dismutase, catalase and reduced glutathione, lowered thiobarbituric acid reactive substances and significantly increased whole-brain GABA in the leaf- and stem-treated groups.
α-Glucosidase Inhibitory Effect and Simultaneous Quantification of Three Major Flavonoid Glycosides in Microctis folium
The methanol extract of Microctis Folium inhibited alpha-glucosidase with an IC50 of 61.30 micrograms per millilitre, and its three principal compounds gave IC50 values of 244.0 micromolar for vitexin, 266.2 for isovitexin and 275.4 for isorhamnetin 3-O-beta-D-rutinoside. A validated HPLC-DAD method quantified the three in eleven samples from different Guangdong sites: vitexin 0.10-2.31, isovitexin 1.17-5.65 and isorhamnetin 3-O-beta-D-rutinoside 1.66-5.16 mg per gram, with totals from 4.23 to 11.55 mg per gram. The three are proposed as the chemical markers of the drug.
Variations of Flavone Glycosides Profile Underscore the Necessity of Quality Control of Prepared Microctis Folium Slices
A ten-compound flavone glycoside profile of Microctis Folium was established by UPLC-ESI-qTOF-MS and a quantitative analysis of multi-components by single marker method developed with vitexin as reference and validated by HPLC. Applied to 21 batches of prepared slices collected from different hospital pharmacies, it found obvious variation in both total glycoside content and individual compounds, which is the direct evidence that dispensed material is not consistent.
References
- Jiang YQ, Liu EH. Microcos paniculata: a review on its botany, traditional uses, phytochemistry and pharmacology . Chinese Journal of Natural Medicines (2019) [DOI]
- Bandara KANP, Kumar V, Jacobsson U, Molleyres LP. Insecticidal piperidine alkaloid from Microcos paniculata stem bark . Phytochemistry (2000) [DOI]
- Feng SX, Lin LD, Xu HH, Wei XY. Two new piperidine alkaloids from the leaves of Microcos paniculata . Journal of Asian Natural Products Research (2008) [DOI]
- Zhang G, Zhang N, Xu L, Wu HT, Chen D, Lin QH, Luo LZ. A new piperidine alkaloid from the leaves of Microcos paniculata L. . Natural Product Research (2017) [DOI]
- Bai Y, Jia Q, Su W, Yan Z, Situ W, He X, Peng W, Yao H. Integration of molecular networking and fingerprint analysis for studying constituents in Microctis Folium . PLOS One (2020) [DOI]
- Liang XL, Liang YW, Tian J, Mo FF, Pan TM, Chen YF, Shao XQ, Li KP. Structural characterization and oxidative stress modulation activity of an acidic Heteropolysaccharide from Microctis folium . Carbohydrate Polymers (2025) [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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