Chen Xiang
StarAquilaria sinensis (Lour.) Gilg
Traditionally used for
- Cough & breathing
- Digestion
- Sleep
- Pain & joints
☯ TCM Properties
Moves Qi and Alleviates Pain; Warms the Middle Burner and Stops Vomiting; Directs Rebellious Qi Downward and Stops Hiccup; Aids the Kidneys in Grasping Qi
Traditional Chinese Uses
Chen Xiang (agarwood, aquilaria resinous wood) is a warm, acrid, bitter aromatic substance considered among the most precious of all herbs in Chinese medicine. It warms the middle burner and Kidney to relieve cold-type abdominal pain, nausea, and hiccup; descends Lung and Kidney Qi to calm wheezing from Kidney Qi failing to grasp Qi; and powerfully moves stagnant Qi downward throughout the body. Its strong descending, warming, and aromatic properties make it a premier herb for conditions involving cold Qi obstruction in the middle and lower burner.
Western Herbalism Properties
Pharmacological Effects
- Spasmolytic: Decoction inhibited spontaneous and histamine/ACh-induced contraction of isolated guinea pig ileum and reduced ACh-induced intestinal peristalsis in cats — a direct smooth-muscle action.
- Central inhibitory: Extract prolonged hexobarbital sleep, reduced spontaneous activity and inhibited electroshock seizures in mice (max at 60 min after oral dosing).
- Other effects: Decoction inhibited Mycobacterium tuberculosis hominis, Bacillus typhosus and B. dysenteriae; essential oil reported anesthetic and analgesic.
Source: Zhu YP. Chinese Materia Medica: Chemistry, Pharmacology and Applications. Harwood Academic, 1998, p. 388.
Relationships
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Botanical Description
Aquilaria sinensis is an evergreen tree in the family Thymelaeaceae, native to southern China, Hainan, and Hong Kong, where it grows in moist evergreen broadleaf forests. Mature trees reach 6-20 meters, with smooth grayish bark and a dense rounded crown. The alternate, leathery, oblong to lanceolate leaves are 5-9 cm long, glossy dark green above and paler below, with fine secondary venation. Small, yellow-green, fragrant flowers are borne in axillary or terminal umbellate clusters, producing woody, ovoid, two-valved capsules that split to reveal one or two seeds suspended on threadlike stalks. In response to wounding and fungal infection of the heartwood, the tree produces a dense, dark, fragrant oleoresin known as agarwood or Chen Xiang, the prized medicinal and aromatic product.
Active Constituents
Agarotetrol
2-(2-Phenylethyl)chromoneConcentration: the pharmacopoeial marker; the quality-evaluation literature reports the Chinese Pharmacopoeia requirement as not less than 0.10% agarotetrol together with not less than 10.0% ethanol-soluble extractive
The single most useful authenticity marker for this drug. Takamatsu and Ito found agarotetrol as a large peak in every sample of medical-grade and artificially induced agarwood and in most incense-grade samples, but entirely absent from Aquilaria wood that carried no resin deposits. It is therefore a direct chemical test of the thing that makes agarwood agarwood, namely resin formation, and it survives into decoctions because it is concentrated in the water-extractable fraction.
2-(2-Phenylethyl)chromone derivatives
ChromoneConcentration: about 130 chromone derivatives have been reported from Aquilaria sinensis, the most commonly isolated compound type in the drug
With the sesquiterpenes, the defining constituent class of agarwood. They include isoagarotetrol and the aquilarones, and more recently chromone-sesquiterpenoid hybrids in which a phenylethylchromone is linked to a sesquiterpenoid. They accumulate only in resinous tissue.
delta-Guaiene
Guaiane sesquiterpeneConcentration: the major product of the three Aquilaria sinensis sesquiterpene synthases characterised to date
Xu and colleagues cloned three full-length sesquiterpene synthases from Aquilaria sinensis, expressed them in Escherichia coli and showed all three were active with delta-guaiene as the major product. Expression was significantly induced by methyl jasmonate with a corresponding rise in sesquiterpene production, which is the molecular evidence that agarwood chemistry is a wound response rather than a normal wood constituent.
alpha-Agarofuran and baimuxinol
Agarofuran sesquiterpeneConcentration: characteristic of Aquilaria sinensis resin; content varies enormously with grade and induction method
Agarofuran-type sesquiterpenes are among the classic aroma-bearing constituents of Chinese agarwood and are used, with the agarospiranes, in chemical profiling of the drug.
Agarospirol and oxo-agarospirol
Agarospirane sesquiterpeneConcentration: characteristic of Aquilaria resin; no fixed pharmacopoeial limit
Spiro-sesquiterpenes reported from agarwood of Aquilaria and used in gas chromatography-based species and grade profiling.
Jinkoh-eremol
Eremophilane sesquiterpeneConcentration: reported from agarwood; no fixed pharmacopoeial limit
An eremophilane sesquiterpene of agarwood. Eremophilanes, eudesmanes and guaianes are the numerically largest sesquiterpene groups in the drug.
Mangiferin and genkwanin-5-O-primeveroside
Xanthone C-glycoside and flavone glycosideConcentration: constituents of Aquilaria sinensis LEAF, not of the resinous wood that constitutes the drug Chen Xiang
Recorded here deliberately, because they are the compounds behind the widely cited laxative pharmacology of agarwood. That work used ethanol extracts of agarwood leaves, and mangiferin and genkwanin-5-O-primeveroside were identified as the main constituents responsible. Chen Xiang is the resin-impregnated wood and does not deliver them. Leaf-derived agarwood tea and the medicinal wood are chemically different products and their evidence should not be pooled.
⚠ Drug Interactions
Adulterated and substituted agarwood: other Aquilaria species and non-Aquilaria woods including Santalum album, Dalbergia latifolia, Terminalia catappa, Cocos nucifera, Pinus contorta var. latifolia, Thuja species and Strychnos ignatii
Agarwood is among the most valuable and most counterfeited botanicals in trade, and its identity cannot be settled by appearance. Two lines of published work document the problem directly. Lee and colleagues built a DNA barcode reference library from seven Aquilaria species and used it to identify the source species of agarwood sold in the market, proposing trnL-trnF plus ITS2 as the best barcode combination and validating it on blind commercial samples. A later study by the same group extended the reference set specifically to seven catalogued adulterant species: Cocos nucifera, Dalbergia latifolia, Pinus contorta var. latifolia, Santalum album, Strychnos ignatii, Thuja species and Terminalia catappa, and showed that DNA barcoding with high-resolution melting using an ITS1 mini-barcode gives rapid species-specific detection of both Aquilaria and its adulterants. One of those catalogued adulterants, Strychnos ignatii, is the source of the strychnine-bearing Saint Ignatius bean; the barcoding paper does not state which tissue of it is used in counterfeit product. A separate and commoner form of adulteration needs no other species at all: ordinary resin-free Aquilaria wood, dyed or soaked, sold as agarwood. That form is chemically detectable, because agarotetrol is present in medical-grade and artificially induced agarwood but absent from Aquilaria wood without resin deposits.
Clinical note: Buy only material whose species origin can be evidenced, and require an agarotetrol assay or at least the pharmacopoeial ethanol-soluble extractive figure. Genuine agarwood is resin formed by the living tree in response to wounding and microbial infection, not the ordinary wood of the tree, so heavy, dark, resin-laden and sinking material is the drug and pale light wood is not, however correct the species. Treat any unusually cheap agarwood as adulterated until shown otherwise.
Agarwood in international trade, which is CITES Appendix II listed
All species of Aquilaria, together with Gyrinops, were included in CITES Appendix II on the proposal brought to the thirteenth Conference of the Parties in Bangkok in 2004, the listing taking effect on 12 January 2005. The listing exists because demand for agarwood has driven the genus into endangerment, a point made in the primary literature on the species as well as by the Convention. Trade in parts and derivatives is governed by the annotation attached to the listing, and a limited personal and household effects allowance exists under Resolution Conf. 13.7 of up to 1 kg of woodchips, 24 ml of oil and two sets of beads or prayer beads per person. Cultivated, artificially induced agarwood is a partial answer to the supply problem rather than an exemption from the listing: the whole-tree agarwood-inducing technique raises yield from cultivated Aquilaria sinensis by four to twenty-eight times over earlier methods and gives quality comparable to wild agarwood.
Clinical note: Source from suppliers holding valid CITES documentation and keep the paperwork with the stock. Do not carry agarwood across borders on the assumption that a small clinic quantity is exempt, and do not order it internationally without checking your own country's implementing rules.
Muscarinic antagonists (atropine, hyoscine butylbromide, oxybutynin) taken with agarwood LEAF preparations
An ethanol extract of Aquilaria sinensis leaves increased stool frequency and weight in loperamide-constipated mice and increased isolated jejunal and ileal tension in guinea pigs. That tension increase was blocked by atropine but not by granisetron, pyrilamine or a bradykinin antagonist peptide, and pre-administration of atropine abolished the laxative effect in vivo, placing the mechanism at muscarinic acetylcholine receptors. Notably the leaf extract did not cause the diarrhoea that senna caused in the same experiments. The interaction is flagged as theoretical and confined to leaf products because the material studied was leaf, not the resinous wood that Chen Xiang is.
Clinical note: Distinguish clearly, when a patient reports taking agarwood, whether they mean the prescribed resinous wood or a commercial agarwood leaf tea. Only the leaf product has this documented cholinergic gut activity, and only it would be expected to be blunted by an anticholinergic drug.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction (added late) | 1–5 g | Daily | — | — | 中国药典 2020 【用法与用量】1～5g，后下。 【性味与归经】辛、苦,微温。归脾、胃、肾经。 — 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 move qi and descend rebellion, relieving chest and abdominal fullness from qi counterflow due to emotional constraint.
Core pair of a classical formula — Si Mo Tang, Ji Sheng Fang (Yan Yonghe)
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
0
Observational / case report
0
In vitro / animal
4
2 verified · 2 unverified
Show 4 studies
- Identification of genes related to agarwood formation: transcriptome analysis of healthy and wounded tissues of Aquilaria sinensis
- Agarwood Alcohol Extract Protects against Gastric Ulcer by Inhibiting Oxidation and Inflammation
- Agarwood Induced Laxative Effects via Acetylcholine Receptors on Loperamide-Induced Constipation in Mice
- Laxative effects of agarwood on low-fiber diet-induced constipation in rats
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
Identification of genes related to agarwood formation: transcriptome analysis of healthy and wounded tissues of Aquilaria sinensis
The molecular demonstration of what agarwood actually is. Two cDNA libraries were sequenced from healthy and wounded Aquilaria sinensis, yielding 89,137 unigenes, of which 30 putatively encode enzymes of the sesquiterpene biosynthesis pathway, alongside transcription factors and protein kinases involved in wound signal transduction. Three sesquiterpene synthases were cloned, expressed in Escherichia coli and shown to be active with delta-guaiene as the major product, and methyl jasmonate induction significantly raised their expression and sesquiterpene output. The paper states plainly that only wounded trees produce agarwood and that all Aquilaria species are consequently listed in CITES Appendix II.
Agarwood Alcohol Extract Protects against Gastric Ulcer by Inhibiting Oxidation and Inflammation
The one animal study here that uses the resinous wood rather than the leaf. Mice were pretreated for seven days with alcohol extracts of agarwood produced three different ways, by the whole-tree inducing technique at 0.71, 1.42 and 2.84 g/kg, by axe wounding of wild trees at 2.84 g/kg, and by burning, chiselling and drilling at 2.84 g/kg, before gastric ulcers were induced with absolute ethanol. The two higher doses gave ulcer inhibition above 60%, lowered nitric oxide and raised glutathione and superoxide dismutase, lowered interleukin-1 beta and interleukin-6 while raising interleukin-10, and suppressed nuclear factor kappa B and phosphorylated p38. Whole-tree induced agarwood performed better than the burn-chisel-drill material and comparably to wild agarwood at the same dose, which is directly relevant to sourcing.
Agarwood Induced Laxative Effects via Acetylcholine Receptors on Loperamide-Induced Constipation in Mice
Ethanol extracts of agarwood LEAVES from Aquilaria sinensis and Aquilaria crassna, and their main constituents mangiferin and genkwanin-5-O-primeveroside, increased stool frequency and weight in loperamide-constipated mice without the severe diarrhoea that senna caused. The Aquilaria sinensis leaf extract raised isolated guinea pig jejunal and ileal tension, an effect blocked by atropine but not by granisetron, pyrilamine or a bradykinin antagonist peptide, and atropine pretreatment abolished the laxative effect in vivo. The mechanism is therefore muscarinic. This study is frequently cited as evidence for Chen Xiang; it is evidence about the leaf, not about the resinous wood.
Laxative effects of agarwood on low-fiber diet-induced constipation in rats
An ethanol extract of Aquilaria sinensis LEAVES at 150, 300 and 600 mg/kg by mouth increased stool frequency, weight and water content and accelerated carmine egestion in rats made constipated by a low-fibre diet, and increased stool frequency and weight in normal rats at 600 mg/kg. Senna at 150 and 300 mg/kg produced comparable effects but also severe diarrhoea, while the agarwood leaf extract did not. Again the material is leaf, and this study should not be read as evidence for the wood drug.
⚠ Safety & Contraindications
Contraindications
Its use is cautious in patients with vigorous fire due to yin deficiency, or syndrome of sinking of qi deficiency.
Source: Xi S, Gong Y. Essentials of Chinese Materia Medica and Medical Formulas. Academic Press/Elsevier, 2017, pp. 171–182.
Historical Texts
Ming Yi Bie Lu
compiled by Tao Hongjing, Liang dynasty, about 500 CEXin Xiu Ben Cao
Tang dynasty, 659 CEBen Cao Gang Mu
Ming dynastyReferences
- Gao M, Han X, Sun Y, Chen H, Yang Y, Liu Y, Meng H, Gao Z, Xu Y, Zhang Z, Han J. Overview of sesquiterpenes and chromones of agarwood originating from four main species of the genus Aquilaria . RSC Advances (2019) [DOI]
- Takamatsu S, Ito M. Agarotetrol in agarwood: its use in evaluation of agarwood quality . Journal of Natural Medicines (2020) [DOI]
- Lee SY, Ng WL, Mahat MN, Nazre M, Mohamed R. DNA Barcoding of the Endangered Aquilaria (Thymelaeaceae) and Its Application in Species Authentication of Agarwood Products Traded in the Market . PLOS ONE (2016) [DOI]
- Lee SY, Lamasudin DU, Mohamed R. Rapid detection of several endangered agarwood-producing Aquilaria species and their potential adulterants using plant DNA barcodes coupled with high-resolution melting (Bar-HRM) analysis . Holzforschung (2019) [DOI]
- Liu Y, Chen H, Yang Y, Zhang Z, Wei J, Meng H, Chen W, Feng J, Gan B, Chen X, Gao Z, Huang J, Chen B, Chen H. Whole-tree Agarwood-Inducing Technique: An Efficient Novel Technique for Producing High-Quality Agarwood in Cultivated Aquilaria sinensis Trees . Molecules (2013) [DOI]
- Convention on International Trade in Endangered Species of Wild Fauna and Flora. Appendices I, II and III . CITES Secretariat, Geneva; Aquilaria spp. and Gyrinops spp. included in Appendix II with effect from 12 January 2005 (2005)
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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