Gu Jing Cao
StarEriocaulon buergerianum Koern.
Traditionally used for
- Eye health
Cautions & contraindications
- Diabetes
☯ TCM Properties
Disperses Wind-Heat; Brightens the Eyes; Brightens the Eyes and Removes Visual Obstructions; Clears Liver Heat
Traditional Chinese Uses
Gu Jing Cao (pipewort scapeflower, eriocaulon) is a cool herb used in Chinese medicine primarily as an ophthalmic remedy. It disperses Wind-Heat from the head and face, clears the eyes of redness and inflammation, and dissolves corneal opacities. Its affinity for the eyes is so well-recognized that classical physicians considered its efficacy in brightening the eyes and resolving corneal cloudiness superior to chrysanthemum for certain conditions. It is used for red, painful, light-sensitive eyes from Wind-Heat or Liver Heat.
Relationships
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Botanical Description
Eriocaulon buergerianum is a small aquatic to semi-aquatic annual herb in the Eriocaulaceae, growing in shallow standing water, rice paddies, and wet boggy margins across eastern Asia. It forms a basal rosette of narrow, grass-like, soft, translucent linear leaves 4-10 cm long. From the rosette arise numerous slender, twisted, longitudinally ribbed scapes 15-30 cm tall, each terminating in a single small button-like head 4-6 mm across composed of many tiny greyish-white to ash-coloured staminate and pistillate florets enclosed by chaffy involucral bracts. The dried scapes with attached flower heads, collected in autumn, constitute the medicinal Gu Jing Cao. The persistent papery heads remain after fruiting.
Active Constituents
Patuletin glycosides
Flavonol glycosideAcid hydrolysis of the aqueous extract shows the flavonoids of this plant are principally flavonol glycosides built on patuletin, making these the defining constituent class of authentic Gu Jing Cao. Isolated glycosides inhibited alpha-glucosidase weakly, with IC50 values of 170 to 547 micromolar, while the free aglycones patuletin and quercetin were much more potent at 57.0 and 14.5 micromolar.
Hispidulin and its 7-O-beta-D-glucoside and 7-O-(6-O-E-coumaroyl)-beta-D-glucoside
Flavone and flavone glycosidesAmong the ten compounds isolated from commercial Eriocauli Flos and used as its HPLC and UPLC identity markers. Hispidulin is the flavone most often invoked for the anti-inflammatory activity ascribed to this herb, though the pharmacology in question has been done on the pure compound from other sources rather than on Gu Jing Cao extract.
Apigenin and its 7-O-beta-D-glucoside and 7-O-(6-O-E-coumaroyl)-beta-D-glucoside
Flavone and flavone glycosidesPart of the marker panel for the drug. The coumaroylated glucosides are the more diagnostic of the pair, since free apigenin is ubiquitous.
Jaceosidin and jaceosidin 7-O-beta-D-glucoside
Flavone and flavone glycosideFurther members of the ten-compound marker set isolated from commercial Eriocauli Flos.
Toralactone and toralactone-9-O-beta-D-glucopyranoside
NaphthopyranoneNaphthopyranones are chemotaxonomically important here: profiling of 72 compounds across four Eriocaulon species found Eriocaulon buergerianum abundant in flavonols and naphthopyranones, whereas the substitute species are not. Their presence is therefore part of what identifies the authentic drug rather than an adulterant.
1,3,6-Trihydroxy-2,5,7-trimethoxyxanthone
XanthoneA minor constituent of Eriocaulon buergerianum, isolated among 24 compounds of which 10 showed antibacterial activity against Staphylococcus aureus with MICs of 32 to 256 micrograms/mL. Xanthones dominate in the substitute species Eriocaulon faberi rather than in the official drug.
Feruloyl glucuronopyranosyl glycerols
Phenylpropanoid glyceroglycosideThree of these were described new from the capitulum in 2022. The 2'-feruloyl isomer inhibited TGF-beta-induced alpha-smooth-muscle actin and fibronectin expression in LX-2 human hepatic stellate cells. Structural chemistry with a single in vitro assay behind it; no in vivo or clinical follow-up exists.
⚠ Drug Interactions
Substitute Eriocaulon species dispensed as Gu Jing Cao (Eriocaulon faberi, E. sexangulare, E. cinereum)
Several Eriocaulon species are used regionally as Gu Jing Cao and are hard to tell apart in the dried drug. HPLC-DAD-ESI-MS profiling of 72 compounds across four species showed the differences are not subtle: Eriocaulon buergerianum is rich in flavonols and naphthopyranones with minor flavones and xanthones, E. cinereum is dominated by isoflavones and flavones with few naphthopyranones, E. sexangulare is flavone-rich, and E. faberi is xanthone-rich. A separate survey of Taiwanese herbal markets found the commercial material differed from authentic E. buergerianum in both morphology and chemical profile.
Clinical note: Specify Eriocaulon buergerianum on the order and, where it matters, ask for a chromatographic profile. There is no evidence that the substitutes are dangerous, only that they are chemically different plants sold as this one.
Gu Jing Cao supplied as capitulum without the peduncle
The official drug is the dried flower head together with its stalk. The Taiwan market survey found most material sold there is the capitulum alone, and that samples with and without the peduncle differ widely in both morphology and the content of the ten marker compounds. This is a partial-drug substitution rather than a species substitution.
Clinical note: Check that the peduncle is present. Weight-for-weight dosing across the two forms is not equivalent.
Oral antidiabetic drugs, particularly alpha-glucosidase inhibitors (acarbose, miglitol)
The patuletin-based flavonol glycosides of this plant inhibit alpha-glucosidase in vitro, but only at 170 to 547 micromolar, and the more potent aglycones are not what is present in the drug. There is no absorption, no dosing and no animal data, so this is an enzyme-assay finding rather than a pharmacological effect. It is recorded here only because a practitioner reading the 2026 paper might otherwise read more into it than it supports.
Clinical note: No monitoring change is warranted. Do not present Gu Jing Cao as a hypoglycaemic herb on the strength of this.
Dosage
| Form | Amount | Frequency | Duration | Population | Notes |
|---|---|---|---|---|---|
| decoction | 5–10 g | Daily | — | — | 中国药典 2020 【用法与用量】5～10g。 【性味与归经】辛、甘，平。归肝、肺经。 — Chinese Pharmacopoeia 2020, quoted verbatim; route and cautions preserved. Replaces a cleared category-filler value. |
Evidence Tier
Limited evidence · 2 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
2
0 verified · 2 unverified
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
Eriocaulon buergerianum extract protects PC12 cells and neurons in zebrafish against 6-hydroxydopamine-induced damage
An ethanol extract of Eriocaulon buergerianum, at 25 to 200 micrograms/mL, dose-dependently protected PC12 cells against 6-hydroxydopamine and reduced nuclear fragmentation and apoptotic body formation. In zebrafish it prevented the 6-OHDA-induced loss of tyrosine-hydroxylase-positive dopaminergic neurons and the associated fall in locomotor activity. The mechanism tracked with inhibition of nitric oxide production and iNOS expression. Cell and zebrafish models only, and unrelated to the herb's traditional ophthalmic indication.
Antibacterial phenolic components from Eriocaulon buergerianum
Five new phenolic compounds, including a trimethoxyxanthone, a trimethoxyisoflavone, toralactone-9-O-glucoside and two acylated patuletin glycosides, were isolated alongside 19 known compounds. All 24 were tested against Staphylococcus aureus ATCC 25923; ten were active, with MICs from 32 to 256 micrograms/mL. These are weak antibacterial concentrations and no in vivo work followed.
Historical Texts
Kai Bao Ben Cao
Northern Song dynastyReferences
- Qiao X; Ye G; Liu CF; Zhang ZX; Tu Q; Dong J; Li YQ; Guo DA; Ye M. Chemical analysis of Eriocaulon buergerianum and adulterating species by high-performance liquid chromatography with diode array detection and electrospray ionization tandem mass spectrometry . Journal of Pharmaceutical and Biomedical Analysis (2012) [DOI]
- Lee IJ; Chung CP; Chang SJ; Lin YL. Morphological and chemical analyses of Eriocauli Flos sold in Taiwan markets . Journal of Food and Drug Analysis (2017) [DOI]
- Ho JC; Chen CM. Flavonoids from the aquatic plant Eriocaulon buergerianum . Phytochemistry (2002) [DOI]
- Yao H; Zhu J; Zhou Z; Xu Z; Chen K; Zhu W; Zhang Y. Flavonol glycosides from Eriocaulon buergerianum Körn. and their α-glucosidase inhibitory effects . Natural Product Research (2026) [DOI]
- Zhang Y; Li H; Xu Z; Shi Y; Li B; Li J; Aisa HA; Zang Y; Zhu W. Three new feruloyl glucuronopyranosyl glycerols from Eriocaulon buergerianum with their anti-fibrotic effects on hepatic stellate cells . Natural Product Research (2022) [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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