Traditionally used for
- Urinary & fluids
- Menstrual & women's health
☯ TCM Properties
Astringes Jing and restrains vaginal discharge
Traditional Chinese Uses
Long Yan Hua is the dried flower of the longan tree (Dimocarpus longan, Sapindaceae; Flos Longanae), used as an astringent herb entering the Liver and Kidney channels. Its role is to astringe Essence (Jing) and restrain leakage of fluids: it is used for spermatorrhea and seminal loss and for excessive or persistent vaginal discharge (leukorrhea), and by extension for turbid, frequent urination associated with Kidney insufficiency. It is a relatively minor materia medica item, far less used than longan fruit flesh (Long Yan Rou).
The flower is typically prepared as an infusion or decoction. It is best suited to consolidating, deficiency-type leakage patterns and is usually combined with tonifying and stabilizing herbs; it should be used under professional guidance rather than as a stand-alone remedy.
Western Herbalism Properties
Relationships
Full-screen graph →Click a node for details · double-click to expand it · Ctrl/⌘ + scroll or two fingers to zoom and pan.
Botanical Description
Long Yan Hua refers to the dried flowers of Dimocarpus longan (Sapindaceae), the longan tree, an evergreen tropical species 10–20 m tall native to southern China and Southeast Asia. Leaves are alternate, paripinnate, 15–30 cm long, with 6–10 leathery, elliptic-lanceolate leaflets glossy above and dull beneath. Inflorescences are large terminal or subterminal panicles 15–40 cm long bearing many small, yellowish to brownish actinomorphic flowers about 5–6 mm across, each with 5–6 sepals, 5 petals, 6–10 stamens and a bilobed ovary; pubescence is rusty-stellate. The flowers are valued aromatic by-products of fruit cultivation in Fujian and Guangdong.
Active Constituents
Corilagin
EllagitanninConcentration: about 54.6 mg/g of a longan flower water extract and about 37.7 mg/g of a longan flower ethanol extract
The single most abundant identified phenolic of the flower and its characteristic marker. Corilagin significantly reduced nitric oxide production in LPS-stimulated RAW 264.7 macrophages and BV-2 microglia, which is the main documented pharmacological property of the flower's tannin fraction.
Gallic acid
Phenolic acidConcentration: about 33.7 mg/g of a longan flower water extract
A dominant simple phenolic of the flower, contributing to the extract's measured radical-scavenging capacity.
(-)-Epicatechin
Flavan-3-olConcentration: about 30.3 mg/g of a longan flower water extract
Epicatechin and proanthocyanidin A2 are the constituents to which the high antioxidant activity of longan flower has been attributed.
Ellagic acid
Phenolic (ellagitannin-derived dilactone)Concentration: about 23.0 mg/g of a longan flower water extract
Like corilagin, reduced nitric oxide production under LPS stimulation in both macrophage and microglial models.
Procyanidin A2
A-type proanthocyanidin dimerConcentration: about 3.5 mg/g of a longan flower water extract; total oligomeric proanthocyanidins about 15.9 mg/g of an ethanol extract
One of the two compounds credited with the flower's antioxidant activity. A-type dimers of this kind are relatively resistant to digestion and are the usual carriers of proanthocyanidin activity in food extracts.
Rutin
Flavonol glycosideConcentration: about 4.7 mg/g of a longan flower water extract
A minor flavonol glycoside of the flower; part of the total flavonoid fraction measured at about 233 mg/g in an ethanol extract.
Quercetin and kaempferol (aglycones)
FlavonolConcentration: trace: about 0.22 mg/g and 0.08 mg/g respectively of a longan flower water extract
Present only in trace amounts as free aglycones; the flower's flavonoid load is overwhelmingly in glycosylated and oligomeric form.
⚠ Drug Interactions
Sedative-hypnotics and other CNS depressants (benzodiazepines, z-drugs, sedating antihistamines, alcohol)
Longan flower water extract at 25 mg/kg orally for 7 or 14 days significantly prolonged total sleep duration in mice in an isoflurane loss-of-righting-reflex model, and raised brain serotonin and dopamine and circulating melatonin. In cell models the extract upregulated TPH1, DDC, AANAT and ASMT and increased serotonin secretion. This is animal and cell-model work only, but a serotonin-melatonin effect of this kind is the pattern that would add to sedative drugs.
Clinical note: Worth mentioning to a patient already on a hypnotic, particularly if the flower is being given in quantity for urinary or discharge complaints and sedation is not the intended effect.
Oral iron salts and other drugs subject to tannin complexation
The flower is a tannin-dominated drug: corilagin alone is present at roughly 37-55 mg/g of extract, with total polyphenols around 171 mg/g. Ellagitannins at that level precipitate iron and alkaloidal bases in the gut lumen. This is a class effect of high-tannin drugs, not a case report specific to longan flower.
Clinical note: Separate from oral iron by at least two hours.
Long Yan Rou (Dimocarpus longan aril) supplied in place of Long Yan Hua
The two drugs come from the same species but are not equivalent. Long Yan Rou, the fleshy aril, is the long-established Pharmacopoeia drug used to nourish Blood and quiet the Spirit. Long Yan Hua is the flower, a regional Fujian drug whose chemistry is a tannin and proanthocyanidin profile dominated by corilagin, gallic acid and epicatechin, with no meaningful sugar-rich aril fraction. Long Yan Hua is by far the less commonly stocked of the two.
Clinical note: If a supplier cannot demonstrate that the material is the flower, assume the aril has been sent. The two look nothing alike and the substitution should be visible on inspection.
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
Longan flower water extract promotes sleep in mice via the serotonin–melatonin axis
Male C57BL/6 mice received longan flower water extract orally at 25 mg/kg daily for 7 or 14 days, with sleep assessed by an isoflurane-induced loss-of-righting-reflex model and neurotransmitters and melatonin measured by ELISA. The extract significantly prolonged total sleep duration at both time points without shortening sleep latency, and raised brain serotonin and dopamine and circulating melatonin, pointing to enhanced sleep maintenance rather than faster sleep onset. LC-MS quantified corilagin at 54.61 mg/g, gallic acid at 33.74 mg/g and epicatechin at 30.25 mg/g of the extract.
Longan Flower Ethanol Extract, Dimocarpus longan Lour, Mitigates Oxidative Damage and Inflammatory Responses While Promoting Sleep-Related Enzymes in Cell Models
A longan flower ethanol extract containing about 171 mg/g total polyphenols, 233 mg/g total flavonoids, 15.9 mg/g oligomeric proanthocyanidins and 37.7 mg/g corilagin was tested in RAW 264.7 macrophages, BV-2 microglia, SH-SY5Y neuroblastoma and QGP-1 cells. It reduced intracellular ROS concentration-dependently, raised GPx and SOD activity and glutathione, and lowered TNF-alpha, IL-6 and nitric oxide. It also upregulated TPH1, DDC, AANAT and ASMT (2.1- to 4.3-fold) and increased serotonin secretion three- to four-fold. Cell models only.
Historical Texts
Quanzhou Ben Cao
Modern regional Fujian materia medica, 20th centuryShen Nong Ben Cao Jing
Han dynasty, compiled by the 2nd century CEReferences
- Ya-Yuan Tang, Xue-Mei He, Jian Sun, Chang-Bao Li, Li Li, Jin-Feng Sheng, Ming Xin, Zhi-Chun Li, Feng-Jin Zheng, Guo-Ming Liu, Jie-Min Li, Dong-Ning Ling. Polyphenols and Alkaloids in Byproducts of Longan Fruits (Dimocarpus Longan Lour.) and Their Bioactivities . Molecules (2019) [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.
📝 Notes
Public notes from the community and your own private notes on Long Yan Hua.
No notes yet.