Dr. Grey AI

Longan

Dimocarpus longan (Longan or Dragon Eye) is a tropical fruit related to lychee, consumed widely in Asia. Preclinical research suggests neuroprotective and cognitive-enhancing effects from the seed and fruit extracts. NO GRADED OUTCOMES - limited human research on medicinal use. The fruit flesh is nutritious but not unique; bioactive compounds are concentrated in seeds and peel. Traditional use includes tonifying blood and calming the spirit in TCM. Safe as a food; medicinal use of extracts lacks human validation.

Quick Answer

What it is

Dimocarpus longan (Longan or Dragon Eye) is a tropical fruit related to lychee, consumed widely in Asia. Preclinical research suggests neuroprotective and cognitive-enhancing effects from the seed and fruit extracts.

Key findings

  • Grade C: Neuroprotection
  • Grade C: Bone Health
  • Grade D: Inflammation

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts: Longan

Quick Facts: Longan

  • Best Evidence:Grade C
  • Conditions Studied:4
  • Research Outcomes:7
  • Key Effect:Alzheimer’s Disease
Outcomes by grade:
A0
B0
C2
D5
4 conditions · 7 outcomes

Detailed Outcomes

|
C
Neuroprotection
In rodent models of Parkinson's and Alzheimer's disease, longan flower, aril, and polysaccharide extracts consistently attenuated neurotoxicity, improved learning and memory, increased BDNF expression, reduced amyloid-beta and phosphorylated-tau, and enhanced microglial phagocytosis via RAS/MEK/ERK and PI3K/Akt/mTOR pathways. No human studies on cognition exist.
moderate↑Improves
C
Bone Health
A 12-week double-blind RCT in 50 elderly participants found longan pulp and seed extract significantly reduced alkaline phosphatase levels versus placebo (mean difference -7.06 U/L, p=0.023), though other bone turnover markers did not reach significance. In vitro studies show longan fruit extract stimulates osteoblast differentiation via Erk1/2-dependent RUNX2 activation.
small↑Improves
D
Inflammation
In rodent carrageenan-induced edema models, longan pericarp extract (400 mg/kg) reduced paw edema to 58% of controls, decreased serum NO, and inhibited TNF-alpha by 45%. Longan seed extract similarly reduced edema and inflammatory cytokines via MAPK pathway inhibition. In vitro, flower extract suppressed NF-kB and AP-1 signaling in macrophages. No human anti-inflammatory trials exist.
moderate↓Improves
D
Uric Acid Levels
In potassium-oxonate-induced hyperuricemic mice, longan flower extract reduced plasma uric acid by 80% and seed extract by 72%, approaching the efficacy of allopurinol (89%). Mechanisms include dose-dependent xanthine oxidase inhibition and modulation of urate transporters GLUT1 and GLUT9. No human trials have been conducted.
moderate↓Improves
D
Blood Glucose
In mice, longan pericarp extract inhibited alpha-glucosidase (IC50 11.68 ug/mL) and improved glucose tolerance at 10 mg/kg over 5 days by enhancing Irs-1, PPARgamma, and Glut4 expression. In db/db diabetic mice, longan extract ameliorated fasting blood glucose and reduced excessive fat accumulation via hypothalamic POMC/AgRP regulation. No human glycemic trials exist.
small↓Improves
D
Antioxidant Status
In animal and in vitro studies, longan extracts (particularly pericarp and flower) demonstrate potent antioxidant activity exceeding glutathione and Trolox. In rodent models, longan pericarp extract increased catalase (121-144%), SOD (128-153%), and GPx (111-126%) while reducing lipid peroxidation markers. Key bioactive polyphenols include ellagic acid, corilagin, and epicatechin.
moderate↑Improves
D
Immune Function
In immunosuppressed mice, longan pulp polysaccharide-protein complex (100 mg/kg/day) significantly increased antibody production, splenocyte proliferation, macrophage phagocytosis, and NK cell cytotoxicity, with efficacy comparable to ganoderan. In vitro, a novel longan polysaccharide (LP4) activated macrophages via TLR2/4-mediated PI3K/AKT and MyD88/TRAF6 pathways.
moderate↑Improves

Research Citations (14)

Longan Aril polysaccharides ameliorate cognitive impairment in AD mice via restoration of the immune phagocytosis of microglia
(2025)
PMID: 39923958
Longan (Dimocarpus longan Lour.) Aril ameliorates cognitive impairment in AD mice induced by combination of D-gal/AlCl3 and an irregular diet via RAS/MEK/ERK signaling pathway
(2021)
PMID: 33249246
Longan (Dimocarpus longan Lour.) Fruit Extract Stimulates Osteoblast Differentiation via Erk1/2-Dependent RUNX2 Activation
(2016)
PMID: 26975768
Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-kB and AP-1 signaling pathways
(2016)
PMID: 26721218
Evaluation of Xanthine Oxidase Inhibitory Potential and In vivo Hypouricemic Activity of Dimocarpus longan Lour. Extracts
(2016)
PMID: 27279708
Anti-inflammatory effect of longan seed extract in carrageenan stimulated Sprague-Dawley rats
(2016)
PMID: 27746869
Neuroprotective Effects of Longan (Dimocarpus longan Lour.) Flower Water Extract on MPP+-Induced Neurotoxicity in Rat Brain
(2012)
PMID: 22920583
Antioxidant and Anti-Inflammatory Properties of Longan (Dimocarpus longan Lour.) Pericarp
(2012)
PMID: 22966244
Longan seed extract reduces hyperuricemia via modulating urate transporters and suppressing xanthine oxidase activity
(2012)
PMID: 22928829
In vitro antifungal activities of longan (Dimocarpus longan Lour.) seed extract
(2012)
PMID: 22245574

Related Supplements

Myricetin

3 shared conditions · 8 outcomes

Myricetin is a flavonoid found in berries, vegetables, and wine, structurally related to quercetin and kaempferol. Among flavonoids, myricetin has been particularly associated with bone health and anti-osteoporotic effects in preclinical research. Also has antioxidant and potential anti-diabetic properties. NO GRADED OUTCOMES - human research is limited. Found in foods like berries, onions, and red wine. Not widely available as an isolated supplement. Low bioavailability may limit therapeutic use.

7,8-Dihydroxyflavone

3 shared conditions · 15 outcomes

7,8-DHF is a natural flavonoid which can reach the brain and activate a receptor (TrkB) that promotes neuronal growth. Some animal evidence suggests that 7,8-DHF may have some cognitive and motor benefits and may be nootropic, but no human evidence for these claims exists to date.

Vitamin D

2 shared conditions · 308 outcomes

Vitamin D is a fat-soluble vitamin that our skin synthesizes when exposed to the sun. It benefits us in many ways, from bone health to mood.

Salidrosides

2 shared conditions · 11 outcomes

Salidroside is a glucoside compound and one of the main bioactive constituents of Rhodiola rosea. Often standardized in Rhodiola extracts (typically 1-3%). Has neuroprotective and adaptogenic properties. Research shows anti-fatigue, anti-stress, and potential anti-depressant effects. Mechanism involves HPA axis modulation, AMPK activation, and antioxidant effects. Most clinical evidence is for the whole Rhodiola rosea extract rather than isolated salidroside. May be more effective as part of whole plant extract than in isolation.

Probiotics

2 shared conditions · 215 outcomes

Probiotics are microorganisms that can have a positive effect on health.

Poly-Îł-Glutamic Acid

2 shared conditions · 7 outcomes

Poly-Îł-glutamic acid (Îł-PGA) is a polymer produced by Bacillus bacteria, found naturally in natto (fermented soybeans). Used in skincare (hydration), food industry (texture), and has research interest for health applications. NO GRADED OUTCOMES - research is mostly preclinical. May have calcium absorption, immune, and antioxidant properties. Biodegradable and safe. Primarily used topically in cosmetics rather than as an oral supplement.

Pelargonidin

2 shared conditions · 6 outcomes

Pelargonidin is one of six anthocyanidins (anthocyanin aglycones) responsible for red/orange coloring in plants, particularly strawberries. It is the simplest anthocyanidin structurally. NO GRADED OUTCOMES - very limited human research. Better to obtain through strawberry/berry consumption than as an isolated supplement. Has antioxidant and potential neuroprotective properties in preclinical research. Bioavailability may be enhanced by other flavonoids like quercetin.

Orange Peel

2 shared conditions · 7 outcomes

Orange peel is rich in hesperidin (citrus flavonoid), polymethoxyflavones (PMFs), vitamin C, and fiber. Hesperidin has B-grade evidence for blood pressure reduction and vascular function. PMFs (tangeretin, nobiletin) have unique metabolic and neuroprotective effects in preclinical studies. Orange peel extracts used for cardiovascular health and chronic venous insufficiency. Essential oil (d-limonene) used topically and for aromatherapy. Standardized extracts dosed by hesperidin content.