Supplement
Longan is a tropical fruit whose pulp and seed extracts are sold as supplements, rich in polyphenols that act as antioxidants. Its best-supported finding involved bone health, where a 12-week trial in 50 older adults found lower alkaline phosphatase, a bone turnover marker, than placebo, while other markers showed no clear difference. Evidence is limited, and most other research, on memory, inflammation and blood sugar, comes from animal or lab studies.
Sources: PMID 22245574; PMID 22902805
- Updated
- How we grade
- 14 studies cited
- Best evidence
- Grade C
- Conditions studied
- 4
- Outcomes
- 7
- Graded outcomes
- 0025
Evidence by condition
- Strong
- Moderate
- Limited
- Very limited
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| 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. | Improves (the measure goes up) | Small effect | 4 studies | 50 people | ||
Studies that measured bone health
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General
- Inflammation: improves
- Uric Acid Levels: improves
- Blood Glucose: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| 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. | Improves (the measure goes down) | Moderate effect | 6 studies | |||
Studies that measured inflammation
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| 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. | Improves (the measure goes down) | Moderate effect | 5 studies | |||
Studies that measured uric acid levels
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| 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. | Improves (the measure goes down) | Small effect | 4 studies | |||
Studies that measured blood glucose
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Antioxidant Status
- Antioxidant Status: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| 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. | Improves (the measure goes up) | Moderate effect | 5 studies | |||
Studies that measured antioxidant status
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Autoimmune Health
- Immune Function: improves
| Grade | Outcome | Effect | Size | Studies | People | Studies list |
|---|---|---|---|---|---|---|
| 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. | Improves (the measure goes up) | Moderate effect | 4 studies | |||
Studies that measured immune function
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Key findings
- NeuroprotectionImproves (the measure goes up)
- Bone HealthImproves (the measure goes up)
- InflammationImproves (the measure goes down)
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- Grade C
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Studies cited
14 studies from PubMed
- Longan Aril polysaccharides ameliorate cognitive impairment in AD mice via restoration of the immune phagocytosis of microglia
- 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
- Longan (Dimocarpus longan Lour.) Fruit Extract Stimulates Osteoblast Differentiation via Erk1/2-Dependent RUNX2 Activation
- Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-kB and AP-1 signaling pathways
- Evaluation of Xanthine Oxidase Inhibitory Potential and In vivo Hypouricemic Activity of Dimocarpus longan Lour. Extracts
- Anti-inflammatory effect of longan seed extract in carrageenan stimulated Sprague-Dawley rats
- Neuroprotective Effects of Longan (Dimocarpus longan Lour.) Flower Water Extract on MPP+-Induced Neurotoxicity in Rat Brain
- Antioxidant and Anti-Inflammatory Properties of Longan (Dimocarpus longan Lour.) Pericarp
- Longan seed extract reduces hyperuricemia via modulating urate transporters and suppressing xanthine oxidase activity
- In vitro antifungal activities of longan (Dimocarpus longan Lour.) seed extract
- Safety evaluation of longan seed extract: acute and repeated oral administration
- Potential roles of longan flower and seed extracts for anti-cancer
- Immunomodulatory activity of polysaccharide-protein complex of longan (Dimocarpus longan Lour.) pulp
- The memory-enhancing effects of Euphoria longan fruit extract in mice