 Gen info
- Genus Dimocarpus contains six species viz., Dimocarpus longan, D. dentatus, D. gardneri, D. foveolatus, D. fumatus and D. australianus. The major cultivated longan in different areas is D. longan.
- longan in Chinese Cantonese, luhna-ngaahn,
referring to the fruits resemblance to an eyeball when it is shelled, and the black seed shows through the transluscent flesh like an eye,
Botany
Ochrocarpus pentapetalous is a large tree that grows up to 40 m tall with a round topped-crown of dense leaves. Leaves are compound, with elliptical leaflets that have soft hairs above at the basal part of of the mid-rib and tufts of soft hairs beneath mainly on the midrib and nerves. Trunk reaches 1 m in diameter, sometimes buttressed. Branches terete with five faint grooves, sometimes with warty pores (lenticels), and densely covered with rusty-brown soft hairs. Inflorescence terminal, 8-40 cm long, densely covered with soft hairs, bearing fragrant flowers that are soft yellow-brown. Fruit is a yellow-brown drupe, each containing a single shiny, small, round, hard, and blackish-brown seed covered by a thin translucent white fleshy layer. (2)
Distribution
- Native to the Philippines.
- Also native to Andaman Is., Assam, Bangladesh, Borneo, Cambodia, China, East Himalaya, Laos, Malaya, Maluku, Myanmar, Nicobar Is., Sri Lanka,
Sulawesi, Sumatra, Thailand, Vietnam. ( 1)
- IUCN status: Near threatened.
Constituents
- Longan fruit yields 12 important compounds: ß-sitosterol (1), 2-phenylethanol (2), 2-methyl-1,10-undecanediol (3), (24R)-6ß-hydroxy-24-ethyl-cholest-4-en-3-one (4), oleanolic acid (5), pinoresinol (6), nicotinic acid (7), 4-hydroxybenzoic acid (8), ß-daucosterol (9), 1-O-mrthyl-D-myo-inositol (10), uracil (11), and adenosine (12). (3)
- Longan shell yielded antioxidant compounds like isovanillin, scopoletin, quercetin. hyperin, astragalin,
and ß-phenylethyl alcohol. Main functional metabolites include polysaccharides, flavonoids, alkaloids, and carotenoids. Vitamins and minerals include iron, magnesium, phosphorus, and potassium and large amounts of vitamins A and C. (3)
- Study
of ethyl acetate and 80% methanol extract of aerial parts yielded triterpenes and/or sterols +. carbohydrates and/or glycosides, flavonoids, and tannins, with absence of coumarins, saponins, and alkaloids and/or nitrogenous compounds. (3)
- Nutritional value of longan per 100g fresh weight showed : water 81g, protein 1.2g, fat 0.1g, carbohydrates 16g, vitamin c 60mg, thiamine 0.04mg, niacin 1.0mg, riboflavin 0.03mg, phosphorus 26mg, iron 0.4mg, calcium 13mg. (3)
- Phytochemical study of pericarp yielded gallic acid, corilagin, (-)=epicatechin, ellagic acid and its conjugates, quercetin, flavones glycosides, glycosides of quercetin and kaempferol, protocatechuic acid, and brevifolin. Seeds yielded gallic acid, corilagin, ellagitannins corilagin, ellagic acid-4-O-a-L-arabinofuranoside, isomallotinic acid,
- Study of
longan seed for gallic acid and ellagic acid by RP-HPLC yielded 23.3 and 156 mg/100 seeds, respectively. (8)
- Study of leaves by quantitative analysis of multicomponents by a single marker (QAMS) method
yielded five components, i.e., ethyl gallate, (C1). astragalin (Ç2). quercetin (C3), luteolin (C4), and kaempferol (C5). (11)
Properties
- In traditional Chinese medicine, longan fruits are considered warm, sweet and astringent.
- Studies have suggested
antioxidant, anti-inflammatory, anti-hepatitis C, anti-aging,, anticancer, CNS depressant antidiarrheal, analgesic, antihyperuricemic, antiproliferative, hypoglycemic, anti-osteoporosis properties.
Parts used
Fruits, leaves, seeds and roots.
Uses
Edibility
- Fruit are edible: fresh dried, frozen or processed.
- Fruit flesh is juicy. low in acid, high in sugar.
Folkloric
- In traditional Chinese medicine dried fruits relieves anxiety; fruits also used to treat insomnia.
- Chinese formulations used for treatment of neural pain and swelling.
- The roots are used for treatment of diabetes and gonorrhea.
Studies
• Antioxidant / Anti-Inflammatory / Pericarp: Study evaluated the antioxidant and anti-inflammatory activities of water extract of longan pericarp. Rh extract exhibited radical scavenging, reducing activity, and liposome protection activity. The extract also inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production in macrophages. The extract also showed concentration-dependent inhibition of paw edema development following carrageenan treatment in mice. The anti-inflammatory effect may be related to NO and tumor necrosis factor (TNF-α) suppression and increase in the activities of antioxidant enzymes, including catalase, superoxide dismutase, and glutathione peroxidase. (4)
• Anti-Hepatitis C Activity / Leaves: Hepatitis is caused by the Hepatitis C virus that causes chronic hepatitis, cirrhosis, and hepatocellular carcinoma. Current treatment is a combination of pegylated interferon-α plus ribavirin with NS3 protease inhibitors. Such treatment is expensive and fraught with side effects. This study evaluated the antiviral activity of a crude extract from Dimocarpus longan leaves against HCV. Results showed anti-HCV activity with 50% effective concentration (EC50) of 19.4 µg/ml. The extract exhibited activity at both entry and post-entry steps. There was direct virucidal effect with a marginal inhibition of virion assembly. Co-treatment of extract with cyclosporine A or teleprevir, an NS3 protease inhibitor, showed additive and synergistic antiviral effects, respectively. (5)
• By-Products as Functional Foods: The processing of Sapindaceae fruits including longan and rambutan, produce a large quantity of by-products that are discarded, which account for 24,9-40.7 and 52.0-74.7% of the whole fruit on a fresh weight basis, respectively. The by-products are rich in gallic acid, ellagic acid, and geraniin The phenolc compounds possess a wide range of beneficial products. Effective recovery and value-added utilization of natural phenolics are possible. (6)
• Formulation of Natural Antioxidant Cream / Photo-Aging / Peels: Photo-aging is a common problem due to chronic exposure to ultraviolet rays. The use of antioxidants is an effective approach to prevent symptoms related to photo-induced aging of the skin. Study reports on the formulation and evaluated the antioxidant cream from a methanol peel extract of Dimocarpus longan. The extract contained three major polyphenolic compounds viz., corilagin, gallic acid, and ellagic acid, which are responsible for the antioxidant properties. The peels extract showed higher antioxidant activity with IC50 23.5 µg/ml compared to seeds with 32.13 µg/ml. A 2.5% peel cream formulations showed good pH, homogeneity, appearance, ease to remove, spreadability good consistency, and no microbial growth. Evaluation parameters of F2 formulation showed good results and safety for skin use and showed good potential for development of a cosmetic product. (7)
• Potential Bioactivities of By-Products Seed and Pericarp: The longan commerce produced a large amount of byproducts such as pericarp and seed, which contributes to environmental pollution. Study evaluated the functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids in longan byproducts. Total phenolic and total flavonoid contents in the pericarp where slightly higher than those in seeds, while seeds possessed higher alkaloid content than the pericarp. Four polyphenolic compounds, i.e., gallic acid. ethyl gallate, corilagin and ellagicc acid were identified, and among them, corilagin was the major compound in both pericarp and seed. The alkaloid seed extract showed highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Flavonoids in seed and alkaloids in pericarp had potential to be developed as antihyperglycemic agents. (9)
• Anticancer / Antioxidant / Pericarp: Longan fruit pericarp was extracted with 50% ethanol extract using high pressure (HPEL) and conventional extraction (CEL) methods. Anticancer activity was tested using HepG2, A549, and SGC 7901 cancer cell lines. HPEL showed excellent antioxidant and anticancer activities, which were higher than CEL. Three phenolic compounds, viz., corilagin, gallic acid, and ellagic acid were identified. (10)
• CNS Depressant / Analgesic / Antidiarrheal / Seeds: Study evaluated crude dried seed extract of Dimocarpus longan for central nervous system depressant, analgesic, and antidiarrheal activities in a rat model. In hole cross method, the ethyl acetate extract showed the most effective depressant effect, while in the open field test all extracts showed significant (p<0.01) depressant effect. In acetic acid induced pain test, the petroleum ether extract showed the lowest number of writhing and the highest inhibition, which was statistically significant. The extracts exhibited significant (p<0.01) suppression of licking activity in both phases of formalin-induced licking test. In the antidiarrheal test, diarrheal suppression was highest at 300 mg/kg dose for all extracts. (12)
• Hypouricemic / Xanthine Oxidase Inhibitory / Flowers: Study the effect of D. longan extracts pf flowers. pericarp, seeds, leaves, and twigs on potassium-oxalate induced hyperuricemia in mice and its xanthine-oxidase (XO) inhibitory activity. Results showed the ethyl acetate fraction of longan exhibited strong XO-inhibitory activity, and the flower extracts (IC50 115.8 µg/ml) showed more potent XO activity than the pericarp, twigs, seeds, and leaves. A 75 mg/kg dose markedly reduced plasma uric acid levels in decreasing order of flowers 80% > seeds 72% > pericarp 64% > twigs 59% > leaves 41%, compared to allopurinol at 89%. Of compounds isolated from flowers, proanthocyanidin A2 and acetinyl- geraniin A significantly inhibited XO activity in vivo. Results suggest insights into the urate-reducing effect of phenolic dimer and hydrolyzable tannins, which can be developed into hypouricemic agents. (13)
• Antiproliferative / Leaves: Study evaluated the antiproliferative activity of longan leaf extracts against cancer-derived cell lines in vitro. Of the tested extracts and fractions, the ethanol extract exhibited significant cytotoxity with the lowest LC50 value using brine shrimps Lethality assay. The ethanol extract showed marked antiproliferative activity on WEHI-164 cells (mouse fibrosarcoma cancer cell), THP-1 cells (human peripheral blood acute monocyte cell). The extract had low effect to vero cells. Results confirmed that the longan leaf ethanol extract possesses marked antiproliferative activity on cancer-derived cell lines. (14)
• Stimulation of Osteoblast Differentiation: Study used a cell-based herbal signaling extract to evaluate a longan fruit extract (LFE) as an activator of osteoclast differentiation. The LFE up-regulated alkaline phosphatase activity, induced mineralization, and activated Runx2, gene expression in MC3T3-E1 cells. Results suggest LFE exerts its osteogenic activity through activation of the ERK signaling pathway and may have potential as an herbal therapeutic or preventive agent for the treatment of osteoporosis. (15)
• Anti-Aging / Leaves: Study evaluated various leaf extracts for antioxidant, inhibition of hyaluronidase, collagenase, MMP-2 and MMP-9. Results showed the hydroethanolic extract had a higher yield of total phenolics and flavonoids content with superior biologic activity compared to the ethanolic extract. The HE extract also showed radical scavenging activity on DPPH an hydrogen peroxide with with IC50s of 30.03 and 71.40 µg/ml, respectively. There was inhibition of lipid peroxidation. The HE hyaluronidase and collagenase with IC50 234.80 and 314.44 µg/ml, respectively. The HE extract also demonstrated MMP-2 and MMP-9 inhibition, which is more potent than gallic acid, Results suggest the HR extract of longan leaves showed high potential as an invitro antioxidant and inhibitor of enzymatic activities with potential for further development of anti-aging products. (16)
• Silver Nanoparticles . Antibacterial / Anti-Prostate Cancer / Peel: Study reports on the eco-friendly biosynthesis of silver nanoparticles using Dimocarpus longan peel aqueous extract. The longan peel extract acted as a strong reducing and stabilizing agent during synthesis. The AgNPs showed potent bactericidal activities against gram-positive and gram-negative bacteria with a dose-dependent effect. The AgNPs also showed dose-dependent cytotoxicity against PC-3 cells through a decrease of state 3, bcl-3. and survivin as well as an increase in caspase-3. Further research is suggested to focus on the molecular mechanisms and in vivo effects on prostate cancer. (17)
• Floral Induction by Potassium Chlorate Application: It has been reported that potassium chlorate could be successfully applied to promote flowering in longan. The compound has been used in on-season and off-season production of fruits. Review summarizes the application methods, influencing factors and physiological and molecular mechanisms associated with KClO3-mediated induction of longan flowering. The leaves may play a crucial role in in the transport and response to KClO3. Leaves supply carbon and nitrogen nutrition, and hormone and signaling molecules needed for differentiation of apical buds. (20)
• Enhancement of Phenolic Content and Biologic Activities / Thermal and Ageing Process: Study compared the chemical compositions and biologic activities of a conventional dried longan with a novel black longan that underwent a thermal ageing process. Pericarp, aril, and seeds of both were macerated in 95% v/v ethanol. After exposure to heating and ageing, the gallic acid and ellagic acid contents were increased tenfold, while the corilagin content was doubled. Black longan seed was the most potent anti-hyaluronidase and antioxidant with the strongest free radical scavenging and reduction power while black longan aril extract showed the highest inhibition of inflammatory cytokine secretion. Black D. longan contained more biologically active compounds and more potent biological activities than conventional dried D longan. Results suggest thermal ageing treatment is suggested for producing black D. longan and its seed extract is suggested as a cosmeceutical active ingredient and as anti-inflammation. (21)
• Anti-HIV Effects / Aerial Parts: Study evaluated various extracts of aerial parts for anti-HIV effect. using syncytia formation assay. The ethyl acetate extract showed anti-HIV activity while the other extracts showed less activity. Phytochemical analysis yielded triterpenes, flavonoids, tannins, and carbohydrates. (22)
• Antioxidant / Bark and Leaves: Study evaluated 80% methanol extracts of bark and leaves for antioxidant activity. The extracts showed almost the same radical scavenging activity and reducing power. The contents of ellagic acid in the extracts were 0.91 and 3.723 mg/g dry samples, respectively. After hydrolysis, the EA content increase three- to four-fold. Study suggests the ellagic acid exists mainly in the form of ellagitannins. Results suggest the barks and leaves are excellent sources of free radical inhibitors, and also a potential source for the production of ellagic acid. (23)
• Antimicrobial / Antimalarial / Seeds: Study evaluated a methanolic extract of seeds for antibacterial and antimalarial (antiplasmodial) activity and cytotoxicity using sulforhodamin B (SRB) assay with Vero cells (African green monkey kidney cell line). Results showed the longan seed extract at 10 mg/ml inhibited the growth of S. aureus, P. aeruginosa and C. albicans with MICs of 3.19, 1.59, and 1.59 mg/ml, respectively. The seed extract also showed antimalarial activity against Plasmodium falcifarum with IC50 of 2.78 µg/ml with no cytotoxicity effect on Vero cells. (24)
• Longan Wine Incorporated with Seeds / Antioxidant: The seeds of longan contain several bioactive compounds. Study reports on the development of longan wine by incorporating its seeds during juice preparation and evaluated the antioxidant activities and volatile compounds. Results suggest Saccharomyces cerevisiae EC-1118 was suitable for fermentation of longan juice supplemented with 50% seed and 20% initial soluble solids at optimum temperature of 30°C. Antioxidant activity was increased with increasing the seed content. Dominant volatile compounds, which were independent of winemaking conditions, were ethylene alcohol, 2,3-butylene glycol, 5-hydroxymethyl-2-furaldehyde, ethyl hydrogen succinctness, and 4-hydroxyphenethyl alcohol. These compounds highly influenced the antioxidant activities of longan wine produced by incorporating the seeds. (25)
• Increase in Fruit Shelf Life / Use of Fumigation and Retardant: Cold-stored food removed from storage under gradual temperature increase or with oxidation retardant addition maintained a shelf life for 32 hours at ambient temperature. Sulfur fumigation was favorable in retaining the original skin color and flesh eating quality. Fruit fumigated with sulfur and oxidation retardant maintained 100% marketability after 78 hours at room temperature. (26)
• Hypoglycemic / Phenolic Compounds / Fruit Shell: Study evaluated the in vitro hypoglycemic effect of longan fruit by inhibition of α-glucosidase and ß-galactosidase activities. The IC50s of hot water and 50% ethanol extracts against α-glucosidase were 9.2 and 13.4 mg/mL and 12.0 and 19.7 mg/mL against ß-galactosidase, respectively. Two phenolic compounds, gallic acid and ellagic acid, were identified as major phenolics in hot water extracts from the longan fruit shell against the enzymes. The inhibition of α-glucosidase and ß-galactosidase were proven as a therapeutic approach for decreasing postprandial hyperglycemia. Results suggest the longan fruit shell extracts may have potential for early treatment of postprandial hyperglycemia. (27)
Availability
- Wild-crafted.
- Commercial cultivation for its fruit.
- Market availability
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