Longan - Euphoria Fruit - by Ray Sahelian, M.D.

Euphoria Fruit (Euphoria longan) is a small, round, undistinguished-looking fruit. The brittle light brown skin encloses delicious translucent, juicy soft flesh around a single large, black inedible pit. The Chinese name for this fruit is long yan rou, which literally means “dragon eye flesh”. In the grocery markets, Euphoria fruits are simply known as longans. Longan is consumed throughout Asia and is a major crop in Thailand.

Chemical Composition of Longan fruit
Longan fruit contains several vitamins and minerals, including iron, magnesium, phosphorus and potassium, and large amounts of vitamins A and C. Euphoria fruit also has phenolic compounds in the fruit, such as gallic acid, corilagin, and ellagic acid, indicating that the fruit may have antioxidant, chemo-preventive, and liver protective properties. The Euphoria seed contains the highest levels of the three phenolics, and pulp contains the lowest.
     From the pulp of Euphoria longana (Longan Arillus), three cerebroside molecular species have been isolated. Six known cerebrosides, soyacerebrosides I and II, 1-O-beta-D-glucopyranosyl-(2S,3R,4E,8E)-2-(2'-lignoceroylamino)-4,8-octadecadiene-1,3-diol (longan cerebroside I) and its 8Z isomer (longan cerebroside II), momor-cerebroside I, and phytolacca cerebroside, were identified as major components of these cerebroside molecular species.

Longan fruit research
Adenosine, the anxiolytic-like principle of the Arillus of Euphoria longana - Longan fruit.
Planta Med. 1999 Mar;65(2):115-9. Faculty of Pharmaceutical Sciences, Chiba University, Japan
According to traditional usage, the extract of Longan Arillus was tested for its anxiolytic-like effect by application of the Vogel-type anti-conflict method in mice. The extract indicated significant activity at a dose of 2 g/kg, s.c., and results of the bioassay-oriented isolation revealed adenosine to be the active principle. Adenosine produced the anti-conflict effect significantly at a dose of 30 mg/kg, s.c. Adenine, uridine, and 5-methyluridine did not exhibit the effect, although these compounds were isolated from the Euphoria longana extract. Some other related compounds such as AMP and c-AMP showed no effect, except for inosine. Adenosine also contributed to the analgesic effect which was observed in the extract by the writhing method.