Regular consumption of fruit and vegetables is associated with a lower risk of some chronic diseases
including various forms of cancer and cardiovascular diseases. The health-promoting potential of
these foods may be due, in part, to the phytochemical bioactive compounds present in the plants.
Fruit of Euphoria longana Lam. (longan) are consumed throughout Asia and are a major crop in
Thailand. In the present study phytochemicals were extracted with 70% methanol from peel, pulp,
and seed tissues of longan fruit, and the major components were identified as gallic acid, corilagin
(an ellagitannin), and ellagic acid. A high-through-put reversed phase HPLC method was developed
to determine the content of these three compounds in different parts of the longan fruit and among
different cultivars. The analyses showed that there was a large variation in the contents of gallic
acid, corilagin, and ellagic acid in different plant tissues and cultivars. Seed contained the highest
levels of the three phenolics, and pulp contained the lowest. Among commercial cultivars, Biewkiew
and Edor contained the highest levels of gallic and ellagic acid while Srichompoo contained the highest
content of corilagin. These three cultivars may be used in directed breeding and cultivation programs
and to develop concentrated longan seed extracts to promote good health. Utilization of this byproduct
material will support the use of thousands of tons of waste longan seeds after the production of
canned longan pulp.