About the Tropical Fruit Longan: Its Nutrition and Medicinal Uses
It is uncertain whether the magnificent longan tree originated from the Indian subcontinent or Southern China. Longan fruit ( Dimoncarpus longan), a relative of litchi and rambutan, was certainly embraced by Chinese medicine and has been consumed in Asia for thousands of years. The fruit’s propagation was spread throughout South East Asia by Chinese immigrants hundreds of years ago. The Chinese call longan ‘eye of the dragon’; a reference to the white oval shaped mark on the fruit’s inedible brown seed.
Nowadays Thailand is the worlds predominant producer of longan, where the fruit is canned in syrup or dried and exported. Dried longan’s look like large raisins. The fruit is cultivated throughout South East Asia, also in the United States, China and Australia.
The longan tree is evergreen with heavy foliage and grows up to 130 feet. The fruit of the bountiful longan tree is sweet with a slight musky aroma. Many say that its taste is better than litchi, although longan isn’t as juicy. Longan fruit grows in bunches and each fruit has an orange shell that turns brown when the longan is ripe. Its flowers are pale yellow and its leaves are glossy on top and fuzzy underneath.
Longan fruit is part of the Sapindacease botanical family and is closely related to soapnut. As such its seeds contain saponin, a type of chemical compound that produces foam when dissolved in water. The Chinese use longan seeds to produce shampoo and soap.
Logan fruit in Traditional Medicine: Chinese traditional food therapy utilizes longan fruit as a remedy for many ailments. The fruit is believed to calm the nerves and revitalize the circulatory system. It is used to treat insomnia, amnesia, edema and cardiac palpitations. Longan wine tonic is said to enrich the blood, beatify the skin, and is a remedy for grey hair. Combined with don quai and white peony root as a tonic, it is said to increase a woman’s sexual libido. Aside from the flesh of the logan fruit, the leaves, root and flowers of the longan tree are used in Chinese medicine and can be bought at stores selling Chinese herbs.
Logan Fruit and Nutrition: longan fruit is a good source of vitamins C and A. The fruit is high in potassium, fiber, protein, magnesium, copper and per pound contains more iron that spinach. A single logan fruit is 83% water and contains 15g of carbohydrate.
The skin, seeds, and to a lesser extent the pulp, of longan fruit contain high amounts of phenolic acids. Researchers at the Chinese Academy of Science found that the principle polyphenol antioxidants in longan fruits are gallic acid, ellagic acid and corilagin. Ellagic acid is a powerful free-radical scavenger that is known to inhibit the growth of carcinogens. Other foods with ellagic acid are cranberries, pomegranate and strawberries. Gallic acid is an organic compound that is antifungal and antiviral. It is a free-radical scavenger that helps protect us against chronic diseases. Corilagin is a type of gallotannin or hydrolysable tannin that has antibacterial effects. It is also used in pharmaceuticals for drugs that help prevent HIV replication.
A fruit vendor in New York's China Town sells over ripe longan fruit. This image belongs to Sharilyn Neidhardt at flickr.com.