|Lo Han Guo
A Literature Review
Edward M. Croom, Jr.
The Chinese plant Lo Han Guo Siraitia grosvenorii is a perennial vine in the Cucurbitaceae (cucumber or melon) family. Lo Han fruits are used both inside and outside the People's Republic of China as a food, beverage, and traditional medicine. The most unique chemicals reported for the plant are the triterpene glycoside non-caloric sweeteners known as mogrosides in Lo Han fruits. Although millions of Lo Han fruit are consumed worldwide each year, Lo Han fruits in Europe and the United States are mostly sold by Chinese grocery and herb stores. The literature review is intended to serve as the basis for determining the known information on the current uses and potential expansion of Lo Han Guo as a food, seasoning, beverage, or non-caloric sweetener crop plant.
Lo Han Guo-Siraitia grosvenorii (Swingle) C. Jeffrey ex Lu & Zhang. Botanical synonyms are Momordica Grosvenorii Swingle and Thladiantha grosvenorii (Swingle) C. Jeffrey.
Common names: Lo Han Guo, Lo Han Kuo, Arhat Fruit, Fructus Momordicae, Momordicae Grosvenori Fructus.
Plant Family: Cucurbitaceae. The cucumber, melon, squash, and gourd family.
Botanical Notes and Description. The original botanical description of Lo Han Guo was published in 1941 by W.T. Swingle from plants collected in southern China. Swingle named the plant Momordica Grosvenori in honor of Dr. Gilbert Grosvenor, the president of the National Geographic Society, the sponsor of an expedition to collect Lo Han Guo in China by Professor G.W. Groff. In 1941, Swingle described the plant as a cultivated dioecious vine with bifid tendrils, climbing 2-5 meters with tuberous, perennial roots. The fruits and leaves of the four principal cultivated varieties were described as showing "rather striking differences in the shape and color of the fruit and in the shape and size of the leaves….” Fruits of plants that were of wild origin were not studied by Swingle (Swingle, 1941).
Charles Jeffrey at Kew is the foremost Western taxonomic expert on the Asian Cucurbitaceae and after examining more plant specimens moved Lo Han from the genus Momordica to Thladiantha in 1979 and to Siraitia in 1980. Jeffrey (1990b) includes all three genera and the genus Indofevillea in the same subtribe ("Thladianthinae) of the tribe Joliffleae (which only contains one additional genus Telfairia),and the subfamily Cucurbitoideae.
Distribution and Center of Cultivation. All reported locations are from the southern Chinese provinces and autonomous regions of Guangxi, Guangdong, Guizhou, Hunan, Jiangxi, and Hainan island (Swingle, 1941; Jeffrey, 1980; Lu and Zhang, 1984).
Distribution of Lo Han Guo's Closest Plant Relatives. The subtribe Thladianthinae has four genera Indofevillea, Momordica, Siraitia, and Thladiantha with 73 species from Asia, Malaysia, and tropical Africa (Jeffrey, 1990b). Based on Jeffrey's preliminary studies in 1980 of the Cucurbitaceae in Eastern Asia, the three species most closely related to S. grosvenorii are S. siamensis (Craib) C. Jeffrey (=Thladiantha siamensis Craib, Momordica tonkinensis Gagnep., China, Thailand, and Vietnam), S. sikkimensis (Charkr.) C. Jeffrey (=Neoluffa sikkimensis Chakr., India), and S. silomaradjae Merr. (Sumatra). Jeffrey's research to date leaves open the question of whether these are one or four true species. Therefore the plants most likely to have similar sweet fruits are these species. In China, the genus Siraitia has been described to include the four species S. grosvenorii, S. siamensis, S. borneensis, and S. taiwaniana (Lu and Zhang, 1984). The latest revision of the genus Thladiantha described 23 species from eastern Asia and Indomalaysia (Lu and Zhang, 1982; Jeffrey, 1990b).
Although fairly recent revisions and floristic works have been done on the Chinese species of Siraitia (Lu and Zhang, 1984), the genus Thladiantha (Lu and Zhang, 1982) and the Chinese Cucurbitaceae (Lu and Chen, 1986), Jeffrey (1990a) cautions that the generic relationships in this tribe requires clarification. In fact, the lack of taxonomic research on the Asian Cucurbitaceae is a major problem in evaluating the true plant identity of most chemical reports on Asian Cucurbitaceae.
Historical uses. The most complete report in English on the traditional uses of Lo Han Guo in China is the unpublished manuscript written in 1938 by Professor G.W. Groff and Hoh Hin Cheung. In China, the fruits were reported as frequently used as the main ingredient in "cooling drinks" or "cooling tea". The juice of fresh fruits were reported to be very sweet. Groff and Hoh reported that all Lo Han fruits of commerce were carefully dried over fires in special drying sheds.
Groff and Hoh reported that the "Lo-Han fruit of commerce when cooked with pork or steeped with tea provides a common Chinese household remedy for colds and congestion of the lungs." Groff and Hoh concluded from interviews and the fact that Lo Han was not listed in several classical Chinese Medical texts that the plant had only become extensively used in China in recent history. However, the development of distinct cultivars and the amount of knowledge of Lo Han's growth, pollination, climatic, and drying requirements implies a fairly long history of use by some group of people. The origin of the planes common name is uncertain but Lo Han in Chinese culture is associated with the saints that surrounded Buddha and Guo or kuo generally refers to a fruit. If the plant was brought into cultivation by aboriginal or tribal people as proposed by Groff, then the common name may have had a different meaning to the original tribe. Although Swingle (1941) reported the plant to be cultivated by the non-Chinese Miao-tze people, the Zhuangs are the most numerous of the more than ten nationalities that live in Guangxi Zhuang autonomous region.
The earliest report of Lo Han in America is Professor Groff’s report that during a visit in 1917 to United States Department of Agriculrure botanist Dr. Frederick Coville's office, Groff was shown a Lo Han fruit obtained from a local Chinese store in Washington, DC that was purchased by Dr. Coville and Dr. Walter T. Swingle. Seeds from Lo Han fruits purchased in a San Francisco Chinese store were included in Swingle's original botanical description of the species in 1941.
Current uses. Dried fruits are used whole, powered or in block forms as a beverage, seasoning, and as a traditional medicine for analgesic, expectorant, antitussive, and to treat infiltration of the lungs (Takamoto, et al., 1978). The Encyclopedia of Traditional Chinese Medicine (Jiangsu New Medical College, 1977) recommends the use of dried fruits as good for lung complaints including dry coughs and as a laxative at a consumption rate of 10-15 g or one fruit boiled in water per day. The Chinese book Fruit as Medicine (Dai and Liu, 1986) reports the fruits are used for heat stroke with thirst, acute and chronic throat inflammation, aphonia, chronic cough, constipation in the aged, and as a sugar substitute for diabetics. In general, the preparation is to boil or simmer the fruit in water and drink as an herb tea. As a sugar substitute in cooking, the fruits may be simmered into a thick juice and added during the preparation of the food. The prepared block form "Luohanguo Chongji" is reported to be a popular treatment for colds in China (Dai and Liu, 1986).
In the United States, there is, in general, a strict dichotomy of foods and medicines. To provide a more accurate understanding of the use of Lo Han by the Chinese we should consider the role of food and medicine from the Chinese perspective. As emphasized in Food in Chinese Culture, an overriding idea about food in China is that food is intimately relevant to health and "Food, therefore, is also medicine." In south China, Anderson and Anderson (1977) report that the major concern is to balance "cooling" and "heating" foods to maintain good health. They report that carrots and watercress are consumed almost as often as "cooling" medicines as for food.
Anderson, EN, Jr and ML Anderson. 1977. Modern China: South. pp. 317-382 in Food in Chinese Culture, Chang, KC (ed.), Yale University Press, New Haven, CT.
Chang, KC (ed.). 1977. Food in Chinese Culture. Yale University Press, New Haven, CT.
Groff, GW and HC Hoh. 1938. The Lo-han fruits of Kwangsi. Photocopy of unpublished manuscript, G. Weidman Groff collection, Pennsylvania State University, University Park, PA.
Jeffrey, C. 1980. The Cucurbitaceae of Eastern Asia. Royal Botanic Gardens, Kew.
Jeffrey, C. 1990a. Systematics of the Cucurbitaceae: an overview. pp. 3-9 in Biology and Utilization of the Cucurbitaceae, Bates, DM et al. (eds.), Comstock, Ithaca, NY.
Jeffrey, C. 1990b. An outline classification of the Cucurbitaceae. Appendix, pp. 449-463 in Biology and Utilization of the Cucurbitaceae, Bates, DM et al. (eds.), Comstock, Ithaca, NY
Jiangsu New Medical College. 1977. Zhongyao Dachidian (Encyclopedia of Traditional Chinese Medicine). People's Publishing Co., Shanghai, China.
Lu, AM and SK Chen, eds. 1986. Cucurbitaceae. Flora Republica Popularis Sinica 73: 84-301.
Lu, AM and ZY Zhang. 1982. A revision of genus Thladiantha Bunge (Cucurbitaceae). Bull Bot Res (Harbin) 1:61-96.
Lu, AM and ZY Zhang. 1984. The genus Siraitia Merr. in China. Guihaia 4: 27-33.
Makapugay, HC, NP Dhammika Nanayakkara, DD Soejarto, and AD Kinghorn. 1985. High-performance liquid chromatographic analysis of the major sweet principle of Lo han kuo Fruits. J. Agri. Food Chem. 33: 348-350.
Swingle, WT. 1941. Momordica grosvenori Sp. Nov. the source of the Chinese Lo han kuo. J. Arn. Arb. 22: 197-203.
Takemoto, T, T. Nakajima, S. Arihara, and M. Okuhira. 1978. Glycosides Having Sweetness. United States Patent 4,084,010. Assignees T. Takemoto and Nippon Shoji Kaisha.
Zhou, LC, SY Xu, ZH Jiang, YX Ling, and X Zhuge. 1987. Report on the Lo Han Guo resources in Guilin District, Guangxi. Plant Introduction and Acclimatization 4: 121-128.