Monk fruit is also known as Lo Han Guo in mandarin. Luo Han Guo, literally translated, means “arhat fruit” in English. Thanks to its amazing health benefits on cough relief, colon cleansing, weight loss, physique enhancement, this Chinese herb has long been hailed as “the immortals’ fruit”. Hence, at the end of spring and the beginning of summer, average family in China loves to use it to make tea for the treatment of cough caused by lung infection or by a cold due to seasonal weather variations. This fruit is high in nutritional value too and can be consumed in a few simple ways. Besides making tea with boiling water, you can also use it to stew soup and make congee. Either way, it can go a long way in achieving good health and keeping your bodies strong. By the way, it mainly comes from Thailand or southern China, especially from mountainous area of Yongfu County and Lingui District in Guilin Guangxi.
What is a monk fruit?
As its name implies, it means the dried fruits of Momordica grosvenori Swingle, which is an herbaceous perennial vine in the family Cucurbitaceae. Other names of it include Momordica grosvenori fruit, Buddha fruit, Monordica fruit, luo han kuo, Siraitia grosvenorii, Grosvener Siraitia, arhat fruit, monk’s fruit, luo han guo, longevity fruit, lohan kuo, luohanguo, la han qua (Vietnamese), rakanka (Japan), and so on. It is mainly produced in Guangxi and usually collected in Fall, in particular when they are turning from light green to dark green. And then it needs to dry them at the fire and get rid of hair. And it is usually used raw medicinally.
Its plant is a perennial climbing vine. Immature stems are covered with white pubescence and red glandular hair. Old stems are dark purple and with vertical edges. Alternate leaves are in the shape of ovoid or long ovoid, 11 to 16cm long, 10 to 13cm wide, and with acute or acuminate apex, cordate base, and entire margin. Unisexual flowers are dioecious; all peduncle, pedicel, sepals, and petals are pubescent and covered with glandular hairs; male flowers are axillary and 5 to 7 of them arrange in racemes; female flowers are solitary in leaf axils. Pepo is round, oblong or obovate; it is dark reddish brown when young and green and pubescent when mature. Flowering time is from June to August and fruiting time is from August to October.
It mainly contains non-sugar natural sweetener – the triterpenoid glycosides, which include mogroside Ⅴ (esgoside), mogroside Ⅳ, and D-mannitol. According to the result of a measurement, the natural sweetness of them is 256-344, 126, and 0.55-0.65 times of that of sugar. And it still contains large amounts of glucose, 14% fructose, protein, vitamin C, and 26 kinds of inorganic elements like manganese, iron, nickel, selenium, tin, iodine, molybdenum and others. What’s more, fatty acids include linoleic acid, oleic acid, palmitic acid, stearic acid, palmitic acid, myristic acid, lauric acid, and decanoic acid.
Monk fruit benefits
As for whether or not it is a yin tonic, currently there is still a debate as no relevant documentation is found in traditional Chinese medical literature. But it is certain that this herb does clear heat and moisten lung. Modern medical studies have proven that it contains one kind of sweetener that is more than 300 times sweeter than cane sugar. More importantly, it produces no calories. For that reason, it becomes the best sugar substitute for those who can’t eat sugar, for example patients of obesity and diabetes.
As mentioned above, it has plenty of health benefits. First and foremost, being one of best sweeteners for diabetics, this fruit itself can help to treat diabetics too. Besides, it is rich in vitamin C, which makes it a wonder herb with anti-aging, anti-cancer, and skin-care properties. Last but not least, it can help decrease lipid, lose weight, and assist the treatment of HLP (hyperlipidaemia).
Apart from being one of healthy and safe sugar substitutes, clinically it is widely used for the treatments of whooping cough, constipation, acute bronchitis, acute tonsillitis, sore throats, cute gastritis, etc. Different parts of grosvener siraitia have particular emphasis on different medicinal uses. Its mashed root is able to cure stubborn psoriasis, carbuncles, boils, etc. in external use; fruit hair can be used for wounds; fruit tea can be a cool refreshing drink that can prevent respiratory infections. And it can prolong life too if drunk in daily basis. In addition, the monk fruit concentrate and extract are often utilized as a condiment to make nourishing stew, broth, cakes, candy, cookies, granules, syrups, fruit essence, cough syrup, and so on.
Modern pharmacological actions of Lo Han Guo
1. D-mannitol can relieve cough. It is used to treat cerebral edema as it can improve blood osmotic pressure and increase intracranial pressure. And it is stronger than urea on dehydration and time of duration. Also it is often used for edema caused by large area burns and scalds, acute renal failure, glaucoma, and so on;
2. Luo Han Guo tea (15% tea, 77.5% monk fruit, and 7.5% its preparation) has no significant effect on the spontaneous activity of mouse’s isolated small intestine. However, in vitro it can enhance the spontaneous activity of the small intestine of rabbits and dogs. And it plays an antagonistic role to acetylcholine or barium chloride induced intestinal tonic contraction and then brings relaxation to bowel spasm. In addition, it also has antagonistic action on epinephrine induced intestinal relaxation, which thus restore the spontaneous activity of bowel. That shows that this tea has dual-direction regulation on the motor function of the small intestine;
3. Luo Han Guo tea has on effect on normal rabbits’ gastric electrical activity. That’s to say, it won’t affect the normal gastrointestinal motor function. And the gavage to anesthetized dogs showed no noticeable changes on their blood pressure and ECG.
Selected herbal remedies on Luo Han Guo
The Chinese Materia Medica says that it is sweet in flavor and cool in properties and goes to meridians of lung and spleen. Basic functions include clearing away the lung-heat to relieve sore throat, expelling phlegm to arrest coughing, and relaxing bowel. Main indications are phlegm-fire cough, sore throat, tonsillitis, acute gastritis, and constipation. Recommended dosage is from 15 to 30 grams in decoction, fricassee, or tea with boiling water.
1. According to Ling Nan Cai Yao Lu (Records of Herb Collection in Lingnan), it is stewed with lean pork meat to treat phlegm-fire cough.
2. According to Guangxi Zhong Yao Zhi (Guangxi Journal of Chinese Herbal Medicines), it can be used to cure cough and constipation due to blood dryness and stomach heat.
3. It is formulated with Zhe Bei Mu (Fritillaria Bulb), Shan Ci Gu (Cremastra), Feng Li Ke (chestnut shell), etc. to treat tuberculosis of cervical lymph nodes. (“TCM clinical applications”, the Guangdong People’s Publishing House, 1975:586)
Monk fruit side effects and contraindications
The acute toxicity test of monk fruit tea showed that it has lower toxicity. And as of this writing, no known side effects and drug interactions have been reported. TCM wise, it shouldn’t be used in the case of deficiency-cold in spleen and stomach due to its cool nature.