What Is the Benefit of Monk Fruit?

Monk Fruit is the fruit of Momordica grosvenori Swingle, a perennial herbaceous vine in the family Cucurbitaceae. It is a traditional specialty of the northern Guangxi region and is an economically and medicinally unique plant in China. It is high in nutritional value and contains fructose, protein and various vitamins. It is sweet and cool in nature, and has the effects of clearing away heat and relieving summerheat, antibacterial and anti-inflammatory, and relieving cough and moistening the lungs. The progress of research on its pharmacological activity is described below.

1 Pharmacological activity

1.1 Cough suppressant and expectorant

Mogrosides have significant antitussive and expectorant activities. The main active ingredient is mogroside V. Chen Yao et al. [1] used ammonia to induce coughing and phenol red to stimulate tracheal secretion to observe the effects of Mogroside aqueous extract on mouse coughing and tracheal secretions. The results showed that when the oral dose of mogroside was greater than 15 g/kg, it could significantly reduce the number of coughs and increase the amount of tracheal secretions in mice, suggesting that it has a significant antitussive and expectorant effect. Liu Ting et al. [2] observed the effects of the water extract, 95% alcohol extract, and 50% alcohol extract (mainly containing mogroside V) of Luo Han Guo on the number and latency of coughs caused by concentrated ammonia water in mice, as well as the effect of mogroside V in the 50% alcohol extract on the phenol red excretion of mice.

Results: The number of coughs in mice was significantly reduced by oral administration of 50 g of Luo Han Guo decoction, 50 g of 50% alcohol extract and 300, 150 and 75 mg of Mogroside V/kg. Intraperitoneal administration of 50% alcohol extract 50 g raw medicine / kg and mogroside V 300 mg / kg can also significantly prolong the cough latency period of mice; intraperitoneal administration of mogroside V 150 mg / kg can significantly increase the excretion of phenolic red in the trachea of mice. Description Mogroside V has a significant antitussive and expectorant effect. Li Jian et al. [3] used the guinea pig citric acid cough induction method, capsaicin cough induction method and mechanical stimulation cough induction method to observe the effect of Luo Han Guo water extract on the number of coughs and the cough latency period in animals. The results showed that Luo Han Guo water extract can significantly reduce the number of coughs caused by citric acid or capsaicin and prolong the cough latency period, and inhibit the number of coughs caused by mechanical stimulation in guinea pigs.

1.2 Antioxidant

Monk Fruit saponin is an effective free radical scavenger that significantly protects against tissue damage caused by free radicals produced by high-intensity exercise. It improves the body's antioxidant capacity, and the main antioxidant active ingredient is sweetener V. Yao Jiwei et al. [4] investigated the effects of Monk Fruit extract on the exercise tolerance and antioxidant damage to liver tissue in Kunming male mice. The results showed that the time for mice to swim until exhaustion was significantly prolonged after administration of Luo Han Guo extract; the hemoglobin and liver tissue superoxide dismutase and glutathione peroxidase activities of the experimental group of mice that were administered Luo Han Guo extract immediately after exhaustion and 24 h after recovery were significantly higher than those of the control group that was not administered Luo Han Guo extract, while the blood lactate, serum lactate dehydrogenase, alanine aminotransferase and malondialdehyde content in liver tissue were significantly lower than those in the control group. Malondialdehyde is a metabolic product of lipid peroxidation, which indirectly reflects the level of free radicals in the body.

It was shown that Luo Han Guo can significantly inhibit the increase in malondialdehyde content in mouse liver tissue, promptly remove excessive free radicals produced during exercise, and effectively prevent or inhibit lipid peroxidation in the body. Qi Xiangyang et al. [5] used the D-deoxyribose method, anti-superoxide anion reagent kit method and colorimetric method to analyze the effect of Luo Han Guo saponin in scavenging free radicals and resisting lipid peroxidation. The results showed that the mogroside extract can effectively scavenge free radicals, inhibit lipid peroxidation in rat liver tissue, and protect against Fe2 + and H2O2 -induced liver tissue peroxidation damage, and can reduce the occurrence of red blood cell hemolysis. Mogroside V has a comparable effect to the saponin extract in scavenging hydroxyl radicals, and a better scavenging effect on O2 - than the saponin extract.

1.3 Liver protection

Mogroside V has a protective effect on acute liver injury and immune liver injury in mice. Xiao Gang et al. [6] studied the protective effect of Mogroside V on acute liver injury induced by carbon tetrachloride and immune liver injury induced by BCG plus lipopolysaccharide in Kunming mice. The results showed that Mogroside V can reduce acute the activity of alanine aminotransferase and aspartate aminotransferase in the serum of mice with acute and immune liver injury; it can increase the activity of superoxide dismutase and reduce the content of malondialdehyde in the homogenate of liver tissue with immune liver injury, and can significantly reduce the degree of pathological changes in liver tissue. The mechanism of Luo Han Guo protecting the liver may be related to resisting lipid peroxidation.

1.4 Enhancing the body's immune function

The Luo Han Guo saponin extract can regulate the antigen expression of spleen lymphocytes in diabetic mice through an immune regulatory mechanism, antagonizing the imbalance of cellular immune function that occurs during diabetes. It can significantly improve the phagocytic function of immunosuppressed macrophages and T cell proliferation, increase the quality of immune organs, and enhance the immune function of the body. Chen Weijun et al. [7] investigated the effects of Luo Han Guo saponin extract on the subpopulations of splenic lymphocytes and cytokine expression in diabetic Balb/c mice. The results showed that Luo Han Guo saponin extract, especially at low doses, can lower blood glucose, improve the degree of pancreatic damage, and down-regulate the expression levels of interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). increased the number of CD4+ lymphocytes in the spleen of diabetic mice, and restored the CD4/CD8 ratio to normal; it also significantly increased the expression of interleukin-4 (IL-4) in the lymphocytes of the spleen of normal mice and diabetic mice, but had no significant effect on other indicators in normal mice. Li Jun et al. [8] gave mice Luo Han Guo saponin extract by gavage, and after 30 days, measured the thymus index, spleen index, phagocytic function of peritoneal macrophages, hemolysin formation in the serum and lymphocyte transformation rate. The results showed that Luo Han Guo saponin extract significantly increased the quality of immune organs such as the thymus and spleen in mice at both high and low doses, increased the percentage of macrophages in the abdominal cavity of mice that phagocytized chicken red blood cells and the phagocytic index, increased the level of mouse serum lysozyme, and increased the lymphocyte transformation rate and thymus and spleen index of mice.

1.5 Effect on blood lipids

Monk Fruit has the pharmacological effects of regulating blood lipids, resisting platelet aggregation, and preventing thrombosis, and has the function of positively regulating the body's blood lipid metabolism. Zhao Yan et al. [9] used a high-fat diet to feed ICR mice to establish a hyperlipidemia animal model, and fed tap water, 2% Luo Han Guo concentrated juice, and 0.08% Mogroside solution at the same time. After 60 days, the total serum cholesterol, triglycerides, and high-density lipoprotein cholesterol levels of mice in each group were measured. The results showed that the average total serum cholesterol levels of mice in the Luo Han Guo concentrate group and Mogroside group were 98.14 mg/dL and 86.07 mg/dL, respectively, which were 17.3% and 27.5% lower than the tap water-fed high-fat model group; the average triglyceride levels were 153.54 mg/dL and 118.98 mg/dL, respectively, which were 28.4% and 44.5% lower; The average high-density lipoprotein cholesterol levels were 73.89 mg/dL and 70.01 mg/dL, respectively, an increase of 34.4% and 27.3%, respectively.

The study proved that Luo Han Guo can significantly reduce the total cholesterol and triglyceride levels in the blood serum of animal models with hyperlipidemia, and significantly increase the high-density lipoprotein cholesterol levels. Chen Quanbin et al. [10] used 20–25 g NIH mice and 200–250 g SD rats as research subjects to explore the pharmacological effect of Luo Han Guo flavonoids on activating blood circulation and resolving blood stasis. The results showed that although the anti-thrombotic effect of monomeric flavonoids from Luo Han Guo was not as good as aspirin enteric-coated tablets, it still had a certain protective effect on cerebral thrombosis. It can inhibit adenosine-5-diphosphate sodium salt-induced platelet aggregation in rats, significantly reduce the total cholesterol and triglyceride levels in mice with hypercholesterolemia, increase the high-density lipoprotein cholesterol level, and prolong the clotting time of mice.

1.6 Effect on blood sugar

Although the sweetness of the sweeteners contained in Luo Han Guo is high, Luo Han Guo has a significant therapeutic effect on diabetic mice and has basically no effect on normal human blood sugar. The glycosidic bond in the structure of Luo Han Guo glycoside is a β bond, which will not break down into individual glucose in the human body, so it will not raise blood sugar. Zhang Liqin et al. [11] gave diabetic mice caused by 50, 100, 300, 500 mg/kg doses of Luo Han Guo saponin extract by gavage for 30 consecutive days, and measured blood glucose indicators by taking blood from the orbital cavity after the last administration. Results showed that the 100, 300 and 500 mg/kg dose groups could reduce blood glucose in mice with diabetes caused by tetracycline, and the medium dose of 100 mg/kg had the best hypoglycemic effect. Xu Qing et al. [12] studied the effect of a single high-dose administration of Mogroside on blood glucose levels in humans. The subjects orally administered 30% Mogroside 200 mg/kg for the first time, and then orally administered sucrose 3000 mg/kg for the second time. Blood was taken after the oral administration of the reagents, and the blood glucose level was measured using a blood glucose meter. The results showed that a single oral dose of 30% Mogroside 200 mg/kg had no significant effect on blood glucose levels in healthy adults. This provides a basis for the selection of sweeteners for people who need to limit their sugar intake and for people with diabetes.

1.7 Effect on physiological functions

Monk Fruit has the effect of improving the ability of mice to tolerate hypoxia, high temperatures and exercise. Yao Jiwei et al. [13] used Kunming mice as the research object, and established an experimental model of swimming training with increasing loads by gavage of Monk Fruit extract in mice to measure the time of exhaustion swimming and exhaustion climbing rope, as well as the tolerance to hypoxia and high temperatures. The results show that within a certain range, the degree of improvement in mouse physiological function is directly proportional to the dose of Luo Han Guo extract taken. At the same time, the effect of different doses of Luo Han Guo extract on mouse physiological function shows a typical two-way effect, with the effect gradually increasing with increasing dose, but instead of inhibition, a certain value is reached.

1.8 Antibacterial

The extracts of the fruit, leaves and stems of Luo Han Guo all have strong antibacterial activity, and have a strong inhibitory effect on Streptococcus mutans, Pseudomonas aeruginosa and Escherichia coli. Zhou Ying et al. [14] prepared a crude extract of dried Luo Han Guo fruit in order to identify and purify the antibacterial components. The crude extract was separated by high performance liquid chromatography (HPLC) to obtain 50 components, and their antibacterial activity was verified by a rapid colorimetric method and the blood agar method. Results: Two HPLC components of the fruit extract of Luo Han Guo, #18-19 and #34-35, have strong inhibitory activity against Streptococcus mutans, while the other components have no or only very weak activity, and Mogroside V has no antibacterial activity.

Ye Min et al. [15] investigated the antibacterial effects of ethanol extracts from the leaves and stems of Luo Han Guo on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Micrococcus luteus and Candida albicans. The samples were extracted with 50% ethanol, and the antibacterial rates of the samples against different test bacteria were determined using the dichotomy method. Results: The ethanol extract of the leaves and stems had the best antibacterial activity against Pseudomonas aeruginosa. The antibacterial rates of the ethanol extract of the leaves and stems were 90.9% and 76.7%, respectively, when the concentration of the extract reached 50.00 mg/mL; the antibacterial rate of the stem extract against Escherichia coli was 70.2%; however, the antibacterial rates of the ethanol extracts of the leaves and stems against Staphylococcus aureus, Micrococcus luteus and Candida albicans were all below 50%.

1.9 Antispasmodic

Mogroside V has antispasmodic activity on organs, providing a basis for its regulation of respiratory tract and digestive tract motility. Liu Ting et al. [2] also studied the effects of Mogroside V, a component of 50% alcohol extract, on the contraction of isolated guinea pig ileum and isolated trachea caused by histamine. The results showed that 5 g/L Mogroside V could significantly antagonize the contraction of ileum caused by histamine, 2.5 and 1.25 g/L mogroside V also significantly antagonized the contraction of the trachea caused by histamine. Wang Qin et al. [16] studied the effect of Luo Han Guo on the spasm of isolated ileum in rabbits and mice caused by acetylcholine or barium chloride, and found that Luo Han Guo had an antagonistic effect on this spasm.

1.10 Laxative

Wang Qin et al. [16] also observed the effect of a water extract of Luo Han Guo on defecation in normal mice and mice with water deprivation and dry constipation. The result showed that the water extract of Luo Han Guo has a laxative effect.

1.11 Anticancer

Takao Kijima [17] studied the anticancer effect of Luo Han Guo. 2,2-Dimethylbutylamine (DMBA) was used as the initiator and 1,3-butadiene (TPA) as the promoter to carry out a two-stage skin carcinogenesis test in mice. The results showed that the anticancer effect of loganin V is the same as or even stronger than that of stevioside, indicating that loganin has an anti-cancer-promoting effect and that Luo Han Guo can be used as an anti-cancer drug.

1.12 Toxicity test

Monk Fruit is a basically non-toxic substance and is basically safe as a medicine, food and condiment. Chen Quanbin et al. [10] gavaged mice with the maximum mass concentration (0.5071 g/mL) and maximum volume (0.4 mL/10 g) of Monk Fruit flavones, and administered the drug three times within 24 h. After 7 days, the mice were observed for toxic side effects after administration. The results showed that all mice were healthy, with no toxic side effects, and their weight grew normally, indicating that the toxicity of mogroside is very low. Su Xiaojian et al. [18] conducted an acute toxicity test using mice, and the results showed that the median lethal dose (LD50) of mogroside for male and female mice was higher than 10 g/kg, which is practically non-toxic. The results of the reverse mutation test (Ames) using Salmonella typhimurium and the dog mutation test were negative; Mogroside 3.0 g/kg (equivalent to 360 times the human dose) was given to dogs by gavage for 4 weeks, and there was no significant effect on the dog's hematological indicators, liver and kidney function, blood glucose and urine sugar, or morphological changes in the liver, heart, spleen, lungs, and kidneys.

2 Conclusion

Traditional medicine believes that Luo Han Guo is sweet and cool in nature, non-toxic, and enters the lung and large intestine channels. It has the effects of clearing the lungs and relieving the pharynx, resolving phlegm and relieving cough, and moistening the intestines and promoting bowel movement. It is suitable for treating symptoms such as cough due to lung heat, whooping cough, sore throat, and constipation due to dry intestines. Modern research has shown that Luo Han Guo mainly contains triterpenoid glycosides, including Simonin I, monk fruit glycoside ⅡE, monk fruit glycoside Ⅲ, monk fruit glycoside ⅢE, monk fruit glycoside Ⅴ, monk fruit glycoside Ⅵ, monk fruit neo-glycoside, flavonoids, and is also rich in protein, glucose, fructose, various vitamins and trace elements. Luohan fruit can be used as a single medicine, such as decoction or directly brewing with boiling water, or made into Luohan fruit essence, Luohan fruit granules, etc.; it can also be combined with other traditional Chinese medicines to make Luohan fruit compound preparations, such as Luohan fruit cough syrup, Luohan fruit antiasthmatic tablets, antitussive expectorant mixture, and Fabanxia Luohan fruit Chuanbei loquat syrup.

The fruit of the monk fruit is highly sweet, has no peculiar smell, is non-toxic and safe to eat. It can be used as a new type of medicine and health product. The sweetness of the sweetener V is more than 300 times that of sucrose, and it does not have the disadvantages of ordinary sugar. It is a good food and medicine for diabetics and obese people. The medicinal parts of Luo Han Guo are not just the fruit, but also the root, stem, leaves and flowers, which also have certain medicinal value. However, current research and product development mostly focuses on its fruit, and there is not enough research on its root, stem, leaves and flowers, and there is not much development and utilization; moreover, most of the current products are extensive, and there are very few high-tech, deep-processed products, which is of great value for further research and development. The chemical composition of Luo Han Guo is complex, with a variety of active substances. It is important to clarify the active ingredients and content, health functions and pharmacological effects of its roots, stems, leaves, flowers and fruits. This will help the research and development of new drugs and the full utilization and development of Luo Han Guo resources.

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