What Is the Benefit of Luo Han Guo?

Luo Han Guo is the dried fruit of the Siraitia grosvenorii (Swingle) C. Jeffrey ex A. M. Lu et Z. Y. Zhang plant in the Cucurbitaceae family. It has been used in Guangxi folk medicine for more than 300 years [1]. Luohan fruit is sweet and cool in nature, entering the lung and large intestine meridians. It has the effects of clearing away heat, moistening the lungs, relieving sore throat and opening the voice, and lubricating the intestines to promote bowel movement [2]. It is widely used in the treatment of sore throat and cough. It is an ideal natural sweetener [3] with the characteristics of high sweetness and low calories, so it can be consumed by patients with diabetes, hypertension, etc.

He Chaowen et al. [4] observed the toxicity of mice by administering large doses, and the results showed that fresh monk fruit extract has low acute toxicity, is basically non-toxic, and is safe to use. Zhang Hong et al. [5] studied the genotoxicity of monk fruit and observed the effects of monk fruit water extract on the micronucleus rate of bone marrow cells and the sperm deformity rate of the epididymis in male mice. The results showed that monk fruit has no genotoxicity in male mice. Since Luo Han Guo is basically non-toxic and has pharmacological effects such as relieving coughs and phlegm, inhibiting bacteria, and anti-oxidation, it has also been widely developed into foods, health foods, and medicines. This paper summarizes the pharmacological research and product development of Luo Han Guo in recent years as follows.

1 Pharmacological research on Luo Han Guo

1.1 Cough suppressant and expectorant

Tang Huiqin et al. [6] investigated the effects of different factors on the cough suppressant effect of Luo Han Guo. The results showed that all had a cough suppressant effect, and that the fruit growth period and commercial specifications had an effect on the cough suppressant effect of Luo Han Guo. Li Jian et al. [7] studied the cough suppressant effect of a water extract of Luo Han Guo, and found that the extract could significantly reduce the number of coughs caused by citric acid or capsaicin in guinea pigs and prolong the cough latency period, as well as suppressing the number of coughs caused by mechanical stimulation. Lin Wu [8] studied the expectorant effect of Luo Han Guo extract from different harvest periods, different varieties, different specifications, different commercial grades and different origins, and all of them had an expectorant effect.

1.2 Antibacterial effect

He Kaixia et al. [9] used 30% ethanol to ultrasonically extract the total flavonoids of Luo Han Guo to study the antibacterial effect of the flavonoids in the fruit of Luo Han Guo. The results showed that it had a significant inhibitory effect on gram-positive bacteria, but had no inhibitory effect on Escherichia coli, Proteus, penicillium and Aspergillus niger.

1.3 Antioxidant

Xia Xing et al. [10] investigated the protective effect of loganin against exogenous oxidative damage in PC12 cells, and found that it can enhance the antioxidant capacity of PC12 cells. Gan Sheng et al. [11] showed that the extract of the fruit of the logan fruit has strong antioxidant activity. Huang Dehong et al. [12] studied the effect of extracts from different parts of the stem of the Luo Han Guo fruit in scavenging DPPH free radicals. The results showed that the aqueous extract of the stem of the Luo Han Guo fruit had the strongest scavenging ability, and that extracts in different solvents all had antioxidant effects. Zhang et al. [13] studied the immunomodulatory and antioxidant effects of Luo Han Guo polysaccharides in mice.

1.4 Anti-aging

Xiao et al. [14] studied that Luo Han Guo sweet glycosides can increase the activity of superoxide dismutase (SOD) in the brain tissue and serum of aging mice, and reduce the content of malondialdehyde (MDA) in the serum and brain tissue. The effect of different doses of Luo Han Guo sweet glycosides on the lifespan of Drosophila was observed, and the results showed that it can prolong the lifespan of Drosophila, indicating that Luo Han Guo sweet glycosides have the effect of delaying aging.

1.5 Laxative

Chen Yao et al. [15] studied the effects of monomeric myo-inositol on intestinal motility, defecation time, and defecation quality in mice. The results of the xylene and carrageenan-induced inflammation experiments showed that monomeric myo-inositol can increase the number and weight of defecations, reduce the time to first defecation, and increase the rate of ink propulsion in constipated mice. It had no significant effect on the inflammatory model, indicating that monomeric myo-inositol has a laxative effect.

1.6 Hepatoprotective effect

Chen Xiangyun et al. [16] found that monomeric myristin could significantly reduce the content of α-SMA in the liver tissue of rats with liver fibrosis and reduce hepatocyte apoptosis, and it also had a protective effect on rat liver fibrosis. Xiao Gang et al. [17] studied the effect of Luo Han Guo sweeteners on carbon tetrachloride-induced liver fibrosis in rats and found that they had a very good protective effect. Song Kaijuan et al. [18] studied the effect of Luo Han Guo sweeteners on the activation and apoptosis of human liver stellate cells LX-2 in vitro, and found that they played an anti-liver fibrosis role. Long Ying et al. [19] studied the effects of Luo Han Guo sweeteners on rat hepatic stellate cells. The results showed that Luo Han Guo sweeteners can induce HSC-T6 apoptosis, inhibit collagen production, and promote extracellular matrix degradation.

1.7 Hypoglycemic and hypolipidemic

Rao Rong [20] studied the hypoglycemic efficacy of the fruit and leaf extracts of Luo Han Guo in a type 2 diabetes model rat, and the results showed that the leaf extract of Luo Han Guo had a better hypoglycemic effect on type 2 diabetes than the fruit extract. Zheng et al. [21] observed the therapeutic effect of Luo Han Guo total flavonoids on experimental diabetic rats, and the results showed that Luo Han Guo total flavonoids have hypoglycemic and hypolipidemic effects on STZ diabetic rats. Zhang Jianyi et al. [22] observed the effect of the traditional Chinese medicine Luo Han Guo on the blood lipid disorder of 50 male SD rats. The results showed that it can significantly reduce the serum TC and LDL-C of experimental rats, indicating that Luo Han Guo has a lipid-lowering effect.

1.8 Effect on the nervous system

Ju Peijun et al. [23] investigated the behavioral effects of loganin V on a mouse model of schizophrenia, and found that it has a certain regulatory effect on the high activity and impaired PPI of the mouse model of schizophrenia.

1.9 Anti-fatigue effect

Zhang Xiaofeng et al. [24] studied the anti-exercise fatigue effect of Luo Han Guo extract on 144 male ICR mice. The results showed that the concentrations of liver glycogen and muscle glycogen in the low, medium and high dose groups of Luo Han Guo extract were significantly higher than those in the control group, which was statistically significant, indicating that supplementing Luo Han Guo extract has a significant anti-fatigue effect on exercise-fatigued mice. Yu Cong et al. [25] studied the effect of Luo Han Guo extract on the material metabolism and anti-exercise fatigue of 90 male Wistar rats, and found that Luo Han Guo extract can significantly improve the rats' resistance to exercise fatigue.

1.10 Anti-cancer

Liu Can et al. [26] studied the induction of apoptosis in lung cancer cells A549 by Luo Han Guo extract and found that Luo Han Guo alcohol induces apoptosis and cell cycle arrest in lung cancer cells A549 by regulating the expression of p21 and Bcl-2.

2 Development and application of Luo Han Guo

Luo Han Guo and Luo Han extract are the most widely produced products on the market. The most widely used ingredient in Luo Han Guo is Luo Han Guo glycoside, which is highly sweet and low in calories. It is widely developed into health products, cough and phlegm medicines, sore throat medicines and food.

2.1 Health food

Check the China Food and Drug Administration (CFDA) for domestic health food products. Luo Han Guo is used as a sugar substitute in Luo Han Guo sugar, to boost immunity in the health food Luo Han Guo green tea powder, and to soothe the throat in Luo Han Guo snow pear paste (Qian Ba brand), Luo Han Guo and honeysuckle lozenges (Bao Jian brand), and Tong Ren Tang Luo Han Guo lozenges.

2.2 Cough and phlegm medicines

Luohanguo is often combined with Chinese herbal medicines that relieve coughs and phlegm to create compound preparations with cough-relieving and phlegm-resolving effects, such as Compound Luohanguo Cough Tablet [27], Compound Luohanguo Cough Granules [28], and Qingfei Luohanguo Syrup [29].

2.3 Throat-soothing medicines

Luohanguo has the effect of relieving the pharynx, and has been developed into pharyngeal drugs such as Luohanguo effervescent tablets [30] and Luohanguo throat tablets [31].

2.4 Food

Luohanguo fermented wine, Luohanguo cake, Luohanguo candied fruit, Luohanguo compound drinks, etc. have been developed into foods [32].

3 Summary

In summary, Luo Han Guo has a variety of pharmacological effects, but research on its pharmacological effects has mainly focused on animal experiments, with relatively little clinical research. The most studied is the application of Luo Han Guo sweet glycosides, while there is less research on other ingredients. In the market, Luo Han Guo has been developed into more health foods, medicines and foods. Because Luo Han Guo is high in sweetness and low in calories, it can be eaten by patients with diabetes, hypertension, etc. There have also been reports of adverse reactions to Luo Han Guo, mainly that it causes drowsiness. Although there are not many cases, it should be noted. Therefore, in future research, further studies can be carried out on the other components of Luohanguo, and further research can also be carried out on the clinical use of Luohanguo, not limited to pharmacological studies, but also adverse reactions and toxicity. This will allow Luohanguo to be further developed into health foods and medicines in the future for the benefit of patients.

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