What Is the Benefit of Luo Han Fruit Extract Mogroside?

Siraitia grosvenorii (Swingle) C. Jeffrey is a traditional Chinese medicinal herb with great potential as a natural product resource. Mogroside is the main active ingredient in Siraitia grosvenorii, and has a wide range of biological properties. Mogroside V is a component of Siraitia grosvenorii fruit with a high content and sweetness. Its content is about 1%, and its sweetness is 350 times that of sucrose. It is the main sweetening ingredient [1]. Luo Han Guo sweet glycoside belongs to the cucurbitane glycosides type of compound, which is safe, has a good taste, no peculiar smell; high sweetness; good thermal stability; light color; easy to use; unaffected by pH (pH between 2 and 10) when used. The FDA (US Food and Drug Administration) approved Mogroside for use in food in 1995, and China also approved it as a food additive at the 17th meeting of the National Food Additives Committee in July 1996. Currently, Mogroside is permitted as a food additive in Japan, South Korea, Taiwan, Hong Kong, Thailand, Singapore, the United Kingdom, and other countries and regions [2]. This paper reviews research on the extraction, isolation and purification, determination, and biological activity of Mogroside since 1993.

1 Extraction, isolation and determination of Mogroside

1.1 Extraction and isolation

How to efficiently extract the active ingredients is one of the key techniques in the research and development of traditional Chinese medicine and its modernization. Luo Han Guo sweet glycoside is the main active ingredient of Luo Han Guo. With the wide application of Mogroside in the fields of food and medicine, how to maximize the use of Luo Han Guo resources and improve the quality of Mogroside has attracted particular attention. Li Yanqun et al. [3] used domestically produced materials and a relatively simple method to extract and purify Luo Han Guo sweet glycoside. The yield of the sweetener using water as the solvent is higher than that of the ethanol aqueous solution, and the solvent volume is appropriate at 6 times the weight of the raw material. Ca (OH) 2 is a better clarifying agent than alum and AlCl 3, and it does not cause significant loss of the sweetener. Clarification should be carried out at room temperature. Strong base resins D290 and D280 have better decolorization effects than acidic resins. decolorization should be carried out at 25 ° C at a slow speed; AB-8 adsorption resin is suitable for the adsorption of Mogroside at room temperature of about 20 ° C at a flow rate of SV2; Mogroside can be desorbed from AB-8 adsorption resin by using 50% aqueous ethanol solution.

Li Jun et al. [4] used an orthogonal test design to systematically study the ethanol extraction process of Mogroside from dried Luo Han Guo, optimize the process parameters, and provide a theoretical basis for large-scale production. The optimal process was used: 30% ethanol was used, which was 30 times the weight of the raw material, and the mixture was extracted at 75–80°C for 3 h in a state of micro-boiling. obtaining an extract with a mogroside content of 60%. Zhu Xiaoyun et al. [5] used orthogonal experiments to investigate the effect of microwave technology on the yield of water-extracted mogroside, and the optimal process was selected: the liquid ratio of the fresh Luo Han Guo feed was 1:8, the microwave output power was 750W, extraction time 15min, microwave extraction of mogroside efficiency is significantly better than the conventional boiling method, mogroside yield of 7.346mg/g, 21.87% higher than the conventional boiling method, is a time-saving, energy-saving, easy-to-operate new extraction method.

Ma Shaomei et al. [6] used ultrasound extraction to explore a new process for the extraction of Mogroside with ethanol. The use of this new extraction technology of ultrasound-assisted extraction has improved the extraction rate of Mogroside and provides a reference basis and method for the industrial extraction of Mogroside. The optimal process is extracted three times. Li Junsheng et al. [7] believe that ultrasonic treatment can significantly improve the extraction rate of Mogroside, and that the effect of high-frequency ultrasound on Mogroside extraction is significantly better than that of low-frequency ultrasound. At the same frequency, the extraction rate of Mogroside increases with the increase of output power. It is also worth noting that the output power of ultrasonic waves with a frequency of 50 kHz is only 80 W, but the extraction effect is better than that of ultrasonic waves with a frequency of 28 kHz and an output power of 200 W or 400 W. This shows that the extraction of Mogroside is related to the frequency of ultrasonic waves.

1.2 Separation and purification

In order to obtain Mogroside with high purity, many scholars have been studying Mogroside purification processes since the 1970s. However, the separation and purification methods used mostly employ inorganic adsorbents and inorganic decolorants, such as activated carbon, magnesium oxide, magnesium silicate, etc., which are complicated to operate and difficult to produce industrially. With the development of equipment and technology, many researchers have optimized the Mogroside purification process. Li Yanqun et al. [8,9] initially studied the adsorption performance of the macroporous adsorption resin AB-8 on Mogroside, compared the adsorption rates at 15 °C and 65 °C, obtaining the breakthrough adsorption amounts at three airspeeds (SV2, SV5, SV8); and proposing the use of a mobile phase consisting of a mixture of n-butanol, glacial acetic acid and water (4:1:1) and a silica gel column as the stationary phase to separate Mogroside, with obvious results.

Liu Zhongdong [10] proposed a purification process for Mogroside V using a combination of macroporous adsorption resin and ion exchange resin. The treatment conditions for the eluent of the adsorbed Luohanguo fruit treated with the exchange resin were: pH 5.0, eluent concentration 1%, and the yield of Mogroside V was 0.7%. Yu Lijuan et al. [11] proposed a high-performance liquid chromatography method for the preparation of Mogroside V standard products, which has the advantages of being easy to operate, reproducible, and having a high product purity. Qi Xiangyang et al. [12] explored a new method for preparing high-purity Mogroside extract by improving and optimizing the process conditions for the separation and purification of Mogroside using macroporous adsorption resins based on the structure and characteristics of Mogroside, providing a new way for further large-scale preparation of high-purity Mogroside and in-depth research on the biological activity of Mogroside. The results showed that the content of several main components of mogroside was higher than that of mogroside water extract before separation, among which the content of mogroside V was 69.24%, an increase of 41.12%.

1.3 Content determination

In order to more accurately evaluate the content and quality of mogrosides, many scholars have conducted methodological research on the quantitative detection methods of mogrosides. At present, the determination of mogrosides mostly uses colorimetric methods. For example, Li Yanquan et al. [9] used vanillin-sulfuric acid reagent as a color developer for colorimetric quantitative determination of mogrosides. Gao Shanlin [13] and Li Haibin [14] used the vanillin-perchloric acid colorimetric method to determine the content of saponins in Luo Han Guo, and proposed the optimal conditions for using vanillin-perchloric acid as a color developer.

This method is simple to operate, highly sensitive and relatively accurate. However, the stability and specificity of the spectrophotometric method are not ideal. In order to establish a better detection method for Mogroside, Liang Chengqin et al. [15] established a method for determining the content of Mogroside V using thin-layer scanning. The sample was spotted on a silica gel G plate, and butanol-ethanol-water (8:2:3) was used as the developing agent. 10% sulfuric acid ethanol was used for color development, single wavelength reflection sawtooth scanning, λ = 500 nm. Mogroside V has a good linear relationship in the range of 2.0-16.0 μg, with an average recovery rate of 97.62% and an RSD of 2.59% (n = 4). Chen Weijun et al. [16] established the high performance liquid chromatography separation conditions for Mogroside and the HPLC quantitative analysis method for Mogroside V. This method can achieve primary separation of the main saponin components in Mogroside extracts, with good separation and a simple sample pretreatment process.

Li Dianpeng et al. [17] used a ZORBAX SB-C18 (4.6 mm × 150 mm, 5 μm) column, acetonitrile-water (25:75) as the mobile phase, a flow rate of 1 ml/min, a column temperature of 25 °C, a diode array detector, and a detection wavelength of 203 nm. The content of loganin II E and loganin III in logan was determined by external standard method. Loganin II E was in the range of 1.934-25.142 μg, and loganin III was in the range of 2.070-26.910 μg, showing a linear relationship. with an average recovery of 96.6% and 97.9%. Zhang Yunzhu et al. [18] established a rapid and efficient high-performance liquid chromatography method for the simultaneous determination of the main sweet glycoside components in Luo Han Guo, including Luo Han Guo Sweet Glycoside V, 11-O-Mogroside V, Mogroside IV and Simonin I. Zheng Ling et al. [19] used high performance liquid chromatography to determine the sweetener in Mogroside. The results showed that the sweetener had a good linear relationship in the range of 0.1-2 mg/L in the sample solution, with a recovery rate of 89.9%-94.7% and a detection limit of 5 mg/kg. The relative standard deviation of the measurement results was less than 5%. The method is simple to operate and the results are accurate and reliable.

2 Pharmacological effects of Mogroside

2.1 Expectorant effect

Mogroside (purity >98%) at 100 mg/kg and 200 mg/kg, given by gavage, significantly increased the excretion of phenol red in the trachea of mice, and the effect was dose-dependent. Luo Han Guo sweet saponin at a concentration of 20 mg/ml added to the frog esophagus for 0.5 h significantly enhanced the movement of ciliated cells [20]. Luohanguo saponin (purity 50%) at a dose of 8.0g/kg significantly increased the phenol red excretion of the trachea in mice and also significantly increased the amount of sputum excreted in rats (capillary tube method) [21]. Mogroside (total glycoside >80%) 0·2g/kg, 0·4g/kg, 0·8g/kg, gavage, 0·4g/kg, 0·8g/kg, significantly increased the amount of tracheal secretions in rats [22].

2.2 Antitussive effect

Mogroside (purity > 98%) 80 mg/kg, 160 mg/kg, 320 mg/kg, gavage, has an antitussive effect in mice induced by ammonia spray. When the dose reaches 160 mg/kg and 320 mg/kg, it exhibits a significant antitussive effect and is dose-dependent [20]. Mogroside (purity 50%) at doses of 4.0g/kg and 8.0g/kg significantly reduced the number of coughs induced by concentrated ammonia in mice, and the 8.0g/kg dose significantly prolonged the latency of SO2-induced coughs in mice [21]. Mogroside (total glycoside >80%) at doses of 0.2g/kg, 0.4g/kg, and 0.8g/kg significantly reduced the number of coughs in mice induced by ammonia, but had no significant effect on the latency to induce coughing with ammonia [22].

2.3 Free radical scavenging and antioxidant activity [23]

Mogroside extract (total glycosides ≥98%, Mogroside V content 65.20%) has a certain scavenging effect on both hydroxyl radicals and superoxide anion radicals. With the increase in the concentration of Mogroside extract, the removal effect gradually increases, showing a certain dose-effect relationship; Mogroside extract has a significant inhibitory effect on the oxidative hemolysis of rat RBCs during in vitro incubation. Within the range of 0.041.15mg/ml, Mogroside extract has an inhibition rate of more than 50% on the oxidative hemolysis of red blood cells, Mogroside extract has a good protective effect on RBC autoxidation and hemolysis.

The protective effect of Mogroside extract on RBC autoxidation and hemolysis does not show a dose-effect relationship, and the intermediate dose of 0·46 mg/ml is optimal, with an inhibition rate of 85·55%. Malondialdehyde (MDA) is the end product of lipid peroxidation, can be used to evaluate the strength of lipid peroxidation. Mogroside extract has a strong inhibitory effect on the generation of MDA during the autoxidation and hemolysis of rat erythrocytes; Mogroside extract has a good inhibitory effect on the spontaneous generation of MDA in rat liver homogenates. The inhibitory effect is best at a concentration of 0.875 mg/ml, reaching 23.63%. Mogroside extract can inhibit lipid peroxidation in rat liver tissue, and has a protective effect on Fe2+ and H2O2-induced peroxidation damage to liver tissue, and can reduce the occurrence of red blood cell hemolysis. Mogroside extract can significantly inhibit the generation of MDA in liver mitochondria, and the inhibition rate increases with increasing concentration.

2.4 Immune enhancement [24]

Mogroside was administered to normal and cyclophosphamide (CTX)-suppressed mice by gavage. It had no significant effect on the immune function of normal mice, but significantly improved the macrophage phagocytic function and T cell proliferation of CTX immunosuppressed mice. This indicates that Mogroside has a positive regulatory effect on the cellular immune function of CTX immunosuppressed mice.

2.5 Effect on blood glucose

Mogroside (total glycosides >80%) 0.1g/kg, 0.2g/kg, 0.4g/kg doses have no effect on the elevated blood glucose levels of diabetic mice. The high dose (0.4g/kg) of Mogroside does not significantly increase the blood glucose levels of normal mice [22]. A single oral dose of 30% Mogroside 200 mg/kg had no significant effect on blood glucose levels or liver enzyme activity in healthy adults. Mogroside V is a safe sweetener that does not affect blood glucose levels in normal people [25].  Mogroside 150 mg/kg and 300 mg/kg doses were administered by gavage. Although the water intake and blood glucose levels of mice were not restored to normal, they were significantly lower than those of mice with type 1 diabetes induced by 4-oxopyrimidine [26].

2.6 Anticancer effect [27]

A two-stage skin carcinogenesis experiment was conducted in mice using DMBA as the initiator and TPA as the promoter. Mogroside V (mogroside V) had the same or stronger anti-carcinogenic effect as stevioside, indicating that it has an anti-promoting effect. Therefore, mogroside V can be used as an anti-cancer agent.

2.7 Toxicity

Acute toxicity test was performed on mice using 81.6% Mogroside, with an LD50>10000mg/kg. The Ames mutagenicity test was performed using Salmonella typhimurium, with a negative result. Mogroside 3.0g/kg (equivalent to 360 times the human dosage) was administered orally for 4 weeks. had no significant effect on the hematological indicators, liver and kidney function, blood glucose and urinary glucose, or the morphological changes in the heart, liver, kidney, lungs and spleen of the dog [26]. Mice given 15 g/kg Mogroside solution had normal activity within two weeks and did not die [22]. Luo Han Guo sweet glycoside is a basically non-toxic substance and is safe to take.

In summary, the technology for extracting and purifying mogroside is gradually maturing, and it has a scientific guiding role in further developing the resources of Luo Han Guo and promoting the industrial production of high-quality mogroside. Mogroside is non-toxic and safe; it has a high sweetness; it has good thermal stability; it is a safe health sweetener that does not affect normal blood glucose levels; and it has broad market prospects as a new type of sweetener.

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