Rapid identification and quantification of five major mogrosides in Siraitia grosvenorii (Luo-Han-Guo) by high performance liquid chromatography–triple quadrupole linear ion trap tandem mass spectrometry combined with microwave-assisted extraction

Efficient production of the high-intensity natural sweetener siamenoside I by the exo-1,3-beta glucanase (Exo15) from Meyerozyma guilliermondii LHGNSJ-VS01

The scarcity of siamenoside I (SI) hindered its widespread application. Addressing this challenge, we devised an innovative biocatalytic strategy and biological solution for large-scale SI production. Endo 15, an endophyte from Siraitia grosvenorii, exhibited excellent proficiency in SI synthesis, achieving a remarkable 50.65% SI abundance. By harnessing the extracellular protein of Endo 15 (EP), we further escalated SI abundance to 83.59 ± 2.5%, accompanied by full substrate conversion. Delving into the underlying mechanisms, we identified Exo15, a distinct functional protein derived from EP, displaying merely 48.88% amino acid similarity to the yeast exo-1,3-beta glucanase (Exg1). Successfully overexpressing Exo15 in E. coli, we confirmed its functionality in line with EP. Exo15 exhibited exceptional catalytic prowess, efficiently hydrolyzing mogroside V into the high-potency sweetener SI, with unparalleled activity and specificity. Our groundbreaking approach yielded an impressive SI titer of 54 g/L, coupled with an average conversion rate of 2.5 g/L per hour. These outstanding outcomes underscore the immense potential of Exo15 in cost-effective industrial production of the premium natural sweetener, siamenoside I, paving the way for its widespread adoption.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04260-2.

Siraitia grosvenorii Extract Protects Lipopolysaccharide-Induced Intestinal Inflammation in Mice via Promoting M2 Macrophage Polarization

Siraitia grosvenorii has anti-inflammatory, antioxidant, and immune-regulating effects, while macrophages play an important role in reducing inflammation. However, it is still unclear whether Siraitia grosvenorii extract (SGE) is effective in reducing inflammation by regulating macrophages. This study investigated the regulatory effect of SGE on macrophage polarization in a lipopolysaccharide (LPS)-induced intestinal inflammation model after establishing the model in vitro and in vivo. The results from the in vivo model showed that, compared with the LPS group, SGE significantly improved ileal morphology, restored the ileal mucosal barrier, and reduced intestinal and systemic inflammation by increasing CD206 and reducing iNOS proteins. In the in vitro model, compared with the LPS group, SGE significantly reduced the expression of iNOS protein and cytokines (TNF-α, IL-1β, and IFN-γ) while significantly increasing the protein expression of CD206 in RAW264.7 cells. In conclusion, SGE can alleviate intestinal inflammation, protect the mucus barrier, and block the systemic immunosuppressive response by increasing M2 macrophages.

Production of Siamenoside I and Mogroside IV from Siraitia grosvenorii Using Immobilized β-Glucosidase

Siraitia grosvenorii is a type of fruit used in traditional Chinese medicine. Previous studies have shown that the conversion of saponins was often carried out by chemical hydrolysis, which can be problematic because of the environmental hazards it may cause and the low yield it produces. Therefore, the purpose of this study is to establish a continuous bioreactor with immobilized enzymes to produce siamenoside I and mogroside IV. The results show that the immobilization process of β-glucosidase exhibited the best relative activity with a glutaraldehyde (GA) concentration of 1.5%, carrier activation time of 1 h and binding enzyme time of 12 h. After the immobilization through GA linkage, the highest relative activity of β-glucosidase was recorded through the reaction with the substrate at 60 °C and pH 5. Subsequently, the glass microspheres with immobilized β-glucosidase were filled into the reactor to maintain the optimal active environment, and the aqueous solution of Siraitia grosvenorii extract was introduced by controlling the flow rate. The highest concentration of siamenoside I and mogroside IV were obtained at a flow rate of 0.3 and 0.2 mL/min, respectively. By developing this immobilized enzyme system, siamenoside I and mogroside IV can be prepared in large quantities for industrial applications.

The Challenge of Measuring Sweet Taste in Food Ingredients and Products for Regulatory Compliance: A Scientific Opinion

The Codex Alimentarius Commission, a central part of the joint Food and Agricultural Organization/World Health Organizations Food Standards Program, adopts internationally recognized standards, guidelines, and code of practices that help ensure safety, quality, and fairness of food trade globally. Although Codex standards are not regulations per se, regulatory authorities around the world may benchmark against these standards or introduce them into regulations within their countries. Recently, the Codex Committee on Nutrition and Foods for Special Dietary Uses (CCNFSDU) initiated a draft revision to the Codex standard for follow-up formula (FUF), a drink/product (with added nutrients) for young children, to include requirements for limiting or measuring the amount of sweet taste contributed by carbohydrates in a product. Stakeholders from multiple food and beverage manufacturers expressed concern about the subjectivity of sweetness and challenges with objective measurement for verifying regulatory compliance. It is a requirement that Codex standards include a reference to a suitable method of analysis for verifying compliance with the standard. In response, AOAC INTERNATIONAL formed the Ad Hoc Expert Panel on Sweetness in November 2020 to review human perception of sweet taste, assess the landscape of internationally recognized analytical and sensory methods for measuring sweet taste in food ingredients and products, deliver recommendations to Codex regarding verification of sweet taste requirements for FUF, and develop a scientific opinion on measuring sweet taste in food and beverage products beyond FUF. Findings showed an abundance of official analytical methods for determining quantities of carbohydrates and other sweet-tasting molecules in food products and beverages, but no analytical methods capable of determining sweet taste. Furthermore, sweet taste can be determined by standard sensory analysis methods. However, it is impossible to define a sensory intensity reference value for sweetness, making them unfit to verify regulatory compliance for the purpose of international food trade. Based on these findings and recommendations, the Codex Committee on Methods of Analysis and Sampling agreed during its 41st session in May 2021 to inform CCNFSDU that there are no known validated methods to measure sweetness of carbohydrate sources; therefore, no way to determine compliance for such a requirement for FUF.

Prediction of the sweetening effect of Siraitia grosvenorii (luo han guo) fruits by two-dimensional quantitative NMR

During the last decade, dried fruits of Siraitia grosvenorii (luo han guo), also known as monk fruit, have become popular food ingredients. Luo han guo extracts, which are promoted as non-caloric natural sweeteners, are now incorporated into dietary supplements, soft drinks, and energy shakes. The compounds responsible for the sweetening effect are glycosylated cucurbitane-type triterpenoids, the so-called mogrosides. However, of the more than 40 known mogroside compounds, only 11-α-hydroxy-mogrosides exhibit a sweetening effect, whereas the other triterpenoids are non- or bitter-tasting. We have used two-dimensional quantitative NMR to determine selectively the content of 11-α-hydroxy-mogrosides in these dried fruits and thus to predict their sweetening potential. Homonuclear (H,H COSY) and heteronuclear (HSQC) methods were developed, validated, and compared. Both techniques were found suitable for the quality control of luo han guo fruits and extracts, the COSY experiment being advantageous with regard to accuracy, precision, and limit of quantification.

Adsorption mechanism of triterpenoid saponins in reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography: Mogroside V as test substance

In this paper, adsorption mechanism of triterpenoid saponins in reversed-phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC) was proposed based on the study of the retention behavior of mogroside V as test substance. The change of peak shape of mogroside V and its influencing factors was first investigated. As the increase of sample loading, a tailing peak of mogroside V was observed in MeOHH₂O of both two modes. It was the fronting peak in ACNH₂O of HILIC while there was a transition from fronting peak to tailing peak in ACNH₂O of RPLC that was largely affected by column temperature and ACN concentration. The adsorption isotherm of mogroside V in ACNH₂O of RPLC was fitted by Moreau model, where a monolayer adsorption with large inter-molecular interaction was formed on the C18 surface. While in ACNH₂O of HILIC, the adsorption of mogroside V was in accordance with BET model, showing multilayer adsorption behavior. In MeOHH₂O of both HILIC and RPLC, there was always monolayer adsorption, which was fitted by Langmuir model. At last, by choosing the suitable chromatographic mode, controlling the key factors such as the solvent concentration and column temperature, and predicting the broadening trend of peak, three methods were screened out, namely, C18 column with 22% ACN (30 °C), Click XIon column with 90% MeOH or 70% ACN, to get mogroside V of purity greater than 98% from Siraitia grosvenorii extract. Among them, the RPLC method of 22% ACN that showed the highest loading sample per hour (1.92%) and the lowest solvent consumption emerged as the best approach.

Mogroside IIIE attenuates gestational diabetes mellitus through activating of AMPK signaling pathway in mice

As one kind of complications of pregnancy, gestational diabetes mellitus (GDM) can influence the health of maternal-child in clinical practice. The C57 BL/KsJ^db/+(db/+) mice, genetic GDM model, and C57 BL/KsJ^+/+ (wild-type) mice were purchased and classified into three groups: normal pregnancy (C57 BL/KsJ^+/+), GDM (C57 BL/KsJ^db/+), and GDM plus Mogroside IIIE (20.0 mg/kg) group. GDM symptoms (maternal body weight, serum glucose, and insulin levels), glucose and insulin tolerance, and reproductive outcome (body weight at birth and litter size of offspring) were investigated. The inflammatory factors such as IL-1β, IL-6, and TNF-α in the serum and the pancreas were detected by ELISA and qRT-PCR, while the expression of pAMPK, AMPK, pHDAC4, HDAC4, and G6Pase in the livers were analyzed by Western Blot. Mogroside IIIE greatly improved glucose metabolism, insulin tolerance, and reproductive outcome of the GDM mice. Moreover, Mogroside IIIE treatment significantly decreased inflammatory factors expression and relieved GDM symptoms through enhanced AMPK activation, inhibited HDAC4 expression, and reduced production of G6Pase. The alleviation of GDM by Mogroside IIIE was mediated by elevated AMPK activation, which in turn inhibited HDAC4 phosphorylation, and eventually down-regulated G6Pase expression and activity.

Developmental, chemical and transcriptional characteristics of artificially pollinated and hormone-induced parthenocarpic fruits of Siraitia grosvenorii

Unpollinated ovaries of Siraitia grosvenorii grew parthenocarpically in response to the application of GA₃ and CPPU.