Rebaudioside M (Reb M) does not have a defined pharmacological target. It functions as a non-nutritive sweetener interacting with sweet taste receptors (T1R2/T1R3). No specific receptor binding data (IC50, Ki, EC50) are reported in the provided articles. [1,2,3]

Rebaudioside M (Reb M) In enzymatic cascade synthesis: The fusion enzyme UGT76G1-91C1 (with a (GGGGS)₃ linker) was used to convert rebaudioside A to rebaudioside M. The fusion enzyme displayed optimal activity at approximately 42°C and pH 7.0. The peptide linker consisting of three repeats of GGGGS enhanced substrate channeling and the synthesis rate of rebaudioside M by 1.8-fold compared to the enzyme without linker. [2]
Solubility: Crystalline rebaudioside M is slightly soluble in water (0.1 g/100 mL at 25°C in 5 min) and in ethanol. Its amorphous material has a solubility of 1.1%-1.3% in water at 25°C. The thermodynamic equilibrium solubility in water is 0.26% at 25°C. [1]
Stability in solution: As a dry powder, rebaudioside M is stable for at least one year at ambient temperature under controlled humidity conditions. In aqueous solution, it is most stable at pH 4-8 and noticeably less stable below pH 2. Stability decreases with increasing temperature. Its stability is very similar to rebaudioside A. In heat-processed beverages (flavored ice-tea, juices, sport drinks, flavored milk, drinking yogurt, non-acidified teas), rebaudioside M shows good stability during High Temperature Short Time heat processing and subsequent product storage. [1]
Degradation pathways: Under hydrolytic conditions (pH 2-8), the major reaction pathways for rebaudioside M include: isomerization of the C-16 olefin to form the C-15 isomer (compound 12), hydration of the C-16 olefin to yield compound 13, hydrolysis of the glycosidyl ester at C-19 to form rebaudioside B (compound 2), and isomerization of the C-16 olefin in compound 2 to form compound 16. All these degradation products are sweet, with compound 12 being sweeter than compounds 2, 13, and 16, having similar taste properties to rebaudioside M. [1]
In vitro metabolism: Upon in vitro metabolism, rebaudioside M, like rebaudioside A, is primarily converted to its aglycone steviol and to steviol glucuronide. [1]

---

As a high-intensity steviol glycoside, the in vitro activity of Rebaudioside M primarily manifests in its metabolic stability toward gut microflora. When incubated under anaerobic conditions using human fecal homogenates, Rebaudioside M is rapidly hydrolyzed by gut microbiota to the final metabolite steviol, a process typically completed within 24 hours, with the majority of metabolism occurring within the first 8 hours. Rebaudioside M exhibits high affinity for the T1R2/T1R3 taste receptor, which forms the structural basis for its sweetness, though direct functional activation in cell-free enzyme/receptor binding assays typically requires intact membrane environments.

The in vivo activity of Rebaudioside M primarily manifests as its indirect sweet taste effect and pharmacological activity following metabolism in the intestine. The compound itself lacks direct biological activity in vivo; after oral administration, it reaches the colon intact and is sequentially hydrolyzed by β-glucosidases encoded by gut microbiota, ultimately undergoing complete conversion to the aglycone steviol. Steviol is the sole active metabolite absorbed into the bloodstream, and thus all in vivo activities of Rebaudioside M are essentially attributed to its metabolite steviol. In vivo studies have demonstrated that different doses of Rebaudioside M (e.g., 0.2 mg/mL and 2.0 mg/mL) exhibit consistent metabolic rates in rat or human fecal homogenates, with complete conversion to steviol within 24 hours, and the metabolic process is identical to that of well-studied steviol glycosides such as Rebaudioside A. This qualitative finding provides a scientific basis for using a read-across approach from the existing toxicological databases of steviol and Rebaudioside A to support the safety of Rebaudioside M.

Rebaudioside M (Reb M) Fusion enzyme UGT76G1-91C1 activity assay: The fusion enzyme (with (GGGGS)ₙ linker where n=0,1,3,5) was expressed in Pichia pastoris and purified by Ni²⁺ affinity chromatography. The purified enzyme was characterized for optimal temperature and pH. The enzyme showed optimal activity at approximately 42°C and pH 7.0. The fusion with a (GGGGS)₃ linker enhanced substrate channeling and the synthesis rate of rebaudioside M by 1.8-fold compared to the enzyme without linker. [2]

---

In vitro metabolism studies of Rebaudioside M are typically conducted under anaerobic conditions. The protocol is as follows: Fresh fecal samples from healthy volunteers are collected to prepare 10% (w/v) human fecal homogenates as the enzyme source. Rebaudioside M is added to the incubation system at concentrations of 0.2 mg/mL or 2.0 mg/mL and incubated at 37°C under anaerobic conditions. Samples are taken at various time points (e.g., 0, 2, 4, 8, 24 hours), and the reaction is terminated by heating. After centrifugation and solid-phase extraction cleanup, samples are analyzed by HPLC-MS/MS to quantify the remaining parent compound and the formation of metabolites such as steviol and steviolbioside. For sweet taste receptor binding studies, surface plasmon resonance (SPR) technology or radioligand binding assays are commonly used, where recombinantly expressed human T1R2/T1R3 receptor proteins are immobilized on a chip to determine the binding affinity (KD value) of Rebaudioside M to the receptor.

In vitro cellular assays for Rebaudioside M are primarily used to evaluate genotoxicity. Standard protocols include the bacterial reverse mutation assay (Ames test) and the in vitro micronucleus assay. In the Ames test, various concentrations of Rebaudioside M (typically 5-6 dose groups) are incubated with histidine-auxotrophic strains of Salmonella typhimurium (e.g., TA98, TA100) in the presence or absence of a metabolic activation system (S9). After 48 hours, revertant colonies are counted to determine positivity. For the in vitro micronucleus assay, human peripheral blood lymphocytes or CHO cells are exposed to Rebaudioside M for 24-48 hours, followed by cytochalasin B treatment to block cytokinesis. Harvested cells are stained, and the frequency of micronuclei in binucleated cells is counted under a microscope. Available data indicate that Rebaudioside M tests negative in these assays, suggesting an absence of genotoxicity.

In vivo animal studies of Rebaudioside M generally follow conventional designs for toxicological evaluation. Since all steviol glycosides are metabolized to the common metabolite steviol in vivo, and existing evidence indicates that Rebaudioside M shares the same metabolic pathway as other substances in this class, safety data can be evaluated using a read-across approach. A typical 90-day subchronic toxicity study uses rats (10-20 animals per group, both sexes), administering Rebaudioside M at various doses (e.g., 0, 500, 1000, 2000 mg/kg body weight/day) by gavage or dietary admixture. Clinical signs are observed daily, and body weight and food intake are recorded weekly. At study termination, hematology, serum biochemistry, urinalysis, and histopathological examination of major organs (liver, kidney, heart, etc.) are performed. Additionally, standard animal studies include pharmacokinetic evaluations, where blood samples are collected at various time points after single or repeated oral administration to determine steviol plasma concentrations.

In vitro metabolic studies have shown that, similar to rebaudioside A, rebaudioside M is mainly metabolized to its aglycones steviol and steviol glucuronide. [1] The stability of rebaudioside M in aqueous solution (pH 2–8) was investigated. The main degradation pathways include C-16 olefin isomerization to form the C-15 isomer, C-16 olefin hydration, and C-19 glycoside hydrolysis. These degradation products have been identified, some of which retain a sweet taste. [1]

---

The pharmacokinetic properties of Rebaudioside M are consistent with those of the steviol glycoside class. After oral administration, Rebaudioside M itself is minimally absorbed from the gastrointestinal tract and reaches the colon intact. In the colon, it is sequentially hydrolyzed by β-glucosidases encoded by gut microbiota, initially removing glucose moieties to form intermediates such as Rebaudioside D and A, and ultimately undergoing complete hydrolysis to the aglycone steviol. Steviol is the sole form absorbed into the bloodstream. Once absorbed, steviol is primarily conjugated with glucuronic acid in the liver to form steviol glucuronide, which is excreted via bile into the intestine, undergoing enterohepatic circulation, and finally eliminated mainly in urine. Since all steviol glycosides are converted to the same active metabolite steviol, the entire class shares the same PK characteristics and an acceptable daily intake (ADI) of 4 mg/kg body weight/day (expressed as steviol equivalents).

The literature mentions that Rebaudioside M received a "no objection letter" from the U.S. FDA regarding its "Generally Recognized As Safe" (GRAS) status. [1]

---

Rebaudioside M (Reb M) Upon in vitro metabolism, rebaudioside M, like rebaudioside A, is primarily converted to its aglycone steviol and to steviol glucuronide. [1]
No detailed pharmacokinetic parameters (absorption, distribution, excretion, half-life, oral bioavailability) are reported in the provided articles. [1,2,3]

---

Rebaudioside M (Reb M) has received a Letter of No Objection concerning its Generally Recognized as Safe (GRAS) status from the US FDA. [1]
No detailed toxicity data (LD50, hepatotoxicity, nephrotoxicity, or other adverse effects) are reported in the provided articles. [1,2,3]

---

The toxicological profile of Rebaudioside M has been well characterized, and it is generally considered safe as a food additive under intended conditions of use. Genotoxicity assessments show that Rebaudioside M tests negative in both the bacterial reverse mutation assay and the in vitro micronucleus assay, indicating an absence of genotoxicity. Regarding potential impurities, kaurenoic acid, which exhibits potential genotoxicity, was not detected in the final product using an analytical method with a limit of detection of 0.3 mg/kg, dispelling related concerns. Based on its complete metabolism to steviol by gut microflora and the scientific consensus that all steviol glycosides share the same metabolic pathway, the safety of Rebaudioside M can leverage the existing toxicological database for Rebaudioside A and stevioside. The European Food Safety Authority (EFSA) has confirmed that the existing acceptable daily intake (ADI) of 4 mg/kg body weight/day (expressed as steviol equivalents) also applies to Rebaudioside M produced via fermentation.

[1]. Development of Next Generation Stevia Sweetener: Rebaudioside M. Foods. 2014 Feb 27;3(1):162-175.

[2]. Fusion glycosyltransferase design for enhanced conversion of rebaudioside A into rebaudioside M in cascade. Molecular Catalysis. 2023 Aug, 547: 113317.

[3]. Stevioside acts directly on pancreatic beta cells to secrete insulin: actions independent of cyclic adenosine monophosphate and adenosine triphosphate-sensitive K+-channel activity. Metabolism. 2000 Feb;49(2):208-14.

Rebaudioside M is a derivative of rebaudioside A, in which the hydroxyl groups at positions 2 and 3 of the β-D-glucose ester moiety are converted to the corresponding β-D-glucosides. It is found in extremely low concentrations in stevia (Stevia rebaudiana) leaves and is more than 200 times sweeter than sucrose. It is a sweetener. It is both a β-D-glucoside and a rebaudioside. Functionally, it is associated with rebaudioside A, rebaudioside D, and β-D-Glcp-(1->2)-[β-D-Glcp-(1->3)]-β-D-Glcp.
See also: Stevia leaves (partial).

---

Rebaudioside M is a natural, non-caloric stevioside sweetener isolated from stevia (Stevia rebaudiana Bertoni). [1]
Sensory evaluations conducted by a trained sensory evaluation team indicated that rebaudioside M has a refreshing sweetness with a slightly bitter or licorice-like aftertaste, but not as pronounced as rebaudioside A. Its sweetness is estimated to be 200-350 times that of sucrose using the Bedler model. [1]
Mixing rebaudioside M with other sweeteners (e.g., rebaudioside A, D, B, erythritol) can improve sensory properties such as total sweetness and sweetness characteristics, and reduce bitterness and aftertaste, thus exhibiting a synergistic effect and enhancing mouthfeel. [1]
Rebaudioside M can be widely used in various foods and beverages. Typical usage concentrations range from 100-600 mg/kg in carbonated beverages, 50-600 mg/L in non-carbonated beverages, 200-2000 mg/kg in powdered soft drinks, and up to 6000 mg/kg in chewing gum. Rebaudioside M exhibits good stability during storage in products such as soft drinks, table sweeteners, chewing gum, and yogurt. [1]
The pure compound has very low solubility in water (thermodynamic equilibrium solubility of 0.26% at 25°C). The dried powder is stable for at least one year at room temperature. In solution, it is most stable at pH 4–8. [1]

---

Rebaudioside M (Reb M) is one of the minor sweet components of Stevia rebaudiana Bertoni. It is a glycoside of the ent-kaurene diterpenoid aglycone known as steviol. [1]
Sensory attributes: Using the Beidler Model, rebaudioside M was estimated to be 200-350 times more potent than sucrose. Sensory evaluations showed that rebaudioside M possesses a clean, sweet taste with a slightly bitter or licorice aftertaste. Compared to rebaudioside A, rebaudioside M showed reduced perception of bitterness, astringency, and bitter lingering, with similar sweetness intensity. In acidified water, rebaudioside M displayed faster sweetness onset, reduced non-sweet taste (bitterness, sour, astringency), and reduced bitter lingering. Trained descriptive panels did not detect any significant bitter or licorice off-taste when evaluating rebaudioside M in water at approximately 10% sucrose equivalency levels. Rebaudioside M and aspartame have similar high-potency sweetener profiles. The sweetness temporal profile showed that rebaudioside M had the longest extinction time, followed by aspartame and then sucrose, and the longest appearance time. [1]
Blending: Rebaudioside M can be blended with other sweeteners including rebaudioside A, rebaudioside D, rebaudioside B, and erythritol. Blends showed improvement in total sweetness, overall sweetness profile, and reduced off-notes. Rebaudioside M and sucrose blends (20%-80% contribution from rebaudioside M) exhibit flavor and temporal profiles very close to sugar. Sweet-tasting amino acids (glycine, alanine, glutamine, proline, serine) and salts (sodium chloride, potassium chloride) also improve the taste of rebaudioside M. [1]
Food applications: Rebaudioside M is functional in a wide variety of food and beverage products including carbonated soft drinks (100-600 mg/L), still beverages (50-600 mg/L), powdered soft drinks (200-2000 mg/kg), tabletop sweeteners (800-4000 mg/kg), bakery products (200-1000 mg/kg), dairy products (150-1000 mg/kg), chewing gum (300-6000 mg/kg), confections (100-1000 mg/kg), cereals (200-1000 mg/kg), edible gels (200-1000 mg/kg), nutraceuticals (200-1000 mg/kg), and pharmaceuticals (50-1000 mg/kg). In soft drinks (cola and lemon-lime), rebaudioside M-sweetened products remained acceptably sweet throughout 26 weeks storage. Table-top sweetener formulations were stable for at least 52 weeks. Rebaudioside M was stable and functional in chewing gum for 26 weeks. In plain yogurt, there was no significant loss of sweetness during pasteurization (190°F for 5 min) and fermentation, and it remained stable throughout a 6-week storage period (40°F). [1]
Biosynthesis: The biosynthetic pathway of steviol glycosides involves a series of glucosylation reactions catalyzed by UDP-dependent glycosyltransferases. UGT76G1 from S. rebaudiana and UGT91C1 from Oryza sativa are key enzymes for adding C3'-glucosyl and C2'-glucosyl groups respectively. Rebaudioside M can be synthesized from naturally abundant rebaudioside A via a cascade reaction using these two UGTs. [2]
Fusion enzyme design: A fusion enzyme UGT76G1-91C1 was developed with a flexible peptide linker (GGGGS)ₙ (n=0,1,3,5) to create an artificial intramolecular substrate channel. The fusion enzyme was expressed in Pichia pastoris with a yield of approximately 25 mg purified protein per liter of culture. Whole-cell catalysts with intracellular overexpression of the fusion enzyme demonstrated higher catalytic efficiency, thermostability, and recyclability than mixed cells expressing UGT76G1 or UGT91C1 separately, or mixed purified enzymes. [2]

C56H90O33

1291.2940

1290.536

1220616-44-3

92023628

White to off-white solid

1.67±0.1g/ml(Predicted)

-6

20

33

19

89

2400

36

C[C@@]12CCC[C@@](C)(C(=O)O[C@@H]3O[C@H](CO)[C@@H](O)[C@H](O[C@@]4([H])[C@@H]([C@@H](O)[C@H](O)[C@@H](CO)O4)O)[C@H]3O[C@@]3([H])[C@@H]([C@@H](O)[C@H](O)[C@@H](CO)O3)O)[C@@]1([H])CC[C@]13CC(=C)[C@](O[C@]4([H])O[C@H](CO)[C@@H](O)[C@H](O[C@@]5([H])[C@@H]([C@@H](O)[C@H](O)[C@@H](CO)O5)O)[C@H]4O[C@@]4([H])[C@@H]([C@@H](O)[C@H](O)[C@@H](CO)O4)O)(CC[C@@]21[H])C3

GSGVXNMGMKBGQU-PHESRWQRSA-N

InChI=1S/C56H90O33/c1-19-11-55-9-5-26-53(2,7-4-8-54(26,3)52(77)88-50-44(86-48-40(75)36(71)30(65)22(14-59)80-48)42(32(67)24(16-61)82-50)84-46-38(73)34(69)28(63)20(12-57)78-46)27(55)6-10-56(19,18-55)89-51-45(87-49-41(76)37(72)31(66)23(15-60)81-49)43(33(68)25(17-62)83-51)85-47-39(74)35(70)29(64)21(13-58)79-47/h20-51,57-76H,1,4-18H2,2-3H3/t20-,21-,22-,23-,24-,25-,26+,27+,28-,29-,30-,31-,32-,33-,34+,35+,36+,37+,38-,39-,40-,41-,42+,43+,44-,45-,46+,47+,48+,49+,50+,51+,53-,54-,55-,56+/m1/s1

[(2S,3R,4S,5R,6R)-5-hydroxy-6-(hydroxymethyl)-3,4-bis[[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy]oxan-2-yl] (1R,4S,5R,9S,10R,13S)-13-[(2S,3R,4S,5R,6R)-5-hydroxy-6-(hydroxymethyl)-3,4-bis[[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy]oxan-2-yl]oxy-5,9-dimethyl-14-methylidenetetracyclo[11.2.1.01,10.04,9]hexadecane-5-carboxylate

REBAUDIOSIDE M; rebaudioside X; Fema No. 4895; Fema No. 4922;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~100 mg/mL (~77.44 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (1.94 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (1.94 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

---

View More

Solubility in Formulation 3: ≥ 2.5 mg/mL (1.94 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)