Glycosidic Bond Structure and Cleavage Mechanisms—Chemical and Enzymatic Cleavage of O-, N-, S-, and C-Glycosides
Glycosidic Bond Structure and Cleavage Mechanisms—Chemical and Enzymatic Cleavage of O-, N-, S-, and C-Glycosides
Introduction
In glycosides, the anomeric carbon of the sugar can be linked to the non-sugar moiety through an oxygen, nitrogen, or sulfur atom, or it can form a direct carbon–carbon bond with a carbon atom of the aglycone. The mode of linkage alters the electronic structure of the anomeric reaction center, the properties of the leaving group, and the types of bond-cleavage processes that can occur, thereby affecting the cleavage behavior of glycosides under acidic, basic, and enzymatic conditions.[1-6]
The actual cleavage rate is also influenced by factors such as sugar-ring structure, the aglycone or leaving group, molecular conformation, pH, temperature, and catalysts. Glycosides with the same type of linkage may exhibit different reaction rates and cleavage pathways depending on their structures and reaction conditions.[1-4,7]
The chemical significance of glycosidic bond structure lies not only in distinguishing O-, N-, S-, and C-glycosides, but also in determining which reactions can occur at the anomeric center. Typical O-glycosides can undergo acid-catalyzed hydrolysis; some O-glycosides can undergo cleavage through neighboring-group participation under strongly basic conditions; and C-glycosides lack the C1—O—aglycone linkage characteristic of typical O-glycosides and therefore require different pathways for cleavage of the C—C bond.[1,5,7-9]
1 Linkage Structures of O-, N-, S-, and C-Glycosides
1.1 Modes of Linkage Between the Sugar Anomeric Carbon and the Aglycone
When a monosaccharide cyclizes from its open-chain form to form a cyclic hemiacetal or hemiketal, the original carbonyl carbon becomes the anomeric carbon. In aldoses such as glucose, the anomeric carbon is C1 when a pyranose ring is formed. During glycoside formation, the anomeric carbon forms a new covalent linkage with another group.
The major structural differences among O-, N-, S-, and C-glycosides are shown below.
Glycoside Type | Anomeric Linkage | Representative Compounds or Compound Classes |
O-Glycoside | Sugar-C1—O—aglycone | Flavonoid O-glycosides, etc. |
N-Glycoside | Sugar-C1—N—aglycone | Nucleosides such as adenosine |
S-Glycoside | Sugar-C1—S—non-sugar moiety | Glucosinolates |
C-Glycoside | Sugar-C1—C—aglycone | Puerarin, etc. |
In adenosine, the anomeric carbon of ribose forms an N-glycosidic bond with a nitrogen atom of adenine. Glucosinolates are β-D-thioglucosides in which the anomeric carbon of glucose is linked to the non-sugar moiety through a sulfur atom. Puerarin, by contrast, is a C-glycoside in which the anomeric carbon of glucose forms a direct C—C bond with a carbon atom of the daidzein skeleton.[3,5,6]
The linking atom and its neighboring structural environment influence the electronic environment around the anomeric carbon and the properties of the leaving group. The glycosidic oxygen in O-glycosides can participate in acid-catalyzed reactions; C-glycosides lack the corresponding C1—O—aglycone structure, and the hydrolysis pathways characteristic of typical O-glycosides do not apply to their C—C linkages.[1,5,8]
1.2 Linkage Type and Cleavage Rate
The O-, N-, S-, or C-linkage type alone is insufficient to determine the cleavage rate of a specific glycoside. Even within the same linkage type, substituents, conformation, and reaction conditions can produce substantial kinetic differences.[1,3,4,7]
Adenosine provides an experimental example of the stability of N-glycosides. Stockbridge et al. measured the spontaneous cleavage of the N-glycosidic bond in adenosine and obtained an uncatalyzed cleavage rate constant of approximately 3.7 × 10⁻¹² s⁻¹ at 25 °C and pH 7, demonstrating the high kinetic stability of adenosine under neutral conditions.[3]
Acidic environments can markedly alter the cleavage behavior of purine nucleosides. Jordan and Niv compared several substituted purine nucleosides and found that base substitution and changes in glycosidic conformation could produce differences of several hundred-fold in acid-catalyzed hydrolysis rates, with differences of approximately 110-fold and 700-fold observed between some derivatives.[4]
O-Glycosides also exhibit pronounced structural and condition dependence. 4-Nitrophenyl β-D-glucopyranoside can undergo different cleavage pathways in acidic, near-neutral, and basic regions; phenyl β-D-glucoside and the structurally related xyloside also exhibit substantial differences in cleavage rates under strongly basic conditions.[1,7]
The cleavage rate of a specific glycoside is determined collectively by the mode of linkage, sugar structure, aglycone or leaving group, conformation, and reaction conditions. A universally applicable fixed ranking of hydrolysis rates therefore cannot be established solely on the basis of classification as an O-, N-, S-, or C-glycoside.
2 Chemical Cleavage of O-Glycosides
2.1 Acid-Catalyzed Cleavage of O-Glycosidic Bonds
In O-glycosides, the anomeric carbon of the sugar is linked to the aglycone through an oxygen atom. Kinetic studies using aryl O-glucosides as model compounds have shown that, under acidic conditions, a protonated substrate conjugate acid can first be formed, followed by heterolytic cleavage of the glycosidic C—O bond.[1,2]
2.1.1 Protonation of the Glycosidic Oxygen
The anomeric linkage of a typical O-glycoside can be represented as:
Sugar-C1—O—R
R represents the aglycone or an organic group in a model substrate.
In an acidic medium, an oxygen atom associated with the glycosidic linkage accepts a proton to form the substrate conjugate acid. Protonation alters the electron distribution around the glycosidic oxygen and increases the leaving ability of the group attached to the anomeric carbon.[1]
Kinetic studies of 4-nitrophenyl β-D-glucopyranoside measured an H₃O⁺/D₃O⁺ kinetic isotope effect of approximately 0.65 in the acidic region, supporting formation of the substrate conjugate acid followed by heterolytic cleavage of the glycosidic C—O bond.[1]
2.1.2 Heterolytic Cleavage of the Anomeric C—O Bond
Following protonation, the C—O bond between the anomeric carbon C1 and the aglycone-side oxygen undergoes heterolytic cleavage. Carbon-13 kinetic isotope effect studies have shown that acid-catalyzed glucoside hydrolysis can proceed through a stepwise dissociation–association process and can form a glycosyl intermediate state with pronounced oxocarbenium-ion character.[2]
This process can be represented as:
Protonated O-glycoside → C1—O bond heterolysis → Oxocarbenium-ion-like glycosyl reactive state
Differences in leaving groups, sugar-ring substitution, and conformation among glycosides can alter both the extent of anomeric C—O bond cleavage and the stability of the intermediate state.[1,2]
2.1.3 Attack of Water at the Anomeric Reaction Center
The electrophilic glycosyl center formed after cleavage of the anomeric C—O bond reacts with water. Water acts as a nucleophile and attacks the anomeric carbon, followed by proton transfer to form the corresponding monosaccharide and release the aglycone.
The overall reaction is:
O-Glycoside + H₂O → Corresponding monosaccharide + aglycone (H⁺ catalysis)
The same 4-nitrophenyl β-D-glucopyranoside can also enter other cleavage pathways, including bimolecular reactions or intramolecular participation, when the pH changes. This indicates that acid-catalyzed mechanisms cannot be generalized to all O-glycosides independently of the specific substrate and reaction conditions.[1]
2.2 Cleavage of O-Glycosides Under Basic Conditions
Some O-glycosides exhibit relatively high stability under mildly basic conditions; O-glycosides with suitable sugar-ring structures and leaving groups can nevertheless undergo cleavage of the anomeric linkage under more strongly basic conditions.[1,7]
2.2.1 Neighboring-Group Participation and Intramolecular Nucleophilic Substitution
Takenoshita et al. compared the reactions of phenyl β-D-glucopyranoside (PhG) and phenyl β-D-xylopyranoside (PhX) under strongly basic conditions. Both compounds contain an anomeric C1—O—phenyl linkage.[7]
In 1.0 mol/L NaOD/D₂O, cleavage of both glycosides involves deprotonation of the C2 hydroxyl group to form an oxyanion. When the sugar ring adopts a favorable conformation, the C2 oxyanion attacks the anomeric carbon C1 intramolecularly, accompanied by cleavage of the C1—OAr bond.[7]
The principal reaction changes are:
C2—OH → C2—O⁻
C2—O⁻ attacks C1 → C1—OAr bond cleavage
Under basic conditions, the nucleophilicity of the neighboring oxygen group is increased, allowing an oxygen-containing group within the sugar molecule to participate in intramolecular substitution at the anomeric center. This pathway differs from protonation of the glycosidic oxygen and dissociative C—O bond cleavage under acid-catalyzed conditions.[1,7]
2.2.2 Effect of Sugar-Ring Structure on the Rate of Base-Promoted Cleavage
Under the conditions described above, PhX undergoes cleavage markedly faster than PhG. PhG contains a C6 hydroxymethyl moiety, whereas PhX lacks the C6 carbon. At 100 °C, the measured activation entropies, ΔS‡, were approximately −22.0 cal·mol⁻¹·K⁻¹ for PhG and −10.8 cal·mol⁻¹·K⁻¹ for PhX.[7]
Computational analysis showed that, in the transition state of the PhG reaction, the departing phenoxide ion can form a relatively strong hydrogen bond with the C6 hydroxyl group, producing an unfavorable entropic effect. The reactive conformations of PhG and PhX also differ in stability and conformational flexibility.[7]
These results demonstrate that, even among O-glycosides, sugar-ring structure and conformation alone can significantly alter the kinetics of cleavage under basic conditions.
2.3 Factors Affecting the Cleavage Rate of O-Glycosides
Studies of acidic and basic cleavage of O-glycosides show that the anomeric linkage is only one of the factors determining reactivity.[1,2,7]
Factor | Effect on the Cleavage Reaction |
Anomeric linkage structure | Influences the electronic environment of the reaction center and the bond-cleavage pathway |
Aglycone or leaving group | Influences the leaving process and the stability of the associated reactive state |
Sugar-ring substituents | Affect the reaction through electronic effects, hydrogen bonding, and neighboring-group participation |
Sugar-ring conformation | Influences the spatial orientation of the reacting groups |
pH | Alters protonation and deprotonation states and reaction pathways |
Temperature | Alters the reaction rate and may promote subsequent transformations |
Sugar-ring size, substitution pattern, and conformation are all relevant to reactivity, and their effects must be evaluated in the context of the specific substrate and experimental conditions.[1,7]
3 Cleavage of C-Glycosides: Puerarin as an Example
3.1 The C—C Glycosidic Linkage in Puerarin
Puerarin is the 8-C-glucosylated derivative of daidzein, in which the anomeric carbon of glucose forms a direct C—C bond with C8 of the daidzein skeleton.[5,9]
Its anomeric linkage can be represented as:
Glucose-C1—C8-daidzein
In contrast, the anomeric linkage of a typical O-glucoside is:
Glucose-C1—O—aglycone
Classical glycoside hydrolysis mechanisms primarily act on substrates containing a C1—O linkage. C-Glycosides lack this leaving-group pathway and therefore exhibit relatively high stability toward common chemical hydrolysis conditions and classical glycoside hydrolases.[5,8]
Puerarin can nevertheless undergo biological deglycosylation. Reported microbial systems first oxidize the sugar moiety and then cleave the C—C linkage between the sugar and the aglycone through a specialized elimination reaction.[5,8,9]
3.2 Oxidation of the Sugar Moiety to Form a 3″-Oxo Intermediate
In the puerarin-metabolizing system of the human gut bacterial PUE strain, DgpA first oxidizes the C3 position of the glucose moiety of puerarin to generate 3″-oxo-puerarin. Subsequently, the C-deglycosylase complex composed of DgpB-C acts on this oxidized intermediate and releases daidzein.[5]
The reaction sequence is:
Puerarin
→ Oxidation at C3 of the glucose moiety
→ 3″-Oxo-puerarin
→ Cleavage of the sugar—aglycone C—C bond
→ Daidzein
Oxidation of the C3 hydroxyl group to a carbonyl group generates a 3-ketosugar structure, altering the electronic state of the sugar moiety and providing the basis for the subsequent β-elimination reaction.[5,8]
3.3 Cleavage of the Sugar—Aglycone C—C Bond by β-Elimination
Bitter et al. conducted structural and kinetic studies on the enzymatic cleavage of 3-keto O- and C-glycosides. Following C3 oxidation of puerarin to form a 3-keto substrate, cleavage can be catalyzed by the C-glycoside-deglycosylating β-elimination enzyme PuCGE.[8]
PuCGE contains an Mn²⁺ active center. Structural and computational studies indicate that a histidine residue in the active site participates in abstraction of the C2 proton, while the 3-keto structure and metal center contribute to substrate positioning and charge stabilization. Positioning of the daidzein moiety and the ionization state of its 7-hydroxyl group also participate in C—C bond cleavage.[8]
Kinetic measurements for 3-keto-puerarin gave a kcat value of 18 ± 0.4 s⁻¹ and a Km value of 0.8 ± 0.1 mmol/L for PuCGE, demonstrating that the oxidized C-glycoside can serve as an effective substrate for this β-elimination enzyme.[8]
The core reaction of this deglycosylation pathway is:
C3 oxidation of the sugar moiety → 3-Keto C-glycoside → Enzymatic β-elimination → C—C linkage cleavage
C-Glycosides exhibit relatively high stability toward classical hydrolytic pathways. Their microbial deglycosylation proceeds through oxidative activation and β-elimination rather than direct hydrolysis of the sugar—aglycone C—C bond.[5,8]
3.4 Two-Step C-Deglycosylation Systems in Different Microorganisms
The soil microorganism Paenarthrobacter sp. No. 37, reported in 2025, also possesses the ability to deglycosylate puerarin. In this system, PurA first catalyzes oxidation of the sugar moiety of puerarin, after which the PurBC complex formed by PurB and PurC acts on the oxidized product and completes cleavage of the C—C linkage.[9]
PurA exhibits oxidative activity toward multiple C-glycosides, whereas PurBC has a narrower substrate range. Among the substrates tested in the study, PurBC was active toward 3″-keto-puerarin, 3″-keto-orientin, and 3′-keto-aloesin, and showed relatively high activity toward 3″-keto-puerarin.[9]
Although gut bacteria and soil bacteria use different specific oxidases, both systems share a two-step reaction pattern in which the sugar moiety is first oxidized and the C—C linkage is subsequently cleaved.[5,9]
4 N- and S-Glycosides and Enzymatic Cleavage
4.1 Cleavage of N-Glycosides Is Influenced by Molecular Structure and Reaction Conditions
N-Glycosides can undergo acid-catalyzed cleavage, and their rates are influenced by the protonation state of the nitrogen-containing aglycone, substituents, and glycosidic conformation. The uncatalyzed cleavage rate of adenosine is very low under neutral conditions, whereas substituted purine nucleosides can exhibit differences of several hundred-fold in cleavage rates under acidic conditions.[3,4]
Studies of purine nucleoside hydrolysis support an acid-catalyzed pathway in which the base is protonated first, followed by heterolytic cleavage of the N-glycosidic bond. Different substituents and conformations affect reaction kinetics by altering protonation states and the glycosyl–base bond-cleavage process.[4]
The N-linkage defines the basic structural connection between the anomeric carbon and the nitrogen-containing aglycone, whereas the specific stability of a glycoside still depends on the complete nucleoside structure and the reaction environment.
4.2 Enzymatic Cleavage of S-Glycosides
Glucosinolates are β-D-thioglucosides. Myrosinase (β-thioglucosidase) can catalyze cleavage of the thioglycosidic linkage in glucosinolates.[6]
Burmeister et al. determined the crystal structures of myrosinase from white mustard (Sinapis alba) and of a covalent glycosyl–enzyme intermediate. Glu409 serves as the catalytic nucleophilic residue and forms a covalent intermediate with the glycosyl group; the overall architecture of the enzyme active site is highly similar to that of related O-glycosidases.[6]
The glutamate residue that serves a general acid/base catalytic function in related O-glycosidases is replaced by Gln187 at the corresponding position in white mustard myrosinase. The non-sugar moiety of glucosinolates has relatively good leaving-group ability, reducing the dependence of the initial bond-cleavage step on a general acid catalytic residue. During hydrolysis of the glycosyl–enzyme intermediate, Gln187 mainly participates in positioning the water molecule.[6]
The enzymatic cleavage of S-glycosides demonstrates that the active site can provide a catalytic environment adapted to the linkage structure and leaving-group properties of the substrate.
4.3 Substrate Selectivity of Glycoside-Cleaving Enzymes
The substrate selectivity of glycoside-cleaving enzymes can be influenced simultaneously by sugar type, anomeric configuration, linkage mode, aglycone structure, and substitution position. Enzymes that catalyze cleavage of the same class of glycosides may also have different substrate spectra and catalytic efficiencies.[5,9,10]
Körnig et al. investigated myrosinases in the horseradish flea beetle (Phyllotreta armoraciae) and found that PaMyr1 is primarily responsible for myrosinase activity in adults, whereas PaMyr2 is primarily responsible for activity in larvae. Recombinant PaMyr1 and PaMyr2 showed different substrate preferences toward different glucosinolates.[10]
C-Glycoside deglycosylation systems also exhibit pronounced substrate selectivity. PurA, reported in 2025, can oxidize multiple C-glycosides, whereas PurBC displays cleavage activity toward only some of the oxidized C-glycosides.[9]
Enzyme substrate recognition is determined collectively by multiple interactions between the active site and the sugar, linkage structure, and non-sugar moiety. Structural changes in the substrate can therefore significantly alter catalytic efficiency.
5 Selection of Cleavage Conditions and Experimental Risks
5.1 Reaction Characteristics of Acidic, Basic, and Enzymatic Cleavage
Acids, bases, and enzymes act on glycosides through different structural principles and under different applicable conditions.[1,5-9]
Cleavage Method | Principal Reaction Basis | Structural Characteristics | Main Limitations |
Acid-catalyzed cleavage | Protonation of the glycosidic linkage promotes bond cleavage at the anomeric center | Effective for a variety of acid-sensitive O-glycosides | Rate is influenced by the sugar, aglycone, and acidity; stronger conditions can increase side reactions |
Base-promoted cleavage | Deprotonation, neighboring-group participation, intramolecular substitution, etc. | Some O-glycosides with suitable structures can undergo cleavage | Strongly dependent on structure and reaction conditions |
Glycoside hydrolases | The active site provides an environment for substrate binding, nucleophilic catalysis, and acid/base catalysis | Often exhibit pronounced substrate selectivity | Catalytic scope depends on the specific enzyme and substrate |
Reported C-glycoside oxidation–deglycosylation enzyme systems | The sugar moiety is first oxidized, followed by cleavage of the C—C linkage through β-elimination or related pathways | Can process C-glycosides that are difficult to cleave through classical hydrolytic pathways | Require compatible oxidases, deglycosylating enzymes, and substrate structures |
Stronger acidic or basic conditions and higher temperatures can increase the cleavage rates of certain glycosides, while also affecting the stability of other functional groups. Selection of cleavage conditions therefore requires consideration of both the reactivity of the target glycosidic bond and the stability of the aglycone.
5.2 Aglycones Released by Acid Hydrolysis May Undergo Further Transformation
After cleavage of the glycosidic bond, the released aglycone remains in the original reaction medium. Acid-sensitive aglycones can subsequently undergo dehydration, isomerization, rearrangement, or other transformations, causing the products ultimately detected to differ from the original non-sugar moiety present in the glycoside.
Skouroumounis and Sefton studied several β-D-glucosides and their corresponding free alcohols in a model system at pH 3 and found that the free aglycones generally underwent conversion to subsequent products more rapidly than the corresponding glycosides. Reaction temperature also altered the relative composition of the final products.[11]
For certain structures, increasing the temperature or extending the duration of acid treatment can promote glycoside cleavage while simultaneously increasing the extent of further aglycone transformation. Products obtained from acid hydrolysis experiments therefore need to be interpreted in conjunction with the stability of the aglycone under the same conditions.[11]
5.3 Basis for Selecting Cleavage Conditions
Glycoside cleavage experiments involve three interrelated structural questions:
① How is the anomeric carbon linked to the non-sugar moiety?
② Which reaction pathway does the target linkage follow under the specified acidic, basic, or enzymatic conditions?
③ Do the released sugar and aglycone remain stable under the same conditions?
Depending on their specific structures, typical O-glycosides can be subjected to acid-catalyzed cleavage, specific base-promoted reactions, or corresponding glycoside hydrolases. Cleavage of N- and S-glycosides depends on their nitrogen- or sulfur-containing linkages and the corresponding catalytic environment. C-Glycosides such as puerarin can undergo cleavage of the C—C linkage through specific microbial oxidation–deglycosylation systems.[1,3-10]
The sugars and aglycones obtained from glycoside cleavage can also provide compositional information for structural studies. Complete determination of sugar identity, linkage position, sugar-chain sequence, and stereochemical configuration still requires integration of mass spectrometry, nuclear magnetic resonance spectroscopy, and other structural evidence.
6 Representative Chemicals for Studies of the Cleavage Mechanisms and Enzymology of O-, N-, S-, and C-Glycosides
Table 1 Glycoside-Cleaving Enzymes, Chromogenic Substrates, and Chromogenic Products
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
β-Glucuronidase | 9001-45-0 | β-Glucuronidase from Escherichia coli | Recombinant, ≥20,000,000 units/g protein, expressed in E. coli, aqueous glycerol solution | For enzymatic hydrolysis of β-glucuronides, enzyme activity assays, determination of kinetic parameters, and substrate selectivity studies. | |
β-Glucuronide chromogenic substrate | 10344-94-2 | 4-Nitrophenyl β-D-glucuronide [β-glucuronidase substrate] | ≥98% (HPLC) | For β-glucuronidase activity assays, enzymatic cleavage kinetics, and quantification of p-nitrophenol release. | |
β-Glucosidase | 9001-22-3 | β-Glucosidase | Bioactive, recombinant, ActiBioPure™, high-performance, EnzymoPure™, ≥90% (SDS-PAGE), ≥5 U/mg enzyme powder; ≥25 U/mg protein | For enzymatic cleavage of β-O-glucosides, substrate selectivity studies, anomeric configuration recognition, and enzyme kinetics studies. | |
β-Glucoside chromogenic substrate | 2492-87-7 | 4-Nitrophenyl β-D-glucopyranoside | ≥98% | For studies of the hydrolysis mechanisms of β-O-glucosides under acidic and basic conditions, enzymatic cleavage, kinetics, and p-nitrophenol formation. | |
α-Glucosidase | 9001-42-7 | Recombinant α-glucosidase (AGH) | Bioactive, recombinant, ActiBioPure™, high-performance, EnzymoPure™, ≥15 U/mg enzyme powder; ≥100 U/mg protein | For enzymatic hydrolysis of α-O-glucosides, substrate selectivity studies, and comparison of cleavage behavior between α/β anomeric configurations. | |
α-Glucoside chromogenic substrate | 3767-28-0 | p-Nitrophenyl α-D-glucopyranoside | ≥99% | For α-glucosidase activity assays, kinetic analysis, and comparison of substrate selectivity between α- and β-glucosides. | |
Phenolic chromogenic product | 100-02-7 | p-Nitrophenol | ≥99%, contains ~3% water | As a cleavage product of nitrophenyl glycosides; for standard curves, product quantification, and analysis of glycoside cleavage rates. | |
Thioglucosidase | 9025-38-1 | Thioglucosidase | Bioactive, ActiBioPure™, natural, high-performance, EnzymoPure™, ≥100 U/g enzyme powder; from Sinapis alba (white mustard) seed | For enzymatic cleavage of thioglucosides, enzyme activity assays, substrate selectivity studies, and investigation of isothiocyanate formation pathways. |
Table 2 O-Glycoside Model Compounds, Natural O-Glycosides, Sugars, and Aglycones
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Alkyl α-O-glycoside | 97-30-3 | Methyl α-D-glucopyranoside | Moligand™, ≥98% | For studies of acid-catalyzed hydrolysis of α-glucosides, anomeric configuration effects, and glycosidic bond-cleavage transition states. | |
Alkyl β-O-glycoside | 709-50-2 | Methyl β-D-glucopyranoside | Moligand™, 10 mM in Water | Used together with methyl α-D-glucopyranoside to investigate the effects of α/β anomeric configuration on hydrolysis rates and cleavage mechanisms. | |
Aryl β-O-glycoside | 1464-44-4 | Phenyl β-D-glucoside | Moligand™, ≥98% | For studies of the chemical cleavage of aryl O-glycosides, aglycone leaving-group characteristics, and the effects of sugar structure on hydrolysis behavior. | |
Salicyl alcohol β-glucoside | 138-52-3 | D(-)-Salicin | Analytical standard, Moligand™, ≥99% | A natural aryl O-glycoside model; for acid hydrolysis, β-glucosidase-mediated cleavage, and studies of aglycone release. | |
Hydroquinone β-glucoside | 497-76-7 | Arbutin | Analytical standard, ≥99% | For β-O-glucoside hydrolysis, β-glucosidase substrate studies, and analysis of hydroquinone release. | |
Dihydrochalcone O-glycoside | 60-81-1 | Phlorizin | Moligand™, ≥98% | For enzymatic deglycosylation of dihydrochalcone O-glycosides, formation of phloretin, and comparison of the stability of O- and C-glycosides. | |
Dihydrochalcone aglycone | 60-82-2 | Phloretin | Moligand™, ≥98% | As an aglycone reference after deglycosylation of phlorizin; for confirmation of hydrolysis products, determination of conversion rates, and glycoside–aglycone comparisons. | |
Cyanogenic diglycoside | 29883-15-6 | Amygdalin | Analytical standard, ≥98% | For studies of stepwise enzymatic hydrolysis of cyanogenic glycosides, sugar-chain cleavage sequence, substrate selectivity, and hydrolysis products. | |
Hexoaldose | 50-99-7 | D-(+)-Glucose | Anhydrous grade, UltraBio™, ≥99.5% (HPLC), sum of enantiomers | For confirmation of hydrolysis products of glucose-containing glycosides, glycosyl composition analysis, and controls in glycosidase reaction systems. | |
Pentoaldose | 58-86-6 | D-Xylose | Analytical standard, Moligand™, ≥99% | For comparing the effects of pentose and hexose structures on glycoside cleavage behavior and for analysis of hydrolysis products from xylose-containing glycosides. |
Table 3 N-Glycoside Nucleosides, Nucleobases, and Ribose
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Adenine nucleoside | 58-61-7 | Adenine nucleoside (adenosine) | Analytical standard, Moligand™ | A typical purine N-glycoside; for studies of spontaneous N-glycosidic bond cleavage, acid- and base-catalyzed hydrolysis, kinetics, and enzyme-catalyzed reaction rates. | |
Adenine base | 73-24-5 | Adenine | For cell culture, ≥99% | As a nucleobase product reference for cleavage of the N-glycosidic bond in adenosine; for depurination reactions and product quantification studies. | |
Guanine nucleoside | 118-00-3 | Guanosine | PharmPure™, USP, endotoxin <500 EU/g; microbial limit ≤100 CFU/g | For studies of purine N9-glycosidic bond stability, acid-catalyzed cleavage, and the effects of different purine bases on hydrolysis behavior. | |
Guanine base | 73-40-5 | Guanine | UltraBio™ | As a nucleobase reference for cleavage of the N-glycosidic bond in guanosine; for confirmation of hydrolysis products and studies of purine nucleoside deglycosylation. | |
Hypoxanthine nucleoside | 58-63-9 | Inosine | Moligand™, ≥98% | For studies of N-glycosidic bond hydrolysis in purine nucleosides, nucleosidase substrate selectivity, and comparison of cleavage behavior among different purine structures. | |
Cytosine nucleoside | 65-46-3 | Cytidine | For cell culture, endotoxin <500 EU/g; microbial limit ≤100 CFU/g | For studies of pyrimidine N1-glycosidic bond stability and hydrolysis and for structural comparison with the cleavage behavior of purine N9 nucleosides. | |
Uracil nucleoside | 58-96-8 | Uridine | For cell culture, ≥99% | For studies of pyrimidine N-glycosidic bond hydrolysis, nucleoside structural differences, and stability comparisons between purine and pyrimidine nucleosides. | |
Deoxyadenine nucleoside | 958-09-8 | 2′-Deoxyadenosine (anhydrous) | Moligand™, ≥98% (HPLC)(T) | For comparing the effects of ribose and deoxyribose structures on the stability and cleavage behavior of the adenine N-glycosidic bond. | |
Ribose-type pentoaldose | 50-69-1 | D-(-)-Ribose | For cell culture, ≥99% (HPLC) | For studies of nucleoside sugar composition, confirmation of hydrolysis products, and the effects of ribose structure on N-glycosidic bond cleavage. |
Table 4 S-Glycoside Cleavage Products, C-Glycosides, and Corresponding Aglycones
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Aliphatic thioglucoside | 21414-41-5 | Glucoraphanin potassium salt | ≥98% | For enzymatic cleavage of aliphatic thioglucosides, studies of thioglycosidic bond reactions, and analysis of cleavage-product profiles. | |
Isothiocyanate | 57-06-7 | Allyl isothiocyanate | ≥95%, stabilized with BHT | As a representative isothiocyanate product of enzymatic cleavage of allyl thioglucosides; for product confirmation and reaction pathway analysis. | |
Isoflavone 8-C-glucoside | 3681-99-0 | Puerarin | Moligand™, ≥98% | For enzymatic deglycosylation of C—C glycosidic bonds, oxidative activation of the sugar moiety, linkage-position identification, and substrate selectivity studies. | |
Isoflavone aglycone | 486-66-8 | Daidzein | Moligand™, ≥98% | As an aglycone reference after C-deglycosylation of puerarin; for confirmation of C—C bond-cleavage products and determination of deglycosylation conversion rates. | |
Apigenin 8-C-glucoside | 3681-93-4 | Vitexin | Analytical standard, ≥98% | Used with isovitexin as an 8-position/6-position C-glycoside comparison; for studies of linkage-position selectivity and cleavage behavior of C-deglycosylating enzymes. | |
Apigenin 6-C-glucoside | 38953-85-4 | Isovitexin | ≥98% | Used in comparison with vitexin to investigate the effects of glycosyl linkage position on C-glycoside stability, oxidative activation, and enzymatic deglycosylation selectivity. | |
Apigenin aglycone | 520-36-5 | Apigenin | Moligand™, ≥98% (HPLC) | As an aglycone reference after deglycosylation of vitexin and isovitexin; for product confirmation and C-glycoside conversion analysis. | |
Luteolin 8-C-glucoside | 28608-75-5 | Orientin | ≥97% (HPLC) | Used with isoorientin as an 8-position/6-position C-glycoside comparison; for studies of C-deglycosylase substrate selectivity and linkage-position effects. | |
Luteolin 6-C-glucoside | 4261-42-1 | Isoorientin | Analytical standard, ≥98% | Used in comparison with orientin to investigate the effects of C-glycosyl linkage position on oxidative activation, C—C bond cleavage, and enzymatic deglycosylation behavior. | |
Luteolin aglycone | 491-70-3 | Luteolin | Analytical standard, Moligand™, ≥98% | As an aglycone reference after deglycosylation of orientin and isoorientin; for product confirmation and analysis of the extent of C-glycoside deglycosylation. | |
Xanthone C-glycoside | 4773-96-0 | Mangiferin | Analytical standard, Moligand™, ≥98% | For studies of the stability and oxidative activation of xanthone-type C-glycosides and the substrate range of enzymatic deglycosylation across C-glycosides with different aglycone skeletons. | |
Dihydrochalcone C-glycoside | 11023-94-2 | Nothofagin | ≥98% | For studies of the stability and C—C glycosidic bond cleavage of dihydrochalcone-type C-glycosides and comparison of deglycosylation behavior among different aglycone skeletons. | |
Anthraquinone C-glycoside | 1260-17-9 | Carminic acid | ≥80%, natural dye | For studies of the stability and oxidative activation of the sugar moiety in anthraquinone-type C-glycosides and the substrate range of microbial C-deglycosylation systems. |
Note: The products listed above are representative Aladdin products related to scientific research. Their specific applications should be determined in conjunction with product specifications, batch COAs, and the intended reaction or evaluation system. Additional information on product specifications, grades, and COAs can be retrieved from the Aladdin website using the “product name/CAS/catalog number.”
References
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[5] Mori T, Kumano T, He H, et al. C-Glycoside metabolism in the gut and in nature: identification, characterization, structural analyses and distribution of C-C bond-cleaving enzymes. Nature Communications, 2021, 12: 6294. DOI: 10.1038/s41467-021-26585-1.
[6] Burmeister W P, Cottaz S, Driguez H, Iori R, Palmieri S, Henrissat B. The crystal structures of Sinapis alba myrosinase and a covalent glycosyl-enzyme intermediate provide insights into the substrate recognition and active-site machinery of an S-glycosidase. Structure, 1997, 5(5): 663-675. DOI: 10.1016/S0969-2126(97)00221-9.
[7] Takenoshita S, Hosoya T, Miyafuji H. Reactivity differences in glycosidic bond cleavage between phenyl β-D-glucoside and xyloside under basic conditions: mechanistic insights from kinetic and computational approaches. Cellulose, 2025, 32: 4161-4181. DOI: 10.1007/s10570-025-06506-x.
[8] Bitter J, Pfeiffer M, Borg A J E, et al. Enzymatic β-elimination in natural product O- and C-glycoside deglycosylation. Nature Communications, 2023, 14: 7123. DOI: 10.1038/s41467-023-42750-0.
[9] Kumano T, Watanabe S, Kusakari M, Terashita Y, Hashimoto Y, Kobayashi M. Characterization of the initial degradation mechanism involved in C-glycosylated isoflavone puerarin in soil microorganism. Applied and Environmental Microbiology, 2025, 91(12): e01593-25. DOI: 10.1128/aem.01593-25.
[10] Körnig J, Ortizo K, Sporer T, Yang Z L, Beran F. Different myrosinases activate sequestered glucosinolates in larvae and adults of the horseradish flea beetle. Insect Biochemistry and Molecular Biology, 2023, 163: 104040. DOI: 10.1016/j.ibmb.2023.104040.
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