Studies on the homolytic and heterolytic cleavage of kaempferol and kaempferide glycosides using electrospray ionization tandem mass spectrometry

UPLC-QTOF-MS-Based Quantification and Antiplatelet Activity Evaluation of Herb Pair Interactions Between Red Ginseng and Trogopterus Feces

Red ginseng (RG) and Trogopterus Feces (TF) are one of the drug pairs in "nineteen medicaments of mutual antagonism" and not recommended for drug compatibility in Chinese Pharmacopoeia. In addition, RG functions to "tonify Qi" and "nourish the blood," while TF can "promote blood circulation" and "relieve pain." Therefore, the two drugs are often combined to treat blood stasis syndrome in the clinical practice of traditional Chinese medicine (TCM). Nevertheless, the combined application of RG and TF in TCM formulas has attracted much attention but still lacks in-depth research. To bridge this gap, our investigation employed UPLC-QTOF-MS technology coupled with in vitro pharmacological models to systematically examine both compositional alterations and functional consequences of RG-TF compatibility. Key findings revealed that co-decoction of these two herbal medicines induced a significant reduction in the content of bioactive ginsenosides derived from RG, while concurrently diminishing the antiplatelet aggregation efficacy observed in the single-herb decoction of RG. This chemical-pharmacological correlation provides compelling evidence for the incompatibility of RG with TF and elucidates the biochemical basis of their mutual antagonism documented in classical TCM literature.

Detailed investigation of the composition and transformations of phenolic compounds in fresh and fermented Vaccinium floribundum berry extracts by high-resolution mass spectrometry and bioinformatics

INTRODUCTION

Blueberries are known for their very high content of biologically active phenolic compounds; nonetheless, differently from the North American and European species of blueberries, Neotropical blueberries have not been extensively studied yet.

OBJECTIVES

In the present paper, the phenolic composition of Vaccinium floribundum Kunth, which is endemic to the Andean regions and grows 1,600 to 4,500 meters above sea level, was investigated by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). Native and fermented berries were compared in terms of phenolic composition as well as antioxidant activity, total phenolic content, and total anthocyanin content.

MATERIALS AND METHODS

V. floribundum native and fermented berries were extracted and analyzed by UHPLC-HRMS. The acquired datasets were processed by Compound Discoverer 3.1 using a dedicated data analysis workflow that was specifically set up for phenolic compound identification.

RESULTS

In total, 309 compounds were tentatively identified, including anthocyanins, flavonoids, phenolic acids, and proanthocyanidins. The molecular transformations of phenolic compounds during fermentation were comprehensively investigated for the first time, and by a customized data processing workflow, 13 quinones and quinone methides were tentatively identified in the fermented samples. Compared to other species of the genus Vaccinium, a peculiar phenolic profile is observed, with low abundance of highly methylated compounds.

CONCLUSION

Andean berries are a rich source of a wide variety of phenolic compounds. Untargeted MS analyses coupled to a dedicated data processing workflow allowed expanding the current knowledge on these berries, improving our understanding of the fate of phenolic compounds after fermentation.

Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar 'Yae-no-amacha' using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.

Molecular networking-guided strategy for the pharmacokinetic study of herbal medicines: Cudrania tricuspidata leaf extracts

In this study, the pharmacokinetic profiles of the bioactive components in the leaf extract of the medicinal herb, Cudrania tricuspidate, were investigated using an MS/MS-based molecular networking system. To identify the major active components of the C. tricuspidate leaf extract (CLE), HPLC-DAD analysis was conducted with a standard mixture of six flavonoids (rutin, isoquercitrin, nicotiflorin, kaempferol 3-O-glucoside, quercetin, and kaempferol). The unknown peaks were determined via molecular networking analysis using the mass dataset obtained by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). For the subsequent pharmacokinetic study, CLE (1 g/kg) was orally administered to rats, and plasma samples were collected. The product ion mass data of plasma samples using LC-QTOF/MS were obtained and subjected to molecular networking analysis. The resulting molecular networking map indicated that the glucuronide metabolites of quercetin and kaempferol were the major circulating species. Accordingly, quercetin and kaempferol were determined following β-glucuronidase treatment, and their pharmacokinetic parameters were calculated. These findings indicate that the proposed molecular network-based approaches are potential and efficient methods for the pharmacokinetic study of herbal medicines.

Andean Blueberry of the Genus Disterigma: A High-Resolution Mass Spectrometric Approach for the Comprehensive Characterization of Phenolic Compounds

Wild neotropical blueberries, endemic of Central and South American areas, are promising yet still undisclosed sources of bioactive compounds. Most research studies have addressed wild and cultivated blueberries from Europe and North America, despite the extremely wide variety of wild neotropical species. In the present paper, for the first time, the phenolic composition of Disterigma alaternoides was investigated through ultra-high-performance liquid chromatography coupled to high-resolution mass-spectrometric analysis followed by accurate data analysis and compound validation with a dedicated structure-based workflow. D. alaternoides, which belongs to a closely related genus to that of the common blueberry, grows exclusively in the Andean regions over 2000 above sea level. Thanks to the dedicated analytical platform, 249 phenolic compounds were tentatively identified, including several anthocyanins, flavonoids, phenolic acids, and proanthocyanidins. Thenature and heterogeneity of identified phenolic compounds demonstrate once more the need for a more profound knowledge of such still uncharted matrices.

Identification and characterization of the chemical components of Iris tectorum Maxim. and evaluation of their nitric oxide inhibitory activity

RATIONALE

Iris tectorum Maxim. is a traditional medicinal herb that is commonly used to treat inflammatory conditions. The present study investigated the fragmentation patterns of isoflavone glycosides and their qualitative analysis. In addition, lipopolysaccharide (LPS)-induced RAW264.7 macrophages were used to evaluate the anti-inflammatory properties of I. tectorum Maxim. samples collected at different time points during the year.

METHODS

High-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (HPLC/QTOF-MS/MS) and HPLC with diode-array detection were employed for qualitative and quantitative analysis. The fragmentation patterns of the isoflavones were observed in negative electrospray ionization mode with collision-induced dissociation (CID). Their anti-inflammatory activity was assessed via nitric oxide (NO) production in LPS-treated RAW264.7 macrophages.

RESULTS

A total of 15 chemical components were observed and tentatively identified using HPLC/QTOF-MS/MS. At low collision energy, the relative abundances of the aglycone radical anions Y₀ ^- , [Y₀  - H]^-• , [Y₀  - CH₃ ]^-• and [Y₀  - H- CH₂ ]^-• were used for the structural characterization of tectoridin and tectorigenin-4'-O-β-D-glucoside. The radical ions [Y₀  - CH₃ ]^-• and [Y₀  - H - 2CH₃ ]^-• were also employed to differentiate between iristectorin A and iristectorin B based upon their high-energy CID spectra. Levels of 9.02 mg/g of tectoridin and 1.04 mg/g of tectorigenin were found in samples collected in June, which exhibited 69.7% NO inhibitory activity.

CONCLUSIONS

The characteristic fragmentation patterns enabled us to reliably identify isoflavone glycosides. The results of the quantitative determination and NO inhibitory activity offer insight into the optimal I. tectorum Maxim. harvesting time.

Comprehensive evaluation of the antioxidant capacity of Sceptridium ternatum using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis

Sceptridium ternatum is a medicinal herb with multiple health benefits. However, its antioxidant activity and active components have not been clarified. In this study, the antioxidant capacity of S. ternatum was comprehensively investigated using multiple colorimetric methods and 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography analysis. First, the phenolic content, flavonoid content, and radical scavenging ability of S. ternatum were parallelly determined using colorimetric methods performed in 96-well microplates. The flavonoid content, rather than the phenolic content, was highly correlated with its antioxidant activity. Sceptridium ternatum was shown to be a rich source of flavonoids, with a highest flavonoid yield of 3.44 ± 0.11 mg/g. Subsequently, 1,1-diphenyl-2-picrylhydrazyl-high-performance liquid chromatography experiment and quadrupole time-of-flight mass spectrometry analyses were carried out for rapid screening of the individual antioxidants. A total of 14 O-glycosyl flavonoids with quercetin or kaempferol aglycone have been characterized. Particularly, quercetin 3-O-rhamnoside-7-O-glucoside exhibited the most potent antioxidant ability. Its half-maximal effective concentrations for scavenging 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) radicals were 70.55 ± 2.69 and 106.90 ± 1.76 µg/mL, respectively, which were comparable with those of l-ascorbic acid. Our results indicated that the combined colorimetric and chromatographic methods provided a practical strategy for the discovery of bioactive compounds from natural products.

A New Italian Purple Corn Variety (Moradyn) Byproduct Extract: Antiglycative and Hypoglycemic In Vitro Activities and Preliminary Bioaccessibility Studies

The reuse of byproducts from agricultural and food industries represents the key factor in a circular economy, whose interest has grown in the last two decades. Thus, the extraction of bioactives from agro-industrial byproducts is a potential source of valuable molecules. The aim of this work was to investigate the in vitro capacity of byproducts from a new Italian corn variety, named Moradyn, to inhibit the accumulation of advanced glycation end products (AGEs) involved in several chronic age-related disorders. In addition, the hypoglycemic effect of Moradyn was tested by in vitro enzymatic systems. A Moradyn phytocomplex and its purified anthocyanin fraction were able to inhibit fructosamine formation and exhibited antiglycative properties when tested using BSA-sugars and BSA-methylglyoxal assays. These properties could be attributed to the polyphenols, mainly anthocyanins and flavonols, detected by RP-HPLC-DAD-ESI-MSⁿ. Finally, a Moradyn phytocomplex was submitted to a simulated in vitro digestion process to study its bioaccessibility. Moradyn could be considered as a promising food ingredient in the context of typical type 2 diabetes risk factors and the study will continue in the optimization of the ideal formulation to preserve its bioactivities from digestion.

Nutraceutical Value of Pantelleria Capers (Capparis spinosa L.)

Unopened flower buds of Capparis spinosa L. (capers), generally used in the Mediterranean area as food flavoring, are known to be a good source of bioactive compounds. The aim of this work was to evaluate the nutraceutical value of salt-fermented capers collected from different areas of Pantelleria Island (Italy), testing their methylglyoxal and glyoxal trapping capacity and antioxidant activity by 2,2-diphenyl-1-picryl hydrazyl (DPPH), [2,2-azinobis(3-ethylben- zothiazoline-6-sulfonic acid)] diammonium salt (ABTS), and oxygen radical absorbance capacity (ORAC) assays. Hydrophilic extracts were also characterized by high-performance liquid chromatography-electrospray ionization/mass spectrometry. Among 24 detected compounds, several flavonol derivatives and glucosinolates were identified. The levels of kaempferol and quercetin derivatives varied considerably among the five accessions considered (6.46 to 267.93 and 22.39 to 367.14 mg kaempferol and quercetin equivalent /g fresh weight, respectively), with kaempferol derivatives more representative than quercetin ones. Person's coefficient indicated a high correlation between total phenolic content and anti-DPPH radical capacity (R² = 0.665), as well as between total flavonoid content and antioxidant capacity (by ORAC assay; R² = 0.888) and between total flavonoid content and glyoxal and methylglyoxal trapping capacity (R² = 0.918). Results indicate that capers from Pantelleria Island represent a rich source of bioactive compounds with potential nutraceutical relevance. PRACTICAL APPLICATION: The findings of this study highlight the health benefits of Pantelleria capers consumption due to their composition in antioxidants and their biological properties (antiradical and alpha-dicarbonyls trapping) correlated with the development of a high number of chronic-degenerative diseases. These results are also important for the agricultural and commercial sectors involved in the production of capers from Pantelleria, which received the Protected Geographical Indications recognition.

LC-ESI-Q-TOF-MS/MS profiling and antioxidant activity of phenolics from L. Sativum seedcake

Lepidium sativum is widely used as a culinary and medicinal herb and is claimed to cure many diseases. In this study, an attempt was made to investigate the biochemical composition and functional properties of L. sativum ethanolic extract. The extract contained a total phenolic content of 11.03 ± 0.75 (mg GAE/g dw plant material) and a flavonoid content of 4.79 ± 0.24 (mg QE/100 g dw plant material). Further, the extract was characterized by LC-ESI-Q-TOF-MS/MS profiling and the results showed that the ethanolic fraction contains many important phenolics such as Kaempferol, Coumaroylquinic acid, p-Coumaroyl glycolic acid, Caffeic acid. The identified compounds are known for their biological properties and therefore, the functional properties of the extract as a whole were also studied. The extract showed significant antioxidant activity (IC50 values) 162.4 ± 2.3, 35.29 ± 1.02, 187.12 ± 3.4 and 119.32 ± 1.5 μg/ml in terms of DPPH, ABTS, Superoxide scavenging activity and metal chelating property respectively. Further, the extract showed IC50 values, 73.72 ± 1.23 and 121.78 ± 1.03 μg/ml in HRBC membrane stabilization ability and protein denaturation inhibition capacity respectively, which in turn is a measure of its anti-inflammatory activity. The results of the study are promising and serve basis for further investigation into the plant and possible consideration for use in nutraceuticals and functional foods.

Structural Characterization of Flavonoid Glycoconjugates and Their Derivatives with Mass Spectrometric Techniques

Mass spectrometry is currently one of the most versatile and sensitive instrumental methods applied to structural characterization of plant secondary metabolite mixtures isolated from biological material including flavonoid glycoconjugates. Resolution of the applied mass spectrometers plays an important role in structural studies of mixtures of the target compounds isolated from biological material. High-resolution analyzers allow obtaining information about elemental composition of the analyzed compounds. Application of various mass spectrometric techniques, including different systems of ionization, analysis of both positive and negative ions of flavonoids, fragmentation of the protonated/deprotonated molecules and in some cases addition of metal ions to the studied compounds before ionization and fragmentation, may improve structural characterization of natural products. In our review we present different strategies allowing structural characterization of positional isomers and isobaric compounds existing in class of flavonoid glycoconjugates and their derivatives, which are synthetized in plants and are important components of the human food and drugs as well as animal feed.

Evaluation of Radical Scavenging Activity of Sempervivum tectorum and Corylus avellana Extracts with Different Phenolic Composition

Sempervivum tectorum L. and Corylus avellana L. are traditional herbal remedies exhibiting antioxidant activity and representing diverse phenolic composition. The aim of this study was to reveal the contribution of certain compounds to total radical scavenging activity by studying S. tectorum and C. avellana extracts prepared with solvents of different selectivity for diverse classes of phenolics. Antioxidant activity of S. tectorum and C. avellana samples was determined in the ABTS and DPPH radical scavenging assays, and phenolic composition was evaluated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Correlations between antioxidant activity and phenolic content of houseleek extracts have been revealed. Significant differences regarding antioxidant activity have been shown between S. tectorum 80% (v/v) methanol extract and its fractions. Additionally, synergism among the constituents present together in the whole extract was assumed. Significantly higher radical scavenging activity of hazel extracts has been attributed to the differences in phenolic composition compared with houseleek extracts.

Extraction and analysis of antioxidant compounds from the residues of Asparagus officinalis L

Asparagus residues were used as materials to obtain antioxidant compounds by solid-liquid extraction in this study. The effects of different extraction parameters including extraction solvents, time, temperature and liquid-solid ratio on the contents of total flavonoids, total phenolics and total antioxidant activity were investigated. Antioxidant activity of the extract from asparagus residues was evaluated by HPLC- ABTS · (+) and the bioactive components were identified by HPLC- MS/MS. The results showed that the extraction yield was significantly influenced (P < 0.05) by solvent composition, extraction time and temperature. The appropriate parameters were preferred as extraction solvent of 50 % ethanol with liquid-solid ratio of 30:1, extraction temperature of 80 °C and time of 2 h. Antioxidant activity evaluation of the extract indicated flavonoids and phenolics were dominant bioactive compounds. Five antioxidant compounds were identified as ferulic acid, kaempferol, quercetin, rutin and isorhamnetin.

Novel pyrano and vinylphenol adducts of deoxyanthocyanidins in sorghum sourdough

This study determined the fate of deoxyanthocyanidins in sorghum sourdoughs. Sourdoughs prepared from the red sorghum variety Town were fermented with the caffeic acid-decarboxylating strains Lactobacillus plantarum FUA3171 and the decarboxylase negative L. casei FUA3166. Deoxyanthocyanidins were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Apigeninidin and methoxyapigeninidin were the major deoxyanthocyanidins prior to fermentation. During fermentation, novel deoxyanthocyanidins were formed. Purification by preparative LC, followed by NMR analysis and high-resolution MS identified two of the compounds as 6-deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin. To identify pathways for their formation, sorghum was fermented with single strains, L. plantarum or L. casei. 6-Deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin were formed only during fermentation with L. plantarum FUA3171, indicating a role of vinylphenol in their formation. Chemical synthesis confirmed that 6-deoxyanthocyanidin-vinylphenol and pyrano-3-deoxyanthocyanidin are formed from apigeninidin with vinylphenol but not with p-coumaric acid as reactants. In conclusion, the products of microbial decarboxylation of hydroxycinnamic acids convert apigeninidin and methoxyapigeninidin to pyrano-3-deoxyanthocyanidins and vinylphenol adducts.

Identification of phenolic constituents in red chicory salads (Cichorium intybus) by high-performance liquid chromatography with diode array detection and electrospray ionisation tandem mass spectrometry

Phenolic acids and flavonoids extracted from several types of Cichorium intybus var. silvestre salads ("Chioggia", "Treviso", "Treviso tardivo", and "Verona") were characterised by high-performance liquid chromatography-electrospray ionisation/mass spectrometry. Among the 64 compounds detected, several hydroxycinnamic acid derivatives including 8 mono- and dicaffeoylquinic acids, 3 tartaric acid derivatives, 31 flavonol and 2 flavone glycosides, as well as 10 anthocyanins were characterised based on UV spectra and MS(n) fragmentation patterns. Furthermore, several isomers of caffeic acid derivatives were distinguished for the first time by their specific mass spectral data. This is the first study reporting the glycosylation type and position of mono- and diglycosylated flavonoids in red salads.

Identification of phenolic constituents in Cichorium endivia var. crispum and var. latifolium salads by high-performance liquid chromatography with diode array detection and electrospray ioniziation tandem mass spectrometry

Chicory is a widely consumed vegetable and a source of phenolic compounds. Phenolic acid and flavonoid derivatives were identified in Cichorium endivia var. crispum and var. latifolium and fully characterized using complementary information from two different high-performance liquid chromatography detectors, diode array and mass spectrometer, in positive and negative modes. We describe about 40 phenolic compounds, some of which have never previously been reported in these plants, such as hydroxycinnamic acid derivatives (i.e., different mono- and dicaffeoylquinic acid isomers) and mono- and diglycosides of quercetin, kaempferol, and myricetin (differing also by the glycosylation site). These data provide a contribution to a more exhaustive identification of phenolic compounds in C. endivia vegetables.

Antioxidant, anti-glycation and anti-inflammatory activities of phenolic constituents from Cordia sinensis

Nine compounds have been isolated from the ethyl acetate soluble fraction of C. sinensis, namely protocatechuic acid (1), trans-caffeic acid (2), methyl rosmarinate (3), rosmarinic acid (4), kaempferide-3-O-β-D-glucopyranoside (5), kaempferol-3-O-β-D-glucopyranoside (6), quercetin-3-O-β-D-glucopyranoside (7), kaempferide-3-O-α-L-rhamnopyranosyl (1→6)-β-D-glucopyranoside (8) and kaempferol-3-O-α-L-rhamno-pyranosyl (1→6)-β-D-glucopyranoside (9), all reported for the first time from this species. The structures of these compounds were deduced on the basis of spectroscopic studies, including 1D and 2D NMR techniques. Compounds 1-9 were investigated for biological activity and showed significant anti-inflammatory activity in the carrageen induced rat paw edema test. The antioxidant activities of isolated compounds 1-9 were evaluated by the DPPH radical scavenging test, and compounds 1, 2, 4 and 7-9 exhibited marked scavenging activity compared to the standard BHA. These compounds were further studied for their anti-glycation properties and some compounds showed significant anti-glycation inhibitory activity. The purity of compounds 2-5, 8 and 9 was confirmed by HPLC. The implications of these results for the chemotaxonomic studies of the genus Cordia have also been discussed.

Identification of common glycosyl groups of flavonoid O-glycosides by serial mass spectrometry of sodiated species

Flavonoid O-glycosides are a ubiquitous and important group of plant natural products in which a wide variety of sugars are O-linked to an aglycone. Determining the identity of the sugars, and the manner in which they are linked, by mass spectrometry alone is challenging. To improve the identification of common O-linked di- and trisaccharides when analysing mixtures of flavonoid O-glycosides by liquid chromatography/mass spectrometry (LC/MS), the fragmentation of electrosprayed sodium adducts in an ion trap mass spectrometer was investigated. The sodium adducts [M + Na](+) of kaempferol 3-O-glycosides generated sodiated glycosyl groups by the neutral loss of kaempferol. The product ion spectra of these sodiated glycosyl groups differed between four isomeric kaempferol 3-O-rhamnosylhexosides and four isomeric kaempferol 3-O-glucosylhexosides in which the primary hexose was either glucose or galactose and bore the terminal glucose or rhamnose at either C-2 or C-6. Fragmentation of sodiated glycosyl groups from linear O-triglucosides and branched O-glucosyl-(1 → 2)-[rhamnosyl-(1 → 6)]-hexosides produced sodiated disaccharide residues, and the product ion spectra of these ions assisted the identification of the complete sugar. The product ion spectra of the sodiated glycosyl groups were consistent among flavonoid O-glycosides differing in the position at which the sugar was O-linked to the aglycone, and the nature of the aglycone. The abundance of sodiated species was enhanced by application of a pre-trap collision voltage, without the need to dope with salt, allowing automated LC/MS methods to be used to identify the glycosyl groups of common flavonoid O-glycosides, such as rutinosides, robinobiosides, neohesperidosides, gentiobiosides and sophorosides.

Mass spectrometric stereoisomeric differentiation between α- and β-ascorbic acid 2-O-glucosides. Experimental and density functional theory study

L-Ascorbic acid and two distinct anomers, namely the α-D-glucopyranosyl and β-D-glucopyranosyl-(1→2)-L-ascorbic acid (stereoisomers), were studied within the scope of collision-induced dissociation (CID) experiments, performed by linear ion acceleration and collision with argon atoms inside a hexapole quadrupole hexapole ion beam guide, which is coupled to an ion cyclotron resonance (ICR) cell with a 12 Tesla magnet for high-resolution measurements. Loss of C(2)H(4)O(2) neutral from the [M-H](-) anion of L-ascorbic acid was observed. Density functional theory (DFT) calculations on the 6-311+G(2d,p)//6-31+G(d) level of theory reveal a new concerted mechanism for an intramolecular gas-phase rearrangement, through which the observed ejected neutral C(2)H(4)O(2) can take place. A similar rearrangement also occurs in the case of α- and β-D-glucopyranosyl-(1→2)-L-ascorbic acid. For the α isomer, only homolytic glycoside fragmentation was observed. For the β isomer, both homolytic and heterolytic glycoside cleavages were possible. The mechanisms behind all observed fragmentation pathways were fully understood by the implementation of accurate DFT calculations. Stereoisomeric differentiation between α and β isomers of the L-ascorbic acid-2-O-glucoside could be revealed by tandem mass spectrometry (MS/MS) experiments and were explained theoretically.