Structural characterization and discrimination of the Paris polyphylla var. yunnanensis and Paris vietnamensis based on metabolite profiling analysis

Steroidal saponins from rhizome of Paris polyphylla var. chinensis and their anti-inflammatory, cytotoxic effects

Five undescribed compounds, including two cholestane glycosides parispolyosides A and E, and three spirostanol glycosides parispolyosides B-D, were isolated from rhizome of Paris polyphylla var. chinensis (Franch.) Hara, together with twenty-one known steroidal saponins. Their chemical structures were elucidated on the basis of comprehensive analysis of 1D and 2D NMR, as well as HR-ESI-MS spectroscopic data. Two of these compounds demonstrated potent inhibitory effect on NO production stimulated by lipopolysaccharide in raw 264.7 cells with IC50 values of 61.35 μM and 37.23 μM. Four compounds exhibited moderate inhibitory activity against HepG2 cells with IC50 values ranging from 9.43 to 24.54 μM. Molecular docking analysis revealed that the potential mechanism of NO inhibition by the active compounds was associated with the interactions with iNOS protein.

The photo- and microbial degradation kinetics and pathways of sulfadoxine in seawater elucidated by liquid chromatography coupled with time-of-flight mass spectrometry

Sulfadoxine (SDX) is a broad-spectrum veterinary antibiotic, which was used alone for the treatment of various infections in the past, and detected ubiquitously in the aqueous environment. However, understanding SDX's photo- and microbial degradation within the environment, especially in marine matrixes, remains limited. This research hones in on SDX's degradation dynamics in seawater. Photodegradation emerges as the dominant process, surpassing microbial degradation in speed and efficiency. Notably, 90% of SDX is photo-degraded within 12 h, while only 52% is removed via microbial degradation over two weeks. Time-of-flight mass spectrometry provides high-resolution molecular mass information on degradation products. The molecular structures of hydrolysis, photo-, and microbial degradation products are deduced from accurate precursor and fragment ion masses, alongside an integrated data processing workflow. Six hydrolysis products arise from the treatment, and photodegradation and microbial degradation yield nine and eighteen products, respectively. Molecular insights from these products inform plausible degradation pathways involving hydrolysis, photodegradation, and microbial degradation. Processes like bond cleavage, methylation, hydroxylation, oxidation, reduction, and methoxylation are identified and associated with degradation. This study presents a comprehensive workflow for acquiring and processing degradation product data linked to emerging organic pollutants. Moreover, it contributes to our comprehension of the environmental fate of veterinary drugs in marine ecosystems.

Cytotoxic Steroidal Saponins Containing a Rare Fructosyl from the Rhizomes of Paris polyphylla var. latifolia

A phytochemical investigation of the steroidal saponins from the rhizomes of Paris polyohylla var. latifolia led to the discovery and characterization of three new spirostanol saponins, papolatiosides A-C (1-3), and nine known compounds (4-12). Their structures were established via extensive spectroscopic data analysis and chemical methods. Interestingly, compounds 1 and 2 possessed a fructosyl in their oligosaccharide moiety, which is rare in natural product and was firstly reported in family Melanthiaceae. The cytotoxicity of these saponins against several human cancer cell lines was evaluated by a CCK-8 experiment. As a result, compound 1 exhibited a significant cytotoxic effect on LN229, U251, Capan-2, HeLa, and HepG2 cancer cells with IC₅₀ values of 4.18 ± 0.31, 3.85 ± 0.44, 3.26 ± 0.34, 3.30 ± 0.38 and 4.32 ± 0.51 μM, respectively. In addition, the result of flow cytometry analysis indicated that compound 1 could induce apoptosis of glioma cells LN229. The underlying mechanism was explored by network pharmacology and western bolt experiments, which indicated that compound 1 could induce glioma cells LN229 apoptosis by regulating the EGFR/PI3K/Akt/mTOR pathway.

Cytotoxic steroidal glycosides from the rhizomes of Paris polyphylla var. yunnanensis

Paris polyphylla var. yunnanensis (Franch.) Hand.-Mazz. (Melanthiaceae), an important specie of the genus Paris, has long been in a traditional Chinese medicine (TCM) for a long time. This study aimed to isolate and identify the structures of bioactive saponins from the rhizomes of P. polyphylla var. yunnanensis and evaluate their cytotoxicity against BxPC-3, HepG2, U373 and SGC-7901 carcinoma cell lines. Seven previously undescribed and seven known saponins were identified, and Paris saponins VII (PSVII) showed significant cytotoxicity against the BxPC-3 cell line with IC₅₀ values of 3.59 μM. Furthermore, flow cytometry, transmission electron microscopy and western-bolt analysis revealed that PSVII inhibited the proliferation of BxPC-3 cells and might be involved in inducing apoptosis and pyroptosis by activating caspase-3, -7 and caspase-1, respectively.

Steroidal saponin components and their cancer cell cytotoxicity from Paris rugosa

The chemical components and availability of Paris rugosa were investigated for the first time, using a UPLC-MS/MS-based molecular networking strategy and phytochemical research. Ultimately, eleven undescribed steroidal saponins, parisrugosides A-K, and ten known analogs were identified. Their structures were confirmed using comprehensive spectroscopic data and chemical methods. The aglycones of parisrugosides A-D are first spirostanes with an epoxy group at C-5/C-6, a hydroxy group at C-7, and a double bond at C-8/C-9 or C-8/C-14. Parisrugosides G and H possess an undescribed spirostane aglycone with two double bonds located at C-5/C-6 and C-8/C-9, which are conjugated with a carbonyl group at C-7. The isolates were evaluated for their cytotoxicity against five human cancer cell lines (human HL-60 leukemia, A549 lung, MCF-7 breast, SMMC-7721 liver, and SW480 colon solid cancer cell lines). Parisyunnanoside D, kingianoside K, and dichotomin displayed significant cytotoxicity against these cancer lines, with IC50 values ranging from 0.50 to 19.58 μM.

Study of Chemical Compositions and Anticancer Effects of Paris polyphylla var. Chinensis Leaves

Paris polyphylla var. chinensis (Franch.) Hara is a perennial herb belonging to the Trilliaceae family. Ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC/Q–TOF MS) was used to detect the composition of different fractions of Paris polyphylla var. chinensis leaves. Meanwhile, the extracts of different fractions were evaluated for their cytotoxic activities against four selected human cancer cell lines and one human normal epithelial cell line based on the MTT assay method. Multivariate statistical analysis was performed to screen differential compounds and to analyze the distributions between different fractions. Finally, more than 60 compounds were obtained and identified from the different fractions of Paris polyphylla var. chinensis leaves, and the chloroform and n−butanol extracts showed significant cytotoxic effects on these four cancer cells. Several compounds were preliminarily identified from different fractions, including 36 steroidal saponins, 11 flavonoids, 10 ceramides, 8 lipids, 6 organic acids, and 8 other compounds. Various compounds were screened out as different chemical components of different fractions, which were considered as a potential substance basis for the cytotoxicity of Paris polyphylla var. chinensis leaves.

Extended application of deep learning combined with 2DCOS: Study on origin identification in the medicinal plant of Paris polyphylla var. yunnanensis

INTRODUCTION

Medicinal plants are very important to human health, and ensuring their quality and rapid evaluation are the current research concerns. Deep learning has a strong ability in recognition. This study extended it to the identification of medicinal plants from the perspective of spectrum.

OBJECTIVE

In order to realise the rapid identification and provide a reference for the selection of high-quality resources of medicinal plants, a combination of deep learning and two-dimensional correlation spectroscopy (2DCOS) was proposed.

METHODS

For the first time, Fourier transform mid-infrared (FT-MIR) and near-infrared (NIR) spectroscopy 2DCOS images combined with residual neural network (ResNet) was used for the origin identification of Paris polyphylla var. yunnanensis. In total 1593 samples were collected and 12821 2DCOS images were drawn. The climate of different origins was briefly analysed.

RESULTS

The xishuangbanna, puer, lincang, honghe and wenshan are the five regions with more ecological advantages. The synchronous 2DCOS models of FT-MIR and NIR could realise origin identification with the accuracy of 100%. The synchronous images were suitable for the identification of medicinal plants with complex systems. The full band, feature band and different contour models had no big difference in distinguishing ability, so they were not the key factors affecting the discrimination results.

CONCLUSION

The ResNet models established were stable, reliable, and robust, which not only solved the problem of origin identification, expanded the application field of deep learning, but also provided practical reference for the related research of other medicinal plants.

Steroidal saponins with cytotoxic activity from the stems and leaves of Paris fargesii

The stems and leaves of P. fargesii are rich in steroidal glycosides, some of which display significant cytotoxic activity.

Insight into chemical basis of traditional Chinese medicine based on the state-of-the-art techniques of liquid chromatography-mass spectrometry

Traditional Chinese medicine (TCM) has been an indispensable source of drugs for curing various human diseases. However, the inherent chemical diversity and complexity of TCM restricted the safety and efficacy of its usage. Over the past few decades, the combination of liquid chromatography with mass spectrometry has contributed greatly to the TCM qualitative analysis. And novel approaches have been continuously introduced to improve the analytical performance, including both the data acquisition methods to generate a large and informative dataset, and the data post-processing tools to extract the structure-related MS information. Furthermore, the fast-developing computer techniques and big data analytics have markedly enriched the data processing tools, bringing benefits of high efficiency and accuracy. To provide an up-to-date review of the latest techniques on the TCM qualitative analysis, multiple data-independent acquisition methods and data-dependent acquisition methods (precursor ion list, dynamic exclusion, mass tag, precursor ion scan, neutral loss scan, and multiple reaction monitoring) and post-processing techniques (mass defect filtering, diagnostic ion filtering, neutral loss filtering, mass spectral trees similarity filter, molecular networking, statistical analysis, database matching, etc.) were summarized and categorized. Applications of each technique and integrated analytical strategies were highlighted, discussion and future perspectives were proposed as well.

Molecular-networking-guided discovery of species-specific markers for discriminating five medicinal Paris herbs

BACKGROUND

Paridis Rhizoma (PR) is a famous traditional herbal medicine. Apart from two officially recorded species, viz. Paris polyphylla Smith var. yunnanensis (Franch.) Hand. - Mazz. (PPY) and P. polyphylla Smith var. chinensis (Franch.) Hara (PPC), there are still many other species used as folk medicine. It is necessary to understand the metabolic differences among Paris species.

PURPOSE

To establish a strategy that can discover species-specific steroidal saponin markers to distinguish closely-related Paris herbs for quality and safety control.

METHODS

A new strategy of molecular-networking-guided discovery of species-specific markers was proposed. Firstly, the ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) was applied to obtain the MS and MS/MS data of all samples. Then, molecular networking (MN) was created using MS/MS data to prescreen the steroidal saponins for subsequent analysis. Next, the principal component analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA) models were established to discover potential markers. Finally, the verification, identification and distribution of chemical markers were performed.

RESULTS

A total of 126 steroidal saponins were screened out from five species using MN. Five species were classified successfully by OPLS-DA model, and 18 species-specific markers were discovered combining the variable importance in the projection (VIP) value, P value (one-way ANOVA) and their relative abundance. These markers could predict the species of Paris herbs correctly.

CONCLUSION

These results revealed that this new strategy could be an efficient way for chemical discrimination of medicinal herbs with close genetic relationship.

The degradation dynamics and rapid detection of thiacloprid and its degradation products in water and soil by UHPLC-QTOF-MS

Thiacloprid is a neonicotinoid insecticide used to control sucking and chewing insects of fruits and vegetables. Hydrolysis, photolysis of thiacloprid in aqueous solutions, and soil degradation of three typical types of soil in China were studied. UHPLC-QTOF/MS was used to acquire high-resolution mass spectrometry information of thiacloprid's degradation products in water and soil samples, and the UNIFI platform with integrated data processing function was used to find and identify degradation products. The degradation kinetics of thiacloprid was determined. Six transformation products (M271, M287, M269, M295, M279, M267) were found after the data processing workflow in the UNIFI platform by using the raw MS^E data. The structure of putative transformation products can be inferred based on the accurate mass of fragment ions and the automated spectral interpretation tools in the UNIFI platform. The structure of M271 was validated to be thiacloprid amide by comparing the ESI-MS² fragment ions in soil samples and thiacloprid amide standard. The TrendPlot function of UNIFI was used to demonstrate the kinetics of the transformation products. Reduction, hydrolysis, oxidation are the main reactions of thiacloprid in three tested soil in China and buffer solutions. This study provided a reference for the rapid identification of the transformation products of other pesticides in specific environmental conditions.

Structural characterization and discrimination of Paris polyphylla var. yunnanensis by a molecular networking strategy coupled with ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry

RATIONALE

Paris polyphylla var. yunnanensis (Franch) Hand Mazz (PPY) is a traditional Chinese medicine with antitumor, antibacterial, hemostatic, and anthelmintic activities. Identification of the chemical composition in PPY is helpful to discover its active ingredients and can be used to establish its quality control protocols.

METHODS

The composition of PPY was identified using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS/MS) coupled with a molecular networking strategy. First, the UHPLC/QTOF-MS/MS approach was optimized for chemical compound profiling. Then, the MS data were processed using PeakView™ combined with an in-house database to quickly characterize the secondary metabolites. Finally, molecular networking excavated new molecular weights to discover unknown or trace natural products based on the characteristics of each cluster.

RESULTS

A total of 222 compounds, including 77 isospirostanols, 2 spirostanols, 19 furostanols, 10 pseudospirostanols, 6 cholesterols, 10 C₂₁ steroids, 5 insect metamorphosis hormones, 3 plant sterols, 6 five-ring triterpenoids, 4 flavonoids, 8 fatty acids, 2 phenylpropanoids, and 8 other compounds, were characterized in PPY by comparing their main fragmentation characteristics and pathways with the literature data, and 62 of them, 54 steroidals and 8 phenylpropanoids, were discovered or tentatively identified for the first time.

CONCLUSIONS

This study extended the application of a molecular networking strategy to traditional herbal medicines and developed a molecular networking based screening approach with a significant increase in efficiency for the discovery and identification of trace novel natural products.

Structural characterization and discrimination of Ophiopogon japonicas (Liliaceae) from different geographical origins based on metabolite profiling analysis

The root tuber of Ophiopogon japonicus (Thunb.) Ker-Gawl ("Maidong" in Chinese), with steroidal saponins and homoisoflavonoids as its representative chemical compositions, is a representative medicinal herbs with multiple major producing areas. This study aimed to distinguish the O. japonicas samples from Zhejiang and Sichuan by using an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS)-based metabolome analysis. Firstly, a global chemical constituent identification of O. japonicas was carried out by using both automatic and manual methods. An integrated steroidal saponins structural identification strategy in O. japonicas based on exact mass information, fragmentation characteristics and retention time was developed. Overall, 135 steroidal saponins, 47 homoisoflavonoids and 9 other metabolites were quickly identified or tentatively identified from the MS^E continuum data. Furthermore, multivariate statistical analysis revealed that O. japonicas from Zhejiang and Sichuan can clearly be separated and some markers were screened. Moreover, some major active components including total soluble sugar, total soluble polyphenol, total flavonoid, total saponin and 10 specific compounds were analyzed quantitatively. In general, these results showed that there were many differences between the metabolic profile data of O. japonicas from different producing areas, O. japonicas from Sichuan showed higher level steroidal saponins and samples from Zhejiang had higher contents of homoisoflavonoids specifically, and indicated that metabolite profiling by UPLC/Q-TOF MS is an effective approach for the discrimination of medicinal herbs from different geographical origins.

Data Fusion of Fourier Transform Mid-Infrared (MIR) and Near-Infrared (NIR) Spectroscopies to Identify Geographical Origin of Wild Paris polyphylla var. yunnanensis

Origin traceability is important for controlling the effect of Chinese medicinal materials and Chinese patent medicines. Paris polyphylla var. yunnanensis is widely distributed and well-known all over the world. In our study, two spectroscopic techniques (Fourier transform mid-infrared (FT-MIR) and near-infrared (NIR)) were applied for the geographical origin traceability of 196 wild P. yunnanensis samples combined with low-, mid-, and high-level data fusion strategies. Partial least squares discriminant analysis (PLS-DA) and random forest (RF) were used to establish classification models. Feature variables extraction (principal component analysis—PCA) and important variables selection models (recursive feature elimination and Boruta) were applied for geographical origin traceability, while the classification ability of models with the former model is better than with the latter. FT-MIR spectra are considered to contribute more than NIR spectra. Besides, the result of high-level data fusion based on principal components (PCs) feature variables extraction is satisfactory with an accuracy of 100%. Hence, data fusion of FT-MIR and NIR signals can effectively identify the geographical origin of wild P. yunnanensis.

Structural characterisation and discrimination of the aerial parts of Paris polyphylla var. yunnanensis and Paris polyphylla var. chinensis by UHPLC-QTOF-MS coupled with multivariate data analysis

INTRODUCTION

As sources of Rhizoma Paridis are facing shortages, utilising the aerial parts of Paris polyphylla has emerged as a promising additional source. However, the components in the aerial parts still need to be explored, and it is difficult to distinguish the aerial parts of P. polyphylla Smith var. yunnanensis (PPY) and P. polyphylla var. chinensis (PPC), two varieties of P. polyphylla.

OBJECTIVE

This study aimed to establish a comprehensive platform to characterise steroid saponins from the aerial parts of PPY and PPC and to discriminate these two varieties.

METHODOLOGY

A dereplication approach and ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) analysis were used for the characterisation of steroidal saponins in the aerial parts of PPY and PPC. Multivariate statistical analysis was performed to differentiate these two varieties and screen discriminant variables. In addition, a genetic algorithm-optimised for support vector machines (GA-SVM) model was developed to predict P. polyphylla samples. The distribution of steroidal saponins in PPY and PPC was visualised by a heatmap.

RESULTS

A total of 102 compounds were characterised from the aerial parts of PPY and PPC by dereplication. A clear separation of PPY and PPC was achieved, and 35 saponins were screened as marker compounds. The established GA-SVM model showed excellent prediction performance with a prediction accuracy of 100%.

CONCLUSIONS

Many steroid saponins that have been reported in Rhizoma Paridis also exist in the aerial parts of P. polyphylla. Samples from the aerial parts of PPY and PPC could be discriminated using our platform.

Traceability the provenience of cultivated Paris polyphylla Smith var. yunnanensis using ATR-FTIR spectroscopy combined with chemometrics

The conventional procedures, based on attenuated total reflectance-Fourier transform infrared spectrometry (ATR-FTIR), have been developed for the origins traceability of cultivated Paris polyphylla Smith var. yunnanensis (PPY) samples with the help of partial least square discriminant analysis (PLS-DA) and random forest. In this study, a set of 219 batch cultivated PPY samples, containing the cultivation years of 5, 6 and 7, and covering the municipal districts of Chuxiong, Dali, Honghe, Lijiang and Yuxi in Yunnan Province, China, were used to build the discrimination models. Firstly, a visualized analysis was carried out by t-distributed stochastic neighbor embedding (t-SNE) to reduce each data point in a two-dimensional map and make a knowledge of the sample distribution tendency. Secondly, the single spectra data sets of Paridis rhizome and leaf tissues, and the combination of these two data sets with variable selection (mid-level data fusion strategy), were used to establish PLS-DA and random forest models, and parallelly compared the model performance. Results demonstrated that the discrimination ability of PLS-DA preceded the random forest model, and the classification performance was remarkably improved after mid-level data fusion. These results verified each other by 5-, 6- and 7-year old Paridis samples and indicated that the model performance established in the present study was reliable. Besides, five agronomic characters, including the plant height, dry weight of rhizome and leaf tissues, and the allocation of rhizome and leaf were determined and analyzed, results of which indicated that the dry weight and their allocation was significantly different among various origins and fluctuated with the cultivation years. This study was using a comprehensive and green analytical method to discriminate the cultivated Paridis according to their provenances, which was simultaneously benefited for the appropriate cultivation areas selection based on the dry weight of rhizome tissues.

Comparative analysis of proteomic and metabolomic profiles of different species of Paris

An extract prepared from species of Paris is the most widely consumed herbal product in China. The genus Paris includes a variety of genotypes with different medicinal component contents but only two are defined as official sources. Closely related species have different medicinal properties because of differential expression of proteins and metabolites. To better understand the molecular basis of these differences, we examined proteomic and metabolomic changes in rhizomes of P. polyphylla var. chinensis, P. polyphylla var. yunnanensis, and P. fargesii var. fargesii using a technique known as sequential window acquisition of all theoretical mass spectra as well as gas chromatography-time-of-flight mass spectrometry. In total, 419 proteins showed significant abundance changes, and 33 metabolites could be used to discriminate Paris species. A complex analysis of proteomic and metabolomic data revealed a higher efficiency of sucrose utilization and an elevated protein abundance in the sugar metabolic pathway of P. polyphylla var. chinensis. The pyruvate content and efficiency of acetyl-CoA-utilization in saponin biosynthesis were also higher in P. polyphylla var. chinensis than in the other two species. The results expand our understanding of the proteome and metabolome of Paris and offer new insights into the species-specific traits of these herbaceous plants. SIGNIFICANCE: The traditional Chinese medicine Paris is the most widely consumed herbal product for the treatment of joint pain, rheumatoid arthritis and antineoplastic. All Paris species have roughly the same morphological characteristics; however, different members have different medicinal compound contents. Efficient exploitation of genetic diversity is a key factor in the development of rare medicinal plants with improved agronomic traits and malleability to challenging environmental conditions. Nevertheless, only a partial understanding of physiological and molecular mechanisms of different plants of Paris can be achieved without proteomics. To better understand the molecular basis of these differences and facilitate the use of other Paris species, we examine proteomic metabolomic changes in rhizomes of Paris using the technique known as SWATH-MS and GC/TOF-MS. Our research has provided information that can be used in other studies to compare metabolic traits in different Paris species. Our findings can also serve as a theoretical basis for the selection and cultivation of other Paris species with a higher medicinal value.

Traceability of wild Paris polyphylla Smith var. yunnanensis based on data fusion strategy of FT-MIR and UV-Vis combined with SVM and random forest

Paris polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz (PPY) was a frequently used herbal medicine in pharmaceutical field and different provenances might affect the clinical efficacy. Tracing the geographical origin was an important portion for PPY authentication and quality assessment. Present study was compared low-, mid- and high-level data fusion methodology for geographical traceability of PPY samples (161 batches) combined with multivariate classification methods such as support vector machine gird search (SVM-GS) and random forest (RF) on the basis of Fourier transform mid-infrared (FT-MIR) and ultraviolet-visible (UV-Vis) spectra. Compared with the low- and mid-level data fusion strategy results basing on SVM-GS algorithm, result of high-level data fusion method (calculated by RF) was more satisfying. Result of RF basing on high-level data fusion strategy showed that merely two samples were misclassified and one sample was multiple assigned after voting with fuzzy set theory. Values of specificity, sensitivity, and accuracy rates were exceeded 0.91, 0.99 and 90.91%, for each class respectively, satisfying results of these were shown in training and test sets for high-level data fusion method. This feasible result indicated that the RF algorithm could establish a reliable and good performance model in geographical traceability on the basis of high-level data fusion strategy. Combination of high-level data fusion and RF algorithm could consider as a good choice for establishing a discrimination multivariate model for origins identification of PPY samples.

New Steroidal Saponins from the Rhizomes of Paris vietnamensis and Their Cytotoxicity

Four new spirostanol saponins, named pavitnosides A–D (1–4), with six known steroidal saponins 5–10 were isolated from the rhizomes of Paris vietnamensis. Their chemical structures were determined based on extensive spectroscopic studies and chemical methods. The aglycones of pavitnoside B and pavitnoside C were not reported in previous work. The cytotoxicity of all saponins was evaluated against human glioblastoma U87MG and U251 cell lines. The new spirostanol saponin 1 displayed weak anti-proliferative activity against U87MG cell line and the known saponins 8 and 9 exhibited significant cytotoxicity against the two tumor cell lines, with IC₅₀ values of 2.16 to 3.14 μM, but did not affect the growth of primary cultures of human astrocytes.

A polyacrylamide-based silica stationary phase for the separation of carbohydrates using alcohols as the weak eluent in hydrophilic interaction liquid chromatography

A hydrophilic interaction liquid chromatography (HILIC) stationary phase was prepared by a two-step synthesis method, immobilizing polyacrylamide on silica sphere particles. The stationary phase (named PA, 5μm dia) was evaluated using a mixture of carbohydrates in HILIC mode and the column efficiency reached 121,000Nm^-1. The retention behavior of carbohydrates on PA stationary phase was investigated with three different organic solvents (acetonitrile, ethanol and methanol) employed as the weak eluent. The strongest hydrophilicity of PA stationary phase was observed in both acetonitrile and methanol as the weak eluent, when compared with another two amide stationary phases. Attributing to its high hydrophilicity, three oligosaccharides (xylooligosaccharide, fructooligosaccharide and chitooligosaccharides) presented good retention on PA stationary phase using alcohols/water as mobile phase. Finally, PA stationary phase was successfully applied for the purification of galactooligosaccharides and saponins of Paris polyphylla. It is feasible to use safer and cheaper alcohols to replace acetonitrile as the weak eluent for green analysis and purification of polar compounds on PA stationary phase.