Impact of sulphur fumigation on the chemistry of ginger

Integrating UPLC-QTOF-MS/MS and UPLC-DAD to evaluate the influence of sulfur-fumigated Paeoniae Radix Alba on the overall quality of three Si-Wu-Tang formulations

INTRODUCTION

Sulfur-fumigation of Paeoniae Radix Alba (PRA) could induce the chemical transformation of its bioactive component paeoniflorin into a sulfur-containing derivative paeoniflorin sulfite, and thus alter the quality, bioactivities, pharmacokinetics, and toxicities of PRA. However, how sulfur-fumigated PRA (S-PRA) affects the quality of PRA-containing complex preparations has not been intensively evaluated.

OBJECTIVES

We intend to evaluate the influence of S-PRA on the overall quality of three kinds of Si-Wu-Tang (SWT) formulations, i.e., decoction (SWT-D), granule (SWT-G), and mixture (SWT-M).

MATERIAL AND METHODS

An UPLC-DAD multi-components quantification method was used to compare the transfer rates of paeoniflorin sulfite and other 10 bioactive components between S-PRA-containing and NS-PRA-containing SWT formulations. An UPLC-QTOF-MS/MS-based target metabolomics approach was applied to explore the differential sulfur-containing derivatives in S-PRA-containing SWT formulations.

RESULTS

The transfer rates of paeoniflorin sulfite in three S-PRA-containing SWT formulations were all higher than 100%. Moreover, S-PRA also increased the transfer rate of 5-hydroxymethylfurfural, 1,2,3,4,6-O-pentagalloylglucose, whereas decreased that of paeoniflorin, albiflorin, and ferulic acid in three SWT formulations. Six pinane monoterpene glucoside sulfites originally identified in S-PRA, were also detectable in three S-PRA-containing SWT formulations. In addition, seven phenolic acid sulfites including (3Z)-6-sulfite-ligustilide, (3E)-6-sulfite-ligustilide, 6,8-disulfite-ligustilide, ferulic acid sulfite, neochlorogenic acid sulfite, chlorogenic acid sulfite, and angelicide sulfite (or isomer) were newly identified in these three S-PRA-containing formulations.

CONCLUSION

S-PRA could differentially affect the transfer rate of paeoniflorin sulfite and other bioactive components during the preparation of three SWT formulations and subsequently the overall quality thereof.

Rationality of the ethanol precipitation process in modern preparation production of Zishui-Qinggan decoction evaluated by integrating UPLC-QTOF-MS/MS-based chemical profiling/serum pharmacochemistry and network pharmacology

INTRODUCTION

Zishui-Qinggan decoction (ZQD) is a classical traditional Chinese medicine formula (TCMF) for alleviating menopausal symptoms (MPS) induced by endocrine therapy in breast cancer patients. In the production of TCMF modern preparations, ethanol precipitation (EP) is a commonly but not fully verified refining process.

OBJECTIVES

Chemical profiling/serum pharmacochemistry and network pharmacology approaches were integrated for exploring the rationality of the EP process in the production of ZQD modern preparations.

MATERIAL AND METHODS

Ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) was applied to identify the chemical profiles and absorbed components of ZQD. Network pharmacology was used to identify targets and pathways related to MPS-relieving efficacy.

RESULTS

The chemicals of ZQDs without/with EP process (referred to as ZQD-W and ZQD-W-P, respectively) were qualitatively similar with 89 and 87 components identified, respectively, but their relative contents were different; 51 components were detectable in the serum of rats orally administered with ZQD-W, whereas only 19 were detected in that administered with ZQD-W-P. Key targets, such as AKT1, and pathways, such as the PI3K-Akt signalling pathway, affected by ZQD-W and ZQD-W-P were similar, while the neuroactive ligand-receptor interaction pathway among others and the MAPK signalling pathway among others were specific pathways affected by ZQD-W and ZQD-W-P, respectively. The specifically absorbed components of ZQD-W could combine its specific key targets.

CONCLUSION

The EP process quantitatively altered the chemical profiles of ZQD, subsequently affected the absorbed components of ZQD, and then affected the key targets and pathways of ZQD for relieving MPS. The EP process might result in variation of the MPS-relieving efficacy of ZQD, which deserves further in vivo verification.

Tryptophan sulfonate: A new chemical marker for accurate and efficient inspection of sulfur-treated food products

Sulfur treatment for the pesticidal and antibacterial processing of food products has been criticized since it impairs the quality of treated products. The inspection of sulfur-treated products is thus required to achieve the regulation of sulfur treatment. Sulfite assay is currently available for the inspection, but it bears the disadvantages of inaccurate results and complex experimental procedures. Here we report a new chemical marker, namely tryptophan sulfonate, that can be used for the accurate and efficient inspection of sulfur-treated foods. First, the marker was discovered in sulfur-fumigated ginger, yam, and ginseng by untargeted metabolomics. The marker identity was then elucidated using chromatographic separation, nuclear magnetic resonance analysis and chemical synthesis. Finally, to demonstrate its applicability in the inspection, a tryptophan sulfonate assay was developed to test 50 commercial food samples, and the results indicated that it performed better than the sulfite assay in terms of both accuracy and efficiency.

Impacts of sulfur fumigation on the chemistry and immunomodulatory activity of polysaccharides in ginseng

Ginseng is widely regarded as a panacea in Oriental medicine mainly due to its immunomodulatory activity. We previously found that sulfur fumigation, a commonly used pesticidal and anti-bacterial processing practice, weakened the immunomodulatory activity of ginseng. However, if and how sulfur fumigation affects the polysaccharides in ginseng, the crucial components contributing to the immunomodulatory function, remain unknown. Here we report that polysaccharides extracted from sulfur-fumigated ginseng (SGP) presented different chemical properties with polysaccharides extracted with non-fumigated ginseng (NGP), particularly increased water extraction yield and decreased branching degree. SGP had weaker immunomodulatory activity than NGP in immunocompromised mice, as evidenced by less improved immunophenotypes involving body weight, immune organ indexes, white blood cells, lymphocyte cell populations and inflammation. The different immunomodulatory activities were accompanied by changes in the interaction between the polysaccharides and gut microbiota, in which SGP stimulated the growth of different bacteria but produced less SCFAs as compared to NGP. Fecal microbiota transplantation experiment suggested that gut microbiota played a central role in causing the weakened immunomodulatory activity in vivo. This study provides definite evidence that sulfur fumigation affects the chemistry and bioactivity of ginseng polysaccharides, thereby contributing to understanding how sulfur fumigation weakens the immunomodulatory activity of ginseng.

Novel insight into the role of sulfur dioxide in fruits and vegetables: Chemical interactions, biological activity, metabolism, applications, and safety

Sulfur dioxide (SO2) are a category of chemical compounds widely used as additives in food industry. So far, the use of SO2 in fruit and vegetable industry has been indispensable although its safety concerns have been controversial. This article comprehensively reviews the chemical interactions of SO2 with the components of fruit and vegetable products, elaborates its mechanism of antimicrobial, anti-browning, and antioxidation, discusses its roles in regulation of sulfur metabolism, reactive oxygen species (ROS)/redox, resistance induction, and quality maintenance in fruits and vegetables, summarizes the application technology of SO2 and its safety in human (absorption, metabolism, toxicity, regulation), and emphasizes the intrinsic metabolism of SO2 and its consequences for the postharvest physiology and safety of fresh fruits and vegetables. In order to fully understand the benefits and risks of SO2, more research is needed to evaluate the molecular mechanisms of SO2 metabolism in the cells and tissues of fruits and vegetables, and to uncover the interaction mechanisms between SO2 and the components of fruits and vegetables as well as the efficacy and safety of bound SO2. This review has important guiding significance for adjusting an applicable definition of maximum residue limit of SO2 in food.

Quality assessment of commercial dried ginger (Zingiber officinale Roscoe) based on targeted and non-targeted chemical profiles and anti-inflammatory activity

Dried ginger, a well-known medicine and food homologous production, has been widely circulated in China with high health benefits and economic value. Currently, there is still a lack of quality assessment on whether dried ginger in China exhibits chemically and biologically distinct properties, which creates a barrier to its quality control in commercial circulation. In this study, the chemical characteristics of 34 batches of common dried ginger samples in China were first explored using non-targeted chemometrics based on the UPLC-Q/TOF-MS analysis, leading to the identification of 35 chemicals that contributed to clustering into two categories, with sulfonated conjugates being the key chemically distinct components. By comparing the samples before and after sulfur-containing treatment and the further synthesis of a key differentiating component of [6]-gingesulfonic acid, it was then demonstrated that sulfur-containing treatment was the primary cause of the formation of sulfonated conjugates, as opposed to regional or environmental factors. Furthermore, the anti-inflammatory efficacy of dried ginger with high presence of sulfonated conjugates was significantly decreased. Consequently, for the first time, UPLC-QqQ-MS/MS was used to develop a targeted quantification method for 10 characteristic chemicals in dried ginger, allowing researchers to quickly determine whether dried ginger has been processed with sulfur and quantitatively evaluate the quality of dried ginger. These results provided an insight into the quality of commercial dried ginger in China and a suggested method for its quality supervision as well.

Qualitative Profiling and Quantitative Analysis of Major Constituents in Jinmu-tang by UHPLC-Q-Orbitrap-MS and UPLC-TQ-MS/MS

Jinmu-tang (JMT) is a traditional herbal medicine consisting of five herbal medicines: Poria cocos Wolf, Paeonia lactiflora Pallas, Zingiber officinale Roscoe, Atractylodes japonica Koidzumi, and Aconitum carmichaeli Debeaux. In this study, the JMT components were profiled using UHPLC-Q-Orbitrap-MS, and 23 compounds were identified and characterized. In addition, UPLC-TQ-MS/MS analysis was performed in the positive and negative ion modes of an electrospray ionization source for the simultaneous quantification of the identified compounds. The multiple reaction monitoring (MRM) method was established to increase the sensitivity of the quantitative analysis, and the method was verified through linearity, recovery, and precision. All analytes showed good linearity (R2 ≤ 0.9990). Moreover, the recovery and the relative standard deviation of precision were 86.19-114.62% and 0.20-8.00%, respectively. Using the established MRM analysis method, paeoniflorin was found to be the most abundant compound in JMT. In conclusion, these results provide information on the constituents of JMT and can be applied to quality control and evaluation.

The Chemical Signatures of Water Extract of Zingiber officinale Rosc

Background: Ginger (Z. officinale Rosc.) is a common herb and is widely used as a diet-based or home therapy in traditional medicine worldwide. However, fresh ginger turns into dried ginger after kiln drying and shows a different treatment effect in clinical practice. Objective: To characterize the changes of major bioactive constituents in dried ginger after the processing of fresh ginger. Methods: A novel, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC−QTOF/MS) method was established to characterize the changes in the bioactive constituents of dried ginger. The novel strategy was split into two steps: firstly, the MS selected the most intense precursor ions of tandem MS; then, target MS/MS acquisition with different collision energies (10, 20, and 40 eV) was used to characterize the compound’s accurate MS/MS spectra and compare the MS/MS spectrum with the building MS reference library and reference standards. Result: Fifty-three compounds, including diarylheptanoids, gingerols, gingerodiols, gingerdiones, and shogaol-related compounds, were identified based on summarized fragmentation patterns. Fifteen out of fifty-three compounds were diarylheptanoids, which was different from fresh ginger. Conclusion: These identified compounds could be used to characterize the quality of dried ginger, pharmacologic studies should focus on diarylheptanoids explaining the different treatment effects between fresh ginger and dried ginger.

A sense of ginger fraud: prevalence and deconstruction of the China-European union supply chain

As an important spice, ginger has been widely distributed in the Chinese and the European Union (EU) markets, the two largest trading areas, in various forms. The ginger supply chain between China and the EU is long and complex, providing opportunities for fraudsters to deceive consumers. However, limited attention has been given to food fraud in ginger, and there is a lack of research on this topic. In this review, ginger was used as an example for interpreting the fraud issues within low-priced and high-trade volume spice products. This review aims to summarize the open access information from food and food fraud databases, literature, and stakeholders about ginger fraud, and to map, deconstruct and analyse the food fraud vulnerability in the supply chain. In addition, potential testing strategies to detect ginger fraud were also discussed. The investigation of food fraud databases, a semi-structured literature review and online interviews with stakeholders revealed that adulteration is the major fraud type in ginger products. And the most vulnerable ginger products are ground ginger and finely processed ginger. The ginger supply chain from China to the EU comprises nine stages and is medium vulnerable to food fraud, both in regard to opportunities and motivational drivers. To ensure the integrity of the ginger supply chain, there is a need to apply fraud vulnerability tools in the companies of the industry. In addition, screening and confirmatory techniques based on the characteristics of ginger should be utilised for monitoring fraud issues in the supply chain.

Impact of Sulfur Fumigation on Ginger: Chemical and Biological Evidence

We previously found that sulfur fumigation, a commonly used controversial method for the post-harvest handling of ginger, induces the generation of a compound in ginger, which was speculated to be a sulfur-containing derivative of 6-shogaol based on its mass data. However, the chemical and biological properties of the compound remain unknown. As a follow-up study, here we report the chemical structure, systemic exposure, and anticancer activity of the compound. Chromatographic separation, nuclear magnetic resonance analysis, and chemical synthesis structurally elucidated the compound as 6-gingesulfonic acid. Pharmacokinetics in rats found that 6-gingesulfonic acid was more slowly absorbed and eliminated, with more prototypes existing in the blood than 6-shogaol. Metabolism profiling indicated that the two compounds produced qualitatively and quantitatively different metabolites. It was further found that 6-gingesulfonic acid exerted significantly weaker antiproliferative activity on tumor cells than 6-shogaol. The data provide chemical and biological evidence that sulfur fumigation may impair the healthcare functions of ginger.

Detection and discrimination of sulfur dioxide using a colorimetric sensor array

Discrimination and detection of sulfur dioxide residues in foods using a simple colorimetric array have been achieved. The difference maps before and after the reaction showed that the specific color fingerprint was related to the amount of sulfur dioxide. The results of principal component analysis (PCA), hierarchical clustering analysis (HCA) and linear discriminant analysis (LDA) demonstrated that the as-fabricated colorimetric sensor array have good performance for the discrimination of sulfur dioxide and other interferents, as well as different concentrations of sulfur dioxide. Moreover, the array has been successfully applied to determine the concentration of sulfur dioxide residues in real samples and revealed good accuracy, precision and repeatability.

In this work, a colorimetric sensor array based on six specific color reactions was developed and used for the determination of sulfur dioxide content. The qualitative and quantitative analysis of sulfur dioxide residues in real samples was achieved.

Rapid and practical qualitative and quantitative evaluation of non-fumigated ginger and sulfur-fumigated ginger via Fourier-transform infrared spectroscopy and chemometric methods

A strategy was developed to distinguish and quantitate nonfumigated ginger (NS-ginger) and sulfur-fumigated ginger (S-ginger), based on Fourier transform near infrared spectroscopy (FT-NIR) and chemometrics. FT-NIR provided a reliable method to qualitatively assess ginger samples and batches of S-ginger (41) and NS-ginger (39) were discriminated using principal component analysis and orthogonal partial least squares discriminant analysis of FT-NIR data. To generate quantitative methods based on partial least squares (PLS) and counter propagation artificial neural network (CP-ANN) from the FT-NIR, major gingerols were quantified using high performance liquid chromatography (HPLC) and the data used as a reference. Finally, PLS and CP-ANN were deployed to predict concentrations of target compounds in S- and NS-ginger. The results indicated that FT-NIR can provide an alternative to HPLC for prediction of active components in ginger samples and was able to work directly on solid samples.

The Transcriptome and Metabolome Reveal Stress Responses in Sulfur-Fumigated Cucumber (Cucumis sativus L.)

Sulfur (S) fumigation is a commonly used sterilization method in horticultural facilities against fungal diseases. S fumigation damaged cucumber leaves, although the response mechanism is unclear. This study analyzes the growth, transcriptome, and metabolomic profiles of young and mature leaves, ovaries, and commercial cucumber fruits to decipher the mechanism of cucumber stress response under S fumigation. S fumigation significantly changed the photosynthetic efficiency and reactive oxygen species (ROS) in leaves, but not fruit development, fruit mass, and peel color. Transcriptome analysis indicated that S fumigation strongly regulated stress defense genes. The weighted gene co-expression network analysis revealed that S fumigation regulated ASPG1, AMC1 defense genes, LECRK3, and PERK1 protein kinase. The abscisic acid (ABA)-mediated model of regulation under S fumigation was constructed. Metabolome analysis showed that S fumigation significantly upregulated or downregulated the contents of amino acids, organic acids, sugars, glycosides, and lipids (VIP > 1 and P-value < 0.05). The opposite Pearson's correlations of these differential metabolites implied that cucumber had different metabolic patterns in short-term and long-term S fumigation. Besides, the elevated levels of proline and triglyceride indicated that stress-responsive mechanisms existed in S-fumigated cucumber. Moreover, the comprehensive analysis indicated that S fumigation elevated secondary S-containing metabolites but decreased sulfate absorption and transportation in cucumber. Overall, our results provided a comprehensive assessment of S fumigation on cucumber, which laid the theoretical foundation for S fumigation in protected cultivation.

Less SO2 residue may not indicate higher quality, better efficacy and weaker toxicity of sulfur-fumigated herbs: Ginseng, a pilot study

Sulfur dioxide (SO₂) is a hazardous residue in sulfur-fumigated herbs. Standards limiting SO₂ content have been adopted worldwide for quality control of sulfur-fumigated herbs, and herbs with less SO₂ are believed to be better. However, the standards are based only on the safe dose of SO₂ and may not characterize changes in herbal quality, thereby the efficacy and toxicity, resulting from sulfur fumigation. To confirm this, here the correlation of residual SO₂ content with the quality/efficacy/toxicity of sulfur-fumigated herb was investigated, and ginseng was selected as a pilot study object. Four sulfur-fumigated ginseng samples with different SO₂ contents were systemically compared regarding their quality, anti-inflammatory, anti-shock and anti-stress efficacies, as well as acute and chronic toxicities. The results demonstrated that the SO₂ content did not correlate with the quality, efficacy and toxicity changes of ginseng; more specifically, less SO₂ residue did not indicate higher quality, better efficacy nor weaker toxicity. This fact suggests that SO₂ content cannot characterize the variations in quality, efficacy and toxicity of sulfur-fumigated herbs. Therefore, the standard limiting SO₂ content alone may be inadequate for quality control of sulfur-fumigated herbs, and new standards including other indicators that can exactly reflect herbal efficacy and safety are necessary.

Altered metabolites in guinea pigs with allergic asthma after acupoint sticking therapy: New insights from a metabolomics approach

BACKGROUND

Clinical evidence gathered in Chinese communities suggested that acupoint sticking therapy could be an alternative treatment for asthma-related diseases. However, its underlying mechanism is still poorly understood.

AIM/HYPOTHESIS

In this study, we aimed to investigate the mechanism of the anti-inflammatory effect of acupoint sticking application with 'Treatment of Winter Disease in Summer' (TWDS) prescription by using metabolomics.

METHODS

Allergic asthma in guinea pig was sensitized and challenged by ovalbumin (OVA). Histopathological evaluation of the lung tissue was performed by hematoxylin and eosin (H&E) staining and Masson's trichrome staining. The levels of Th2 cytokine and IgE level in serum were measured using enzyme-linked immunoassay (ELISA). The mRNA expression levels of IL-4, IL-5, IL-13 and orosomucoid-like 3 (ORMDL3) were measured using quantitative reverse transcription polymerase chain reaction (RT-qPCR). Proteins of NF-κB signaling pathway were measured using western blot. The serum metabolomics profiles were obtained by using ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS).

RESULTS

The overall results confirmed that AST with TWDS prescription had a significant protective effect against OVA-induced allergic asthma in guinea pig. This treatment not only attenuated airway inflammation and collagen deposition in the airway, but also decreased the levels of IL-4, IL-5, IL-13 and IgE in serum. In addition, metabolomics results indicated that metabolisms of phospholipid, sphingolipid, purine, amino acid and level of epinephrine were restored back to the normal control level. Moreover, results of the gene expression of ORMDL3 in lung tissues indicated that AST using TWDS could alter the sphingolipid metabolism. Further western blotting analysis also showed that its anti-inflammatory mechanism was by decreasing the phosphorylation of p65 and IκB.

CONCLUSION

The study demonstrated that metabolomics provides a better understanding of the actions of TWDS acupoint sticking therapy on OVA-induced allergic asthma.

Ginger polysaccharides induced cell cycle arrest and apoptosis in human hepatocellular carcinoma HepG2 cells

In this study, ginger polysaccharide (GP) was obtained from ginger by enzymatic method, its chemical properties and antitumor activity were investigated. The results indicated that the composition and proportion of GP were l‑rhamnose, d‑arabinose, d‑mannose, d‑glucose and d‑galactose in a molar ratio of 3.64:5.37:3.04:61.03:26.91, GP had the characteristic absorption peak of polysaccharide. Congo red experiment showed that GP had a triple helix structure, which could have anti-tumor effect. Furthermore, MTT assay, cell morphology observation, nuclear morphology observation and reactive oxygen species observation demonstrated that GP had significant antitumor effect. Flow cytometry suggested that GP could promote apoptosis and arrest cells in G0-G1 phase. Real-time fluorescence quantification and Western blot revealed that GP could up-regulate the expression of Bax, Fas, FasL, caspase-3, p21 and p53, and down-regulate the expression of Bcl-2. These studies suggested that GP would be used as an antitumor drug in foods to promote the development of functional foods.

UPLC-QTOF-MS/MS-guided isolation and purification of sulfur-containing derivatives from sulfur-fumigated edible herbs, a case study on ginseng

In this study, a novel ultra-performance liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry (UPLC-QTOF-MS/MS)-guidance strategy was proposed for preparation of sulfur-containing derivatives in sulfur-fumigated edible herbs. Being versatile in both chromatographic separation and mass spectrometric detection, UPLC-QTOF-MS/MS was inducted into each experimental step for multifaceted purposes including finding, tracking, purity determination and structural elucidation of targeted compounds as well as UPLC-HPLC chromatographic conditions transplantation, whereby the isolation and purification procedures were greatly facilitated. Using this strategy, a new sulfur-containing ginsenoside Rg₁ derivative (named compound I) was obtained from sulfur-fumigated ginseng. The chemical structure of compound I was elucidated to be (3β, 6α, 12β)-3, 12-dihydroxydammar-25-ene-6, 20-diylbis-β-d-glucopyranoside, 24-sulfonic acid by QTOF-MS/MS, ¹H-NMR and ¹³C-NMR analysis, and its generation mechanisms by sulfur-fumigation were accordingly discussed. The research deliverable suggests that the UPLC-QTOF-MS/MS-guidance strategy is promising for targeted preparation of sulfur-containing derivatives from sulfur-fumigated edible herbs.