Sulfur dioxide residue in sulfur-fumigated edible herbs: The fewer, the safer?

Metals/bisulfite system involved generation of 24-sulfonic-25-ene ginsenoside Rg1, a potential quality control marker for sulfur-fumigated ginseng

Ginseng is a most popular health-promoting food with ginsenosides as its main bioactive ingredients. Illegal sulfur-fumigation causes ginsenosides convert to toxic sulfur-containing derivatives, and reduced the efficacy/safety of ginseng. 24-sulfo-25-ene ginsenoside Rg1 (25-ene SRg1), one of the sulfur-containing derivatives, is a potential quality control marker of fumigated ginseng, but with low accessibility owing to its unknown generation mechanism. In this study, metals/bisulfite system involved generation mechanism was investigated and verified. The generation of 25-ene SRg1 in sulfur-fumigated ginseng is that SO2, formed during sulfur-fumigation, reacted with water and ionized into HSO3-. On the one hand, under the metals/bisulfite system, HSO3- generates HSO5- and free radicals which converted ginsenoside Rg1 to 24,25-epoxide Rg1; on the other hand, as a nucleophilic group, HSO3- reacted with 24,25-epoxide Rg1 and further dehydrated to 25-ene SRg1. This study provided a technical support for the promotion of 25-ene SRg1 as the characteristic quality control marker of sulfur-fumigated ginseng.

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.

Unveiling the Chemical Composition of Sulfur-Fumigated Herbs: A Triple Synthesis Approach Using UHPLC-LTQ-Orbitrap MS-A Case Study on Steroidal Saponins in Ophiopogonis Radix

Ophiopogonis Radix (OR) is a traditional Chinese medicine. In recent years, in order to achieve the purpose of drying, bleaching, sterilizing and being antiseptic, improving appearance, and easy storage, people often use sulfur fumigation for its processing. However, changes in the chemical composition of medicinal herbs caused by sulfur fumigation can lead to the transformation and loss of potent substances. Therefore, the development of methods to rapidly reveal the chemical transformation of medicinal herbs induced by sulfur fumigation can guarantee the safe clinical use of medicines. In this study, a combined full scan-parent ions list-dynamic exclusion acquisition-diagnostic product ions analysis strategy based on UHPLC-LTQ-Orbitrap MS was proposed for the analysis of steroidal saponins and their transformed components in sulfur-fumigated Ophiopogonis Radix (SF-OR). Based on precise mass measurements, chromatographic behavior, neutral loss ions, and diagnostic product ions, 286 constituents were screened and identified from SF-OR, including 191 steroidal saponins and 95 sulfur-containing derivatives (sulfates or sulfites). The results indicated that the established strategy was a valuable and effective analytical tool for comprehensively characterizing the material basis of SF-OR, and also provided a basis for potential chemical changes in other sulfur-fumigated herbs.

Impact of sulfur-fumigation on carbohydrate components of Atractylodis Macrocephalae Rhizoma

Atractylodis Macrocephalae Rhizoma (AMR) is one of commonly used medicinal and edible herbs in China. It is often sulfur-fumigated during post-harvest processing. Carbohydrates are important active components of AMR. However, it is unknown whether sulfur-fumigation would induce changes on carbohydrates. Here, carbohydrates including polysaccharides, oligosaccharides and free monosaccharides were comprehensively analyzed to characterize the quality changes of sulfur-fumigated AMR. Determination of both homemade sulfur-fumigated AMR samples and commercial samples from market revealed that sulfur-fumigation did not affect molecular weight distribution of polysaccharides, but altered polysaccharides content and its ratios of constituent monosaccharides, especially glucose (Glc) and fructose (Fru), as well as the contents of oligosaccharides DP2-10 and free monosaccharide Fru. Moreover, the variations enhanced with the increasing of residual SO₂ content. The potential transformation mechanisms could be due to the hydrolysis of polysaccharides. The research outcomes could provide a chemical basis for the safety and efficacy evaluations of sulfur-fumigated AMR.

Effects and contributory factors of sulfur-fumigation on the efficacy and safety of medicinal herbs evaluated by meta-analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Sulfur-fumigation undoubtedly alters the chemical and metabolic profiles, but controversially affects the efficacy and safety of medicinal herbs.

AIM OF THE STUDY

To comprehensively evaluate the effects of sulfur-fumigation on the efficacy and safety of medicinal herbs using a meta-analysis approach and further investigate the potential contributory factors.

MATERIALS AND METHODS

Literatures were retrieved on PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Chinese VIP Information and Wanfang, and the outcomes involved activities and toxicities were extracted using standard data extraction forms. The effects of sulfur-fumigation on the efficacy and safety of medicinal herbs were evaluated by meta-analysis approaches.

RESULTS

A total of sixteen studies were included in this study. Sulfur-fumigation reduced the efficacies of medicinal herbs with immune activity [thymus index (SMD = -1.81; P < 0.00001); spleen index (SMD = -1.11; P < 0.0001)], anti-oxidative activity [MDA (SMD = 2.60; P = 0.04); SOD (SMD = -2.21; P < 0.00001)], analgesic activity [heat tolerate time (SMD = -2.51; P = 0.001); writhing time (SMD = 0.36; P = 0.006)], anti-platelet aggregation activity (SMD = -1.84; P = 0.001), and anti-inflammatory activity [ear swelling degree (SMD = 0.47; P = 0.006)]. The reductions might be ascribed to sulfur-fumigation significantly reduced the contents of active ingredients in medicinal herbs, leading to dramatic decrease in the absorption of these ingredients and their metabolites in vivo. Furthermore, sulfur-fumigation induced the toxicities of medicinal herbs, mainly on hepatotoxicity, which might due to fumigation-induced residues of sulfur dioxide and heavy metal, and generations of sulfur-containing derivatives and toxic metabolites. Besides, administrated with sulfur-fumigated medicinal herbs with high sulfur ratio and/or higher dosage showed more significant toxicity.

CONCLUSION

Sulfur-fumigation reduced the efficacy and safety of medicinal herbs, indicating sulfur-fumigation might not a feasible approach to process medicinal herbs. However, with obvious limitations, much more rigorous designed-trials are still needed to confirm the conclusion.

A Whiff of Sulfur: One Wind a Day Keeps the Doctor Away

Reactive Sulfur Species (RSS), such as allicin from garlic or sulforaphane from broccoli, are fre-quently associated with biological activities and possible health benefits in animals and humans. Among these Organic Sulfur Compounds (OSCs) found in many plants and fungi, the Volatile Sulfur Compounds (VSCs) feature prominently, not only because of their often-pungent smell, but also because they are able to access places which solids and solutions cannot reach that easily. Indeed, inorganic RSS such as hydrogen sulfide (H₂S) and sulfur dioxide (SO₂) can be used to lit-erally fumigate entire rooms and areas. Similarly, metabolites of garlic, such as allyl methyl sulfide (AMS), are formed metabolically in humans in lower concentrations and reach the airways from inside the body as part of one’s breath. Curiously, H₂S is also formed in the gastrointestinal tract by gut bacteria, and the question of if and for which purpose this gas then crosses the barriers and enters the body is indeed a delicate matter for equally delicate studies. In any case, nature is surprisingly rich in such VSCs, as fruits (for instance, the infamous durian) demonstrate, and therefore these VSCs represent a promising group of compounds for further studies.

Practical Protocol for Comprehensively Evaluating Sulfur-Fumigation of Baizhi Based on Metabolomics, Pharmacology, and Cytotoxicity

Sulfur Angelicae Dahuricae Radix (Baizhi) is a common medicinal herb in Asian countries. A practical protocol combining metabolomics, pharmacology, and cytotoxicity was developed to comprehensively evaluate the influence of sulfur-fumigation on the quality of Baizhi. Furocoumarins could be transformed into sulfur-containing compounds during the sulfuring process, among which 1 and 3 were purified with relatively high abundance and identified as 3,4-dihydrobyakangelicin-4-sulfonic acid and (4R,12S)-3,4-dihydrooxypeucedanin hydrate-4-sulfonic acid (OXH-S), respectively. OXH-S was found to be an addition product of sulfite and oxypeucedanin hydrate (OXH-N). Then, the cytotoxicity and anti-inflammatory activity of OXH-N, OXH-S, and water extracts of sulfured (extraction-S), and unsulfured Baizhi (extraction-N) were evaluated. OXH-S and extraction-S were less toxic than OXH-N and extraction-N, respectively. A comparison of OXH-N with OXH-S and extraction-N with extraction-S showed no significant differences in anti-inflammatory activity. These results suggest that sulfur fumigation can reduce toxicity and does not influence the anti-inflammatory activity of Baizhi, even after chemical composition changes. The proposed protocol based on marker screening, pharmacology, and safety evaluation provides a scientific basis for the standardization and regulation of sulfured Baizhi and other medical materials.

Comparison of the antioxidant activities of nonfumigated and sulphur-fumigated Chrysanthemum morifolium cv. Hang-ju induced by oxidative stress

CONTEXT

The traditional drying method, sun drying, for Chrysanthemum morifolium Ramat. cv. Hang-ju (Compositae) (HJ) is widely replaced by sulphur fumigation (SF), which has an unknown effect on its efficacy.

OBJECTIVE

To investigate protective effects of nonfumigated HJ (NHJ) and sulphur-fumigated HJ (SHJ) water extracts against oxidative stress and lipid peroxidation.

MATERIALS AND METHODS

Sprague-Dawley rats were administered high-fat diet to induce hyperlipidaemia and randomly divided into eight groups (n = 6): control, fenofibrate, NHJ and SHJ extracts (1, 2 or 4 g crude drugs/kg/d; intragastric administration for 8 weeks). Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected. Human umbilical vein endothelial cells (HUVECs) were treated with NHJ and SHJ extracts (50, 100 or 200 μg/mL) for 24 h, followed by oxidized low-density lipoprotein (ox-LDL, 20 μg/mL) for 2 h in vitro. Cellular reactive oxygen species (ROS), SOD and MDA levels and apoptosis were evaluated.

RESULTS

NHJ was more effective than SHJ in decreasing serum TG, TC, LDL-C, LDL/HDL and MDA while increasing serum HDL-C and SOD levels at high doses. SHJ (IC₅₀=19.9 mg/mL) suppressed HUVEC growth stronger than NHJ (IC₅₀=186.7 mg/mL). At 200 μg/mL, NHJ was more effective than SHJ in downregulating ROS and MDA levels, reducing HUVECs apoptosis rate and elevating SOD activity in ox-LDL-treated HUVECs.

CONCLUSIONS

SF causes oxidative damage and attenuates antioxidative activity in ox-LDL-treated HUVECs, which promotes lipid peroxidation. SF is not recommended for processing HJ.

An integrated strategy for evaluation of sulfur-fumigated edible herb Astragali Radix based on UPLC-MS/MS platforms and pharmacological analysis

Astragali Radix is an edible herb that has been employed in Traditional Chinese medicine (TCM) and has recently been recognized by various countries; however, it is also one of the most extensively sulfur-fumigated TCM components. This study designed a UPLC-QTOF-MS/MS-guided isolation approach to generate sulfur-containing derivatives, and a novel sulfur-containing marker, namely, astragaloside sulfate, was characterized based on 1D and 2D NMR, which were derived from the main component of Astragali Radix, namely, astragaloside. Pharmacological experiments also showed that the activity of astragaloside decreased after it was converted into sulfate. Moreover, a rapid assay for the determination of astragaloside sulfate content by UPLC-QTRAP-MS/MS was established to evaluate samples that were non-fumigated and sulfur-fumigated at different levels. The method was applied to determine the content of JGS in the different batches of commercial samples. This research reveals that the practical procedure-based typical sulfur-containing indicator can be utilized for quality assurance of sulfur-fumigated and non-fumigated Astragali Radix.

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.

A Practical Protocol for a Comprehensive Evaluation of Sulfur Fumigation of Trichosanthis Radix Based on Both Non-Targeted and Widely Targeted Metabolomics

Trichosanthis Radix (TR) is one of the most severely sulfur-fumigated herbs in the market, whose transformation mechanism of chemical compositions and sulfur-fumigation markers of TR have not been clarified. To excavate characteristic sulfur-fumigation markers of TR samples, this study brings up a practical protocol using both ultra-performance liquid chromatography/quadrupole time-of-flight-mass spectrum (UPLC-ESI-QTOF-MS/MS)-based non-targeted metabolomics and ultra-performance liquid chromatography/electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrum (UPLC-ESI-QTRAP-MS/MS)-based widely targeted metabolomics. The results of study demonstrated that five characteristic markers are sulfur-containing components, which were identified as p-Hydroxybenzyl hydrogen sulfite, cucurbitacin D sulfite I, cucurbitacin D sulfite II, cucurbitacin B sulfite I, and cucurbitacin B sulfite II, respectively. Additionally, cucurbitacin B and D were also filtered and identified as the characteristic sulfur-fumigation markers. Meanwhile, the different sulfur-fumigation extent of TR samples was tested by chemical transformations analysis and sulfur dioxide residues test. Further, 58.16% (139 of 239) of the differential metabolites content significantly reduced in sulfur-fumigated TR samples. Besides, 20 kinds of non-sulfur marker metabolites were tested to evaluate the quality of TR samples before and after sulfur fumigation, predominantly including phenolic acids, amino acids, lipids and nucleotides. Taking TR as an example, this work provides a comprehensive practical protocol for the quality supervision of sulfur-fumigation herbs.

The effects of sulfur fumigation processing on Panacis Quinquefolii Radix in chemical profile, immunoregulation and liver and kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

The influence of sulfur fumigation processing on chemical profile, pharmacological activity and safety of Chinese herbs has attracted great attention. Panacis Quinquefolii Radix (PQR) was more widely used as edible and medicinal than Ginseng because of its tonifying effect and characteristic of not getting inflamed. The disadvantage of sulfur fumigated (SF) Ginseng has been reported, but the systematic study of SF-PQR is deficient and urgently needed.

AIM OF THE STUDY

To systematically describe the influence of sulfur fumigation on chemical profile, characteristic products, immunoregulation and liver and kidney injury of PQR.

MATERIALS AND METHODS

ICP-MS and HPLC-DAD were used to detect 11 inorganic elements and 3 ginsenosides, respectively. Principal component analysis (PCA) was used to distinguish SF-PQR from non-sulfur fumigated (NSF)-PQR by combining the content changes of inorganic elements and ginsenosides. UPLC/Orbitrap-MS was applied to screen the characteristic products (m/z) after sulfur fumigation. For the effectiveness and safety, male KM mice were used to compare the immunomodulatory effects of NSF-PQR or SF-PQR under both healty and cyclophosphamide induced immunosuppressive conditions by net growth rate of body weight, thymus and spleen indices, serum IL-6, SOD, BUN, AST levels, and HE staining of liver and kidney.

RESULTS

Sulfur fumigation processing significantly reduced the contents of ginsenosides Rb₁, Re and Rg₁ with the elevation of inorganic elements in 20 batches PQR. Based on the scatter distribution of PCA, SF-PQR and NSF-PQR can be distinguished. According to the Rt, Precursor ion (m/z) and Product ion (m/z) produced by UPLC/Orbit trap-MS, R₁-SO₃ (m/z, 1059.53), Re-SO₃ (m/z, 1025.55), Rg₁-SO₃ (m/z, 878.47), Ro-SO₃ (m/z, 1035.32), Rb₁-SO₃ (m/z, 1179.58), and Rk₃-SO₃ (m/z, 745.40) could be confirmed as important markers for identifying SF-PQR. The effect of SF-PQR on reversing immunosuppression induced by cyclophosphamide was significantly reduced (P < 0.05) evidenced by the inhibition of net growth rate of body weight, immune organ index, IL-6 level and SOD activity. For healthy mice, SF-PQR not only failed to maintain the normal indexes, but also reduced the indexes to lower levels. After 2 weeks of continuous gastric administration, the abnormal liver and kidney functions in healthy mice were damaged and manifested by the increasing of BUN and AST levels, which was consistent with hepatic lesion area and renal tubular injury observed by HE staining.

CONCLUSION

Sulfur fumigation processing not only reduced the immunomodulatory effect of PQR, but also brought the hidden danger in liver and kidney injury. The sulfonated products provided in this paper can be applied for the identification of SF-PQR accurately.

A proposed protocol based on integrative metabonomics analysis for the rapid detection and mechanistic understanding of sulfur fumigation of Chinese herbal medicines

In the current work, Lonicera japonica Flos (FLJ) was selected as a model Chinese herbal medicine (CHM) and a protocol was proposed for the rapid detection of sulfur-fumigated (SF) CHMs. A multiple metabonomics analysis was conducted using HPLC, NIR spectroscopy and a UHPLC-LTQ-Orbitrap mass spectrometer. First, the group discriminatory potential of each technique was respectively investigated based on PCA. Then, the effect of mid-level metabonomics data fusion on sample spatial distribution was evaluated based on data obtained using the above three technologies. Furthermore, based on the acquired HRMS data, 76 markers discriminating SF from non-sulfur-fumigated (NSF) CHMs were observed and 49 of them were eventually characterized. Moreover, NIR absorptions of 18 sulfur-containing markers were identified to be in close correlation with the discriminatory NIR wavebands. In conclusion, the proposed protocol based on integrative metabonomics analysis that we established for the rapid detection and mechanistic explanation of the sulfur fumigation of CHMs was able to achieve variable selection, enhance group separation and reveal the intrinsic mechanism of the sulfur fumigation of CHMs.

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.

Volatile component interaction effects on compatibility of Cyperi Rhizoma and Angelicae Sinensis Radix or Chuanxiong Rhizoma by UPLC-MS/MS and response surface analysis

Cyperi Rhizoma (Xiangfu) combined with either Angelicae Sinensis Radix (Danggui) or Chuanxiong Rhizoma (Chuanxiong) are herb pairs that are commonly used in clinical settings. To illustrate the herb-herb interactions that occur when extracts from these herbs are obtained together, ultra-high-performance liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry and response surface analysis were used. Volatile components, α-cyperone, nootkatone, ligustilide, senkyunolide A and senkyunolide I, were accurately identified with high precision. When Xiangfu was combined with Danggui at a 1:1 ratio, or with Chuanxiong at a 1:1 or 2:1 ratio, the dissolution rates of α-cyperone and nootkatone from the herbs were greatly increased, compared to those obtained from Xiangfu extract alone. The dissolution rates of ligustilide, senkyunolide A and senkyunolide I from Danggui or Chuanxiong changed proportionally to changes in the ratios of Xiangfu with either Danggui or Chuanxiong. Response surface analysis results presented polynomial regression equations between the dissolution of tested compounds and the corresponding input variables, including compatibility proportions and solvent dosage. Based on the predicted results from response surface analysis, a combination of Xiangfu with Chuanxiong at a ratio of near 1:1, or with Danggui at 1:2, resulted in the maximum dissolution of five volatile components. Our established method could be applied to herb-herb interaction research, and the results may provide a scientific basis for the development of Cyperi Rhizoma-Chuanxiong Rhizoma, or Cyperi Rhizoma-Angelicae Sinensis Radix-based formulas and products.

Rapid discrimination of raw and sulfur-fumigated Smilax glabra based on chemical profiles by UHPLC-QTOF-MS/MS coupled with multivariate statistical analysis

Smilax glabra (SG) is commonly used as a traditional edible herb in eastern Asia. Recently, sulfur-fumigation has been frequently used in order to obtain better color and a longer storage lifetime. However, the chemical alterations caused by this process remain unknown. The aim of this research was to explore potential chemical differences between non-fumigated and sulfur-fumigated SG samples. A novel approach was developed by using ultra-high-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) with principal component analysis (PCA) and orthogonal partial squared discriminant analysis (OPLS-DA). Fifty-eight compounds were unambiguously characterized or tentatively identified in the chemical profiles for the first time. Six newly generated sulfur-containing compounds, namely glucosyringic acid sulfate, 5-O-caffeoylshikimic acid sulfite, 3-O-caffeoylshikimic acid sulfite, 5-O-caffeoylshikimic acid sulfate, 3-O-caffeoylshikimic acid sulfate and astilbin sulfate, were screened out to be the most characteristic markers for distinguishing non-fumigated and sulfur-fumigated SG. This newly proposed approach can not only be applied for exploring chemical markers but can also be used to investigate the chemical transformation mechanism associated with sulfur for other edible herbs.

Effects of sulfur-fumigation on the pharmacokinetics, metabolites and analgesic activity of Radix Paeoniae Alba

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Paeoniae Alba (Baishao, BS), one of the most commonly used traditional Chinese medicinal herbs, has many pharmacological effects including analgesic activity. Previous studies found that sulfur-fumigation, a post-harvest handling process developed to prevent mold contamination of medicinal herbs, altered the quality of BS. However, whether sulfur-fumigation affects the pharmacokinetics, safety and efficacy of BS warrants further investigation.

AIM OF THE STUDY

To evaluate the feasibility of sulfur-fumigation as a post-harvest handling process of BS from the viewpoints of pharmacokinetics, safety and efficacy.

MATERIALS AND METHODS

The pharmacokinetic behaviors of four active components of BS and one characteristic component of sulfur-fumigated BS (S-BS) were evaluated by high performance liquid chromatography triple quadrupole mass spectrometry (HPLC-TQ-MS/MS). The safety was investigated using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) based metabolomics approach after intragastric (i.g.) administration of non-fumigated BS (N-BS) and S-BS in rats. The analgesic efficacy was compared using hot-plate test in mice, after i.g. administration of N-BS and S-BS, at both high and low dosages.

RESULTS

Systemic exposures of paeoniflorin and oxypaeoniflorin, two analgesic components of BS, were significantly decreased in the S-BS treated group compared to the N-BS treated group, while paeoniflorin sulfonate, one of the sulfur-containing derivatives of S-BS, was detected in all time-points of S-BS treated group with the area under the plasma concentration-time curve (AUC_0-t) and the maximum plasma concentration (C_max) as high as 7077.06 ± 2232.97ng/mL*h and 1641.42 ± 634.79ng/mL respectively, which indicated that sulfur-fumigation altered the pharmacokinetic behaviors of BS. Besides, paeoniflorin sulfonate and its four metabolites with ambiguous toxicities, as well as one endogenous metabolite p-cresol glucuronide, the biomarker of disordered homeostasis of intestinal bacteria and bile acid, were identified as the characteristic metabolites in S-BS administered rats, suggesting that sulfur-fumigation reduced the safety of BS. Furthermore, the analgesic effects at both low and high dosages were decreased in different extent when compared to N-BS administered groups, indicating that sulfur-fumigation weakened the efficacy of BS.

CONCLUSION

Sulfur-fumigation altered the pharmacokinetics, as well as reduced the safety and efficacy of BS, suggesting that sulfur-fumigation is not recommended for post-harvest handling of BS.

Elucidation of Characteristic Sulfur-Fumigated Markers and Chemical Transformation Mechanism for Quality Control of Achyranthes bidentate Blume Using Metabolome and Sulfur Dioxide Residue Analysis

Achyranthes bidentata Blume (AB) is a health food and a sulfur-free herbal medicine that is one of the most heavily sulfur-fumigated herbs in the marketplace. In this work, a comprehensive approach using ultra-performance liquid chromatography coupled with quadrupole time-of-flight-MS (UPLC-Q-TOF-MS) and multivariate statistical analysis was developed to identify characteristic sulfur-fumigation markers, elucidate chemical transformation mechanisms and characterize the degree of sulfur-fumigation of AB. Non-fumigated and sulfur-fumigated AB samples were compared by UPLC-Q-TOF-MS/MS analysis. Three triterpene saponins (Betavulgarosides II-IV) and two amides (Feruloyl-4-O-methyldopamine and Moupinamide) were identified as characteristic markers, which were positively correlated with two active AB components, namely oleanic acid and ferulic acid, respectively. Moreover, the extent of the sulfur-fumigation under different weight ratios of sulfur to herbal materials (1:20, 1:40, and 1:80) was analyzed based on chemical transformations and sulfur dioxide residues. Further verification showed that the ratio of 1:40 within 1 h was reasonable and efficient for herb quality preservation and assurance. This study provides a reliable sulfur-fumigation protocol for the quality control of AB and other herbs.

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.

A practical protocol for comprehensive evaluation of sulfur-fumigation of Gastrodia Rhizoma using metabolome and health risk assessment analysis

Gastrodia Rhizoma is one of the most heavily sulfur-fumigated edible and medical herbs in the marketplace. We developed a practical protocol using an ultra-performance liquid chromatography coupled with quadrupole time-of-flight-MS^E (UPLC/QTOF-MS^E)-based metabolome and health risk assessment model to identify characteristic sulfur-fumigated markers, dissect chemical transformation mechanisms, and control the quality of sulfur-fumigated Gastrodia Rhizoma. Two sulfur-containing p-hydroxybenzyl products, one sulfur-containing disaccharide, one glycolipid, and two phospholipids were selected and identified as markers based on multivariate statistical analysis. In particular, the sulfur-containing markers p-hydroxybenzyl hydrogen sulfite and trace p-mercaptobenzyl hydrogen sulfate were positively correlated with the active major phenolics. Moreover, a practical index the time of the minimum content was useful for evaluating the extent of the sulfur-fumigation under different weight ratios of the sulfur to herbal materials (1:20, 1:40, and 1:80). Ultimately, the 1:40 ratio within 1h of sulfur-fumigation was considered as safe and efficient for herb quality preservation under the maximum residue limit of 750mg/kg. This study shows that the practical protocol-based discriminated markers and practical limits can be applied to quality assurance of sulfur-fumigation and non-fumigation Gastrodia Rhizoma and other edible or medical materials.

Sulfur fumigation reducing systemic exposure of ginsenosides and weakening immunomodulatory activity of ginseng

ETHNOPHARMACOLOGICAL RELEVANCE

Ginseng (Ginseng Radix et Rhizoma) is used worldwide for its miracle tonic effects, especially for its immunomodulatory activities. Sulfur fumigation, a fast and convenient method to prevent pesticidal and bacterial contamination in the food industry, has been recently employed during post-harvest processing of ginseng. Our previous studies demonstrated that sulfur fumigation significantly altered the chemical profile of the bioactive ingredients in ginseng. However, the effects of sulfur fumigation on the pharmacokinetics and bioactivities of ginseng remain unknown.

AIM OF THE STUDY

To examine the effects of sulfur fumigation on the pharmacokinetics and immunomodulatory activities of ginseng.

MATERIALS AND METHODS

For pharmacokinetic studies, male Sprague-Dawley rats exposed to single/multiple dosages of non-fumigated ginseng (NFG) and sulfur fumigated ginseng (SFG) were investigated using HPLC-MS/MS analysis. For bioactivity studies, male ICR mice were used to compare the immunomodulatory effects of NFG or SFG under both normal and cyclophosphamide (CY)-induced immunocompromised conditions using white blood cell counts, serum cytokine levels, and spleen and thymus weight indices.

RESULTS

Sulfur fumigation significantly reduced the contents of the bioactive ginsenosides in ginseng, which resulted in drastically low systemic exposure of ginsenosides in SFG-treatment group compared to NFG-treatment group. This observation was consistent with the bioactivities obtained in NFG- and SFG-treatment groups. The bioactivity studies also demonstrated the immunomodulatory effects of NFG but not SFG in the CY-induced immunosuppressed mice.

CONCLUSION

Sulfur fumigation significantly reduced contents of bioactive ginsenosides in ginseng, leading to dramatic decrease in the systemic exposure of these ginsenosides in the body and detrimental reduction of immunomodulatory effects of ginseng. Our results provided scientific evidences and laid a solid foundation for the needs of thorough evaluation of the significant impact of sulfur fumigation on ginseng and other medicinal herbs.