Exploring the nephrotoxicity of sulfur-containing derivatives in sulfur-fumigated Panacis Quinquefolii Radix based on chemical profiling and untargeted metabolomics

ETHNOPHARMACOLOGICAL RELEVANCE

Panacis Quinquefolii Radix (PQR) is often illegally sulfur fumigated to extend shelf life and improve appearance, but existing regulations of detecting SO₂ residues do not accurately identify desulfurized sulfur-fumigated PQR (SF-PQR). Although sulfur-containing derivatives (SCDs) have been reported in some sulfur-fumigated herbs, there is a lack of research on the generation mechanisms and toxicity of SCDs. Our previous study reported the nephrotoxicity of SF-PQR, and there is an urgent necessity to illuminate the mechanism of toxicity as well as its association with SCDs.

AIM OF THE STUDY

To investigate the transformation pattern of chemical components and SCDs in SF-PQR, and to disclose the linkage between SCDs and SF-PQR nephrotoxicity.

MATERIALS AND METHODS

The extracts of PQR (before and after SF) were detected by the UPLC-LTQ-Orbitrap-MS method, and SCDs were screened as quality markers (Q-markers). The composition of sulfur combustion products was examined by ion chromatography to exploit the conversion mechanism of SCDs. After administration of PQR extracts to mice for two weeks, serum was collected for GC-MS-based untargeted metabolomics study to mine for differential metabolites. The upstream genes were traced by network analysis to probe toxicity targets. Molecular docking was used to uncover the interactions between SCDs and the targets.

RESULTS

Thirty-three compounds were identified and 11 SCDs of saponins were screened, including four SO₃ sulfonation products and five H₂SO₃ sulfonation products. Metabolomics study showed significant alterations in serum biochemistry of SF-PQR group, with substantial increases in fumarate and 2-heptanone content, and induced disturbances in glycerolipid metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis in mice. Network analysis revealed that the key toxicity targets were DECR1, PLA2G1B, and CAT. Molecular docking indicated that SCDs had stable interaction forces with the above three toxicity targets.

CONCLUSION

SF-PQR caused kidney damage by affecting glycerolipid metabolism and phenylalanine, tyrosine, and tryptophan biosynthesis. Eleven SCDs were potential nephrotoxic substances and Q-markers for identifying SF-PQR. This study is the first to systematically elucidate the mechanism of SF-PQR-related nephrotoxicity, providing a robust basis for the construction of new quality control standards and a global prohibition of sulfur fumigation.

Sulfur-containing natural hinduchelins derivatives as potential antifungal agents against Rhizoctonia solani

Aryl-oxazole alkaloids are an important class of heterocyclic natural products, and which has been demonstrated to exhibit broad biological functions. During the course of our research for highly active compounds from natural products, the natural hinduchelins A-D with typical aryl-oxazole unit have been synthesized and investigated. So, in order to develop highly potential functional molecules, a series of novel sulfur-containing aryl-oxazole compounds derived from natural hinduchelins was designed and synthesized, and their in vitro fungicidal activities against four common plant pathogenic fungi (oomycetes Phytophthora capsici, ascomycetes Sclerotinia sclerotiorum, deuteromycetes Botrytis cinerea and basidiomycetes Rhizoctonia solani) were evaluated, the results demonstrated that compounds 7b and 7c displayed good selectivity and specificity in vitro against basidiomycetes R. solani. In addition, the in vivo antifungal activities also indicated compounds 7b and 7c can protect the horsebean against infection by R. solani, and the possible mechanism of antifungal action for these compounds has also been investigated.

Effect of sulfur-fumigation process on ginseng: Metabolism and absorption evidences

ETHNOPHARMACOLOGICAL RELEVANCE

Sulfur-fumigation has been developed to prevent insects and molds during post-harvest handling of Panax ginseng C.A. Mey (ginseng) in the near decades. Our previous study indicated sulfur-fumigation could transform ginsenosides, the active components of ginseng, into sulfur-containing derivatives (SFCDs), the artifacts with unknown toxicity. However, whether the biotransformation could be occurred and absorption characteristics between ginsenosides and SFCDs are still needed to further investigate.

AIM OF THE STUDY

To evaluate the effect of sulfur-fumigation process on ginseng through comparing the metabolic profile and absorption characteristics between ginsenoside Rg1, Re and their SFCDs.

MATERIALS AND METHODS

Intestinal microflora and liver S9 fraction were utilized to compare the metabolic profile, and single-pass intestinal perfusion and Caco-2 cell models were applied to compare the absorption characteristics, between Rg1, Re and their SFCDs.

RESULTS

Rg1 and Re were metabolized to 7 none sulfur-containing metabolites, while their SFCDs were metabolized to 18 sulfur-containing metabolites. The intestinal absorption and transport of Rg1 and Re were much greater than their SFCDs. Besides, the uptakes of Rg1 and Re were transport-dependent, but their SFCDs were non-transport-dependent.

CONCLUSION

Ginsenosides and their SFCDs could not be bio-transformed with each other and their absorption characteristics were quite different, which suggested that sulfur-fumigation is not a feasible post-harvest process of ginseng.

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.