DNA metabarcoding analysis of fungal community on surface of four root herbs / 中草药·英文版

OBJECTIVE@#Angelicae Sinensis Radix (ASR, Danggui in Chinese), Cistanches Herba (CH, Roucongrong in Chinese), Ginseng Radix et Rhizoma (PG, Renshen in Chinese), and Panacis Quinquefolii Radix (PQ, Xiyangshen in Chinese), widely used as medicine and dietary supplement around the world, are susceptible to fungal and mycotoxin contamination. In this study, we aim to analyze their fungal community by DNA metabarcoding.@*METHODS@#A total of 12 root samples were collected from three main production areas in China. The samples were divided into four groups based on herb species, including ASR, CH, PG, and PQ groups. The fungal community on the surface of four root groups was investigated through DNA metabarcoding via targeting the internal transcribed spacer 2 region (ITS2).@*RESULTS@#All the 12 samples were detected with fungal contamination. Rhizopus (13.04%-74.03%), Aspergillus (1.76%-23.92%), and Fusarium (0.26%-15.27%) were the predominant genera. Ten important fungi were identified at the species level, including two potential toxigenic fungi (Penicillium citrinum and P. oxalicum) and eight human pathogenic fungi (Alternaria infectoria, Candida sake, Hyphopichia burtonii, Malassezia globosa, M. restricta, Rhizopus arrhizus, Rhodotorula mucilaginosa, and Ochroconis tshawytschae). Fungal community in ASR and CH groups was significantly different from other groups, while fungal community in PG and PQ groups was relatively similar.@*CONCLUSION@#DNA metabarcoding revealed the fungal community in four important root herbs. This study provided an important reference for preventing root herbs against fungal and mycotoxin contamination.

Research progress on pesticide residues of Panacis Quinquefolii Radix / 中国中药杂志

Panacis Quinquefolii Radix is the dry root of Panax quinquefolium, which is a perennial plant of Araliaceae. The plant has a long growth cycle and serious growth barrier problem, which leads to the use of pesticides. As a result, the pesticide residues in Panacis Quinquefolii Radix are arousing great concern. This paper reviews the research findings on the investigation, detection methods, content analysis and risk assessment of pesticide residues in Panacis Quinquefolii Radix since 1993, and compares the pesticide residue limit standards of different countries and regions. The pesticide residues in Panacis Quinquefolii Radix have been changing from organochlorines with high toxicity to triazines and triazoles with low toxicity. The pesticide residues are generally low, while the pollution of pentachloronitrobenzene and other pesticides still exist. The detection method has evolved from chromatography to chromatography-mass spectrometry. There are no reports of health risks caused by pesticide residues of Panacis Quinquefolii Radix. Pesticide residue is a major factor restricting the sound development of Panacis Quinquefolii Radix industry in China. Therefore, we suggest to improve the registration of pesticides applied to the plant, popularize mature ecological planting mode and supporting technology, and strengthen the research on the risk assessment and limit standard of pesticide residue in Panacis Quinquefolii Radix.

Effect of relative humidity on drying characteristic and quality of Panacis Quinquefolii Radix / 中草药

Objective: Taking Panacis Quinquefolii Radix (PQR) as study object, the drying characteristic and quality was investigated under constant relative humidity (RH) and step-down RH drying method in order to provide foundation for improving drying efficient and quality of PQR. Methods: At drying temperature 55 ℃, the effect of constant RH (20%, 30%, and 40%), step-down RH, when RH 40% was kept for 1, 5, and 9 h and then decreased to 20%, and continuously dehumidification drying conditions on drying characteristic, moisture effective diffusion coefficient, rehydration ratio, shrinkage ratio, total ginsenoside content and microstructure were investigated. Results: With constant RH drying condition, the lower the RH was, the higher the drying rate was. When RH was 20%, the drying time was shortened by 6.8% compared with RH of 40%. With step-down RH drying condition, when RH 40% was held for 5 h and then decreased to 20%, the drying time was shortened by 3.4% compared with dehumidification drying method. Also, a transient increasing drying rate phase was appeared. Moisture effective diffusion coefficient ranged from 1.49 × 10-10 to 2.50 × 10-10 m2/s. Rehydration ratio mainly depended on the damage degree of the PQR cellular structure and the moisture content before rehydrating. Additionally, the rehydration ratio and shrinkage ratio increased with the increase of RH. High RH was benefit for reserving and transferring of ginsenoside content. The microstructure results showed that under continuous dehumidification drying process, the PQR surface was crusted so that the drying time was prolonged and rehydration ratio was decreased. On the other hand, step-down RH drying method was benefit for porous structure formation, which was helpful for shortening drying time and improving rehydration ratio. When RH 40% was kept for 5 h and then decreased to 20%, the comprehensive score of this drying condition achieved its maximum value as (0.61 ± 0.01). Such drying condition was regarded as the best drying process with the rehydration ratio, shrinkage ratio and total ginsenoside content of 2.23 ± 0.12, 0.26 ± 0.06, and (5.01 ± 0.04)%, respectively. Conclusion: Step-down RH drying method can improve PQR drying efficient and quality and such conclusion provided theoretical foundation and technical support for how to adjust RH during hot air drying of PQR.

Effect of Sulfur Fumigation on Content of Chemical Constituents in Panacis Quinquefolii Radix and Preliminary Study on Its Identification Method / 中国实验方剂学杂志

Objective: To elucidate the effect of sulfur fumigation on the content of chemical composition and quality of Panacis Quinquefolii Radix, and to discuss the identification method of sulfur fumigated Panacis Quinquefolii Radix. Method: The content changes of ginsenoside Rb1, Re, Rg1 in Panacis Quinquefolii Radix were determined by HPLC-DAD before and after sulfur fumigation. The content changes of 11 inorganic elements in Panacis Quinquefolii Radix before and after sulfur fumigation were detected by microwave digestion method and inductively coupled plasma emission spectrometry tandem mass spectrometry (ICP-MS). The quality difference of Panacis Quinquefolii Radix before and after sulfur fumigation was qualitatively distinguished combined with the principal component analysis. Result: Three ginsenosides were well separated and showed good linearity with R2 ≥ 0.999.Before sulfur fumigation, the contents of ginsenoside Rg1, Re and Rb1 in Panacis Quinquefolii Radix were (0.897±0.045), (13.092±0.639), (12.896±0.430) g ·kg-1, respectively. After sulfur fumigation, the contents of these three components in Panacis Quinquefolii Radix were (0.807±0.032), (11.968±0.627), (11.752±0.696) g ·kg-1, respectively. After fumigation, the contents of inorganic elements (Cr, Mn, Co, Cu, As, Se, Ag, Cd, Sb, Pb and Fe) from Panacis Quinquefolii Radix increased in varying degrees. According to the distribution results of three-dimensional (3D) scattered points, sulfur and non-sulfur fumigation products of Panacis Quinquefolii Radix could be effectively distinguished. Conclusion: After sulfur fumigation, the contents of ginsenoside Re and Rb1 in Panacis Quinquefolii Radix decrease significantly, but the contents of 11 inorganic elements increase, suggesting that sulfur fumigation may have a great influence on the quality of Panacis Quinquefolii Radix.

Correlation analysis between quality characteristics and commercial specifications of Panacis Quinquefolii Radix / 中国中药杂志

This study was aimed to analyze the correlation between commercial specifications of Panacis Quinquefolii Radix and quantitative indexes of sevent kinds of ginsenosides (ginsenosides Rg¹, Re, Rb¹, Rc, Rb₂, Rb₃, Rd) contained in Panacis Quinquefolii Radix by using high performance liquid chromatography (HPLC), explore the correlation between the characteristics of the traditional Panacis Quinquefolii Radix specifications and modern chemical quantitative indicators, and provide a theoretical basis for the quality grade evaluation of Panacis Quinquefolii Radix. The HPLC fingerprint method was used to analyze 40 batches of Panacis Quinquefolii Radix. A total of 19 peaks were marked, and the similarity was above 0.900 for all samples. On this basis, processing methods, product specifications, contents of 7 components, and the total contents of ginsenoside Rg¹, Re and Rb¹ were used as the original variables for cluster analysis and principal component analysis. The results showed great correlation between the quality of Panacis Quinquefolii Radix and the information on their origins, but the difference was less with the characteristics of traditional commercial specifications, indicating some limitations in the division of commercial specifications of Panacis Quinquefolii Radix. The results revealed the intrinsic relationship between the product specifications, traditional qualitative indexes, and quantitative indexes of chemical components of Panacis Quinquefolii Radix, providing a new idea for the objective comprehensive evaluation of the quality of Panacis Quinquefolii Radix.