Discovery of markers for discriminating the age of cultivated ginseng by using UHPLC-QTOF/MS coupled with OPLS-DA.

BACKGROUND: Ginseng (Ginseng Radix et Rhizoma, Panax ginseng C.A. Meyer) is gaining more publicity in modern society due to its health benefit and huge value in market. In the practice of grading and pricing of ginseng, the age is one of the major factor influencing the price and grade of ginseng. Therefore, the age discrimination is an important task for the quality control of ginseng. However, the traditional morphological methods are too subjective to be reproductive in discrimination. PURPOSE: To establish a method that can discriminate the ginseng samples with different cultivation years. STUDY DESIGN: To analyze the correlation between chemical compositions and cultivation years of cultivated ginseng samples of different age and thus discover potential quality marker (Q-marker) for discriminating the age of cultivated ginseng. METHODS: In the present study, the ultra-high performance liquid chromatography coupled with the quadrupole-time of flight mass spectrometry (UHPLC-QTOF/MS) were utilized for the age discrimination and marker discovery. A statistical data processing procedure was established to screen markers and reduce the false positive rate. RESULTS: The results showed that the ginseng samples from 2- to 6-year-old could be well separated in the orthogonal projections on the latent structure - discrimination analysis (OPLS-DA) using the markers screened by the established statistical procedure, which could reduce approximately 20% of the insignificant markers and false positive discoveries. Ultimately, more than 50 compounds contributing to the age discrimination were identified including one new compound (malonylginsenoside). One negative marker (1038.4825@8.98) was discovered for the 2-year-old ginseng, and an equation was established to effectively predict the age of 3- to 6-year-old of ginseng. CONCLUSION: The constructed method can discriminate the ginseng samples with different cultivation years and is a complement to the traditional discrimination method of ginseng age.

Purity assessment of ginsenoside Rg1 using quantitative 1H nuclear magnetic resonance.

Ginseng herbs comprise a group of the most popular herbs, including Panax ginseng, P. notoginseng and P. quinquefolius (Family Araliaceae), which are used as traditional Chinese medicine (TCM) and are some of the best-selling natural products in the world. The accurate quantification of ginsenoside Rg1 is one of the major aspects of its quality control. However, the purity of the commercial Rg1 chemical reference substance (CRS) is often measured with high-performance chromatography coupled with an ultraviolet detector (HPLC-UV), which is a selective detector with unequal responses to different compounds; thus, this detector introduces probable error to purity assessments. In the present study, quantitative nuclear magnetic resonance (qNMR), due to its absolute quantification ability, was applied to accurately assess the purity of Rg1 CRS. Phenylmethyl phthalate was used as the internal standard (IS) to calibrate the purity of Rg1 CRS. The proton signal of Rg1 CRS in methanol-d4 at 4.37ppm was selected to avoid interfering signals, enabling accurate quantitative analysis. The relaxation delay, number of scans, and NMR windowing were optimized for data acquisition. For post-processing, the Lorentz/Gauss deconvolution method was employed to increase the signal accuracy by separating the impurities and noise in the integrated region of the quantitative proton. The method validation showed that the developed method has acceptable sensitivity, linearity, precision, and accuracy. The purity of the commercial Rg1 CRS examined with the method developed in this research was 90.34±0.21%, which was obviously lower than that reported by the manufacturer (>98.0%, HPLC-UV). The cross-method validation shows that the commonly used HPLC-UV, HPLC-ELSD (evaporative light scattering detector) and even LC-MS (mass spectrometry) methods provide significantly higher purity values of Rg1 CRS compared with the qNMR method, and the accuracy of these LC-based methods largely depend on the amount of the sample that was loaded and the properties of the impurities.

[Pilot observation on the effect of integrated control measures against clonorchiasis in Pengjiang District of Jiangmen City].

From June to December in 2008, five villages were randomly chosen from Pengjiang District of Jiangmen city and about five hundred residents from each village were examined for clonorchiasis by Kato-Katz method (three slides per specimen). Fifty residents from each village were re-examined one month after treatment. One year later 50 treated residents were chosen from Dalin village and Sanya village for fecal examination. Questionnairing was conducted to determine the knowledge rate on clonorchiasis prevention among residents. The percentage and usage of sanitary toilets were investigated. The average infection rate of clonorchiasis from five villages was 21.5%(537/2501). 86.6%(465/537) of clonorchiasis received treatment voluntarily. One month after treatment the infection rate in four villages declined significantly. The positive rate showed no significant difference between one month and one year after treatment in Dalin and Sanya villages (P>0.05) . Questionairing indicated that 41.2%(170/413) of the clonorchiasis cases ate raw fish frequently, which was significantly higher than those non-infected people [4.2%, 8/192] (P<0.05). After health education, the knowledge awareness rate raised from 23.1% (135/584) to 84.5% (349/413) (P<0.05). The dissemination and usage of sanitary toilets were 93.2% (38 068/40 848) and 100%, respectively.

[Isolation, identification and sequence analyses of dengue virus type 2 strain GD19/2001].

OBJECTIVE: To identify the virus isolated from Jiangmen, Guangdong province and to discuss the possible origin. METHODS: Using characteristics of indirect fluorescent antibody tests (IFA), reverse transcription-polymerase chain reaction (RT-PCR), mouse neurovirulence and cell culture to identify the isolated virus. According to the nature of dengue virus type 2 NGC strain, two pairs of primers were designed. The structural protein gene of isolated dengue virus type 2 strain was then amplified by RT-PCR, cloned into pMD18-T vector and sequenced. RESULTS: Twenty-two of 37 serum samples showed a positive reaction to dengue antibody IgG, and 36 of 37 with IgM with the highest antibody titer 1:640. Ten samples were resulted in a cytopathy on C6/36 cells and showed a neurovirulence in suckling mice when inoculated intracerebrally. The structural gene of new isolate GD19/2001 containing 2 325 nucleotides which encoded 774 amino acids. Data on nucleotide homology were 98%, 96%, 94%, 94%, 92%, 92%, 92% and 91% compared with TSV01, GD06/93, NGC and 44, ThNH81/93, 04 and GD08/98, and S1 respectively. CONCLUSION: The isolated virus from Jiangmen, Guangdong province belonged to dengue virus type 2, which might come from Australia.