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Objective:To analyze and compare the fishy components in raw, stir-fried, liquorice-processed, vinegar-processed and wine-processed products of Pheretima aspergillum, and explore the material basis and processing principle of fishy smell of P. aspergillum. Method:Heracles Ⅱ ultra-fasted gas chromatography electronic nose technology combined with chemometrics was used for the overall analysis of volatile components in raw P. aspergillum and its processed products. Headspace gas chromatography-mass spectrometry (HS-GC-MS) was used to analyze and identify the volatile compositions in the raw products and processed products. Gas chromatographic conditions were as following：temperature program (initial temperature at 60 ℃, kept for 5 min, up to 120 ℃ with the heating rate of 3 ℃·min-1, and then up to 230 ℃ with the heating rate of 10 ℃·min-1 and finished), the inlet temperature at 280 ℃, high purity helium as the carrier gas, the flow rate of 1.0 mL·min-1, the split ratio of 20∶1. Mass spectrum conditions were as following：electron impact ionization (EI), electron collision energy of 70 eV, ion source temperature of 230 ℃, quadrupole temperature at 150 ℃, scanning range of m/z 50-550. The relative content of each component was calculated by peak area normalization. Result:Principal component analysis (PCA) and discriminant factor analysis (DFA) of the electronic nose showed that the raw products and its processed products could be clearly distinguished from each other. Among them, the difference between raw products and stir-fried, liquorice-processed products was small, but the difference between raw products and vinegar-processed, wine-processed products was large. A total of 25, 27, 22, 26 and 33 components were respectively identified from raw, stir-fried, liquorice-processed, vinegar-processed and wine-processed products of P. aspergillum, there were 13 common components in these products, including 4 aldehydes (isovaleraldehyde, 2-methylbutyraldehyde, hexanal, benzaldehyde), 2 ketones (2-heptanone, 2-tridecanone), 1 carboxylic acid (lauric acid), 4 heterocyclic compounds (2-methylpyrazine, 2,5-dimethyl pyrazine, 2-pentylfuran, 2-ethyl-6-methyl pyrazine), 1 amine (trimethylamine) and 1 alcohol (1-octen-3-ol). Conclusion:The odorous components in the raw products are mainly derived from aldehydes (isovaleraldehyde, 2-methylbutyraldehyde, isobutyraldehyde, 2-ethylhexanal, hexanal) and amines (trimethylamine). Odorous components of P. aspergillum can be reduced effectively by stir-fried and liquorice, vinegar, wine processing, while flavoring substances can be increased by wine processing to cover its ugly odor. This paper can provide scientific basis for the deodorization of P. aspergillum by processing, and also provide reference for the analysis and correction of ugly odor of other animal medicines.
ABSTRACT
Objective: In recent years,with the increase in the commodity price of medicinal pheretima,there have emerged increasing adulterates in the medicine market. Besides,the medicinal materials have mostly lost the main identification features, and are difficult to distinguish. Therefore,it is urgent to establish an accurate and stable method for the identification of pheretima. Method: According to the differences of COI gene DNA sequences among Pheretima aspergillum,Pheretima vulgaris,Pheretima guillelmi,Pheretima pectinifera and adulterants,the variation site was found,the specific primers were designed,the reaction conditions were optimized,and the polymerase Chain reaction(PCR) method for identification was explored and verified in terms of tolerance and feasibility in this study. The specific primers were combined to build multiple PCR systems. An effective,accurate,convenient,highly specific and repeatable Multiplex Allele-Specific PCR identification method was established for identifying medicinal pheretima and its common adulterants. Result: Through the established multiplex PCR reaction system, 366,487,487 and 475 bp of fragments were amplified from DNA templates of P. aspergillum,P. vulgaris,P. guillelmi and P.pectinifera respectively. All of the adulterants were negative by the multiplex PCR assay. The PCR amplification of specific alleles method established in this paper can accurately identify pheretima. Conclusion: The Multiplex Allele-Specific PCR identification method established in this paper can accurately identify medicinal pheretima and its adulterants.
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Objective: To establish a method for the analysis of constituents of Pheretima aspergillum by UPLC-Q-TOF-MS. Methods: The analysis was performed on an Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) by gradient elution. The mobile phase consist of 0.1% formic acid-acetonitrile and 0.1% formic acid-water at a flow rate of 0.3 mL/min. The column temperature was at 35 ℃. The information of the compounds was acquired in positive and negative mode. Results: Total 83 compounds were inferred, contains 11 free amino acids, 26 organic acids, 11 necleosides, 5 dipeptides and cyclic dipeptideds and other 21 nitrogen-containing substances, the rest on a total of 10. Conclusion: The method is accurate, rapid, and sensitive, and provide a basis for further clarifying the material basis of its efficacy and the selection of quality control indicators.
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Objective: To lay a foundation for attenuating the heavy metal accumulation in Pheretima aspergillum by means of genetic engineering technology in further research, we revealed the transcriptional regulation mechanism of MT-2 gene. Methods: The coding sequence of MT-2 gene was amplified by PCR with specific primers, which were designed according to their known cDNA sequences, and the outcomes were contrastively analyzed after the sequencing process. Prior to the isolation of 5' promoter sequence by genome walking technology, three specific primers were designed based on MT-2 cDNA sequence. Meanwhile, the cis-acting elements of MT-2 gene were analyzed by Promoter Prediction online software. Results: After PCR and sequencing processes, a 2 826 bp coding sequence of MT-2 gene were obtained, four exons and four introns were found to compose the coding area by comparing with the known MT-2 cDNA sequence (accession No.KC787373.1). Besides, after genome walking and Promoter Prediction online analysing, a 1 534 bp promoter region of MT-2 was isolated, which contained not only CAAT box, TAAT box, and other core promoter elements, but also three MRE elements which specifically response to heavy metal involved in regulating the MT-2 expression. Conclusion: The expression of MT-2 gene in P. aspergillum can be induced by heavy metal, and the transcriptional level is achieved by MRE regulatory elements located in MT-2 gene promoter region.
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Objective To screen out the polymerase chain reaction ( PCR) primers for specifically identifying Pheretima aspergillum (E. Perrier) , so as to establish a rapid and accurate method to identify the origin of Pheretima aspergillum. Methods Four kinds of earthworms recorded in pharmacopoeia and six kinds of their adulterants commonly seen in the market were collected. The 12SrRNA sequences related to earthworm were downloaded from GenBank database. PCR amplification for ten kinds of samples was performed using the universal primers, and then the products were sequenced. According to the differences between the above sequences, three pairs of specific primers in the non-conservative district were designed for identification of Pheretima aspergillum. Results High-specificity PCR amplification for Pheretima aspergillum with 12St/12Stf primer occurred when the annealing temperature was increased to 64℃, and only Pheretima aspergillum had single amplification strip, while no strips were found in the other adulterants under the same condition. The achieved specific primers could be well verified in 15 kinds of medicinal materials of earthworm purchased in the market, which had the same morphological features showed by the traditional identifying method. Conclusion With 12St/12Stf primer as a specific marker, the identifica tion of Pheretima aspergillum is rapid and accurate in related species of Pheretima aspergillum, and avoids the effect of some factors such as integrity of experimental materials and drying process.
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Objective To establish an effective method for the determining hypoxanthine, xanthine, uridine and uracil in earthworm in Shanghai Pheretima and Pheretima aspergillum (E. Perrier), contributing to quality control of the medicinal material. Methods Hypoxanthine, xanthine, uridine and uracil were extracted from the earthworms with 0.9% NaCl by ultrasonic and determined by HPLC. The chromatographic conditions were: SORBAX SB-Aq column (250 mm×4.6 mm, 5 μm, Aglient Co.,Ltd), 5 mmol/L KH2PO4 (pH 2.9) as the mobile phase with a flow rate of 1 mL/min,the detection wavelength was 254nm, the column temperature was set at 30℃, and the injection volume was 10 μL. Hypoxanthine, xanthine, uridine and uracil were determined by HPLC at the same time. Results The linear range was 0.5-100 μg (r=0.999 9) for hypoxanthine, with the average recovery being 99.37%, RSD=1.36% (n=6). The linear range was 0.5-100 μg (r=0.993 1) for xanthine, with the average recovery being 91.57%, RSD=1.40% (n=6). The linear range was 0.5-100 μg (r=0.999 9) for uridine, with the average recovery being 95.31%, RSD=1.64% (n=6). The linear range was 0.5-100 μg (r=0.999 9) for uracil, with the average recovery being 100.21%, RSD=1.98% (n=6). Conclusion The current method is reproducible and has satisfactory recovery, and it can be used to determine hypoxanthine, xanthine, uridine and uracil in earthworm medicinal material.