Intraspecific DNA Barcoding and Variation Analysis for Citri Reticulatae Pericarpium of Citrus reticulata "Chachi"

Recent advances in the authentication (geographical origins, varieties and aging time) of tangerine peel (Citri reticulatae pericarpium): A review

The consumption of tangerine peel (Citri reticulatae pericarpium, CRP) has been steadily increasing worldwide due to its proven health benefits and sensory characteristics. However, the price of CRP varies widely based on its origin, variety, and aging time, which has led many manufacturers to offer inferior products by exploiting the sensory similarity of CRP, seriously undermining consumers' interests. Therefore, it is essential to identify the authenticity of the CRP. In this study, the research progress on the authenticity of CRP from different origins, years and varieties over the past 10 years and the application and prospects of the main technologies and techniques were reviewed. The advantages and disadvantages of the commonly used methods were also summarized and compared. Mass spectrometry-based and spectroscopy-based techniques are the most commonly used methods for analyzing CRP authenticity. However, designing fast, non-destructive and green methods for identifying CRP authenticity would be the future trend.

Flavonoids contribute most to discriminating aged Guang Chenpi (Citrus reticulata 'Chachi') by spectrum-effect relationship analysis between LC-Q-Orbitrap/MS fingerprint and ameliorating spleen deficiency activity

To further explore the mechanism of "the longer storage time, the better bioactivity" of aged Guang Chenpi, the dry pericarp of Citrus reticulata 'Chachi' (CRC), a series of activity assessments were performed on spleen deficiency mice. The constituents in CRC with different storage years were analyzed by LC-Q-Orbitrap/MS. A total of 53 compounds were identified, and CRC stored for more than 5 years showed higher flavonoid content, especially that of polymethoxyflavones. Anti-spleen deficiency bioactivity analysis among various CRC with different storage years showed aged CRC (stored for more than 3 years) could significantly alleviate fatigue and depression behaviors much better, increase D-xylose and gastrin secretion, and upregulate the expression of the linking protein occludin in the colon walls. Results from 16S rDNA sequencing showed that aged CRC could downregulate the abundance of Enterococcus, Gemmata, Citrobacter, Escherichia_Shigella, and Klebsiella, which were significantly overrepresented in the model group. Bacteroides, Muribaculum, Alloprevotella, Paraprevotella, Alistipes, Eisenbergiella, and Colidextribacter were downregulated in the model group but enriched in the CRC groups. At last, the spectrum-effect relationship analysis indicated that flavonoids such as citrusin III, homoeriodictyol, hesperidin, nobiletin, and isosinensetin in aged CRC showed the highest correlation with better activity in ameliorating spleen deficiency by regulating gut microbiota. Flavonoids contribute most to discriminating aged CRC and could disclose the basis of "the longer storage time, the better bioactivity" of aged Guang Chenpi.

Review of recent advances on health benefits, microbial transformations, and authenticity identification of Citri reticulatae Pericarpium bioactive compounds

The extensive health-promoting effects of Citri Reticulatae Pericarpium (CRP) have attracted researchers' interest. The difference in storage time, varieties and origin of CRP are closely related to the content of bioactive compounds they contain. The consitituent transformation mediated by environmental microorganisms (bacteria and fungi) and the production of new bioactive components during the storage process may be the main reason for 'the older, the better' of CRP. In addition, the gap in price between different varieties can be as large as 8 times, while the difference due to age can even reach 20 times, making the 'marketing young-CRP as old-CRP and counterfeiting origin' flood the entire market, seriously harming consumers' interests. However, so far, the research on CRP is relatively decentralized. In particular, a summary of the microbial transformation and authenticity identification of CRP has not been reported. Therefore, this review systematically summarized the recent advances on the main bioactive compounds, the major biological activities, the microbial transformation process, the structure, and content changes of the active substances during the transformation process, and authenticity identification of CRP. Furthermore, challenges and perspectives concerning the future research on CRP were proposed.

Comparative study on comprehensive quality of Xinhui chenpi by two main plant propagation techniques

Xinhui chenpi (XHCP), the sun-dried peel of the mandarin orange, Citrus reticulata "Chachi," is the most famous crude drug, as well as a traditional seasoning in Chinese cooking. The main cultivation methods of XHCP are cutting and grafting, but it is generally considered that the quality of XHCP after cutting is superior to that obtained from plants propagated by graftings, which had a negative impact on the marketing of the finished product. In our study, a total of 25 samples of XHCP obtained from plants cultivated by either traditional methods (i.e., from cuttings) or by grafting were collected to compare the contents of four types of metabolites (essential oils, flavonoids, synephrine, and total polysaccharides) as well as antioxidant activity. The results revealed that the quality of XHCP did not decline after cutting, and marked individual differences between XHCP samples, even when prepared from plants grown in the same way. In general, grafting had no significant effect on the most essential oils components, total polysaccharides, synephrine, total flavonoids, total polymethoxylated flavones, hesperidin, nobiletin, tangeretin content, and antioxidant activity. Nevertheless, five volatile compounds can be used as potential chemical markers (p < 0.05) to distinguish between cutting XHCP and grafted XHCP, while four volatile compounds showed high content in grafted XHCP. Our study is expected to provide a theoretical basis for XHCP breeding and cultivation, and thereby further standardize the market of XHCP.