Metabolomic Profiling Reveals the Quality Variations in Citri Reticulatae Pericarpium (Citrus reticulata Blanco cv. Chachiensis) with Different Storage Ages in Response to "Candidatus Liberibacter Asiaticus" Infection.

Citri Reticulatae Pericarpium, especially the pericarp of Citrus reticulata Blanco cv. Chachiensis (PCRC), is an important edible and medicinal ingredient for health and pharmacological properties. Citrus Huanglongbing, a devastating disease that currently threatens the citrus industry worldwide, is caused by a phloem-limited alpha-proteobacterium, "Candidatus Liberibacter asiaticus" (CLas). The industry of cultivar Chachiensis has been suffering from HLB. Although HLB affected the quality of citrus fruit, whether the quality of PCRC was affected by HLB remains unclear. In this study, we compared the metabolite profiles between HLB-affected and healthy PCRC from three sources: fresh, 6-month-old, and 9-year-old PCRC, through the untargeted LC-MS method. Compared to healthy controls, various types of bioactive compounds, mainly flavonoids, terpenoids, alkaloids, coumarins, polysaccharides, and phenolic acids, accumulated in HLB-affected PCRC, especially in the HLB-affected 9-year PCRC. In particular, isorhamnetin, isoliquiritigenin, luteolin 7-O-beta-D-glucoside, limonin, geniposide, pyrimidodiazepine, scoparone, chitobiose, m-coumaric acid, malonate, and pantothenic acid, which contributed to the pharmacological activity and health care effects of PCRC, were highly accumulated in HLB-affected 9-year-old PCRC compared to the healthy control. Multibioassay analyses revealed that HLB-affected 9-year-old PCRC had a higher content of total flavonoids and total polyphenols and exhibited similar antioxidant capacity as compared to healthy controls. The results of this study provided detailed information on the quality of HLB-affected PCRC.

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.

Network Pharmacology and Molecular Modeling Techniques in Unraveling the Underlying Mechanism of Citri Reticulatae Pericarpium aganist Type 2 Diabetic Osteoporosis.

Type 2 diabetic osteoporosis (T2DOP) is a common complication in diabetic patients that seriously affects their health and quality of life. The pathogenesis of T2DOP is complex, and there are no targeted governance means in modern medicine. Citri Reticulatae Pericarpium (CRP) is a traditional Chinese medicine that has a long history and has been used in the treatment of osteoporosis diseases. However, the molecular mechanism for the CRP treatment of T2DOP is not clear. Therefore, this study aimed to explore the underlying mechanisms of CRP for the treatment of T2DOP by using network pharmacology and molecular modeling techniques. By retrieving multiple databases, we obtained 5 bioactive compounds and 63 common targets of bioactive compounds with T2DOP, and identified AKT 1, TP 53, JUN, BCL 2, MAPK 1, NFKB 1, and ESR 1 as the core targets of their PPI network. Enrichment analysis revealed that these targets were mainly enriched in the estrogen signaling pathway, TNF signaling pathway, and AGE-RAGE signaling pathway in diabetics, which were mainly related to oxidative stress and hormonal regulation. Molecular docking and molecular dynamics simulations have shown the excellent binding effect of the bioactive compounds of CRP and the core targets. These findings reveal that CRP may ameliorate T2DOP through multiple multicomponent and multitarget pathways.

Citri Reticulatae Pericarpium Limits TLR-4-Triggered Inflammatory Response in Raw264.7 Macrophages by Activating RasGRP3.

Inflammation is an important immune response to pathogen invasion, but excessive inflammation leads to tissue injury and even cytokine storm. Therefore, proper response is needed depending on the intensity of the infection. Ras guanine nucleotide releasing protein 3 (RasGRP3) is a regulator of the TLR-mediated response. In low-intensity inflammation, it negatively regulates production of pro-inflammatory cytokines, especially IL-6. Citri Reticulatae Pericarpium, the peel of Citrus reticulata Blanco, is a major medicinal herb in Korean medicine. The present study aims to investigate whether the Citri Reticulatae Pericarpium extract (CRE) has immunomodulatory activity using the Raw264.7 macrophage. Also, we investigated the effect of CRE on RasGRP3 expression. In the present study, CRE reduced IL-6 production in the low-LPS environment (1 ng/mL) and did not in the high-LPS environment (100 ng/mL). The suppression of IL-6 production in the low-LPS environment (1 ng/mL) was abolished after the pretreatment of RasGRP3 siRNA. The reduced RasGRP3 protein content by 100 ng/mL LPS treatment was increased by CRE treatment. Additionally, nobiletin, a major component of CRE showed a suppressive effect on IL-6 production in the low-LPS environment (1 ng/mL). The present results suggest that CRE alleviates inflammatory response via activating RasGRP3 expression in low-intensity inflammation.

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.

Reduction of Th2 inflammation and fibrosis in eosinophilic esophagitis in a murine model by citri reticulatae pericarpium.

ETHNOPHARMACOLOGICAL RELEVANCE: Inflammation and subepithelial fibrosis play major roles in the early pathology of eosinophilic esophagitis (EoE). However, there are currently no pharmacotherapeutic interventions that directly target eosinophilic esophagitis. Citri Reticulatae Pericarpium (CRP, known as Chen-Pi) is one of most frequently used qi-regulating drugs in Chinese medicine and nutrition. CRP is rich with flavonones and polymethoxy flavones, both of which exhibit superior anti-inflammatory, anti-allergic and anti-fibrosis effects. This study is to investigate intervention effect of CRP on EoE, to identify its active compounds and to explore its underlying mechanisms. METHODS: The CRP extract was obtained by liquid-liquid extraction with 70% ethanol, and its main components were identified by HPLC and TLC chromatography as hesperidin, nobiletin, tangeretin, and narirutin in turn. Furthermore, we evaluated its effect and underlying mechanisms in an PN (Peanut protein extract)-sensitized murine model of food allergy induced EoE. RESULTS: CRP treatment attenuated EoE model mice symptomatology, blocked hypothermia, reduced the production of PN-specific IgE and IgG1 and TH2 cytokines (interleukin (IL)-4 and IL-5), and increased the level of anti-inflammatory cytokines IL-10 and interferon (IFN)-γ. CRP treatment also significantly alleviated the pathological damage and reduced fibrosis in inflamed tissues like esophagus, lung, and intestine. These results were strongly associated with reducing the expression of p-p38 mitogen-activated protein kinase (MAPK), transforming growth factor beta1 (TGF-ß1) and p-Smad 3 proteins. CONCLUSION: CRP extract markedly inhibited TH2 immune response and attenuated subepithelial fibrosis with a dose-dependent manner through down-regulating MAPK/TGF-ß signaling pathway. It is suggested that CRP extract might serve as a potential therapy for food allergy-induced EoE like disease.

Citri Reticulatae Pericarpium-Reynoutria japonica Houtt. herb pair suppresses breast cancer liver metastasis by targeting ECM1-mediated cholesterol biosynthesis pathway.

BACKGROUND: Liver metastasis is a frequent event in breast cancer that causes low survival rate and poor prognosis. Citri Reticulatae Pericarpium-Reynoutria japonica Houtt. (CR), a traditional Chinese herb pair, is used for the treatment of breast cancer liver metastasis or cholesterol gallstone disease in clinics. PURPOSE: This study attempted to investigate the potential therapeutic target and mechanism of CR herb pair on breast cancer liver metastasis. METHODS: The anti-metastatic and cholesterol-lowering activities of CR extract were evaluated in triple-negative breast cancer (TNBC) cell lines and an experimental liver metastasis model. The role of extracellular matrix protein 1 (ECM1) in the cholesterol biosynthesis pathway was determined by the knockdown and overexpression of ECM1 gene of TNBC cells. Changes in the gene and protein expression levels of ECM1 and the cholesterol biosynthesis pathway after CR treatment were detected in vitro and in vivo by real-time PCR and Western blot. RESULTS: The invasive and metastatic potentials and hypercholesterol levels of TNBC cells were positively associated with ECM1 expression. ECM1 knockdown reduced tumor cholesterol levels via downregulating cholesterol biosynthesis genes, including ACAT2, HMGCS1, HMGCR, MVK, and MVD, whereas ECM1 overexpression elicited the opposite effects. CR herb pair exerts the potential therapeutic effects on TNBC liver metastasis, which is partially mediated by disrupting ECM1-activated cholesterol biosynthesis process in TNBC cells. CONCLUSION: This study reveals that ECM1 is a novel target for the activation of cholesterol biosynthesis to promote TNBC liver metastasis occurrence. CR herb pair, an ECM1 inhibitor, maybe be considered to serve as an adjuvant therapeutic drug for liver metastasis in clinical practice.

Progress of research on the role of active ingredients of Citri Reticulatae Pericarpium in liver injury.

BACKGROUND: Liver is a vital organ responsible for metabolizing and detoxifying both endogenous and exogenous substances in the body. However, it is susceptible to damage from chemical and natural toxins. The high incidence and mortality rates of liver disease and its associated complications impose a significant economic burden and survival pressure on patients and their families. Various liver diseases exist, including cholestasis, viral and non-viral hepatitis, fatty liver disease, drug-induced liver injury, alcoholic liver injury, and severe end-stage liver diseases such as cirrhosis, hepatocellular carcinoma (HCC), and cholangiocellular carcinoma (CCA). Recent research has shown that flavonoids found in Citri Reticulatae Pericarpium (CRP) have the potential to normalize blood glucose, cholesterol levels, and liver lipid levels. Additionally, these flavonoids exhibit anti-inflammatory properties, prevent oxidation and lipid peroxidation, and reduce liver toxicity, thereby preventing liver injury. Given these promising findings, it is essential to explore the potential of active components in CRP for developing new drugs to treat liver diseases. OBJECTIVE: Recent studies have revealed that flavonoids, including hesperidin (HD), hesperetin (HT), naringenin (NIN), nobiletin (NOB), naringin (NRG), tangerine (TN), and erodcyol (ED), are the primary bioactive components in CRP. These flavonoids exhibit various therapeutic effects on liver injury, including anti-oxidative stress, anti-cytotoxicity, anti-inflammatory, anti-fibrosis, and anti-tumor mechanisms. In this review, we have summarized the research progress on the hepatoprotective effects of HD, HT, NIN, NOB, NRG, TN, ED and limonene (LIM), highlighting their underlying molecular mechanisms. Despite their promising effects, the current clinical application of these active ingredients in CRP has some limitations. Therefore, further studies are needed to explore the full potential of these flavonoids and develop new therapeutic strategies for liver diseases. METHODS: For this review, we conducted a systematic search of three databases (ScienceNet, PubMed, and Science Direct) up to July 2022, using the search terms "CRP active ingredient," "liver injury," and "flavonoids." The search data followed the PRISMA standard. RESULTS: Our findings indicate that flavonoids found in CRP can effectively reduce drug-induced liver injury, alcoholic liver injury, and non-alcoholic liver injury. These therapeutic effects are mainly attributed to the ability of flavonoids to improve liver resistance to oxidative stress and inflammation while normalizing cholesterol and liver lipid levels by exhibiting anti-free radical and anti-lipid peroxidation properties. CONCLUSION: Our review provides new insights into the potential of active components in CRP for preventing and treating liver injury by regulating various molecular targets within different cell signaling pathways. This information can aid in the development of novel therapeutic strategies for liver disease.

Identification of volatile and nonvolatile compounds in Citri Reticulatae Pericarpium Viride using GC-MS, UPLC-Q-Exactive Orbitrap-MS, and HPLC-PDA.

Gas chromatograph-mass spectrometer (GC-MS), ultra-high-performance liquid chromatograph-Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS), and high-performance liquid chromatography-photodiode array detection (HPLC-PDA) were used to qualitatively and quantitatively analyze the chemical component of Citri Reticulatae Pericarpium Viride "Geqingpi" (GQP). First of all, the volatile components of GQP are identified by GC-MS. Totally 56 volatile components were determined, and γ-Terpinene (33.39%) and D-Limonene (22.95%) were the main terpenes. Secondly, UHPLC-Q-Exactive Orbitrap-MS was used for identifying nonvolatile compositions and 42 compositions were identified totally, including 23 flavonoids, nine organic acids, three coumarins, two alkaloids compounds, and five other compounds, among which nine of the determined constituents were detected for the first time in GQP. Thirdly, the content of seven main constituents in GQP was quantitatively analyzed via HPLC-PDA, which were synephrine, hesperidin, limonin, nobiletin, HMF, tangeretin, and 5-HPMF. Further investigation for quantitative analysis of seven bioactive compounds suggested that the concentration of hesperidin in GQP approximately was 16.0% (160.78 ± 0.95 mg·g-1), which was far higher than the standard for identification and quality control of CRPV in Chinese Pharmacopoeia (2020 edition) that "the content of hesperidin shall not be less than 5.0%." The phytochemicals of GQP were elucidated in this study, which might be supporting information for identification between GQP and Citri Reticulatae Pericarpium Viride "Sihuaqingpi" (SHQP) and provided a scientific basis for the further active ingredient for pharmacological research and development prospects of GQP.

Soil conditions and the plant microbiome boost the accumulation of monoterpenes in the fruit of Citrus reticulata 'Chachi'.

BACKGROUND: The medicinal material quality of Citrus reticulata 'Chachi' differs depending on the bioactive components influenced by the planting area. Environmental factors, such as soil nutrients, the plant-associated microbiome and climatic conditions, play important roles in the accumulation of bioactive components in citrus. However, how these environmental factors mediate the production of bioactive components of medicinal plants remains understudied. RESULTS: Here, a multi-omics approach was used to clarify the role of environmental factors such as soil nutrients and the root-associated microbiome on the accumulation of monoterpenes in the peel of C. reticulata 'Chachi' procured from core (geo-authentic product region) and non-core (non-geo-authentic product region) geographical regions. The soil environment (high salinity, Mg, Mn and K) enhanced the monoterpene content by promoting the expression of salt stress-responsive genes and terpene backbone synthase in the host plants from the core region. The microbial effects on the monoterpene accumulation of citrus from the core region were further verified by synthetic community (SynCom) experiments. Rhizosphere microorganisms activated terpene synthesis and promoted monoterpene accumulation through interactions with the host immune system. Endophyte microorganisms derived from soil with the potential for terpene synthesis might enhance monoterpene accumulation in citrus by providing precursors of monoterpenes. CONCLUSIONS: Overall, this study demonstrated that both soil properties and the soil microbiome impacted monoterpene production in citrus peel, thus providing an essential basis for increasing fruit quality via reasonable fertilization and precision microbiota management. Video Abstract.

Quality control strategies of medicine food homology materials based on fingerprint profiling and chemometrics: Citri Reticulata Pericarpium as an example.

The study aimed to provide a reliable and feasible strategy for the comprehensive quality control of medicine food homology materials (MFHM). The high performance liquid chromatography (HPLC) fingerprints and Fourier transform mid-infrared (FT-MIR) quantized fingerprints were successfully developed to comprehensively evaluate overall quality of Citri Reticulata Pericarpium (CRP) by applying comprehensive quantified fingerprint method (CQFM). All samples were well distinguished and divided into 5 grades. In addition, through principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), the identification ability of HPLC fingerprints and FT-MIR fingerprints on CRP with different storage years was discussed. The results showed that HPLC fingerprints combined with PCA had good discrimination ability, and the PLS-DA model established by the preprocessed FT-MIR fingerprint data could accurately distinguish and predict the storage period of CRP. Finally, based on 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging assay, combined with bivariate correlation analysis, the fingerprint-activity relationship of offline antioxidant activity of CRP samples with the fingerprints peak were studied. In general, the comprehensive strategies provide a reliable and scientific reference scheme for the quality control of MFHM in the future.

Quality Difference Analysis of Raw and Steamed Products of Citri Reticulatae Pericarpium Based on Electronic Eye Technique and Chemical Fingerprint / 中国实验方剂学杂志

ObjectiveTo explore the quality differences between steamed products and raw products of Citri Reticulatae Pericarpium（CRP）. MethodThe color of steamed products and raw products of CRP was determined from the perspective of appearance by electronic eye technique， and the quality differences between them was objectively characterized by the luminous value（L*）， yellow-blue value（b*）， red-green value（a*） and total chromatic value（E*ab）. Based on this， ultra-high performance liquid chromatography（UPLC） was used to establish a fingerprint evaluation method with the mobile phase of acetonitrile（A）-0.1% formic acid aqueous solution（B） for gradient elution（0-5 min， 5%A； 5-30 min， 5%-20%A； 30-60 min， 20%-52%A）， detection wavelength at 270 nm， flow rate of 0.3 mL·min-1 and column temperature of 30 ℃. The quality differences between steamed products and raw products of CRP were compared from the perspective of chemical composition， and correlation analysis was used to reveal the correlation between the difference in appearance color and the difference in internal chemical composition. ResultAfter being steamed， L*， b* and E*ab of CRP showed an overall decreasing trend， indicating that the color of the steamed products darkened and deepened from yellow to blue but still tended to be yellow， while a* showed an overall increasing trend， indicating that the color of the steamed products tended to red. A total of 24 peaks were identified in the fingerprint profiles of raw products and steamed products of CRP， and 13 of the main peaks were identified. The precision， stability and repeatability studies showed that compared with the reference peak （peak 14， hesperidin）， the relative standard deviations（RSDs） of the relative peak area and relative retention time of the remaining peaks were<3.0%.The results of chemometric statistical analysis showed that there were some differences between raw products and steamed products of CRP， and 7 main differential components were identified， among which 5-hydroxymaltol（peak 1） and 5-hydroxymethylfurfural（peak 2） were the characteristic components of steamed products. The correlation analysis results showed that， in addition to the above two characteristic components， four components of peak 4， peak 10 （vicenin-2）， peak 23 （tangeretin） and peak 24 （5-demethylnobiletin） also correlated significantly with the color change （E*ab） of the samples （P<0.05， P<0.01）. ConclusionBefore and after steaming， not only the chemical composition changes， but also the color. Comparing the characteristic peaks of chemical composition difference and color difference before and after steaming of CRP， it is found that 5-hydroxymaltol， 5-hydroxymethylfurfural and peak 4 are common characteristic difference components， which can provide a reference for establishing the characteristic quality control method of steamed products， and quickly evaluating the quality difference between raw products and steamed products of CRP.

Analysis on Components Absorbed into Blood of Citri Reticulatae Pericarpium in Rats Based on Sequential Metabolism and UPLC-HRMS / 中国实验方剂学杂志

ObjectiveTo study the metabolism of chemical components from Citri Reticulatae Pericarpium（CRP）in different parts of rats by sequential metabolism and ultra performance liquid chromatography-high resolution mass spectrometry（UPLC-HRMS）. MethodSD male rats were employed as experimental subjects， and blood samples of intestinal metabolism and hepatic metabolism were prepared after administration of CRP ethanol extract by in situ intestinal perfusion， and comprehensive metabolic samples were collected after intragastric administration. UPLC-HRMS was used to analyze the samples with acetonitrile（A）-0.1% formic acid aqueous solution（B）as the mobile phase for gradient elution（0-10 min， 10%-30%A； 10-30 min， 30%-95%A； 30-31 min， 95%-10%A； 31-35 min， 10%A）at a flow rate of 0.35 mL·min-1， using a heated electrospray ionization with positive and negative ion mode scanning in the range of m/z 100-1 500. Under these conditions， the differences in the profiles of CRP ethanol extract， blank plasma and drug-containing plasma under different treatment groups were compared， and the chemical components of each sample were analyzed and identified based on the retention time， accurate relative molecular mass， primary and secondary ion fragments， and the information of reference substances. ResultA total of 44 chemical components were identified in the CRP ethanol extract， including flavone-O-glycosides， flavone-C-glycosides and polymethoxyflavonoids， etc. The results of sequential metabolism showed that 22 chemical components in CRP were detected in the intestinal metabolic sample， 18 chemical components were detected in the hepatic metabolic sample， and 9 identical chemical components（narirutin， hesperidin， meranzin， 5，7，8，3ʹ，4ʹ，5ʹ-hexamethoxy-flavone， isosinensetin， sinensetin， 3，5，6，7，8，3ʹ，4ʹ-heptamethoxyflavone， nobiletin and tangeretin）could be detected in all three metabolic samples， with a total of 22 compounds entering the blood in prototype form. ConclusionThe identified 21 components with well-defined structures entering the blood as prototypes may be potential active components of CRP， and differences in the components at different metabolic parts can provide an experimental basis for elucidating the in vivo biotransformation process of the metabolic components of CRP.

Analysis of Suitable Processing Time of Rehmanniae Radix Praeparata Processed with Amomi Fructus and Citri Reticulatae Pericarpium Based on UPLC-Q-TOF-MS / 中国实验方剂学杂志

ObjectiveTo investigate the relative content changes of differential metabolites and reducing sugars during the processing process of Rehmanniae Radix Praeparata （RRP） processed with Amomi Fructus （AF） and Citri Reticulatae Pericarpium （CRP）， and to lay the foundation for revealing the processing principle of this characteristic variety. MethodThe samples of the 0-54 h processing process of RRP processed with AF and CRP were taken as the research object， and their secondary metabolites were detected by ultra performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry （UPLC-Q-TOF-MS）. The 0.1% formic acid aqueous solution （A）-acetonitrile （B） was used as the mobile phase for gradient elution （0-1 min， 1%-3%B； 1-10 min， 3%-9%B； 10-15 min， 9%-12%B； 15-22 min， 12%-18%B； 22-31 min， 18%-24%B； 31-35 min， 24%-100%B； 35-36 min， 100%-5%B； 36-40 min， 5%-1%B； 40-45 min， 1%B）， column temperature was 40 ℃， injection volume was 3 μL， flow rate was 0.3 mL·min-1. Electrospray ionization （ESI） was used to scan and collect MS data in the negative ion mode， the scanning range was m/z 50-1 250. Data analysis was carried out using PeakView 1.2 software， and the chemical composition of RRP processed with AF and CRP was identified by combining the literature information and chemical composition databases. The MS data were normalized by MarkerView 1.2， and then the multivariate statistical analysis was applied to screen the differential metabolites， and the changes of the relative contents of the differential metabolites with different processing times was analyzed， finally， correlation analysis was performed between the differential metabolites， the change of the reducing sugar content was combined to determine the most suitable processing time of RRP processed with AF and CRP. ResultA total of 121 compounds were identified from RRP processed with AF and CRP at different processing times， and 12 differential metabolites were screened out by multivariate statistical analysis， including catalpol， hesperidin， isoacteoside， acteoside， narirutin， echinacoside， isomartynoside， decaffeoylacteoside， 6-O-E-feruloylajugol， dihydroxy-7-O-neohesperidin， jionoside D， and rehmapicroside. With the prolongation of processing time， the relative contents of these 12 differential metabolites and reducing sugars changed slightly at 52-54 h. ConclusionUPLC-Q-TOF-MS can comprehensively and accurately identify the chemical constituents of RRP processed with AF and CRP at different processing times， and the suitable processing time of 52-54 h is determined according to the content changes of different metabolites and reducing sugars， which provides a basis for revealing the scientific connotation of the processing principle of this variety.

Discovery of the key active compounds in Citri Reticulatae Pericarpium (Citrus reticulata "Chachi") and their therapeutic potential for the treatment of COVID-19 based on comparative metabolomics and network pharmacology.

Edible herbal medicines contain macro- and micronutrients and active metabolites that can take part in biochemical processes to help achieve or maintain a state of well-being. Citri Reticulatae Pericarpium (CRP) is an edible and medicinal herb used as a component of the traditional Chinese medicine (TCM) approach to treating COVID-19 in China. However, the material basis and related mechanistic research regarding this herb for the treatment of COVID-19 are still unclear. First, a wide-targeted UPLC-ESI-MS/MS-based comparative metabolomics analysis was conducted to screen for the active metabolites of CRP. Second, network pharmacology was used to uncover the initial linkages among these metabolites, their possible targets, and COVID-19. Each metabolite was then further studied via molecular docking with the identified potential SARS-CoV-2 targets 3CL hydrolase, host cell target angiotensin-converting enzyme II, spike protein, and RNA-dependent RNA polymerase. Finally, the most potential small molecule compound was verified by in vitro and in vivo experiments, and the mechanism of its treatment of COVID-19 was further explored. In total, 399 metabolites were identified and nine upregulated differential metabolites were screened out as potential key active metabolites, among which isorhamnetin have anti-inflammatory activity in vitro validation assays. In addition, the molecular docking results also showed that isorhamnetin had a good binding ability with the key targets of COVID-19. Furthermore, in vivo results showed that isorhamnetin could significantly reduced the lung pathological injury and inflammatory injury by regulating ATK1, EGFR, MAPK8, and MAPK14 to involve in TNF signaling pathway, PI3K-Akt signalling pathway, and T cell receptor signaling pathway. Our results indicated that isorhamnetin, as screened from CRP, may have great potential for use in the treatment of patients with COVID-19. This study has also demonstrated that comparative metabolomics combined with network pharmacology strategy could be used as an effective approach for discovering potential compounds in herbal medicines that are effective against COVID-19.

Enzyme-Assisted Extraction of Narirutin from Citri Reticulatae Pericarpium and Anti-allergic Asthma Activity.

BACKGROUND: Asthma is a heterogeneous disorder of the airways related to inflammation; it affects millions of people worldwide. Due to the side effects of inhaled corticosteroids, researchers focused on the therapeutic effects of compounds derived from natural products. OBJECTIVE: To investigate the therapeutic benefits of Narirutin a valuable flavonoid in Citri Reticulatae Pericarpium for asthma. METHODS: Narirutin was extracted using the enzyme-assisted method with the L9 (34) orthogonal array to optimize the temperatures, pH, and reaction time. The mechanism of action of Narirutin was investigated via ELISA, flow cytometry, and Western blot analysis in vivo. RESULTS: Narirutin suppressed inflammatory cell infiltration in the lung tissue and decreased IgE and IgG1 levels in serum in vivo. It can also alleviate interleukin (IL)-4, IL-5, and interferon-γ concentrations in bronchoalveolar lavage fluid in mice. Moreover, it increased the ratio of CD4+/CD8+ T cells. Additionally, Narirutin significantly suppressed p-ERK1/2 and p-JNK expression in the MAPK signaling pathway. CONCLUSION: Narirutin affects the Th1/Th2 imbalance through the p-ERK and p-JNK suppression in the MAPK signaling pathway.

Comparison of Geqingpi and Sihuaqingpi based on ultra-high-performance liquid chromatography-tandem mass spectrometry combined with multivariate statistics, network pharmacology analysis, and molecular docking.

Citri Reticulatae Pericarpium Viride is used in traditional Chinese medicine as Geqingpi and Sihuaqingpi varieties. We used the ultra-high-performance liquid chromatography-quadrupole-Exactive Orbitrap-mass spectrometry method and high-performance liquid chromatography-triple quadrupole-tandem mass spectrometry to analyze the chemical compounds in these varieties. Principal components analysis and orthogonal partial least squares discriminant analysis were used to analyze the quantitative results. Network pharmacology and molecular docking technology were used to forecast Citri Reticulatae Pericarpium Viride treatment mechanisms in irritable bowel syndrome. We identified 44 main compounds in Citri Reticulatae Pericarpium Viride. Compared to Sihuaqingpi, Geqingpi had higher narirutin, didymin, naringenin, and hesperetin, and lower hesperidin, isosinensetin, nobiletin, 3,5,6,7,8,3',4'-hexamethoxyflavone, tangeretin. Tangeretin, nobiletin, narirutin, didymin, and isosinensetin were the main compounds distinguishing Geqingpi from Sihuaqingpi. We found that the MAPK signaling pathway, which is closely related to irritable bowel syndrome, was an important target pathway. TP53, HRAS, MAPK1, AKT1, and EGFR were important targets in this pathway. Eriodictyol-7-O-rutinoside, narirutin, limonin, and hesperidin showed a good binding ability to the five targets. Orientin, unique to Sihuaqingpi, bound well to TP53, MAPK1, AKT1, and EGFR, while rhoifolin bound well to TP53, HRAS, MAPK1, AKT1, and EGFR. Hesperetin, unique to Geqingpi, bound well to TP53, HRAS, and MAPK1, while naringenin bound well to HRAS. Hesperidin and didymin bound well to TP53, MAPK1, AKT1, and EGFR.

Bioinformatics-Guided Identification of Ethyl Acetate Extract of Citri Reticulatae Pericarpium as a Functional Food Ingredient with Anti-Inflammatory Potential.

Citri Reticulatae Pericarpium (CRP) is one of the most commonly used food supplements and folk medicines worldwide, and possesses cardiovascular, digestive, and respiratory protective effects partially through its antioxidant and anti-inflammatory functions. The unique aromatic flavor and mild side effects make CRP a promising candidate for the development of anti-inflammatory functional food. However, recent studies show that the crude alcoholic extract and some isolated compounds of CRP show compromised anti-inflammatory activity, which became the main factor hindering its further development. To identify the bioactive compounds with anti-inflammatory potential, and improve the anti-inflammatory effects of the extract, a bioinformatics-guided extraction protocol was employed in this study. The potential bioactive candidates were identified by combing network pharmacology analysis, molecular docking, principal components analysis, k-means clustering, and in vitro testing of reference compounds. Our results demonstrated that 66 compounds in CRP could be grouped into four clusters according to their docking score profile against 24 receptors, while the cluster containing flavonoids and phenols might possess a more promising anti-inflammatory function. In addition, in vitro anti-inflammatory tests of the seven reference compounds demonstrated that hesperitin, naringenin, and gardenin B, which were grouped into a cluster containing flavonoids and phenols, significantly decreased LPS-induced NO, TNF-α, and IL-6 production of macrophages. While the compounds outside of that cluster, such as neohesperidin, naringin, hesperidin, and sinensetin showed little effect on alleviating LPS-induced NO and proinflammatory cytokine production. Based on the chemical properties of selected compounds, ethyl acetate (EtOAc) was selected as the solvent for extraction, because of its promising solubility of flavonoids and phenols. Furthermore, the ethanol alcoholic extract was used as a reference. The chemical profiling of EtOAc and crude alcoholic extract by HPLC/MS/MS also demonstrated the decreased abundance of flavonoid glycosides in EtOAc extract but increased abundance of phenols, phenolic acid, and aglycones. In accordance with the prediction, the EtOAc extract of CRP, but not the crude alcoholic extract, significantly decreased the NO, IL-6, and TNF-α production. Taken together, the results suggested selective extraction of phenols and flavonoids rich extract was able to increase the anti-inflammatory potential of CRP partially because of the synergistic effects between flavonoids, phenols, and enriched polymethoxyflavones. Our study might pave the road for the development of ethyl acetate extract of CRP as a novel functional food with anti-inflammatory function.

Mechanism of Citri Reticulatae Pericarpium as an Anticancer Agent from the Perspective of Flavonoids: A Review.

Citri Reticulatae Pericarpium (CRP), also known as "chenpi", is the most common qi-regulating drug in traditional Chinese medicine. It is often used to treat cough and indigestion, but in recent years, it has been found to have multi-faceted anti-cancer effects. This article reviews the pharmacology of CRP and the mechanism of the action of flavonoids, the key components of CRP, against cancers including breast cancer, lung cancer, prostate cancer, hepatic carcinoma, gastric cancer, colorectal cancer, esophageal cancer, cervical cancer, bladder cancer and other cancers with a high diagnosis rate. Finally, the specific roles of CRP in important phenotypes such as cell proliferation, apoptosis, autophagy and migration-invasion in cancer were analyzed, and the possible prospects and deficiencies of CRP as an anticancer agent were evaluated.

[Spleen deficiency and phlegm dampness syndrome model in rats treated by Citri Reticulatae Pericarpium based on metabolomics].

The present study analyzed the effect of Citri Reticulatae Pericarpium on endogenous metabolites in spleen deficiency and phlegm dampness syndrome by metabolomics, and explored the underlying mechanism of Citri Reticulatae Pericarpium in the treatment of spleen deficiency and phlegm dampness syndrome.The model of spleen deficiency and phlegm dampness syndrome was induced in rats by the multi-factor modeling method.The intervention effects of Citri Reticulatae Pericarpium on rats with spleen deficiency and phlegm dampness syndrome were preliminarily evaluated by observing the pathological changes of rat liver tissues and measuring the plasma content of pathological and biochemical indexes such as triglyceride(TG), total cholesterol(TC), low-density lipoprotein cholesterol(LDL-C), and high-density lipoprotein cholesterol(HDL-C).Immunohistochemistry was used to detect the expression of AQP2 in the kidney, AQP3 in the colon, and AQP5 in the submandibular gland, and the effect of Citri Reticulatae Pericarpium on aquaporin expression in rats with spleen deficiency and phlegm dampness syndrome was evaluated.Furthermore, UHPLC-ESI-MS/MS was used to analyze the metabolic profiles of rat plasma samples.Multiple methods, such as principal component analysis(PCA) and orthogonal partial least squares discriminant analysis(OPLS-DA) were used for pattern recognition.Differential metabolites were screened out by t-test and variable importance in projection(VIP), followed by pathway analysis based on MetaboAnalyst 5.0.As revealed by experimental results, Citri Reticulatae Pericarpium could improve the pathological changes of liver tissues, increase the levels of HDL-C in the plasma, reduce the levels of TC, TG, and LDL-C, and enhance the expression of AQP2 in the kidney, AQP3 in the colon, and AQP5 in the submandibular gland of rats with spleen deficiency and phlegm dampness syndrome.In addition, 87 differential metabolites of spleen deficiency and phlegm dampness syndrome were screened out by UHPLC-ESI-MS/MS(the levels of 39 metabolites increased significantly and the levels of 48 metabolites decreased significantly), with the representatives of glycine, L-isoleucine, N-acetyl-L-tyrosine, xanthine, hypoxanthine, and trigonelline.The differential metabolites were mainly enriched in the pathways of steroid hormone biosynthesis, linoleic acid metabolism, and purine metabolism.This study distinguished and revealed the characteristic metabolic pattern of spleen deficiency and phlegm dampness syndrome by metabolomics.The preliminary construction of the OPLS-DA model provides an objective basis for the differentiation of spleen deficiency and phlegm dampness syndrome in traditional Chinese medi-cine(TCM), as well as ideas and methods for exploring the biological basis of TCM syndrome from the molecular level and the overall level.