The molecular mechanism for inhibiting the growth of nasopharyngeal carcinoma cells using polymethoxyflavonoids purified from pericarp of Citrus reticulata 'Chachi' via HSCCC.

Polymethoxyflavonoids (PMFs), the main bioactive compounds naturally occurring in the pericarp of Citrus reticulata 'Chachi' (CRCP), possess significant antitumor action. However, the action of PMFs in nasopharyngeal carcinoma (NPC) is currently unknown. The present research study was conducted to investigate the inhibitory mechanisms of PMFs from CRCP on NPC growth in vivo and in vitro. In our research, we used high-speed counter-current chromatography (HSCCC) to separate four PMFs (nobiletin (NOB), 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF), tangeretin (TGN), and 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (5-HPMF)) from CRCP. CCK-8 assay was used to preliminarily screen cell viability following exposure to the four PMFs. Colony formation, Hoechst-33258 staining, transwell, and wound scratch assays were performed to assess the anti-proliferation, invasion, migration, and apoptosis-inducing effects of HMF on NPC cells. NPC tumors in xenograft tumor transplantation experiments were also established to explore the effect of HMF (100 and 150 mg/kg/day) on NPC. The histopathological changes in the treated rats were observed by H&E staining and Ki-67 detection by immunohistochemical techniques. The expressions of P70S6K, p-P70S6K, S6, p-S6, COX-2, p53, and p-p53 were measured by Western blot. The four PMFs were obtained with high purity (>95.0%). The results of the preliminary screening by CCK-8 assay suggested that HMF had the strongest inhibitory effect on NPC cell growth. The results of the colony formation, Hoechst-33258 staining, transwell, and wound scratch assays indicated that HMF had significant anti-proliferation, invasion, migration, and apoptosis-inducing ability in NPC cells. Moreover, HMF suppressed NPC tumor growth in xenograft tumor transplantation experiments. Further investigation suggested that HMF regulated NPC cells proliferation, apoptosis, migration, and invasion by activating AMPK-dependent signaling pathways. In conclusion, HMF-induced AMPK activation inhibited NPC cell growth, invasion, and metastatic potency by downregulating the activation of the mTOR signaling pathway and COX-2 protein levels, as well as enhancing the p53 phosphorylation level. Our study provides a crucial experimental basis for the clinical treatment of NPC, as well as the development and utilization of PMFs from CRCP.

Effects of polymethoxyflavonoids on T helper 17 cell differentiation in vitro and in vivo.

We examined the effects of polymethoxyflavonoids (PMFs) on T helper (Th) 17 cell differentiation in vitro and in vivo. Five different PMFs including nobiletin (NOB), sudachitin (SUD), demethoxysudachitin, heptamethoxyflavone and natsudaidain were used for the in vitro study, and effects of those flavonoids on Th17 responses were investigated. NOB and heptamethoxyflavone significantly suppressed the proliferation response, but SUD, demethoxysudachitin and natsudaidain did not suppress the proliferation response. All of the five flavonoids decreased IL-17A production. Mice with experimentally induced autoimmune encephalomyelitis were used as an in vivo Th17 differentiation model. We focused on two flavonoids, NOB and SUD, and examined the effects of those flavonoids. NOB significantly suppressed Th17 cell proliferation and cytokine responses, but SUD only decreased proliferation responses. The results suggest that the suppressive effect of NOB on Th17 response in vivo is stronger than that of SUD. J. Med. Invest. 70 : 166-170, February, 2023.

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.

The Chemistry and the Anti-Inflammatory Activity of Polymethoxyflavonoids from Citrus Genus.

Polymethoxyflavonoids (PMFs) are a large group of compounds belonging to the more general class of flavonoids that possess a flavan carbon framework decorated with a variable number of methoxy groups. Hydroxylated polymethoxyflavonoids (HPMFs), instead, are characterized by the presence of both hydroxyl and methoxy groups in their structural unities. Some of these compounds are the aglycone part in a glycoside structure in which the glycosidic linkage can involve the -OH at various positions. These compounds are particular to Citrus genus plants, especially in fruits, and they are present mainly in the peel. A considerable number of PMFs and HPMFs have shown promising biological activities and they are considered to be important nutraceuticals, responsible for some of the known beneficial effects on health associated with a regular consumption of Citrus fruits. Among their several actions on human health, it is notable that the relevant contribution in controlling the intracellular redox imbalance is associated with the inflammation processes. In this work, we aim to describe the status concerning the chemical identification and the anti-inflammatory activity of both PMFs and HPMFs. In particular, all of the chemical entities unambiguously identified by isolation and complete NMR analysis, and for which a biochemical evaluation on the pure compound was performed, are included in this paper.

Identification of Prototype Compounds and Their Metabolites in Rat Plasma After Oral Administration of Aurantii Fructus Extract by UPLC-Q-TOF/MS / 中国实验方剂学杂志

Objective:To study the serum pharmacochemistry of Aurantii Fructus （AF）， and to investigate the pharmacological material basis of AF extract in rats. Method:Rapid identification and speculation of the prototype constituents and their metabolites in vivo were carried out according to the relative retention time， accurate relative molecular mass， cleavage fragments of MS/MS and neutral loss of metabolites with ultrahigh performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry （UPLC-Q-TOF/MS） technique by comparing the differences between different samples such as AF extracts， blank plasma， and administered plasma under the same chromatographic and mass spectrometric conditions. Result:After oral administration of the AF extract， 74 transitional constituents absorbed into the blood were detected in serum， in which 49 compounds were prototype constituents and the other 25 were metabolites. The prototype constituents could be divided into dihydroflavones， polymethoxyflavonoids， limonins， coumarins and alkaloids. The identified metabolites included glucuronic acid conjugates， sulfuric acid conjugates， hydroxylated products of flavonoid glycosides and polymethoxyflavonoids， as well as the simultaneous glucuronidation and sulfation products. Conclusion:The constituents absorbed into the blood and their metabolites may be the pharmacodynamic components of AF. Among them， alkaloids， polymethoxyflavonoids and coumarins are mainly introduced into the blood in the prototype form， while naringin and neohesperidin （the index components） exert effect mainly through hydrolysis into aglycones. This work will help to further elucidate the material basis of AF.

[Correlation between lipid-lowering efficacy and components of Pericarpium Citri Reticulatae].

Based on pharmacodynamics-component correlation analysis,the best effective part of hyperlipidemia of Pericarpium Citri Reticulatae( PCR) was screened out to confirm the possible constituents with the lipid regulating effect,in order to provide a basis for the development of new drugs. Hyperlipidemia rats induced by fat emulsion were used to screen out the best hypolipidemic parts of PCR with TC,LDL-c as the index. HPLC-ESI-MS were used to analyze common constituents of the different solvent extracts from PCR. The constituents were classified and identified based on the retention time,m/z and UV spectra. And the HPLC-DAD were used to determine the contents of flavonoids( narirutin,hesperidin,didymin,nobiletin,tangeretin,3,5,6,7,8,3',4'-heptemthoxyflavone).Correlation analysis was conducted on the constituents and efficacy with the method of SPSS ANOVA bivariate correlation. Five extracts could significantly decrease the content of TC,LDL-c of hyperlipemia rats induced by fat emulsion,and the best effective part were95% ethanol and ethyl acetate. There were 19 common peaks in five different solvent extracts from PCR,and 17 flavonoids were identified and classified,including 10 polymethoxyflavonoids and 7 other flavonoids. According to the raw material quantity,the order of content of flavonones arranged from high to low: n-butyl alcohol part> 95% ethanol part> water part> ethyl acetate part> petroleum ether part; and the order of PMFs arranged from high to low: n-butyl alcohol part≈95% ethanol part≈ethyl acetate part > petroleum ether part > water part. The decreased percentage of TC,LDL-c was positively correlated with 10 common PMFs constituents,which suggested that PMFs may be the effective components for reducing blood lipid.

Anti-neuroinflammatory activities of extract and polymethoxyflavonoids from immature fruit peels of Citrus 'Hebesu'.

Chronic neuroinflammation is reported to be associated in the progression of many neurodegenerative diseases and there is an increasing interest for the natural products as neuroprotective and anti-neuroinflammatory agents. In present research, we evaluated the potential inhibitory effects of extract, fractions, and isolated compounds from Citrus 'Hebesu' on lipopolysaccharide (LPS)-induced inflammatory responses using BV-2 murine microglial cells. The dried methanol extract (CH) was suspended in water and partitioned with hexane and ethyl acetate to give hexane soluble (CHH), ethyl acetate soluble (CHE), and water soluble (CHW) fractions. The extract (CH) and fractions CHH and CHE inhibited the expression of mRNA encoding pro-inflammatory cytokine interleukin (IL)-1ß. CHE and CHH were further purified by various column chromatographic methods to obtain hesperidin (1), tangeretin (2), 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (3), 3,5,6,7,8,3',4'-heptamethoxyflavone (4), nobiletin (5), 3,4,5-trimethoxy-trans-cinnamic alcohol (6), and meranzin hydrate (7). Among them, three polymethoxyflavonoids, 3, 4, and 5 significantly inhibited the expression of IL-1ß mRNA. PRACTICAL APPLICATIONS: Citrus 'Hebesu' is a local cultivar in Hyuga City, Miyazaki prefecture, Japan and its immature fruits are consumed with different food recipes. Till now, there is no detailed study on the chemical constituents and anti-neuroinflammatory activity of this cultivar. In this study, seven compounds were isolated from the peels of immature fruits. Methanol extract, hexane, and ethyl acetate fractions and three polymethoxyflavonoids showed a significant inhibitory activity against expression of IL-1ß mRNA. Consumption of peels of Citrus 'Hebesu' might play important role in the prevention and treatment of neurodegenerative diseases, however, detailed mechanism based in vivo studies are necessary in future for providing more scientific evidences.

Synthesis and antiproliferative activities of aminoalkylated polymethoxyflavonoid derivatives.

A series of novel aminoalkylated polymethoxyflavonoid derivatives 3-11 was synthesised from 5-hydroxy-3,7,3',4'-tetramethoxyflavonoid (1) through extending alkoxy chain at the 5-position, and introducing amine hydrogen bond receptor at the end of the side chain. Their antiproliferative activities were evaluated in vitro on a panel of three human cancer cell lines (Hela, HCC1954 and SK-OV-3). The results showed that all the target compounds exhibited antiproliferative activities against investigated cancer cells with IC50 values of 9.51-53.33 µM. Compounds 5, 7, 8, 11 on Hela cells and compounds 4-9, 11 on HCC1954 exhibited more potency as compared to positive control cis-Platin.

Correlation between lipid-lowering efficacy and components of Pericarpium Citri Reticulatae / 中国中药杂志

Based on pharmacodynamics-component correlation analysis,the best effective part of hyperlipidemia of Pericarpium Citri Reticulatae( PCR) was screened out to confirm the possible constituents with the lipid regulating effect,in order to provide a basis for the development of new drugs. Hyperlipidemia rats induced by fat emulsion were used to screen out the best hypolipidemic parts of PCR with TC,LDL-c as the index. HPLC-ESI-MS were used to analyze common constituents of the different solvent extracts from PCR. The constituents were classified and identified based on the retention time,m/z and UV spectra. And the HPLC-DAD were used to determine the contents of flavonoids( narirutin,hesperidin,didymin,nobiletin,tangeretin,3,5,6,7,8,3',4'-heptemthoxyflavone).Correlation analysis was conducted on the constituents and efficacy with the method of SPSS ANOVA bivariate correlation. Five extracts could significantly decrease the content of TC,LDL-c of hyperlipemia rats induced by fat emulsion,and the best effective part were95% ethanol and ethyl acetate. There were 19 common peaks in five different solvent extracts from PCR,and 17 flavonoids were identified and classified,including 10 polymethoxyflavonoids and 7 other flavonoids. According to the raw material quantity,the order of content of flavonones arranged from high to low: n-butyl alcohol part> 95% ethanol part> water part> ethyl acetate part> petroleum ether part; and the order of PMFs arranged from high to low: n-butyl alcohol part≈95% ethanol part≈ethyl acetate part > petroleum ether part > water part. The decreased percentage of TC,LDL-c was positively correlated with 10 common PMFs constituents,which suggested that PMFs may be the effective components for reducing blood lipid.

Effect of Kaempferia parviflora extract on knee osteoarthritis.

Knee osteoarthritis (OA) is becoming more prevalent worldwide due to increases in the numbers of elderly and obese patients. Currently, pharmaceutical medicines used for the treatment of OA are for symptomatic therapy and therefore new therapeutic agents are needed. Kaempferia parviflora (KP) is a plant growing naturally in Southeast Asia and has various pharmacological effects including an anti-inflammatory effect, but no effect on OA has yet been reported. We therefore conducted a search for the effects KP and the active components of KP extract (KPE) exert on OA as well as its mechanism of action. Results from a study of KPE using the monoiodoacetic acid rat OA model revealed that KPE reduced the pain threshold and severity of osteoarthritic cartilage lesions. The mechanism of action and active components were then investigated using IL-1ß-treated human knee-derived chondrocytes. KPE, as well as 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone, which are key constituents of KPE and highly absorbable into the body, reduced the expression of matrix metalloproteinases (MMPs), which are the main extracellular matrix enzymes that degrade collagen within cartilage. As mentioned above, KPE acted to suppress OA and 5,7-dimethoxyflavone and 5,7,4'-trimethoxyflavone were shown to be involved as part of KPE's mechanism that inhibits MMPs.

Effects of ethyl acetate extract of Kaempferia parviflora on brown adipose tissue.

We have previously reported the effects of Kaempferia parviflora (KP), including anti-obesity, preventing various metabolic diseases, and regulating differentiation of white adipose cells. In this study we used Tsumura, Suzuki, Obese Diabetes (TSOD) mice--an animal model of spontaneous obese type II diabetes--and primary brown preadipocytes to examine the effects of the ethyl acetate extract of KP (KPE) on brown adipose tissue, which is one of the energy expenditure organs. TSOD mice were fed with MF mixed with either KPE 0.3 or 1% for 8 weeks. Computed tomography images showed that whitening of brown adipocytes was suppressed in the interscapular tissue of the KPE group. We also examined mRNA expression of uncoupling protein 1 (UCP-1) and ß3-adrenalin receptor (ß3AR) in brown adipose tissue. As a result, mRNA expression of UCP-1 significantly increased in the KPE 1% treatment group, indicating that KPE activated brown adipose tissue. We then evaluated the direct effects of KPE on brown adipocytes using primary brown preadipocytes isolated from interscapular brown adipocytes in ICR mice. Triacylglycerol (TG) accumulation in primary brown preadipocytes was increased by KPE in a dose-dependent manner. Each mRNA expression of peroxisome proliferator-activated receptor γ (PPARγ), UCP-1, and ß3AR exhibited an upward trend compared with the control group. Moreover, some polymethoxyflavonoids (PMFs), the main compound in KP, also increased TG accumulation. This study therefore showed that KPE enhanced the thermogenesis effect of brown adipocytes as well as promoted the differentiation of brown adipocyte cells.

Identification of metabolites of gardenin A in rats by combination of high-performance liquid chromatography with linear ion trap-Orbitrap mass spectrometer based on multiple data processing techniques.

Gardenin A is one of the less abundant hydroxylated polymethoxyflavonoids (OH-PMFs) in nature, and has many potential significant health benefits. In the present study, an efficient strategy was established using high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer to profile the in vivo metabolic fate of gardenin A in rat plasma and various tissues. First, an online LC-MS(n) data acquisition method was developed to trace all the probable metabolites. Second, a combination of offline data processing methods including extracted ion chromatography and multiple mass defect filters was employed to screen the common and uncommon metabolites from the background noise and endogenous components. Finally, structures of the metabolites were elucidated based on an accurate mass measurement, the diagnostic product ions of PMFs, and relevant drug biotransformation knowledge. Based on the proposed strategy, a total of 26 metabolites were observed and characterized. The results indicate that some biotransformations, such as methylation, demethoxylation, demethylation, glucuronide conjugation, sulfate conjugation and their composite reactions, have been discovered for OH-PMFs. Moreover, some diagnostic biotransformation pathways are summarized. Overall, this study gives us a first insight into the in vivo metabolism of gardenin A. The study also provides a practical strategy for rapidly screening and identifying metabolites, which can be widely applied for the other biotransformations.

Rapid screening and identification of target constituents using full scan-parent ions list-dynamic exclusion acquisition coupled to diagnostic product ions analysis on a hybrid LTQ-Orbitrap mass spectrometer.

A highly sensitive and effective strategy for rapid screening and identification of target constituents has been developed using full scan-parent ions list-dynamic exclusion (FS-PIL-DE) acquisition coupled to diagnostic product ions (DPIs) analysis on a hybrid LTQ-Orbitrap mass spectrometer. The FS-PIL-DE was adopted as a survey scan to trigger the MS/MS acquisition of all the predictable constituents contained in traditional Chinese medicines. Additionally, DPIs analysis can provide a criterion to judge the target constituents detected into certain chemical families. Results from analyzing polymethoxylated flavonoids (PMFs) in the leaves of Citrus reticulata Blanco demonstrated that FS-PIL-DE was capable of targeting a greater number of constituents than FS, FS-PIL and FS-DE, thereby increasing the coverage of constituent screening. As a result, 135 PMFs including 81 polymethoxyflavones, 54 polymethoxyflavanones or polymethoxychalcones were identified preliminarily. And this was the first time to systematically report the presence of PMFs in the leaves of Citrus reticulata Blanco, especially for polymethoxylated flavanones and chalcones, most of which were new compounds. The results indicated that the developed FS-PIL-DE coupled to DPIs analysis methodology could be employed as a rapid, effective technique to screen and identify target constituents from TCMs extracts and other organic matter mixtures whose compounds contained can also be classified into families based on the common carbon skeletons.

Rapid identification of polymethoxylated flavonoids in traditional Chinese medicines with a practical strategy of stepwise mass defect filtering coupled to diagnostic product ions analysis based on a hybrid LTQ-Orbitrap mass spectrometer.

INTRODUCTION: The methodology of stepwise mass defect filtering (MDF) approach coupled to diagnostic product ions (DPIs) analysis on a hybrid linear trap quadrupole (LTQ)/orbitrap mass spectrometer was the first to be established to screen and identify structural analogues from complex herbal extracts. OBJECTIVE: To develop an analytical methodology that could be adopted to screen and identify structural analogues in traditional Chinese medicines (TCMs) rapidly and accurately. METHODS: Taking polymethoxylated flavonoids (PMFs) in the leaves of Citrus reticulata Blanco as an example, high-resolution mass data were acquired by high-performance liquid chromatography (HPLC) coupled with a LTQ/orbitrap mass spectrometer. The stepwise MDF with multiple mass defect windows or mass windows enabled the original data to be analysed much faster and more accurately by reducing the potential interferences of matrix ions. Additionally, analysis of DPIs could provide a criterion to classify the target constituents detected into certain chemical families. RESULTS: In total, 81 PMFs, including 50 polymethoxyflavones and 31 polymethoxyflavanones or polymethoxychalcones, were screened and identified from the original data and preliminarily identified. CONCLUSION: The analytical methodology developed could be used as a rapid, effective technique to screen and identify compounds from TCM extracts and other organic matter mixtures with compounds that can also be classified into families based on the common carbon skeletons.