Systematic chemical profiling of Citrus grandis ‘Tomentosa’ by ultra-fast liquid chromatography/diode-array detector/quadrupole time-of-flight tandem mass spectrometry

Four novel Cit7GlcTs functional in flavonoid 7-O-glucoside biosynthesis are vital to flavonoid biosynthesis shunting in citrus

Citrus fruits have abundant flavonoid glycosides (FGs), an important class of natural functional and flavor components. However, there have been few reports about the modification of UDP-glycosyltransferases (UGTs) on flavonoids in citrus. Notably, in flavonoid biosynthesis, 7-O-glucosylation is the initial and essential step of glycosylation prior to the synthesis of flavanone disaccharides, the most abundant and iconic FGs in citrus fruits. Here, based on the accumulation of FGs observed at the very early fruit development stage of two pummelo varieties, we screened six novel flavonoid 7-O-glucosyltransferase genes (7GlcTs) via transcriptomic analysis and then characterized them in vitro. The results revealed that four Cg7GlcTs possess wide catalytic activities towards various flavonoid substrates, with CgUGT89AK1 exhibiting the highest catalytic efficiency. Transient overexpression of CgUGT90A31 and CgUGT89AK1 led to increases in FG synthesis in pummelo leaves. Interestingly, these two genes had conserved sequences and consistent functions across different germplasms. Moreover, CitUGT89AK1 was found to play a role in the response of citrus to Huanglongbing infection by promoting FG production. The findings improve our understanding of flavonoid 7-O-glucosylation by identifying the key genes, and may help improve the benefits of flavonoid biosynthesis for plants and humans in the future.

Diversity in storage age enables discrepancy in quality attributes and metabolic profile of Citrus grandis "Tomentosa" in China

The folk proverb "the older, the better" is usually used to describe the quality of Citrus grandis "Tomentosa" (CGT) in China. In this study, CGT aged for 6-, 12-, 16-, and 19-years were collected for the investigation of infusion color, main bioactive components, antioxidant activity, metabolic composition, and pathway. The results found that infusion color, the total phenolic and flavonoid, and antioxidant activity of CGT were obviously changed by aging process. Through untargeted metabolomics, 55 critical metabolites were identified to in discrimination of CGT with different storage ages, mainly including phenylpropanoids, lipids, and organic oxygen compounds. Twenty compounds that showed good linear relationships with storage ages could be used for year prediction of CGT. Kyoto encyclopedia of genes and genomes enrichment pathway analysis uncovered important metabolic pathways related to the accumulation of naringin, kaempferol, and choline as well as the degradation of benzenoids, thus supporting that aged CGT might be more beneficial to health. Correlation analysis provided that some key metabolites with bitter taste and biological activity were involved in the darkening and reddening of CGT infusion during aging, and total phenolic and flavonoid were more strongly associated with the antioxidant activity of CGT. This study systematically revealed the quality changes and key metabolic pathways during CGT aging at first time. PRACTICAL APPLICATION: This study reveals the differences in quality attributes and metabolic profile between CGT with different storage ages, providing guidance for consumers' consumption, and also providing more scientific basis for the quality evaluation and improvement of CGT.

Bioactives from citrus food waste: types, extraction technologies and application

The Citrus fruits belong to the category where the groups of fruits are recognized to be an admirable repository of bioactive elements and phytochemical constituents, with strong biological potentials. The prominent use of Citrus fruits for nutrition as well as food processing has led to the release of a large amount of waste into the environment and surrounding, and it simultaneously burdens the nature and existence of many organisms including the human population. In order to rectify such consequences, the reuse of food waste from citrus for various advantageous effects. In this regard, the first part of the article primarily focussed on the various strategies available for the extraction of chemical elements from citrus waste and the remaining strand of the article focussed on the various bioactive compounds with special reference to their pharmacological as well as the medicinal benefits and future prospects.

Graphical abstract

Ethanol Extract of Citrus grandis 'Tomentosa' Exerts Anticancer Effects by Targeting Skp2/p27 Pathway in Non-Small Cell Lung Cancer

SCOPE

This study aims to investigate the anticancer properties of Citrus grandis 'Tomentosa' (CGT) in non-small cell lung cancer (NSCLC).

METHODS AND RESULTS

The ethanol extract of CGT (CGTE) is prepared by using anhydrous ethanol and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), revealing that the main chemical components in CGTE are flavonoids and coumarins, such as naringin, rhoifolin, apigenin, bergaptol, and osthole. CGTE at concentrations without inducing cell death significantly inhibits cell proliferation via inducing cell cycle G1 phase arrest by MTT, colony formation, and flow cytometry assays, implying that CGT has anticancer potential. CGTE markedly inhibits the activity of Skp2-SCF E3 ubiquitin ligase, decreases the protein level of Skp2, and promotes the accumulation of p27 by co-immunoprecipitation (co-IP) and in vivo ubiquitination assay; whereas Skp2 overexpression rescues the effects of CGTE in NSCLC cells. In subcutaneous LLC allograft and A549 xenograft mouse models, CGTE, without causing obvious side effects in mice, significantly inhibits lung tumor growth by targeting the Skp2/p27 signaling pathway.

CONCLUSION

These findings demonstrate that CGTE efficiently inhibits NSCLC proliferation both in vitro and in vivo by targeting the Skp2/p27 signaling pathway, suggesting that CGTE may serve as a therapeutic candidate for NSCLC treatment.

Integrated transcriptomic and metabolomic analyses reveal key genes controlling flavonoid biosynthesis in Citrus grandis 'Tomentosa' fruits

As a well-recognized traditional Chinese medicine (TCM), immature fruits of Citrus grandis 'Tomentosa' (CGT) serve to cure chronic cough in humans. Specialized metabolites including flavonoids may have contribute to this curing effect. Knowledge about the molecular mechanisms underlying flavonoid biosynthesis in 'Tomentosa' fruits will, therefore, support the breeding of varieties with improved medicinal properties. Hence, we profiled the transcriptomes and metabolites of the fruits of two contrasting C. grandis varieties, namely 'Zheng-Mao' ('ZM') used in TCM production, and a locally cultivated pomelo, namely 'Guang-Qing' ('GQ'), at four developmental stages. A total of 39 flavonoids, including 14 flavanone/flavone, 5 isoflavonoids, 12 flavonols, and 6 anthocyanins, were identified, and 16 of which were quantitatively determined in the fruits of the two varieties. We found that 'ZM' fruits contain more flavonoids than 'GQ'. Specifically, rhoifolin levels were significantly higher in 'ZM' than in 'GQ'. We annotated 31,510 genes, including 1,387 previously unknown ones, via transcriptome sequencing of 'ZM' and 'GQ.' A total of 646 genes were found to be differentially expressed between 'ZM' and 'GQ' throughout at all four fruit developmental stages, indicating that they are robust expression markers for future breeding programs. Weighted gene co-expression network analysis identified 18 modules. Combined transcriptional and metabolic analysis revealed 25 genes related to flavonoid biosynthesis and 16 transcriptional regulators (MYBs, bHLHs, WD40) that may be involved in the flavonoids biosynthesis in C. grandis 'Tomentosa' fruits.

Metabolic Profiling and Transcriptional Analysis of Carotenoid Accumulation in a Red-Fleshed Mutant of Pummelo (Citrus grandis)

Citrus grandis ‘Tomentosa’, commonly known as ‘Huajuhong’ pummelo (HJH), is used in traditional Chinese medicine and can moisten the lungs, resolve phlegm, and relieve coughs. A spontaneous bud mutant, named R-HJH, had a visually attractive phenotype with red albedo tissue and red juice sacs. In this study, the content and composition of carotenoids were investigated and compared between R-HJH and wild-type HJH using HPLC–MS analysis. The total carotenoids in the albedo tissue and juice sacs of R-HJH were 4.03- and 2.89-fold greater than those in HJH, respectively. The massive accumulation of carotenoids, including lycopene, β-carotene and phytoene, led to the attractive red color of R-HJH. However, the contents of flavones, coumarins and most volatile components (mainly D-limonene and γ-terpinene) were clearly reduced in R-HJH compared with wild-type HJH. To identify the molecular basis of carotenoid accumulation in R-HJH, RNA-Seq transcriptome sequencing was performed. Among 3948 differentially expressed genes (DEGs), the increased upstream synthesis genes (phytoene synthase gene, PSY) and decreased downstream genes (β-carotene hydroxylase gene, CHYB and carotenoid cleavage dioxygenase gene, CCD7) might be the key factors that account for the high level of carotenoids in R-HJH. These results will be beneficial for determining the molecular mechanism of carotenoid accumulation and metabolism in pummelo.

Sequential grade evaluation method exploration of Exocarpium Citri Grandis (Huajuhong) decoction pieces based on "network prediction → grading quantization → efficacy validation"

ETHNOPHARMACOLOGICAL RELEVANCE

Exocarpium Citri Grandis (Huajuhong) is an authentic Chinese materia medica with excellent curative effects on relieving cough and reducing phlegm, which has been reputed as "Southern Ginseng" in China for a long history.

AIM OF THE STUDY

To establish a sequential grade evaluation method with strong operability and controllable quality for Huajuhong decoction pieces.

MATERIALS AND METHODS

(1) Indicators of ingredients and bio-effects were predicted by network pharmacology, and the potential pharmacodynamic ingredients and key targets were analyzed integrating screening results and literatures. (2) 45 batches of Huajuhong decoction pieces from different producing areas were collected and graded by original plant, planting place, and harvesting time. The chemical indicators determination of Huajuhong decoction pieces was conducted by Ultra Performance Liquid Chromatography (UPLC). (3) 112 rats with idiopathic pulmonary fibrosis (IPF) model were used to evaluated the efficacy within graded groups.

RESULTS

(1) There are 22 key targets corresponding to 20 potential ingredients related to immunity and inflammation pathways for Huajuhong. Naringin and rhoifolin were chosen as the chemical indicators, and IL-6, IL-8, MCP-1, MIP-1α, TNF-α, TGF-β1 were selected as bio-indicators for different grades of Huajuhong decoction pieces. (2) The contents of the naringin and rhoifolin can reflect the quality of different grades of Huajuhong decoction pieces. (3) The efficacy of different grades of Huajuhong decoction pieces can delay the progression of IPF in varying degrees via the selected bio-indicators' pathways.

CONCLUSIONS

This sequential grading evaluation method is an attempt to apply systems pharmacology which integrates network pharmacology, quantitative chemical and experiments on animals to the classification of TCM decoction pieces. Combining the concepts of traditional theory and modern technology to explain the complex grading mechanism of TCM decoction pieces is worth popularizing and applying.

Analyses of Physical and Chemical Compositions of Different Medicinal Specifications of CRPV by Use of Multiple Instrumental Techniques Combined with Multivariate Statistical Analysis

Citri Reticulatae Pericarpium Viride (CRPV) is the processed product of Citrus reticulata Blanco. We systematically analyzed two CRPV types, Geqingpi (GQP) and Sihuaqingpi (SHQP), based on powder color, microscopic characteristics, and chemical composition. In addition, we characterized their constituents via ultra-high-performance liquid chromatography with hybrid quadrupole-orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS). Both showed significant differences in their powder color and microscopic characteristics. Fourier-transform infrared (FT-IR) spectroscopic analysis results showed that the C=O peak absorption of carboxylic acids and their carbonyl esters in SHQP was higher than that of GQP, while the C-OH and C-H plane bending peaks of polysaccharides were lower than those of GQP. We analyzed these data via similarity analysis, PCA, and OPLS-DA. GQP and SHQP had large distinct differences. Based on the mass measurements for molecular and characteristic fragment ions, we identified 44 main constituents from CRPV, including different flavonoid glycosides and flavonoid aglycones in SHQP and GQP, respectively. We found luteolin-6-C-glucoside, orientin, rhoifolin, and pilloin solely in SHQP, and naringenin and hesperetin only in GQP. The peak area measurements showed GQP having a higher flavonoid glycoside (narirutin, hesperidin, etc.) content, whereas SHQP had a higher polymethoxyflavone (nobiletin, tangeretin, etc.) content. Since we holistically analyzed two CRPV types, the results can not only support future pharmacological research, but also provide a scientific basis for formulating more reasonable CRPV quality standards and guide its clinical potential as a precision medicine.

Comprehensive Analysis of N6-Methyladenosine Regulatory Genes from Citrus grandis and Expression Profilings in the Fruits of “Huajuhong” (C. grandis “Tomentosa”) during Various Development Stages

Citrus grandis “Tomentosa” (“Huajuhong”) is a famous traditional Chinese medicine. The aim of the present study is to provide a comprehensive characterization of the m6A regulatory genes from C. grandis, and examine their expression patterns in fruits of C. grandis “Tomentosa” during various developmental stages. A total of 26 N6-methyladenosine (m6A) regulatory proteins were identified from the genome of C. grandis, which were distributed across nine chromosomes in C. grandis. Phylogenetic relationships revealed that all m6A regulatory genes were divided into groups of m6A writers, erasers, and readers. The m6A writer groups included CgMTA, CgMTB, and CgMTC three MTs (methyltransferases), one CgVIR (virilizer), one CgHAKAI (E3 ubiquitin ligase HAKAI), and one CgFIP37 (FKBP interacting protein 37). Moreover, 10 CgALKBH (α-ketoglutarate-dependent dioxygenase homolog) members (numbered from CgALKBH1 to CgALKBH10) and 10 CgECT (C-terminal region) members (numbered from CgECT1 to CgECT10) in C. grandis were identified as m6A erasers and readers, respectively. The domain structures and motif architectures among the groups of m6A writers, erasers, and readers were diverse. Cis-acting elements in the promoters of the 26 m6A regulatory genes predicted that the abscisic acid-responsive (ABA) element (ABRE) was present on the promoters of 19 genes. In addition, the expression profiles of all m6A regulatory genes were examined in the fruits of two varieties of C. grandis “Tomentosa” during different growth stages to give basic hints for further investigation of the function of the N6-methyladenosine regulatory genes in C. grandis “Tomentosa”.

The chemical profile of Fubai Chrysanthemum (Fubaiju) and its mechanism in preventing cataract based on ultrahigh-performance liquid chromatography coupled with mass spectrometry and network pharmacology

Chrysanthemum is a kind of herb that can be used for both medicine and food. Although it has been shown to affect the redox damage of the lens, but the mechanism of action has not been systematically studied. This study identified the chemical profile of Fubai Chrysanthemum. Meanwhile, network pharmacology and the enrichment of the Kyoto encyclopedia of genes and genomes pathway were combined to investigate the substance basis of Fubai Chrysanthemum for preventing cataract. The aqueous extracts of Fubaiju mainly contained 39 compounds. Compared with Gongju, Jinsiju and Wild chrysanthemum, Fubai Chrysanthemum showed a higher scavenging rate of 1,1-diphenyl-2-picrylhydrazyl free radicals and higher content of total flavonoid. 14 chemical differences in four kinds of chrysanthemum were found based on principal component difference analysis. Pathway enrichment analysis showed that the main mechanisms of Fubai Chrysanthemum for preventing cataract were affecting the oxidative stress process and regulating cell growth and metabolism. Eventually, 11 key targets of Fubai Chrysanthemum for cataract prevention were identified. The strategy provided a better understanding of the chemical profile of Fubai Chrysanthemum and elucidated that its higher flavonoid content plays an important role in preventing cataract through antioxidant action and regulating cell growth. This article is protected by copyright. All rights reserved.

Comprehensive Analysis of Jumonji Domain C Family from Citrus grandis and Expression Profilings in the Exocarps of “Huajuhong” (Citrus grandis “Tomentosa”) during Various Development Stages

Citrus grandis “Tomentosa” (“Huajuhong”) is a famous Traditional Chinese Medicine. In this study, a total of 18 jumonji C (JMJC) domain-containing proteins were identified from C. grandis. The 18 CgJMJCs were unevenly located on six chromosomes of C. grandis. Phylogenetic analysis revealed that they could be classified into five groups, namely KDM3, KDM4, KDM5, JMJC, and JMJD6. The domain structures and motif architectures in the five groups were diversified. Cis-acting elements on the promoters of 18 CgJMJC genes were also investigated, and the abscisic acid-responsive element (ABRE) was distributed on 15 CgJMJC genes. Furthermore, the expression profiles of 18 CgJMJCs members in the exocarps of three varieties of “Huajuhong”, for different developmental stages, were examined. The results were validated by quantitative real-time PCR (qRT-PCR). The present study provides a comprehensive characterization of JMJC domain-containing proteins in C. grandis and their expression patterns in the exocarps of C. grandis “Tomentosa” for three varieties with various development stages.

Phytochemical and Therapeutic Potential of Citrus grandis (L.) Osbeck: A Review

Citrus grandis or Citrus maxima, widely recognized as Pomelo is widely cultivated in many countries because of their large amounts of functional, nutraceutical and biological activities. In traditional medicine, various parts of this plant including leaf, pulp and peel are used for generations as they are scientifically proven to have therapeutic potentials and safe for human use. The main objective of this study was to review the different therapeutic applications of Citrus grandis and the phytochemicals associated with its medicinal values. In this article different pharmacological properties like antimicrobial, antitumor, antioxidant, anti-inflammatory, anticancer, antiepileptic, stomach tonic, cardiac stimulant, cytotoxic, hepatoprotective, nephroprotective, and anti-diabetic activities of the plant are highlighted. The enrichment of the fruit with flavonoids, polyphenols, coumarins, limonoids, acridone alkaloids, essential oils and vitamins mainly helps in exhibiting the pharmacological activities within the body. The vitamins enriched fruit is rich in nutritional value and also has minerals like calcium, phosphorous, sodium and potassium, which helps in maintaining the proper health and growth of the bones as well as the electrolyte balance of the body. To conclude, various potential therapeutic effects of Citrus grandis have been demonstrated in recent literature. Further studies on various parts of fruit, including pulp, peel, leaf, seed and it essential oil could unveil additional pharmacological activities which can be beneficial to the mankind.

Structural elucidation of flavonoids from Shatianyu (Citrus grandis L. Osbeck) pulp and screening of key antioxidant components

The Citrus genus is a good source of dietary flavonoids, which have many health benefits. As a representative citrus fruit, the flavonoids composition in Shatianyu (Citrus grandis L. Osbeck) pulp remains to be investigated. In the present study, 11 flavonoids were isolated and identified from Shatianyu pulp flavonoid extracts (SPFEs). Among them, 4 flavonoids were previously undescribed and 2 flavonoids were firstly isolated from pummelo. The cellular antioxidant activity (CAA) and oxygen radical absorbance capacity (ORAC) of isolated compounds were evaluated. Naringin and rhoifolin showed the highest ORAC activity, and the presence of a 3-hydroxy-3-methylglutaryl or a 4'-glucose decreased the ORAC activity of flavonoids. The contribution of isolated flavonoids to the holistic antioxidant activity of SPFEs was determined by an online knockout method. Melitidin, bergamjuicin and naringin contributed most to ORAC activity, while bergamjuicin, melitidin and apigenin-4'-O-β-d-glucopyranosyl-7-O-α-l-rhamnopyranosyl-(1 → 2)-[6″-O-(3- hydroxy-3-methylgltaryl)]-β-d-glucopyranoside contributed most to CAA activity.

A strategy to discover selective α-glucosidase/acetylcholinesterase inhibitors from five function-similar citrus herbs through LC-Q-TOF-MS, bioassay and virtual screening

The lack of direct connection between traditional herbal medicines and multiple biological targets is a bottleneck in herbal research and quality evaluation. To solve this problem, a strategy for the discovery of active ingredients from function-similar herbal medicines based on multiple biological targets was proposed in this article. The technical route includes chromatographic separation, mass spectrometry analysis, enzymatic activity detection, pharmacophore analysis and molecular docking. Five citrus herbs of Citri Reticulatae Pericarpium (CRP), Citri Exocarpium Rubrum (CER), Citri Grandis Exocarpium (CGE), Aurantii Fructus Immaturus (AFI) and Aurantii Fructus (AF) were used as the research objects. A total of 136 chemical components were identified from above five herbs based on LC-Q-TOF-MS/MS and database matching. The extracts of the five herbs showed obvious inhibitory effects on α-glucosidase and acetylcholinesterase in a concentration-dependent manner. Interestingly, the different types of components in the herbs exhibited selectivity for different targets: flavanone glycosides are effective on α-glucosidase but ineffective on acetylcholinesterase; polymethoxyflavonoids are effective on acetylcholinesterase but ineffective on α-glucosidase. Furthermore, we found for the first time that the components in citrus herbs exhibit opposite structure-activity relationships on the above two targets. For example, the methoxy group can enhance the activity of compounds on acetylcholinesterase but weaken the activity of compounds on α-glucosidase. The selective action is a supplement to the "multi-components, multi-targets" system of herbal medicines. Pharmacophore analysis and molecular docking were applied to explore the interaction between active ingredients and biological targets from the perspective of ligands and receptors, respectively. By combining the above multiple technologies, a strong connection among herbal medicines, chemical components and multiple biological targets was established. This work not only helps to understand the similar function of citrus herbs for the treatment of diabetes and Alzheimer's disease, but also provides selective lead compounds for the development of related drugs. This strategy is also helpful to improve the quality evaluation of citrus herbs from the perspective of biological activity.

The levels of bioactive ingredients in Citrus aurantium L. at different harvest periods and antioxidant effects on H2 O2 -induced RIN-m5F cells

BACKGROUND

Citrus aurantium L. (Aurantii fructus) is a multi-purpose citrus fruit with high medicinal and nutritional value, but currently there are no data that can be used to investigate the appropriate harvest time to obtain high-quality citrus bioactive ingredients from it.

RESULTS

Phytochemicals and the levels of the main bioactive ingredients were investigated by ultra high performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF/MS). The flavanone, polymethoxyflavone, coumarin, synephrine, and limonin content in the citrus fruit was analyzed at different harvest periods, and significant differences, ranging from 0.03 ± 0.01 to 116.26 ± 40.20 g kg^-1 (DW), were shown. These compounds were present in higher amounts in June and then decreased gradually, while the biomass accumulation of most of them showed an increasing tendency around harvest time. The H₂ O₂ -induced RIN-m5F cells model was employed to evaluate their antioxidant capacity. Citrus fruit harvested from June 11 to July 7 possessed an excellent antioxidant capacity by inhibiting the intensity of intracellular reactive oxygen species (ROS) (P < 0.01) and improving superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH) activity (P < 0.01). The chemical composition and antioxidant capacity of citrus leaves, stems, and roots were also evaluated, and these showed great variation compared with other citrus fruits. Multivariate statistical analysis indicated that harvesting time was related closely to the phytochemical contents and antioxidant capacity.

CONCLUSION

Citrus fruit can be appropriately harvested from June to early July when the levels of bioactive ingredients and antioxidant activity reach higher values. This research provides practical information for producing high-quality citrus products. © 2020 Society of Chemical Industry.

Optimization of extraction flavonoids from Exocarpium Citri Grandis and evaluation its hypoglycemic and hypolipidemic activities

ETHNOPHARMACOLOGICAL RELEVANCE

Exocarpium Citri Grandis (ECG; Huajuhong in Chinese) is a precious traditional Chinese medicine with a history of hundreds of years in China. It has been demonstrated to possess numerous pharmacological properties, including antitussive, expectorant, anti-inflammatory, hypoglycemic, and hypolipidemic. However, no in-depth report exists on the hypoglycemic and hypolipidemic properties of ECG.

AIM OF THE STUDY

This study aimed to evaluate the hypoglycemic and hypolipidemic properties of ECG flavonoids extract in vitro and in vivo so as to lay the foundation for further researches in this field.

MATERIALS AND METHODS

Total flavonoids (TF) and naringin were separately extracted from ECG, and the components of TF were identified by HPLC-MS. The antioxidant capacities of TF and naringin were determined by 2,2,1-diphenyl-1-picrylhydrazyl (DPPH)-free radical scavenging tests, and digestive enzymes activity inhibition assays in vitro in order to evaluate their hypoglycemic properties. Furthermore, diabetic mice experiments were performed to assess the hypoglycemic and hypolipidemic properties of TF and naringin in vivo.

RESULTS

Five compounds were identified from TF, including naringin, rhoifolin, poncirin, bergaptol, and naringenin. The half maximal inhibitory concentration (IC₅₀) of TF and naringin to DPPH-free radicals were 0.269 and 1.946 mg/mL, respectively. TF and naringin demonstrated a certain inhibitory effect on α-glucosidase and a weaker inhibitory effect on α-amylase. The results of animal experiments showed that TF and naringin had no significant effect on the blood glucose levels, but they could lead to significant (p < 0.05 or p < 0.01) increase in the serum insulin level and high-density lipoprotein cholesterol (HDL-C) levels with concomitant reduction in the total cholesterol (TC), total triglycerides (TG), and low-density lipoprotein cholesterol (LDL-C) levels in diabetic mice. In addition, TF and naringin could reduce the liver index of diabetic mice (p < 0.01) and reduce the kidney index at low doses (p < 0.05).

CONCLUSIONS

Our study revealed that the hypoglycemic and hypolipidemic activities of TF is mainly derived from naringin, and other active ingredients in TF also have the effects of alleviating oxidative stress, inhibiting digestive enzyme activity and reducing blood lipids. Our results thus provide a scientific basis for the application of ECG in antidiabetic treatment.

Characterization of antioxidant compounds extracted from Citrus reticulata cv. Chachiensis using UPLC-Q-TOF-MS/MS, FT-IR and scanning electron microscope

Citrus reticulata cv. Chachiensis (CRC) has been widely used in many Chinese medicine prescriptions and developed as various health products. Due to its extensive biological activities, increased interest has focused on CRC as a potential source for the treatment of various diseases. However, there is no systematic and sufficient research on optimization and characterization of ultrasound extraction of antioxidant compounds from CRC up to now. In the present work, three parameters including ultrasonic amplitude (45, 55, 70, 85, 95 %), ultrasonic time (26, 40, 60, 80, 94 min) and ethanol concentration (16, 30, 50, 70, 84 %, v/v) were estimated using central-composite design. Determined optimum conditions, considering four responses (TPC, TFC, DPPH and ABTS) at the same time, were 72 % amplitude, 80 min and 70 % ethanol concentration. The maximum yields were TPC values (145.73 mg GAE/g), TFC values (135.21 mg QE/g), DPPH and ABTS scavenging capacity (87.88 and 76.18 mg TE/g, respectively). 55 phytochemicals were identified in the CRC extract using the UPLC-QTOF-MS/MS, 34 of which were flavonoids, which provided important support for various potential applications of CRC.

Rapid discrimination of Notopterygium incisum and Notopterygium franchetii based on characteristic compound profiles detected by UHPLC-QTOF-MS/MS coupled with multivariate analysis

INTRODUCTION

The herbs Notopterygium incisum (NI) and N. franchetii (NF) are referred to as "Qianghuo" in the Chinese Pharmacopeia and are popular for treatment of certain conditions, including headaches, rheumatoid arthritis and the common cold. Recently, several adulterations of NI and NF have been found in the Chinese herbal market.

OBJECTIVE

The aim of this study was to rapidly identify the unique characteristic compounds of NI and NF, to discriminate Qianghuo from its adulterations.

METHODOLOGY

Twenty-four batches of NI and NF samples with different origins were collected and extracted with methanol. The extracts were analysed using ultrahigh-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS). Principal component analysis (PCA) and orthogonal partial squared discriminant analysis (OPLS-DA) were then used to distinguish between NI and NF and to identify their potential characteristic markers.

RESULTS

Fifty compounds were identified or tentatively characterised according to the retention time, m/z value and MS/MS fragment analysis. Six compounds were selected as potential markers of NI and NF by PCA and OPLS-DA. They were successfully applied to authenticate 17 kinds of Chinese patent medicines containing Qianghuo. The markers could not be detected in three of the Chinese patent medicines, indicating that they were counterfeit products.

CONCLUSION

The UHPLC-QTOF-MS/MS coupled with the multivariate analysis method could discriminate NI and NF from their adulterations. Moreover, the data clearly demonstrated significant differences in the chemical compositions of NI and NF. Further research is needed to examine the relationship between therapeutic efficacy and the chemical constituents of NI and NF.

UPLC-Q-TOF-MS Study of the Mechanism of THSWD for Breast Cancer Treatment

Taohong Siwu decoction (THSWD) is a classic traditional Chinese medicine (TCM) prescription that is widely used in the clinical treatment of gynecological and cerebrovascular diseases. Here we used a method that coupled ultra-performance liquid chromatography to quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) in which both positive and negative ion modes were established to investigate the major constituents in THSWD. A Waters ACQUITY UPLC BEH C18 column (2.1 mm×100 mm, 1.7 μm) was used to separate the aqueous extract of THSWD. The mobile phase consisted of 0.1% aqueous formic acid (A) and acetonitrile (B). Ninety-five components were identified in two different ion modes, including aromatic acids, flavones, polysaccharides, volatile oils monoterpene glycosides, aromatic cyanogenic glycosides, and others. Pathological changes in tumors and serum expression of interleukin-4 in a mouse model of breast cancer were detected after THSWD treatment. The results showed that THSWD had obvious therapeutic effects. This study establishes a material basis for the use of THSWD in the treatment of breast cancer.

A rapid protocol to distinguish between Citri Exocarpium Rubrum and Citri Reticulatae Pericarpium based on the characteristic fingerprint and UHPLC-Q-TOF MS methods

Citri Exocarpium Rubrum and Citri Reticulatae Pericarpium were successfully distinguished by the characteristic fingerprint and UHPLC-Q-TOF MS methods.

Effects of Total Flavonoids from Exocarpium Citri Grandis on Air Pollution Particle-Induced Pulmonary Inflammation and Oxidative Stress in Mice

Exocarpium Citri Grandis (ECG) is a famous traditional Chinese medicine, which has been commonly used to alleviate cough and phlegm for more than several hundred years, and total flavonoids are the main effective components of this medicine. This study investigated the effects of total flavonoids from ECG (TFECG) on pulmonary inflammation and oxidative stress induced by PM_2.5 in mice. Model mice received an intratracheal instillation of PM_2.5 (10 mg/mL) once at day 0. Bronchoalveolar lavage fluid (BALF) was collected after 72 hr to measure the total number of white blood cell (WBC), neutrophils (NEUT), lymphocytes (LYMPH), and monocytes (MONO). The levels of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), interleukin-6 (IL-6), and interleukin-18 (IL-18) in BALF were quantified by using enzyme-linked immunosorbent assay kits. Lung tissues were used to determine the contents of total protein (TP), malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), oxidized glutathione (GSSG) and the activities of superoxide dismutase (SOD), lactate dehydrogenase (LDH), Glutathione Peroxidase (GSH-Px), and inducible nitric oxide synthase (iNOS). We found that TFECG significantly inhibited PM_2.5 -stimulated overproduction of TNF-α, IL-1β, IL-6, and IL-18 and increased the numbers of WBC, NEUT, LYMPH, and MONO in BALF. TFECG observably relieved the PM_2.5 -induced increases in the contents of TP, MDA, and NO, and the activities of LDH and iNOS. TFECG also alleviated PM_2.5 -induced decreases in the activities of iNOS and GSH-Px as well as GSH/GSSG ratio. The results indicate that TFECG has anti-inflammatory and antioxidant activities, which may potentially contribute to the treatment of PM_2.5 -induced lung injury. PRACTICAL APPLICATION: Exocarpium Citri Grandis (ECG) is rich in flavonoids, which are beneficial to improve anti-inflammation and antioxidant capacity. We proved that total flavonoids of ECG had a positive therapeutic effect on PM_2.5 -induced lung injury, which expands the potential applications of ECG in the dietary supplement industries.

Modern Extraction and Purification Techniques for Obtaining High Purity Food-Grade Bioactive Compounds and Value-Added Co-Products from Citrus Wastes

Citrus contains a range of highly beneficial bioactive compounds, such as polyphenols, carotenoids, and vitamins that show antimicrobial and antioxidant properties and help in building the body's immune system. On consumption or processing, approximately 50% of the fruit remains as inedible waste, which includes peels, seeds, pulp, and segment residues. This waste still consists of substantial quantities of bioactive compounds that cause environmental pollution and are harmful to the ecosystem because of their high biological oxygen demand. In recent years, citrus cultivation and the production of processed foods have become a major agricultural industry. In addition to being a substantial source of economy, it is an ideal and sustainable and renewable resource for obtaining bioactive compounds and co-products for food and pharmaceutical industries. In the present article, the various methods of extraction, conventional and modern, as well as separation and isolation of individual bioactive compounds from the extraction mixture and their determination have been reviewed. This article presents both aspects of extraction methods, i.e., on a small laboratory scale and on an industrial mass scale. These methods and techniques have been extensively and critically reviewed with anticipated future perspectives towards the maximum utilization of the citrus waste.

Selection and evaluation of quality markers from Yinlan capsule and its LXRα-mediated therapy for hyperlipidemia

BACKGROUND

The selection of active compounds for the quality evaluation of traditional Chinese medicine (TCM), specifically complex formulas, remains a challenge for researchers, as components selected as indexes usually have no clear relation with the therapeutic effects of interest. As a suggested resolution, quality control markers (Q-markers) showed good perspective for discriminating numerous compounds found for specific efficacies. In the presented study, the components of the Yinlan (YL) capsule, a TCM patent formula comprising four ingredients, were evaluated and selected for their lipid regulatory effects using principles for Q-marker selection.

PURPOSE

The mechanism of TCM therapeutic effects involves several pathways and targets that combine to become an integrated action in the body. Therefore, it is assumed that specific compounds in YL should have good affinity for related targets and obvious effects (both up- and downregulating). Thus, a series of experiments, including cytobiology, animal-based pharmacodynamics, computer-assisted drug design, conventional content determination and pharmacokinetics, would be helpful for the selection and final confirmation of Q-markers.

METHODS

The capsule was first administered to Wistar mice fed a high-fat diet and tested for their triglycerides (TG) and total cholesterol (TC) values to evaluate the effectiveness of YL. Then, liver tissue was extracted for gene expression. According to the results, the compounds in YL with good affiliation were selected and determined using UHPLC-MS-MS, and those with adequate results in the capsule were chosen as Q-marker candidates. Finally, pharmacokinetics research was performed; the candidates with desirable metabolite and bioavailability parameters were confirmed as Q-markers of YL.

RESULTS

YL capsule was capable of lowering TG and TC levels. For target selection, the expression of LXR mRNA increased significantly at all three tested dosages. Downstream genes, such as LCAT, CYP7A1, and ABCA1, and intestinal FXR mRNA also showed significant increases in expression. For screening of the Q-marker candidates, 5 compounds were selected according to abovementioned results. The pharmacokinetics research demonstrated that the rats exploited lupeol and ginsenoside Rb3 in a desirable pattern with adequate bioavailability, which confirmed their roles as lipid regulatory Q-markers.

CONCLUSION

The YL capsule was demonstrated to have obvious lipid regulatory effects, which are mainly exerted by targeting LXR and its related pathway. Lupeol and ginsenoside Rb3 were validated as Q-markers that represent the anti-hyperlipidemia activity of the capsule.

Characterisation and classification of Citri Reticulatae Pericarpium varieties based on UHPLC-Q-TOF-MS/MS combined with multivariate statistical analyses

INTRODUCTION

Citri Reticulatae Pericarpium (CRP), comprising dried pericarps of Citrus reticulata Blanco and its cultivars, is popularly used for its great medicinal and dietary values. Generally, the pericarps from C. reticulate "Chachi" ("Guangchenpi" in Chinese, GCP) is considered to have superior qualities and merit premium price compared with CRP derived from other cultivars (collectively called "Chenpi" in Chinese, CP). Since its multiple origins and derived economic adulteration, it is significant to systematically compare the chemical profiles of different CRP varieties.

OBJECTIVE

The main objective of this work was to identify the chemical profiles of CRP from different varieties and find out potential chemical markers for differentiating GCP and CP.

METHODS

In the present study, a total of 42 CRP samples from 10 varieties (including GCP and CP) were analysed by ultra-high performance liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UHPLC-Q-TOF-MS/MS) for chemical profiling. Obtained MS/MS data were further employed in multivariate statistical methods to screen the main compounds which contributed to the characterisation and classification of CRP.

RESULTS

As a result, 73 compounds (mainly flavonoids) were identified or tentatively characterised in these CRP samples. Based on the obtained chemical profiles data, GCP and CP samples could be easily discriminated from each other by statistical analyses. Moreover, seven compounds were selected as having the most discriminating features which contributed to the classification of CRP.

CONCLUSION

This work obtains a better understanding of the chemical profiles of different CRP varieties and provides a practical strategy for the authentication of GCP and CP.

UFLC-Q-TOF-MS/MS-Based Screening and Identification of Flavonoids and Derived Metabolites in Human Urine after Oral Administration of Exocarpium Citri Grandis Extract

Exocarpium Citri grandis (ECG) is an important Traditional Chinese Medicine (TCM) for the treatment of cough and phlegm, and the flavonoids contained were considered the main effective components. To date, the systematic chemical profiling of these flavonoids and derived in vivo metabolites in human have not been well investigated. ECG was extracted using boiling water and then provided to volunteers for oral administration. Following the ingestion, urine samples were collected from volunteers over 48 h. The extract and urine samples were analyzed using ultra-fast liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS) system to screen and identify flavonoids and derived in vivo metabolites. A total of 18 flavonoids were identified in the ECG extract, and 20 metabolites, mainly glucuronide and sulfate conjugates, were screened in urine samples collected post consumption. The overall excretion of naringenin metabolites corresponded to 5.45% of intake and occurred mainly within 4–12 h after the ingestion. Meanwhile, another 29 phenolic catabolites were detected in urine. Obtained data revealed that flavonoids were abundant in the ECG extract, and these components underwent extensive phase II metabolism in humans. These results provided valuable information for further study of the pharmacology and mechanism of action of ECG.

Characterization of active antiplatelet chemical compositions of edible Citrus limon through ultra-performance liquid chromatography single quadrupole mass spectrometry-based chemometrics

UPLC-SQD-MS-based chemometrics was applied for antiplatelet active compounds screening for the first time, and seven potential biomarkers were found in lemon extract.

Chemical profiling of San-Huang decoction by UPLC-ESI-Q-TOF-MS

San-Huang decoction (SHD), a traditional Chinese medical (TCM) formula, is made from five chinese herbs and has been widely used for centuries to treat metabolic syndrome, such as abdominal obesity and nonalcoholic fatty liver disease. In this work, an ultra high performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS) method in both positive and negative ion mode was first employed to rapidly survey the major constituents in SHD. The analysis was performed on a Waters Acquity UPLC BEH C18 column at 45°C within 17min. 56 compounds in SHD including alkaloids, flavonoids, protostane triterpenoids, coumarins, triterpenoid saponins, organic acids, lignans, lactones and chromones were identified and tentatively characterized by comparison with retention times, accurate mass within 5ppm error and MS fragmentation ions. Among them, twenty-two compounds were clearly identified mainly by the reference standards. Moreover, this method was respectively applied to determine five batches of SHD and the decoctions of relative individual herbs. These results provide a helpful basic chemical profile for further research of SHD in vivo and exploitation of new drug to treat metabolic syndrome.

Developing an Absorption-Based Quality Control Method for Hu-Gan-Kang-Yuan Capsules by UFLC-QTOF-MS/MS Screening and HPLC-DAD Quantitative Determination

Traditional Chinese Medicine Preparations (TCMPs) contain massive numbers of ingredients responsible for their multiple efficacies. An absorption–based quality control method for complicated TCMPs using Hu–gan–kang–yuan Capsule (HGKYC) as an example was developed. To select proper chemical markers for quality control of HGKYC, an ultra–fast liquid chromatography (UFLC) coupled with electrospray ionization quadrupole time–off light mass spectrometry (UFLC–QTOF–MS/MS) method was used for the rapid separation and structural identification of the constituents in the HGKYC extract and the rat serum after oral administration of HGKYC. As a result, one hundred and seven prototype constituents including flavonoids, organic acid, phenylpropanoids, anthraquinones, saponins, alkaloids, terpenes, phenols and amino acids in HGKYC extract, and 43 compounds found in rat serum after oral administration of HGKYC were unambiguously identified or tentatively characterized by comparing retention times and MS information with those of authentic standards or available literature references. Finally, a simple, low–cost and effective method of simultaneous determination for baicalein, wogonin, paeonol and emodin in HGKYC was developed using high performance liquid chromatography coupled with a diode array detector. In conclusion, an absorption–based quality control pattern was developed and successfully used for evaluating HGKYC.

Comparison of chemical profiling and antioxidant activities of fruits, leaves, branches, and flowers of Citrus grandis 'Tomentosa'

Citrus grandis 'Tomentosa' (CGT) is particularly cultivated in China and widely used in health foods. In this study, the chemical profiles of different parts of CGT were comprehensively compared by rapid resolution liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry method. A total of 22 compounds were identified and two C-glucosyl flavones were found for the first time in CGT. Four main constituents (rhiofolin, naringin, meranzin hydrate, and isoimperatorin) in different parts of CGT were simultaneously determined. Overall, the contents of the four main compounds decreased with the ripening process. In parallel, the antioxidant activities of their extracts were also evaluated by three assays (2,2'-azinobis(3-ethylbenzthiazolinesulfonic acid) diammonium salt, 2,2-diphenyl-1-picrylhydrazyl, ferric reducing antioxidant power), and the results indicated a similar tendency: small fruit > flower ∼ medium fruit > large fruit > leaf ∼ branch. The results obtained in the present work may provide useful information for future utilization of CGT.

Antitussive, expectorant and anti-inflammatory activities of different extracts from Exocarpium Citri grandis

ETHNOPHARMACOLOGICAL RELEVANCE

Exocarpium Citri grandis (C. grandis, Huajuhong in Chinese), the epicarp of C. grandis 'Tomentosa', is used as an antitussive, expectorant and anti-inflammatory drug for hundreds of years in China. The study was aimed at evaluating the antitussive, expectorant and anti-inflammatory effects of different extracts of C. grandis, providing experimental evidence for its traditional use, and laying a foundation for its further researches.

MATERIALS AND METHODS

Crude drugs of C. grandis were extracted with four kinds of solvents (water, 50% ethanol, 70% ethanol and 90% ethanol) in reflux conditions, respectively. Solutions were concentrated in reduced pressure and lyophilized in vacuum to yield the aqueous extract, 50% ethanolic extract, 70% ethanolic extract, and 90% ethanolic extract of C. grandis. Antitussive evaluations were carried out with ammonia liquor induced mice cough; expectorant effects were tested with phenol red secretion experiments in mice; anti-inflammatory effects were assessed by murine model of xylene induced ear edema in mice.

RESULTS

Only aqueous and 70% ethanolic extracts of C. grandis displayed significant antitussive, expectorant and anti-inflammatory activities. Aqueous extract of C. grandis significantly decreased cough frequency caused by ammonia liquor, increased phenol red secretion and inhibited the development of ear edema in anti-inflammatory assay at the dose of 1005 mg/kg (P<0.05). However, aqueous extract of C. grandis did not lengthened the cough period. It was worth noting that, 70% ethanolic extract of C. grandis showed strong effect of decreasing cough frequency, prolonging cough period, increasing phenol red secretion and decreasing the extent of ear edema at the dose of 493 mg/kg (P<0.001). The low, middle, and high dose (247, 493, and 986 mg/kg) of 70% ethanolic extract of C. grandis showed significant antitussive, expectorant and anti-inflammatory effects in good dose dependant manner.

CONCLUSION

The results supported the folk use of C. grandis (decoction of C. grandis) with scientific evidence, and indicated that the 70% ethanolic extract of C. grandis might have better effects of antitussive, expectorant and anti-inflammatory than those of aqueous extract. Further investigation needs to be conducted to study the bioactive constituents of 70% ethanolic extract of C. grandis and the mechanism of observed antitussive, expectorant and anti-inflammatory activities.