Pharmacokinetic study of four flavones of Glycyrrhiza in rat plasma using HPLC-MS

Sensitive sensing of GLA and ISL based on highly conductivity nitrogen-doped carbon synergistic dual-template molecularly imprinted ratiometric electrochemical sensor

A novel ratiometric Molecularly Imprinted Electrochemical sensor for the specific marker of Glycyrrhiza glabra L. was developed in this work. To achieve simultaneous detection of two analytes on one sensor, we constructed a double template molecular imprinted electrochemical sensor with glabridin (GLA) and isoliquiritin (ISL) as templates. Further, Ferrocene/ZIF-8 (Fc/ZIF-8) composites were prepared via a one-pot solvothermal reaction and coated on the surface of a glassy carbon electrode (GCE), and the oxidation of Fc was presented as the internal reference signal. Nitrogen-doped carbon (NOC) with high conductivity was further loaded on the modified GCE. Based on theoretical exploration and computer directional simulation of density functional theory (DFT), the optimal functional monomer and the best ratio of double template molecules to functional monomer were screened. Under optimal conditions, the sensor produced electrochemical curves when exposed to a solution containing GLA and ISL. As the concentration of GLA and ISL increased, the peak current intensity of GLA and ISL (IGLA and IISL) also increased, while the peak current intensity of Fc (as a reference signal) remained relatively constant. The values of IGLA/IFc and IISL/IFc showed excellent linear relationships with GLA and ISL concentrations in the range of 0.1-160 μM and 0.5-150 μM, respectively. The detection limits were 0.052 μM and 0.27 μM (S/N = 3), respectively. Due to the imprinting effect of MIP and the existence of a reference signal, the sensor exhibited excellent selectivity and anti-interference ability and was successfully applied to the quality evaluation of Glycyrrhiza glabra L.

Isoliquiritin Ameliorates Ulcerative Colitis in Rats through Caspase 3/HMGB1/TLR4 Dependent Signaling Pathway

BACKGROUND

Isoliquiritin belongs to flavanol glycosides and has a strong antiinflammatory activity. This study sought to investigate the anti-inflammatory effect of isoliquiritin and its underlying mechanism.

METHODS

The inflammatory (trinitro-benzene-sulfonic acid-TNBS-induced ulcerative colitis (UC)) model was established to ascertain the effect of isoliquiritin on the caspase-3/HMGB1/TLR4 pathway in rats. We also explored its protective effect on intestinal inflammation and its underlying mechanism using the LPS-induced inflammation model of Caco-2 cells. Besides, Deseq2 was used to analyze UCassociated protein levels.

RESULTS

Isoliquiritin treatment significantly attenuated shortened colon length (induced by TNBS), disease activity index (DAI) score, and body weight loss in rats. A decrease in the levels of inflammatory mediators (IL-1β, I IL-4, L-6, IL-10, PGE2, and TNF-α), coupled with malondialdehyde (MDA) and superoxide dismutase (SOD), was observed in colon tissue and serum of rats after they have received isoliquiritin. Results of techniques (like western blotting, real-time PCR, immunohistochemistry, and immunofluorescence-IF) demonstrated the potential of isoliquiritin to decrease expressions of key genes in the TLR4 downstream pathways, viz., MyD88, IRAK1, TRAF6, NF-κB, p38, and JNK at mRNA and protein levels as well as inhibit HMGB1 expression, which is the upstream ligand of TLR4. Bioinformational analysis showed enteritis to be associated with a high expression of HMGB1, TLR4, and caspase-3.

CONCLUSION

Isoliquiritin could reduce intestinal inflammation and mucosal damage of TNBS-induced colitis in rats with a certain anti-UC effect. Meanwhile, isoliquiritin treatment also inhibited the expression of HMGB1, TLR4, and MyD88 in LPS-induced Caco-2 cells. These results indicated that isoliquiritin could ameliorate UC through the caspase-3/HMGB1/TLR4-dependent signaling pathway.

Pharmacokinetics and tissue distribution of 12 major active components in normal and chronic gastritis rats after oral administration of Weikangling capsules

ETHNOPHARMACOLOGICAL RELEVANCE

Weikangling Capsules (WKLCs) have been used in the clinic for the treatment of gastrointestinal disorders for more than 30 years. However, the pharmacokinetic characteristics and tissue distribution of its major bioactive components in rats under different physiological and pathological conditions are unclear.

AIM OF THE STUDY

In this study, we aimed to clarify the differences in pharmacokinetic parameters and tissue distribution of the major active components in WKLCs under physiological and pathological states.

MATERIALS AND METHOD

Normal and ethanol-induced chronic gastritis rats received 2.16 g/kg WKLCs by gavage, and urine, feces, plasma, and tissue (heart, liver, spleen, lung, kidney, stomach, and small intestine) samples were obtained. The active components in urine, feces and plasma were detected by ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). A rapid and sensitive analytical method, ultra-high-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS), was established and validated to clarify and compare the pharmacokinetics and tissue distribution of the major active components in normal and chronic gastritis rats.

RESULTS

A total of 36 chemical components in the feces, urine, and plasma of chronic gastritis rats were identified by UHPLC-Q-TOF-MS/MS. Among them, 20 were the prototype components of WKLCs, and 16 were metabolites. The pharmacokinetic characteristics and tissue distribution of 12 prototype components were successfully analyzed by UHPLC-QTRAP-MS/MS. The pharmacokinetic results showed that the C_max, AUC_0-t, and AUC_0-∞ of paeoniflorin, glycyrrhizic acid, and glycyrrhetinic acid were distinctly higher than those of the other components in normal and chronic gastritis rats. Compared to normal rats, the C_max, AUC_0-t, and AUC_0-∞ of albiflorin, liquiritin apioside, liquiritin, isoliquiritin, ononin, isoliquiritigenin, dactylorhin A, and glycyrrhizic acid were significantly increased in chronic gastritis rats (P < 0.05), while the C_max, AUC_0-t and AUC_0-∞ of militarine and liquiritigenin had significantly lower decreases in chronic gastritis rats (P < 0.05). The results of the tissue distribution showed that the 12 components were widely distributed in the heart, liver, spleen, lung, kidney, stomach, and small intestine of rats, of which the liver, kidney, stomach, and small intestine were the main accumulative organs. Compared with normal rats, the concentrations of 12 components in the liver, kidney, stomach, and small intestine of chronic gastritis rats were widely higher than those of normal rats at the same time points.

CONCLUSION

The pharmacokinetic characteristics and tissue distribution of 12 active components of WKLCs were comprehensively characterized and elucidated in normal and chronic gastritis rats. These findings laid a solid foundation for revealing the pharmacodynamic material basis of WKLCs in treating gastrointestinal disorders.

Chemical analysis of the Chinese herbal medicine licorice (Gan-Cao): An update review

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice, called Gan-Cao in China, is one of the most popular traditional herbal medicines. It is derived from the dried roots and rhizomes of Glycyrrhiza uralensis, G. glabra, and G. inflata. Licorice is recorded in the pharmacopoeias of China, Japan, US, and Europe.

AIM

This review updates research progress of licorice from the perspectives of chemical analysis, quality evaluation, drug metabolism, and pharmacokinetic studies from 2009 to April 2022.

MATERIALS AND METHODS

Both English and Chinese literatures were collected from databases including PubMed, Elsevier, Web of Science, and CNKI (Chinese). Licorice, extraction, structural characterization/identification, quality control, metabolism, and pharmacokinetics were used as keywords.

RESULTS

Newly developed analytical methods, including LC/UV, 2DLC, LC/MS, GC/MS, and mass spectrometry imaging (MSI) for chemical analysis of licorice were summarized.

CONCLUSION

This review provides a comprehensive summary on chemical analysis of licorice.

Comparative pharmacokinetics of four major flavonoids in normal and chronic gastritis rats after oral administration of different combinations of Banxia Xiexin Decoction

Chronic gastritis (CG) has become a major threat to human health. Banxia Xiexin Decoction (BXXXD) has been used clinically to treat gastritis by acting on the spleen and stomach for thousands of years. Baicalin, wogonoside, liquiritin and liquiritigenin, are the main bioactive flavonoids of BXXXD. A rapid, sensitive and selective HPLC-TQ-MS/MS method was developed to simultaneously quantify the four flavonoids in rat plasma in this study. With salidroside as internal standard (IS), plasma samples were extracted and separated on a Welch HPLC XB-C18 column (2.1 × 50 mm, 1.8 μm) using gradient elution. An optimized gradient of mobile phase consisted of water (containing 0.1% formic acid) (A) and methanol (B) was used. Detection was implemented in MRM mode with an electrospray negative ionization source. Comparative pharmacokinetics of four analytes in normal and CG rats after oral administration of BXXXD or its different compatibilities were firstly investigated. Results indicated that the pharmacokinetic behaviors of analytes were obviously changed in CG rats. From the comparison between the whole prescription group and the compatibility groups, it was found that the pharmacokinetic behavior of analytes also changed to some extent. The pharmacokinetic alterations of analytes might be due to the pathological conditions of CG.

A validated UHPLC-MS/MS method for pharmacokinetic and brain distribution studies of twenty constituents in rat after oral administration of Jia-Wei-Qi-Fu-Yin

A rapid ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-QqQ MS/MS) approach with high sensitivity and selectivity was developed for the quantification of twenty compounds, including 9 saponins, 8 flavonoids, 2 oligosaccharide esters and 1 phenolic acid, in rat plasma and brain, which was administrated intragastrically with Jia-Wei-Qi-Fu-Yin (JWQFY), Mass spectrometric detection was operated under multiple reaction monitoring (MRM) mode. All calibration curves possessed good linearity with correlation coefficients ( r²) higher than 0.9916 in their respective linear ranges. For intra- and inter-day precision, all the relative standard deviations (RSDs) at different levels were less than 14.68 %. Based on the UHPLC-QqQ MS/MS quantitative results, pharmacokinetic study and brain distribution of multiple components in JWQFY was then successfully performed. As a result, constituents with discrepancy structures showed diverse pharmacokinetic and distribution characteristics. For instance, ferulic acid (phenolic acid), 3, 6'-disinapoyl sucrose and tenuifoliside A (oligosaccharide esters) showed short T_max (< 10 min), whereas the T_max of ginsenosides Rb₁, Rb₂ and Rc (ppd-type terpenoid saponins) were much longer (> 4 h). Besides, ferulic acid, epimedin C, icariin, glycyrrhizin, ginsenoside Rb₁ and ginsenoside Rg₁ were considered as the potential effective ingredients of JWQFY because of their relatively high exposure to blood and brain. Our study would provide relevant information for discovery of pharmacodynamic ingredients, as well as further action mechanisms investigations of JWQFY.

Recent advances in chemical analysis of licorice (Gan-Cao)

Gan-Cao, or licorice, the dried roots and rhizomes of Glycyrrhiza uralensis, G.glabra, and G.inflata, has received considerable interest due to its extensive application in traditional Chinese medicine (TCM) prescriptions (60% approximately), clinical therapy, and as food additives world-wide. Chemical analysis is an important approach to understand the active pharmaceutical components in licorice and its prescriptions, as well as to develop novel methodologies for their quality assessment and control. This comprehensive review describes the advances in the chemical analysis, including sample preparation methods, qualitative and quantitative analysis and biological specimen analysis, based on 113 references for the recent years. Newly established methods are summarized, such as high performance thin layer chromatography (HPTLC), high performance liquid chromatography (HPLC), liquid chromatography tandem mass spectrometry (LC-MS), capillary electrophoresis (CE) and near infrared spectroscopy (NIR), which allows the identification, authentication, and simultaneous detection of multiple compounds in licorice with higher throughput and sensitivity. It is anticipated that this review could provide imperative information for improving the existing quality evaluation methods of licorice and afford scientific basis for further researches on the pharmacodynamic substances of licorice.

Comparative pharmacokinetics of seven bioactive components in normal, sham-operated, and myocardial ischemia-reperfusion injury rats after oral administration of the Salvia Miltiorrhiza-Moutan Cortex herb pair

Recently the Salvia Miltiorrhiza-Moutan Cortex (SM-MC) herb pair is considered as a promising Chinese medicinal mixture exhibiting a range of pharmacological activities, including treating cardiovascular disease due to its unique composition. In this study, we conducted the comparative pharmacokinetic analysis of seven main bioactive components of SM-MC in a different model rat. A straightforward ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) strategy that could simultaneously evaluate the levels of seven compounds was used to ensure the reliability of these pharmacokinetic analyses in rat plasma. The rat plasma samples were collected from normal, sham-operated, and myocardial ischemia-reperfusion injury (MIRI) groups at predetermined time points after the administration of SM-MC. The main pharmacokinetic parameters were detected and calculated. We successfully assessed the maximum concentration (C_max ), time to C_max (T_max ), the elimination rate constant (λ_z ), total half-life (t_1/2 ), total body clearance (CL), and the area under the concentration-time curve from 0 to last sampling time (AUC_0-t ) and extrapolated to infinity (AUC_0-∞ ). To sum up, an optimized UPLC-MS/MS approach that could be used to rapidly, simultaneously, and sensitively detect seven bioactive compounds derived from SM-MC extract preparations was successfully developed, which may offer a pharmacokinetic basis for preclinical and clinical studies of SM-MC herb pair for treating MIRI.

Quantification of 10 bioactive components of Yazhangsan in rat plasma by LC-MS/MS and its application

Yazhangsan (YZS) is a common prescription for the treatment of cough and asthma caused by wind-cold. The purpose of this study was to investigate the pharmacokinetic profiles of 10 bioactive components in YZS. A simple, sensitive and reliable high-performance liquid chromatography coupled with a triple-quadruple mass spectrometry method (LC-MS/MS) was developed and fully validated in this study for the measurement of these 10 bioactive compounds in rat plasma. One-step protein precipitation method using methanol was applied to the treatment of rat plasma samples. Chromatographic separation was conducted on a C₁₈ column by gradient elution, and water (containing 0.1% formic acid) and acetonitrile were chosen as the mobile phase. The analytes were quantified by using a mass spectrometer in multiple reaction monitoring scanning mode, and electrospray ionization was performed in positive and negative ion modes. The established method met the requirements for the quantification of these 10 bioactive compounds in biological samples, and it was successfully applied to the pharmacokinetic study of 10 components in rats after the intragastrical administration of YZS. This study will lay a foundation for the investigation of the mechanism of action of YZS and provide useful data for the rational use of YZS in clinical.

Development of a sensitive and rapid UHPLC-MS/MS method for simultaneous quantification of nine compounds in rat plasma and application in a comparative pharmacokinetic study after oral administration of Xuefu Zhuyu Decoction and nimodipine

Xuefu Zhuyu Decoction (XFZYD) is a traditional Chinese medicine prescription used for the clinical treatment of traumatic brain injury (TBI). The purpose of this work was to develop a sensitive and rapid UHPLC-MS/MS method to simultaneously study the pharmacokinetics of nimodipine and eight components of XFZYD, namely, amygdalin, hydroxysafflor yellow A, rutin, liquiritin, narirutin, naringin, neohesperidin and saikosaponin A, in rats with and without TBI. Multiple reaction monitoring was highly selective in the detection of nine analytes and the internal standard without obvious interference. The calibration curves displayed good linearity (r > 0.99) over a wide concentration range. The mean absolute recoveries of the nine analytes were 85-106%, and all matrix effects were in the range 80-120%. The intra- and inter-day precision and accuracy were acceptable (RSD, <15%; RE%, ±20%). The validated method was successfully applied to compare the pharmacokinetics in four experimental groups, including control rats orally administered XFZYD and TBI model rats orally administered XFZYD, XFZYD and nimodipine, or nimodipine alone. The results showed that herb-drug interactions occurred between XFZYD and nimodipine in the treatment of TBI, nimodipine affected the pharmacokinetics of XFZYD, and XFZYD affected the absorption, distribution and excretion of nimodipine in vivo.

Metabolic profiling of mice plasma, bile, urine and feces after oral administration of two licorice flavonones

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is an ancient food and medicinal plant. Liquiritigenin and liquiritin, two kinds of major flavonoes in licorice, are effective substances used as antioxidant, anti-inflammatory and tumor-suppressive food, cosmetics or medicines. However, their in vivo metabolites have not been fully explored.

AIM OF STUDY

To clarify the metabolism of liquiritigenin and liquiritin in mice.

MATERIALS AND METHODS

In this study, we developed a liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry approach to determine the metabolites in mice plasma, bile, urine and feces after oral administration of liquiritigenin or liquiritin. The structures of those metabolites were tentatively identified according to their fragment pathways, accurate masses, characteristic product ions, metabolism laws or reference standard matching.

RESULTS

A total of 26 and 24 metabolites of liquiritigenin or liquiritin were respectively identified. The products related with apigenin, luteolin or quercetin were the major metabolites of liquiritigenin or liquiritin in mice. Seven main metabolic pathways including (de)hydrogenation, (de)hydroxylation, (de)glycosylation, (de)methoxylation, acetylation, glucuronidation and sulfation were summarized to tentatively explain their biotransformation.

CONCLUSION

This study not only can provide the evidence for in vivo metabolites and pharmacokinetic mechanism of liquiritigenin and liquiritin, but also may lay the foundation for further development and utilization of liquiritigenin, liquiritin and then licorice.

Serotonergically dependent antihyperalgesic and antiallodynic effects of isoliquiritin in a mouse model of neuropathic pain

Chronic neuropathic pain poses a significant health problem worldwide, for which effective treatment is lacking. The current work aimed to investigate the potential analgesic effect of isoliquiritin, a flavonoid from Glycyrrhiza uralensis, against neuropathic pain and elucidate mechanisms. Male C57BL/6J mice were subjected to chronic constriction injury (CCI) by loose ligation of their sciatic nerves. Following CCI surgery, the neuropathic mice developed pain-like behaviors, as shown by thermal (heat) hyperalgesia in the Hargreaves test and tactile allodynia in the von Frey test. Repetitive treatment of CCI mice with isoliquiritin (p.o., twice per day for two weeks) ameliorated behavioral hyperalgesia to thermal (heat) stimuli and allodynia to tactile stimuli in a dose-dependent fashion (5, 15 and 45 mg/kg). The isoliquiritin-triggered analgesia seems serotonergically dependent, since its antihyperalgesic and antiallodynic actions were totally abolished by chemical depletion of spinal serotonin by p-chlorophenylalanine, whereas potentiated by 5-HTP (a precursor of 5-HT). Consistently, isoliquiritin-treated neuropathic mice showed escalated levels of spinal monoamines especially 5-HT, with depressed monoamine oxidase activity. Moreover, isoliquiritin-evoked antihyperalgesia and antiallodynia were preferentially counteracted by the 5-HT_1A receptor antagonist WAY-100635 delivered systematically or spinally. Of notable benefit, isoliquiritin was able to correct co-morbid behavioral symptoms of depression and anxiety evoked by neuropathic pain. Collectively, these findings demonstrate, for the first time, the therapeutic efficacy of isoliquiritin on neuropathic hypersensitivity, and this effect is dependent on the spinal serotonergic system and 5-HT_1A receptors.

Correlation study between the pharmacokinetics of seven main active ingredients of Mahuang decoction and its pharmacodynamics in asthmatic rats

The aim of this study was to investigate the pharmacokinetics and pharmacodynamics of seven main active components of Mahuang decoction (MHD) and its time-concentration-effect relationship. The asthmatic rat model was established by the method of ovalbumin (OVA) sensttization. The plasma concentrations of ephedrine, pseudoephedrine, methylephedrine, amygdalin, liquiritin, cinnamic acid, glycyrrhizic acid in asthmatic model rat were investigated by a selective and rapid HPLC/MS-MS method. Simultaneously, the asthma-involved cytokines including leukotrienes B₄ (LTB₄), thromboxane B₂ (TXB₂), 6-Keto-Prostaglandin F_1α (6-K-PGF_1α) and histamine (HIS) levels in rat plasma were determined by using ELISA. A mathematics method was applied to assess the trend of percentage rate of change among different time intervals of the seven components. The sigmoid E max function was used to establish the PK-PD modeling of MHD. The results indicated that MHD could control or ameliorate asthma. There was a hysteresis between the peaked drug concentration and maximum therapeutic effect of MHD. The PK-PD curves of MHD showed clockwise or counter-clockwise hysteresis loop. In addition, amygdalin might exert a more significant influence on regulating cytokines levels in asthmatic rats among the seven components of MHD.

Simultaneous determination of eight flavonoids in Sedum sarmentosum Bunge from different areas by UHPLC with triple quadrupole MS/MS

Sedum sarmentosum Bunge (SSB) is a traditional Chinese herbal medicine containing multiple components that has been extensively used clinically to treat chronic viral hepatitis and some inflammatory diseases. Total flavonoids are major pharmacologically active components of SSB. To gain a deeper understanding of SSB resources, we analyzed eight chemical constituents in 33 batches of SSB from 11 regions in China. An accurate, precise and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole electrospray tandem mass spectrometry method was developed for the determination of eight flavonoids in SSB. Under the optimized chromatographic conditions, good separation for the eight target components was obtained on an Agilent Zobax SB C₁₈ (50 × 2.1 mm, 5 μm) column within 4 min. The established methods were validated with good linearity (r ≥ 0.9988), precision (RSD ≤ 2.68%), stability (1.43-3.28%) and repeatability (1.14-2.89%). Moreover, the average recoveries were 95.91-100.68%, and the RSDs were 1.50-3.80%. In addition, the analytical conditions of UPLC-ESI-MS/MS provided better sensitivity with a shorter analysis time when compared with the HPLC-DAD method. Hierarchical clustering analysis and principal component analysis were performed to estimate and classify these samples based on the contents of the eight chemical constituents. This study provided the theoretical basis and scientific evidence for the development and utilization of SSB resources.

Pharmacokinetic Study of Main Active Components of Rumex nepalensis Spreng Extract in Rats Plasma by UPLC-MS/MS

Background:

The Rumex nepalensis Spreng (RNS) is a traditional Chinese medicine containing rich anthraquinones. However, through proper investigation we have found that there were no reports on the pharmacokinetics of RNS extract in rats. </P><P> Objective: We study on the pharmacokinetic behaviors of emodin, chrysophanol and physcion after oral administration of RNS extract in rat to achieve a better understanding of further clinical application and conduct the preparation development of the herb.

Methods:

In the present study, a sensitive and rapid ultra-fast liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine the three anthraquinones such as chrysophanol, emodin and physcion in rat plasma along with danthron as the internal standard (IS). The analytes and IS were separated on an Acquity UPLC HSS T3 column (100 mm × 2.1 mm, 1.8 µm) by using the mobile phase of water with 3 mM ammonium acetate and acetonitrile as gradient elution at a flow rate of 0.4 mL min -1. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reactions monitoring (MRM) of the transitions at m/z 253.1 → 225.0 for chrysophanol, 269.0 → 224.9 for emodin, 282.7→ 240.0 for physcion and m/z 239.0 → 211.0 for IS. The limit of detection and lower limit of quantification were both 2 ng mL -1 in rat plasma.

Results:

Good linearity of this method was obtained in the range of 2-1000 ng mL -1 , and the correlation coefficient was greater than 0.990. According to regulatory guidelines, the established method was fully validated, and the results were within acceptable limits.

Conclusion:

The validated method was successfully applied into a pharmacokinetic study of orally administered RNS extract in rats.

The Effects of the Honey-Roasting Process on the Pharmacokinetics of the Six Active Compounds of Licorice

A convenient UPLC-MS/MS method was established to determine the contents of six bioactive compounds, namely, liquiritin apioside, liquiritin, isoliquiritin, liquiritigenin, isoliquiritigenin, and glycyrrhetinic acid, in rat plasma and their pharmacokinetics. By comparing the pharmacokinetic parameters of these compounds in rats by orally administering raw and honey-roasting licorice, the C_max of isoliquiritin showed a significant decrease, while the AUC_0-24h showed no significant differences. The C_max and AUC_0-24h of isoliquiritigenin were increased by 49.3% and 42.7% over those of the raw licorice group, respectively. These results indicate that the absorption of isoliquiritin in rats was reduced while the absorption of isoliquiritigenin was promoted in the honey-roasting process. These results may provide one explanation as to why licorice is more able to relieve cough, while honey-roasting licorice is better at invigorating qi and restoring pulse. Furthermore, the C_max of glycyrrhetinic acid was increased, suggesting that it may enhance the tonic effect of licorice. Additionally, the amount of honey added in the honey-roasting process influenced the pharmacokinetic parameters of the six compounds whose absorption decreased when the 50% honey-roasting licorice water decoction was administered. These results provide an experimental basis for studying the influence of licorice processing on bioactive compound pharmacokinetics.

Influence of Jiegeng on Pharmacokinetic Properties of Flavonoids and Saponins in Gancao

Jiegeng Gancao decoction, which is composed of Jiegeng and Gancao at a weight ratio of 1:2, was widely used for treating pharyngalgia and cough for thousands of years. Our previous work indicated that Gancao could increase the systemic exposure of platycodin D and deapio-platycodin D, two main components in Jiegeng. However, whether Jiegeng could alter the pharmacokinetics of the main compounds in Gancao is still unknown. Thus, the purpose of this study was to compare the oral pharmacokinetics of flavonoids and saponins from Gancao alone vs. after co-administration with Jiegeng. Furthermore, Caco-2 cell transport and fecal hydrolysis were investigated to explain the altered pharmacokinetic properties. Pharmacokinetics results suggested that the bioavailability of liquiritin, isoliquiritin, glycyrrhizin and its metabolite, glycyrrhetinic acid, could be improved while bioavailability of liquiritigenin and isoliquiritigenin deteriorated when co-administered with Jiegeng. The Caco-2 transport study showed no significant difference of the P_app values of the main components in Jiegeng Gancao decoction when compared with those in Gancao decoction (p > 0.05). The in vitro metabolism study suggested that saponins and flavonoids glycosides in Gancao were influenced and the metabolic characteristics of most ingredients were consistent with pharmacokinetic results, such as liquiritin and glycyrrhetinic acid. The hydrolysis of liquiritigenin and glycyrrhizin observed with fecal lysate in vitro appeared consistent with the oral pharmacokinetics. Based on experiments, the pharmacokinetic profiles of six components in Gancao were influenced by Jiegeng. The metabolic process might partially contribute to the altered pharmacokinetic behavior. The metabolism of some components of Gancao appeared to be inhibited when coadministered with Jiegeng, possibly by the Jiegeng constituent platycodin.

Dynamic changes of flavonoids in Abelmoschus manihot different organs at different growth periods by UPLC-MS/MS

Abelmoschus manihot (Linn.) Medicus has been clinically used to treat chronic kidney disease, oral ulcers, burns, and dysmenorrhea in China for many centuries. The major pharmacologically-active components of A. manihot are flavonoids. In this study, a rapid and highly sensitive UPLC-MS/MS analysis method was established and successfully applied to the simultaneous determination of five major flavonoids (rutin, hyperoside, isoquercitrin, quercetin, and myricetin) in different parts of A. manihot harvested at ten growth periods. Under the optimized chromatographic conditions, good separation for five target components was obtained on an Acquity UPLC BEH C18 column within 18min. The total contents of the five investigated flavonoids in A. manihot roots, stems, leaves and flowers ranged from 2.86 to 123.7μg/g, 46.39 to 141.0μg/g, 929.4 to 3096μg/g, and 10,150 to 19,390μg/g, respectively, indicating that the total flavonoids in the four parts could be mainly arranged in a decreasing order as flower>leaf>stem>root. The peak of total flavonoids in flowers and leaves appeared at G8 and G9, respectively. These results will be helpful for the determination of the suitable harvest time of A. manihot and the improvement of the utility value of the disused parts.

Synthetic Isoliquiritigenin Inhibits Human Tongue Squamous Carcinoma Cells through Its Antioxidant Mechanism

Isoliquiritigenin (ISL), a natural antioxidant, has antitumor activity in different types of cancer cells. However the antitumor effect of ISL on human tongue squamous carcinoma cells (TSCC) is not clear. Here we aimed to investigate the effects of synthetic isoliquiritigenin (S-ISL) on TSCC and elucidate the underlying mechanisms. S-ISL was synthesized and elucidated from its nuclear magnetic resonance spectrum and examined using high performance liquid chromatography. The effects of S-ISL on TSCC cells (Tca8113) were evaluated in relation to cell proliferation, apoptosis and adhesion, migration, and invasion using sulforhodamine B assay, fluorescence microscopy technique, flow cytometry (FCM) analysis, and Boyden chamber assay. The associated regulatory mechanisms were examined using FCM and fluorescence microscopy for intracellular reactive oxygen species (ROS) generation, Gelatin zymography assay for matrix metalloproteinase (MMP) activities, and Western blot for apoptosis regulatory proteins (Bcl-2 and Bax). Our data indicated that S-ISL inhibited Tca8113 cell proliferation, adhesion, migration, and invasion while promoting the cell apoptosis. Such effects were accompanied by downregulation of Bcl-2 and upregulation of Bax, reduction of MMP-2 and MMP-9 activities, and decreased ROS production. We conclude that S-ISL is a promising agent targeting TSCC through multiple anticancer effects, regulated by its antioxidant mechanism.

Glycyrrhiza glabra

Liquorice foliage

Study of pharmacokinetic profiles and characteristics of active components and their metabolites in rat plasma following oral administration of the water extract of Astragali radix using UPLC-MS/MS

ETHNOPHARMACOLOGICAL RELEVANCE

Astragali radix is one of the well-known traditional Chinese herbal medicine, and possesses various biological functions, such as hepatoprotective and anticancer. In present study, to investigate the metabolism and pharmacokinetics of the major constituents of A. radix, a sensitive ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-MS/MS) method with shorter chromatographic running time was developed and validated for simultaneous quantification of formononetin, ononin, calycosin, calycosin-7-β-glucoside, astragaloside IV and their glucuronide metabolites in rat plasma after oral administration of water extract of A. radix at two different doses.

MATERIALS AND METHODS

The chromatographic separation was achieved on a C18 column with gradient elution by using a mixture of 0.1% formic acid aqueous solution and acetonitrile as the mobile phase at a flow rate of 0.3mL/min. A tandem mass spectrometric detection was conducted using multiple-reaction monitoring (MRM) via electrospray ionization (ESI) source in positive ionization mode. Samples were pre-treated by a single-step protein precipitation with methanol, and erlotinib was used as internal standard (IS).

RESULTS

The current UPLC-MS/MS assay was validated for linearity, intra-day and inter-day precisions, accuracy, extraction recovery, matrix effects and stability. The lowest limit of quantifications (LLOQ) were 1ng/mL for all analytes. After oral administration, the plasma concentrations of the glucuronides, especially calycosin-3'-glucuronide, were much higher than the parent compounds. The mean half-life (t1/2) was between 1 and 5h, and the metabolites were eliminated faster than the parent constituents. The median (range) time to reach maximum plasma concentration (Tmax) was between 0.5 and 1h.

CONCLUSIONS

This is the first study of the pharmacokinetic study of bioactive compounds and their glucuronides in male rat plasma after oral administration of water extract of A. radix. The results demonstrated the biotransformation between the bioactive isoflavonoids and their glucuronides was extensive in rats and provided a significant basis for better understanding the absorption and metabolism mechanism of A. radix. Furthermore, this study could suggest that future studies should focus on the metabolites and biotransformation between the bioactive constituents when conducting a drug efficacy study.

LC-MS/MS determination and pharmacokinetic study of seven flavonoids in rat plasma after oral administration of Cirsium japonicum DC. extract

ETHNOPHARMACOLOGICAL RELEVANCE

Cirsium japonicum DC., a Traditional Chinese Medicine, has the curative effect of antihemorrhagic and antitumor. Pharmacological studies prove that the curative effect may relate to the flavonoids. A simple and rapid resolution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was first developed and validated for the quantification of seven flavonoids including pectolinarin, linarin, pectolinarigenin, hispidulin, diosmetin, acacetin and apigenin in rat plasma after oral administration of Cirsium japonicum DC. extract.

MATERIALS AND METHODS

The chromatographic separation was achieved on a C18 column with gradient elution by using a mixture of 0.1% formic acid aqueous solution and methanol as the mobile phase at a flow rate of 0.8mL/min. A tandem mass spectrometric detection was conducted using multiple-reaction monitoring (MRM) via an electrospray ionization (ESI) source in positive and negative ionization mode simultaneously. Samples were pre-treated by a single-step protein precipitation with methanol, and sulfamethoxazole was used as internal standard (IS).

RESULTS

The optimized mass transition ion-pairs (m/z) for quantization were 623.4/315.2 for pectolinarin, 593.3/285.1 for linarin, 315.3/300.2 for pectolinarigenin, 301.2/286.2 for hispidulin, 301.2/258.2 for diosmetin, 283.0/267.9 for acacetin, 269.0/117.0 for apigenin and 252.2/155.8 for IS. After oral administration of 6mL/kg Cirsium japonicum DC. extract in rats, the maximum plasma concentration (Cmax) of pectolinarin, linarin, pectolinarigenin, hispidulin, diosmetin, acacetin and apigenin were 876.77±97.34ng/mL, 86.79±1.70ng/mL, 6.13±0.12ng/mL, 32.85±2.50ng/mL, 37.2±2.04ng/mL, 19.02±1.29ng/mL and 148.26±20.63ng/mL, respectively. The time to reach the maximum plasma concentration (Tmax) was 5min for pectolinarin, linarin, pectolinarigenin, hispidulin, diosmetin, acacetin and 360min for apigenin. The intra-day and inter-day precisions (RSD%) for seven compounds were less than 13.16% and 7.77% and the accuracy (RE%) range from -7.92% to 14.77%.

CONCLUSIONS

This is the first research on the pharmacokinetic study of bioactive components in rat plasma after oral administration of Cirsium japonicum DC. extract. The results provided a meaningful basis for better understanding the absorption mechanism of Cirsium japonicum DC. and evaluating the clinical application of this herb medicine.