Development of a dynamic multiple reaction monitoring method for determination of digoxin and six active components of Ginkgo biloba leaf extract in rat plasma

Interaction between Chinese medicine and digoxin: Clinical and research update

Background: Digoxin is one of the most widely and commonly used cardiac drug, which plays an irreplaceable role in treating heart failure and arrhythmia. The 2010 Edition of Pharmacopoeia of the People's Republic of China stipulates that the effective range of digoxin plasma concentration is 0.5-2.0 ng/mL and it is toxic at plasma concentration >2 ng/mL. Its effective plasma drug concentration is close to the toxic concentration, and large individual differences in the effects of the drug have been observed. It is often used in combination with other drugs, but drug interactions have a great impact on the plasma concentration of digoxin and lead to adverse reactions (ADRs), such as poisoning. Most of the reported drug interactions are with Western drugs. However, there are many combinations of traditional Chinese medicine (TCM) and Western drugs, TCM interacting with digoxin comprises monomer components, single medicines, and Chinese patent medicines. Aim of the study: We aimed i) to provide an overview of the TCM formulations affecting the pharmacology of digoxin and their mechanisms of action and ii) to provide a theoretical reference for the safe and rational use of digoxin in combination with TCM in clinical practice and to avoid ADRs. Methods: A literature search of electronic databases, including PubMed, MEDLINE, Cochrane Library, Web of Science, China National Knowledge Infrastructure, and WANFANG Data, was performed to search for articles published between 1 January 1960, and 1 August 2022. Search terms used included "digoxin," "traditional Chinese medicine," "Chinese patent medicine," and "adverse reactions" and their combinations. Results: A total of 49 articles were obtained, including clinical reports, pharmacological experiments and in vitro experiments. The mechanisms of action affecting the pharmacology of digoxin are complex. TCM formulations may affect the pharmacology of digoxin in vivo by influencing gastrointestinal motility or gastric juice pH, regulating P-glycoprotein levels, exerting cumulative pharmacological effects, and enhancing the sensitivity of the heart to digoxin. Although studies have shown that some TCM formulations interact with digoxin, they may be influenced by the complexity of the composition and the pharmacological effects of the TCM, the sensitivity of digoxin concentration determination methods, etc. The results of existing studies are controversial and further in-depth studies are required. Conclusion: Combinations of digoxin and TCM formulations are commonly used. This article serves as a reference to understand the interactions between TCM formulations and digoxin to avoid the occurrence of ADRs and improve the efficacy and safety of digoxin.

Effects of ginkgo leaf tablet on the pharmacokinetics of rosiglitazone in rats and its potential mechanism

CONTEXT

Ginkgo leaf tablet (GLT), a traditional Chinese herbal formula, is often combined with rosiglitazone (ROS) for type 2 diabetes mellitus treatment. However, the drug-drug interaction between GLT and ROS remains unknown.

OBJECTIVE

To investigate the effects of GLT on the pharmacokinetics of ROS and its potential mechanism.

MATERIALS AND METHODS

The pharmacokinetics of 10 mg/kg ROS with 100/200 mg/kg GLT as single-dose and 10-day multiple-dose administration were investigated in Sprague-Dawley rats. In vitro, the effects of GLT on the activity of CYP2C8 and CYP2C9 were determined in recombinant human yeast microsomes and rat liver microsomes with probe substrates.

RESULTS

The t_1/2 of ROS increased from 2.14 ± 0.38 (control) to 2.79 ± 0.37 (100 mg/kg) and 3.26 ± 1.08 h (200 mg/kg) in the single-dose GLT administration. The AUC_0-t (139.69 ± 45.46 vs. 84.58 ± 39.87 vs. 66.60 ± 15.90 h·μg/mL) and t_1/2 (2.75 ± 0.70 vs. 1.99 ± 0.44 vs. 1.68 ± 0.35 h) decreased significantly after multiple-dose GLT treatment. The IC₅₀ values of quercetin, kaempferol, and isorhamnetin, GLT main constituents, were 9.32, 7.67, and 11.90 μmol/L for CYP2C8, and 27.31, 7.57, and 4.59 μmol/L for CYP2C9. The multiple-dose GLT increased rat CYP2C8 activity by 44% and 88%, respectively.

DISCUSSION AND CONCLUSIONS

The metabolism of ROS is attenuated in the single dose of GLT by inhibiting CYP2C8 and CYP2C9 activity, and accelerated after the multiple-dose GLT treatment via inducing CYP2C8 activity in rats, indicating that the clinical dose of ROS should be adjusted when co-administrated with GLT.

A High Throughput Lipidomics Method Using Scheduled Multiple Reaction Monitoring

Lipid compositions of cells, tissues, and bio-fluids are complex, with varying concentrations and structural diversity making their identification challenging. Newer methods for comprehensive analysis of lipids are thus necessary. Herein, we propose a targeted-mass spectrometry based lipidomics screening method using a combination of variable retention time window and relative dwell time weightage. Using this method, we identified more than 1000 lipid species within 24-min. The limit of detection varied from the femtomolar to the nanomolar range. About 883 lipid species were detected with a coefficient of variance <30%. We used this method to identify plasma lipids altered due to vitamin B12 deficiency and found a total of 18 lipid species to be altered. Some of the lipid species with ω-6 fatty acid chains were found to be significantly increased while ω-3 decreased in vitamin B12 deficient samples. This method enables rapid screening of a large number of lipid species in a single experiment and would substantially advance our understanding of the role of lipids in biological processes.

Pharmacokinetic, Metabolism, and Metabolomic Strategies Provide Deep Insight Into the Underlying Mechanism of Ginkgo biloba Flavonoids in the Treatment of Cardiovascular Disease

Ginkgo biloba, known as the "living fossil," has a long history of being used as botanical drug for treating cardiovascular diseases and the content of flavonoids as high as 24%. More than 110 different kinds of flavonoids and their derivatives have been separated from G. biloba, including flavones, flavonols, biflavonoids, catechins, and their glycosides, etc., all of which display the ability to dilate blood vessels, regulate blood lipids, and antagonize platelet activating factor, and protect against ischemic damage. At present, many types of preparations based on G. biloba extract or the bioactive flavonoids of it have been developed, which are mostly used for the treatment of cardiovascular diseases. We herein review recent progress in understanding the metabolic regulatory processes and gene regulation of cellular metabolism in cardiovascular diseases of G. biloba flavonoids. First, we present the cardioprotective flavonoids of G. biloba and their possible pharmacological mechanism. Then, it is the pharmacokinetic and liver and gut microbial metabolism pathways that enable the flavonoids to reach the target organ to exert effect that is analyzed. In the end, we review the possible endogenous pathways toward restoring lipid metabolism and energy metabolism as well as detail novel metabolomic methods for probing the cardioprotective effect of flavonoids of G. biloba.

Target profiling of flavonol glycosides in the extract of Ginkgo biloba leaf and their pharmacokinetics in rat plasma by ultra-high-performance liquid chromatography with tandem mass spectrometry

The extract of Ginkgo biloba leaf is a popular herbal product or dietary supplement in the world to treat various diseases, and flavonol glycosides are considered as the main bioactive constituents. In this study, 37 flavonol glycosides were rapidly screened out by precursor ion scanning in positive ion mode with production ions at m/z 287.05, 303.05, and 317.06. Subsequently, a reliable and sensitive ultra-high-performance liquid chromatography coupled with triple quadrupole-linear ion trap mass spectrometry approach was established and validated to quantify the 20 prototype flavonol glycosides in rat plasma. Calibration curves showed good linearity (R² ≥ 0.9894) over the corresponding concentration range. The precision, accuracy, extraction recovery, matrix effect, and stability were also satisfactory. The validated method was successfully applied to a pharmacokinetic study of prototype flavonol glycosides in rat after oral administration of the extract of G. biloba leaf. As a result, the T_max of flavonol glycosides was short at 0.11-0.60 h. Quercetin-3-O-(2",6″-di-O-rhamnosyl)-glucoside, kaempferol-3-O-(2'',6''-di-O-rhamnosyl)-glucoside, quercetin-3-O-rutinoside, quercetin- 3-O-glucosyl-(1-2)-O-rhamnoside, and kaempferol-3-O-glucoside presented relatively high systemic exposure levels with AUC_0-∞  > 500 μg h/L and C_max  > 100 μg/L. This study would provide the valuable information for further scientific research and clinical application of the extract of G. biloba leaf.

Changes in digoxin pharmacokinetics associated with hepatic P-glycoprotein upregulation in rats with non-alcoholic fatty liver disease

BACKGROUND & OBJECTIVES

Upregulation of hepatic P-glycoprotein (P-gp) expression has been reported in patients with non-alcoholic fatty liver disease (NAFLD) and rodent models thereof. Here, we explored the changes hepatic P-gp expression and activity in a NAFLD rat model and the effects thereof on the pharmacokinetics of digoxin (a probe substrate of P-gp).

METHODS

Rats were fed a 1% (w/w) orotic acid-containing diet for 20 days to induce NAFLD; control rats received a normal diet. P-gp expression and biliary digoxin excretion were examined. The pharmacokinetics of digoxin were evaluated after it had been administered intravenously (10 μg·kg^-1 ) and orally (200 μg·kg^-1 ) to control and NAFLD rats.

RESULTS

The total areas under the plasma concentration-time curves (AUCs) of digoxin after intravenous and oral administration were significantly smaller (by 39.1% and 73.0%, respectively) in NAFLD rats because of faster biliary digoxin excretion, reflecting elevations of hepatic P-gp expression and activity. Notably, the steady-state volume of distribution rose by 98.2%, while extent of oral bioavailability fell by 55.5% in NAFLD rats.

CONCLUSION

This is the first study to report digoxin pharmacokinetic changes caused by hepatic P-gp upregulation in NAFLD. Further studies are needed to explore the clinical impact of enhanced P-gp-mediated biliary excretion on pharmacotherapies using P-gp substrates in patients with NAFLD.

Development of Indirect Competitive Enzyme-Linked Immunosorbent Assay and Lateral-Flow Immunochromatographic Strip for the Detection of Digoxin in Human Blood

Mouse-mouse hybridoma cell lines producing stable, highly specific monoclonal antibodies with good affinity for the cardiac glycoside digoxin (DIG) were established to construct an indirect enzyme-linked immunosorbent assay and lateral-flow immunochromatographic strip to detect DIG in human blood. The hapten DIG was coupled to bovine serum albumin or chicken ovalbumin by sodium periodate oxidation. The highest sensitivity and specificity antibody had a median inhibitory concentration (IC₅₀) of 0.45 ng/mL, a linear range of detection of 0.293-0.7 ng/mL, and low cross-reactivity with several DIG analogues. The cut-off value of the lateral-flow immunochromatographic strip was 5 ng/mL when the strip was tested with human blood. The immunochromatographic lateral flow strip test provides a quick and convenient method for determining DIG in plasma which can be visually observed in only 5 min to promote rational drug use.

Effects of Ginkgo leaf tablets on the pharmacokinetics of atovastatin in rats

Context: Ginkgo leaf tablets (GLT), an effective traditional Chinese multi-herbal formula, are often combined with atorvastatin calcium (AC) for treating coronary heart disease in clinic. Objective: This study investigated the effects of GLT on the pharmacokinetics of AC and the potential mechanism. Materials and methods: The pharmacokinetics of AC (oral administered at a dose of 1 mg/kg) with or without pre-treatment of GLT (oral administered at a dose of 80 mg/kg/day for 10 days) were investigated in male Sprague-Dawley rats. The effects of GLT on the metabolic stability of AC were also investigated using rat liver microsome incubation systems. Results: The results indicated that the C_max increased from 36.84 ± 4.21 to 48.68 ± 6.35 ng/mL, and the AUC_(0-t) increased from 135.82 ± 21.05 to 77.28 ± 12.92 ng h/mL, and t_1/2 also increased from 2.62 ± 0.31 to 3.32 ± 0.57 h when GLT and AC were co-administered. The metabolic stability of AC was also increased (48.2 ± 6.7 vs. 36.7 ± 5.3 min) with the pre-treatment of GLT. Discussion: This study indicated that the main components in GLT could accelerate the metabolism of AC in rat liver microsomes and change the pharmacokinetic behaviours of AC. So these results showed that the herb-drug interaction between GLT and AC might occur, and the clinical efficacy could increase when they were co-administered. Therefore, the clinical dose of AC should be decreased when GLT and AC are co-administered.

Effects of Ginkgo leaf tablets on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its mechanism

CONTEXT

Ginkgo leaf tablets (GLTs) and losartan are often simultaneously used for the treatment of hypertension in Chinese clinics. However, the herb-drug interaction between GLT and losartan is still unknown.

OBJECTIVE

This study investigates the effects of GLT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its potential mechanism.

MATERIALS AND METHODS

The pharmacokinetic profiles of losartan and EXP3174 of orally administered losartan (10 mg/kg) with or without GLT pretreatment (80 mg/kg/day for 10 days) in Sprague-Dawley rats were determined. In vitro, the effects of GLT on the metabolic stability of losartan were investigated with rat liver microsomes.

RESULTS

The C_max (1.22 ± 0.25 vs 1.85 ± 0.37 μg/mL) and the AUC_(0-t) (6.99 ± 1.05 vs 11.94 ± 1.79 mg·h/L) of losartan increased significantly (p < 0.05) with GLT pretreatment, while the C_max (1.05 ± 0.19 vs 0.72 ± 0.12 μg/mL) of EXP3174 decreased significantly (p < 0.05) compared to the control. The t_1/2 of losartan was prolonged significantly from 3.94 ± 0.62 to 4.75 ± 0.52 h (p < 0.05). The metabolic stability of losartan was increased from 37.4 min to 59.6 min with GLT pretreatment.

DISCUSSION AND CONCLUSIONS

The results indicate that GLT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 through inhibiting the metabolism of losartan.

Determination of Total Flavonoids Contents and Antioxidant Activity of Ginkgo biloba Leaf by Near-Infrared Reflectance Method

Background

Total flavonoids content (TFC) is one of the most important quality indexes of Ginkgo biloba leaf, and it is concerned with total antioxidant activity. Near-infrared spectroscopy (NIR) method has showed its advantages in fast, accurate, qualitative, and quantitative analysis of various components in many quality control researches. In this study, a calibration model was built by partial least squares regression (PLSR) coupling with NIR spectrum to quantitatively analyze the TFC and total antioxidant activity of Ginkgo biloba leaf.

Results

During the model establishing, some spectrum pretreatment and outlier diagnosis methods were optimized to establish the final model. The coefficients of determination (R² ) for TFC and total antioxidant activity prediction were 0.8863 and 0.8486, respectively; and the root mean square errors of prediction (RMSEP) were 2.203 mg/g and 0.2211 mM/g, respectively.

Conclusion

These results showed that NIR method combined with chemometrics is suitable for quantitative analysis of main components and their activities and might be applied to quality control of relevant products.

The strategy for establishment of the multiple reaction monitoring based characteristic chemical profile of triterpenes in Alismatis rhizoma using two combined tandem mass spectrometers

It was reported that triterpenes compounds in Alismatis rhizoma (AR) contributed to the lipid lowering effect on high fat diet (HFD)-induced hyperlipidemia. To date only 24 triterpenes (including the isomers) were characterized by LC-QTOF-MS/MS due to the lack of strategies for systematic discovery, classification and identification of triterpenes in AR. In this study, an integrated strategy combining various QTOF-MS/MS and QTRAP-MS/MS scan functions was developed for systematic identification and specific characterization of triterpenes in AR and processed AR. First, MS/MS fragmentation behaviors of different types of triterpenes were investigated and their diagnostic product ions were systematically summarized for discovery and classification of triterpenes. Second, diagnostic product ions were used to filter the data acquired by UHPLC-QTOF MS/MS for efficient identification of targeted triterpenes. Third, MRM-based characteristic chemical profile (CCP) of triterpenes was established using 30 MRM transitions by UHPLC-QTRAP-MS/MS. Fourth, MRM-based CCP was applied for comparative analyses of triterpenes in AR from different regions and from two other processed AR (salt processed AR and bran processed AR). Consequently, a total of 80 triterpenes including 14 novel compounds were identified in the AR, and 7 more triterpenes compounds were discovered using MRM-based CCP in the processed AR. This work is the most comprehensive characterization of triterpenes compounds in AR to date. The established MRM-based CCP of triterpenes compounds can be instructive for qualitative analyses and relative quantitative analyses of triterpenes in AR and its related medicinal products for potential applications including quality control and classification of different AR materials.

Oleic acid derivative of polyethylenimine-functionalized proliposomes for enhancing oral bioavailability of extract of Ginkgo biloba

The present systematic study focused to investigate the oleic acid derivative of branched polyethylenimine (bPEI-OA)-functionalized proliposomes for improving the oral delivery of extract of Ginkgo biloba (GbE). The GbE proliposomes were prepared by a spray drying method at varying ratios of egg yolk phosphatidylcholine and cholesterol, and the optimized formulation was tailored with bPEI-OA to obtain bPEI-OA-functionalized proliposomes. The formulations were characterized for particle size, zeta potential, and entrapment efficiency. The release of GbE from proliposomes exhibited a sustained release. And the release rate was regulated by changing the amount of bPEI-OA on the proliposomes. The physical state characterization studies showed some interactions between GbE and other materials, such as hydrogen bonds and van der Waals forces during the process of preparation of proliposomes. The in situ single-pass perfusion and oral bioavailability studies were performed in rats. The significant increase in absorption constant (Ka) and apparent permeability coefficient (Papp) from bPEI-OA-functionalized proliposomes indicated the importance of positive charge for effective uptake across the gastrointestinal tract. The oral bioavailability of bPEI-OA-functionalized proliposomes was remarkable enhanced in comparison with control and conventional proliposomes. The bPEI-OA-functionalized proliposomes showed great potential of improving oral absorption of GbE as a suitable carrier.

Advancement in the chemical analysis and quality control of flavonoid in Ginkgo biloba

Flavonoids are the main active constituents in Ginkgo biloba L., which have been suggested to have broad-spectrum free-radical scavenging activities. This review summarizes the recent advances in the chemical analysis of the flavonoids in G. biloba and its finished products (from 2009 to 2014), including chemical composition, sample preparation, separation, detection and different quality criteria. More than 70 kinds of flavonoids have been identified in this plant. In this review, various analytical approaches as well as their chromatographic conditions have been described, and their advantages/disadvantages are also compared. Quantitative analyses of Ginkgo flavonoids applied by most pharmacopeias start with an acidic hydrolysis followed by determination of the resulting aglycones using HPLC. But increasing direct assay of individual flavonol glycosides found that many adulterated products were still qualified by the present tests. To obtain an authentic and applicable analytical approach for quality evaluation of Ginkgo and its finished products, related suggestions and opinions in the recent publications are mainly discussed in this review. This discussion on chemical analyses of Ginkgo flavonoids will also be found as a significant guide for widely varied natural flavonoids.