Simultaneous determination of 20(S)-protopanaxadiol and its three metabolites in rat plasma by LC-MS/MS: application to their pharmacokinetic studies

Systematic studies on the kinetic process of 20(S)-protopanaxadiol in rats and dogs: absorption, distribution, metabolism and excretion

Background and Objective

Ginseng has been regarded as a precious medicinal herb with miraculous effects in Eastern culture. The primary chemical constituents of ginseng are saponins, and the physiological activities of ginsenosides determine their edible and medicinal value. The aim of this study is to comprehensively and systematically investigate the kinetic processes of 20(S)-protopanaxadiol (PPD) in rats and dogs, in order to promote the rational combination of ginseng as a drug and dietary ingredient.

Methods

PPD was administered, and drug concentration in different biological samples were detected by liquid chromatography tandem mass spectrometry (LC/MS/MS) and radioactive tracer methods. Pharmacokinetic parameters such as absorption, bioavailability, tissue distribution, plasma protein binding rate, excretion rate, and cumulative excretion were calculated, along with inference of major metabolites.

Results

This study systematically investigated the absorption, distribution, metabolism, excretion (ADME) of PPD in rats and dogs for the first time. The bioavailabilities of PPD were relatively low, with oral absorption nearly complete, and the majority underwent first-pass metabolism. PPD had a high plasma protein binding rate and was relatively evenly distributed in the body. Following oral administration, PPD underwent extensive metabolism, potentially involving one structural transformation and three hydroxylation reactions. The metabolites were primarily excreted through feces and urine, indicating the presence of enterohepatic circulation. The pharmacokinetic processes of PPD following intravenous administration aligned well with a three-compartment model. In contrast, after gastric administration, it fitted better with a two-compartment model, conforming to linear pharmacokinetics and proportional elimination. There were evident interspecies differences between rats and dogs regarding PPD, but individual variations of this drug were minimal within the same species.

Conclusion

This study systematically studied the kinetic process of PPD in rats and also investigated the kinetic characteristics of PPD in dogs for the first time. These findings lay the foundation for further research on the dietary nutrition and pharmacological effects of PPD.

Human Serum Albumin Nanoparticles as a Carrier of 20(S)-Protopanaxadiol via Intramuscular Injection to Alleviate Cyclophosphamide-Induced Myelosuppression

Myelosuppression is a prevalent and potentially life-threatening side effect during chemotherapy. As the main active component of ginseng, 20(S)-protopanaxadiol (PPD) is capable of relieving myelosuppression by restoring hematopoiesis and immunity. In this study, PPD was encapsulated in human albumin nanoparticles (PPD-HSA NPs) by nanoparticle albumin-bound (Nab) technology for intramuscular injection to optimize its pharmacokinetic properties and promote recovery of myelosuppression. The prepared PPD-HSA NPs had a particle size of about 280 nm with a narrow size distribution. PPD dispersed as an amorphous state within the PPD-HSA NPs, and the NPs exhibited in vitro sustained release behavior. PPD-HSA NPs showed a favorable pharmacokinetic profile with high absolute bioavailability, probably due to the fact that NPs entered into the blood circulation via lymphatic circulation and were eliminated slowly. In vivo distribution experiments demonstrated that PPD-HSA NPs were mainly distributed in the liver and spleen, but a strong fluorescence signal was also found in the inguinal lymph node, indicating drug absorption via a lymph route. The myelosuppressive model was established using cyclophosphamide as the inducer. Pharmacodynamic studies confirmed that PPD-HSA NPs were effective in promoting the level of white blood cells. Moreover, the neutrophil and lymphocyte counts were significantly higher in the PPD-HSA NPs group compared with the control group. This preliminary investigation revealed that PPD-HSA NPs via intramuscular administration may be an effective intervention strategy to alleviate myelosuppression.

Elevated serum levels of kynurenine pathway metabolites in patients with Behçet disease

Behçet disease (BD) is an inflammatory, multisystemic vasculitis of unknown etiopathogenesis. However, innate and adaptive immune system involvement and immune-mediated networks play a vital role in the inflammatory cascade. Indoleamine 2,3-dioxygenase 1 (IDO1) is activated in chronic inflammatory states and catalyzes the first and rate-limiting step of tryptophan (TRP) metabolism along the kynurenine pathway (KP). The study aimed to measure KP metabolites levels in patients with BD and investigate the relationship between disease activity and clinical findings with these metabolites. The study included 120 patients with BD and 120 healthy volunteers. Serum TRP, kynurenine (KYN), kynurenic acid (KYNA), 3-hydroxyanthranilic acid (3HAA), 3-hydroxykynurenine (3HK), and quinolinic acid (QUIN) levels were measured with the tandem mass spectrometric method. Demographic data, clinical manifestations, and disease activity score (BDCAF) were recorded. Serum KYN, KYNA, 3HK, 3HAA, QUIN levels, and KYN/TRP ratio were higher (p < 0.05) in patients with BD compared to the control group, while TRP levels were lower (p < 0.05). KYN/TRP ratio and QUIN levels were significantly higher in the presence of neuro-Behçet, while serum KYN levels were significantly higher in the presence of arthritis (p < 0.05). In addition, serum QUIN levels were significantly higher in the presence of thrombosis (p < 0.05). BDCAF score positively correlated with KYN/TRP ratio. Our findings showed that serum KP metabolite levels were elevated in patients with BD, and there is a relationship between these metabolites with disease activity, clinical findings, and inflammatory burden.

Identification of Adenylate Kinase 5 as a Protein Target of Ginsenosides in Brain Tissues Using Mass Spectrometry-Based Drug Affinity Responsive Target Stability (DARTS) and Cellular Thermal Shift Assay (CETSA) Techniques

Ginseng is a very famous Chinese herbal medicine with various pharmacological effects. Ginsenosides, the main effective compounds of ginseng, show favorable biological activities in the central nervous system (CNS), but the protein targets of ginsenosides in brain tissues have not been clarified clearly. First, we screened proteins that interact with ginsenosides by mass spectrometry-based drug affinity responsive target stability (DARTS) and cellular thermal shift assay (CETSA). Then, we identified and confirmed adenylate kinase 5 (AK5) as a target protein of ginsenosides by biolayer interferometry (BLI), isothermal titration calorimetry (ITC), and molecular docking. Finally, an enzyme activity kit was used to determine the effect of 20(S)-protopanaxadiol (PPD), a ginseng saponin metabolite, on AK5 activities in vivo and in vitro. We screened out seven overlapping target proteins by proteomics of DARTS and CETSA. The BLI direct action assays showed that the direct interaction of PPD with AK5 was higher compared to the parental ginsenosides. Subsequently, BLI kinetic analysis and ITC assay showed that PPD specifically bound to AK5. Furthermore, key amino acid mutations predicted by molecular docking decreased the affinity between PPD and AK5. Enzyme activity assays showed that PPD increased AK5 activities in vivo and in vitro. The above-mentioned findings indicated that AK5 is a protein target of ginsenoside in the brain and PPD is considered to be a small-molecular activator of AK5, which can improve comprehension of the molecular mechanisms of ginseng pharmacological effects in the CNS and further develop AK5 activators based on the dammarane-type triterpenoid structure.

LC-MS/MS determination of ginsenoside compound K and its metabolite 20 (S)-protopanaxadiol in human plasma and urine: applications in a clinical study

AIM

Ginsenoside compound K (CK) is considered to be a potential therapeutic drug for rheumatoid arthritis because of its good anti-inflammatory activity. The purpose of this work was to establish a rapid, sensitive and specific method for determination of CK and its active metabolite 20(S)-protopanaxadiol (20(S)-PPD). Materials & methods: The analytes and internal standards were extracted by liquid-liquid extraction. Then, were separated by high performance liquid phase and determined by triple quadrupole mass spectrometry.

RESULTS

A LC-MS/MS using liquid-liquid extraction was developed for determining CK over the concentration range 1.00-1002.00 ng/ml and 0.15-54.30 ng/ml for 20(S)-PPD. The lower limits of quantification for CK and 20(S)-PPD were 1.00 and 0.15 ng/ml, respectively.

CONCLUSION

This method was successfully validated for detecting both CK and 20(S)-PPD in the human plasma and urine, and was proved to be suitable for the pharmacokinetic study of CK in healthy Chinese volunteers.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR-TRC-14004824.