Stereoselective pharmacokinetic and metabolism studies of 20(S)- and 20(R)-ginsenoside Rg 3 epimers in rat plasma by liquid chromatography-electrospray ionization mass spectrometry

Development and validation of a dried blood spots assay for metabolic profiling of ginsenosides using ultra-high performance liquid chromatography-mass spectrometry

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C.A. Meyer., a famous and valuable traditional Chinese medicine with thousand years of history for its healthcare and therapeutic effects. It is necessary and meaningful to study the pharmacokinetic behavior of ginsenosides in vivo as they are the most active components. Dried blood spots (DBS) are a mature and advanced blood collection method with meet the needs for the measurement of numerous analytes.

AIM OF THE STUDY

This study aimed to explore the feasibility on DBS in the metabolic profile analysis of complex herbal products.

MATERIALS AND METHODS

An ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MS/MS) method was developed and validated for the determination of ginsenosides. The preparation of DBS samples was conducted by spiking the whole blood with analytes to obtain 20 μL of blood spots on Whatman 903 collection card. A punched dish of 10 mm in diameter was extracted with 70 % methanol aqueous solution, digoxin was used as an internal standard. Target compounds were separated on a Waters T3 column (2.1 × 100 mm, 1.8 μm) with acetonitrile and water (0.1 % formic acid) at a flow rate of 0.4 mL/min.

RESULTS

The various ginsenosides showed good linearity in the range of 1-2000 ng/mL. The extraction recoveries and matrix effects of the target analytes were above 82.2%. The intra- and inter-batch accuracy and precision were within the limits of ≤15% for all tested concentrations. Moreover, the collected dried blood spot samples could be stably stored at room temperature for 14 days and 4 °C for 1 month without being affected. And it is delightful that the DBS-based analysis is compatible or even superior to the conventional protein precipitation in terms of sensitivity, linearity, and stability. In particular, the target analytes are stable in the DBS sampling under normal storing condition and the sensitivity for some trace metabolites of ginsenosides, such as 20(S)-Rg3, 20(R)-Rg3, F1, Rk1, Rg5, etc. increases 3-4 folds as evaluated by LLOQ.

CONCLUSIONS

The established method was successfully applied to pharmacokinetic studies of ginseng extract in mice, this suggests a more feasible strategy for pharmacokinetic study of traditional and natural medicines both in animal tests and clinical trials.

Differential antiangiogenic and anticancer activities of the active metabolites of ginsenoside Rg3

Background

Epimers of ginsenoside Rg3 (Rg3) have a low bioavailability and are prone to deglycosylation, which produces epimers of ginsenoside Rh2 (S-Rh2 and R-Rh2) and protopanaxadiol (S-PPD and R-PPD). The aim of this study was to compare the efficacy and potency of these molecules as anti-cancer agents.

Methods

Crystal violet staining was used to study the anti-proliferatory action of the molecules on a human epithelial breast cancer cell line, MDA-MB-231, and human umbilical vein endothelial cells (HUVEC) and compare their potency. Cell death and cell cycle were studied using flow cytometry and mode of cell death was studied using live cell imaging. Anti-angiogenic effects of the drug were studied using loop formation assay. Molecular docking showed the interaction of these molecules with vascular endothelial growth factor receptor-2 (VEGFR2) and aquaporin (AQP) water channels. VEGF bioassay was used to study the interaction of Rh2 with VEGFR2, in vitro.

Results

HUVEC was the more sensitive cell line to the anti-proliferative effects of S-Rh2, S-PPD and R-PPD. The molecules induced necroptosis/necrosis in MDA-MB-231 and apoptosis in HUVEC. S-Rh2 was the most potent inhibitor of loop formation. In silico molecular docking predicted a good binding score between Rh2 or PPD and the ATP-binding pocket of VEGFR2. VEGF bioassay showed that Rh2 was an allosteric modulator of VEGFR2. In addition, SRh2 and PPD had good binding scores with AQP1 and AQP5, both of which play roles in cell migration and proliferation.

Conclusion

The combination of these molecules might be responsible for the anti-cancer effects observed by Rg3.

Pseudoginsenoside GQ mitigates chronic intermittent hypoxia-induced cognitive damage by modulating microglia polarization

Obstructive sleep apnea (OSA), a state of sleep disruption, is characterized by recurrent apnea, chronic intermittent hypoxia (CIH) and hypercapnia. Previous studies have showed that CIH-induced neuroinflammatory plays a crucial role in cognitive deficits. Pseudoginsenoside GQ (PGQ) is a new oxytetracycline-type saponin formed by the oxidation and cyclization of the 20(S) Rg3 side chain. Rg3 has been found to afford anti-inflammatory effects, while whether PGQ plays a role of anti-neuroinflammatory remains unclear. The purpose of this study was to investigate whether PGQ attenuates CIH-induced neuroinflammatory and cognitive impairment and the possible mechanism it involves. We found that PGQ significantly ameliorated CIH-induced spatial learning deficits, and inhibited microglial activation, pro-inflammatory cytokine release, and neuronal apoptosis in the hippocampus of CIH mice. In addition, PGQ pretreatment promoted microglial M1 to M2 phenotypic transition in IH-induced BV-2 microglial, as well as indirectly inhibited IH-induced neuronal injury via modulation of microglia polarization. Furthermore, we noted that activation of HMGB1/TLR4/NF-κB signaling pathway induced by IH was inhibited by PGQ. Molecular docking results revealed that PGQ could bind to the active sites of HMGB1 and TLR4. Taken together, this work supports that PGQ inhibits M1 microglial polarization via the HMGB1/TLR4/NF-κB signaling pathway, and indirectly exerts neuroprotective effects, suggesting that PGQ may be a potential therapeutic strategy for cognitive impairment accompanied OSA.

Analysis of metabolites and metabolism-mediated biological activity assessment of ginsenosides on microfluidic co-culture system

In vivo, the complex process of drugs metabolism alters the change in drug composition and determines the final pharmacological properties of oral drugs. Ginsenosides are primary constituents of ginseng, whose pharmacological activities are greatly affected by liver metabolism. However, the predictive power of existing in vitro models is poor due to their inability to mimic the complexity of drug metabolism in vivo. The advance of organs-on-chip-based microfluidics system could provide a new in vitro drug screening platform by recapitulating the metabolic process and pharmacological activity of natural product. In this study, an improved microfluidic device was employed to establish an in vitro co-culture model by culturing multiple cell types in compartmentalized microchambers. Different cell lines were seeded on the device to examine the metabolites of ginsenosides from the hepatocytes in top layer and its resulting efficacy on the tumors in bottom layer. Metabolism dependent drug efficacy of Capecitabine in this system demonstrated the model is validated and controllable. High concentrations of CK, Rh2 (S), and Rg3 (S) ginsenosides showed significant inhibitory effects on two types of tumor cells. In addition, apoptosis detection showed that Rg3 (S) through liver metabolism promoted early apoptosis of tumor cells and displayed better anticancer activity than prodrug. The detected ginsenoside metabolites indicated that some protopanaxadiol saponins were converted into other anticancer aglycones in varying degrees due to orderly de-sugar and oxidation. Ginsenosides exhibited different efficacy on target cells by impacting their viabilities, indicating hepatic metabolism plays an important role in determining ginsenosides efficacy. In conclusion, this microfluidic co-culture system is simple, scalable, and possibly widely applicable in evaluating anticancer activity and metabolism of drug during the early developmental phases of natural product.

Experimental Evidence for the Anti-Metastatic Action of Ginsenoside Rg3: A Systematic Review

Cancer metastasis is the leading cause of death in cancer patients. Due to the limitations of conventional cancer treatment, such as chemotherapy, there is a need for novel therapeutics to prevent metastasis. Ginsenoside Rg3, a major active component of Panax ginseng C.A. Meyer, inhibits tumor growth and has the potential to prevent tumor metastasis. Herein, we systematically reviewed the anti-metastatic effects of Rg3 from experimental studies. We searched for articles in three research databases, MEDLINE (PubMed), EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) through March 2022. In total, 14 studies (eight animal and six in vitro) provide data on the anti-metastatic effects of Rg3 and the relevant mechanisms. The major anti-metastatic mechanisms of Rg3 involve cancer stemness, epithelial mesenchymal transition (EMT) behavior, and angiogenesis. Taken together, Rg3 would be one of the herbal resources in anti-metastatic drug developments through further well-designed investigations and clinical studies. Our review provides valuable reference data for Rg3-derived studies targeting tumor metastasis.

Chinese Herbal Medicine for Primary Liver Cancer Therapy: Perspectives and Challenges

Primary liver cancer (PLC) is one of the most common solid malignancies. However, PLC drug development has been slow, and first-line treatments are still needed; thus, studies exploring and developing alternative strategies for effective PLC treatment are urgently needed. Chinese herbal medicine (CHM) has long been applied in the clinic due to its advantages of low toxicity and targeting of multiple factors and pathways, and it has great potential for the development of novel natural drugs against PLC.

Purpose: This review aims to provide an update on the pharmacological mechanisms of Chinese patent medicines (CPMs) and the latest CHM-derived compounds for the treatment of PLC and relevant clinical evaluations.

Materials and Methods: A systematic search of English literature databases, Chinese literature, the Clinical Trials Registry Platform, and the Chinese Clinical Trial Registry for studies of CHMs for PLC treatment was performed.

Results: In this review, we summarize the clinical trials and mechanisms of CPMs for PLC treatment that have entered the clinic with the approval of the Chinese medicine regulatory authority. These CPMs included Huaier granules, Ganfule granules, Fufang Banmao capsules, Jinlong capsules, Brucea javanica oil emulsions, and compound kushen injections. We also summarize the latest in vivo, in vitro, and clinical studies of CHM-derived compounds against PLC: icaritin and ginsenoside Rg3. Dilemmas facing the development of CHMs, such as drug toxicity and low oral availability, and future developments are also discussed.

Conclusion: This review provides a deeper the understanding of CHMs as PLC treatments and provides ideas for the development of new natural drugs against PLC.

Protective Effect of 20(R)-Ginsenoside Rg3 Against Cisplatin-Induced Renal Toxicity via PI3K/AKT and NF-[Formula: see text]B Signaling Pathways Based on the Premise of Ensuring Anticancer Effect

Although the protective effect of ginsenoside on cisplatin-induced renal injury has been extensively studied, whether ginsenoside interferes with the antitumor effect of cisplatin has not been confirmed. In this paper, we verified the main molecular mechanism of 20(R)-ginsenoside Rg3 (R-Rg3) antagonizing cisplatin-induced acute kidney injury (AKI) through the combination of in vivo and in vitro models. It is worth mentioning that the two cell models of HK-2 and HepG2 were used simultaneously for the first time to explore the effect of the activation site of tumor-associated protein p53 on apoptosis and tumor suppression. The results showed that a single injection of cisplatin (20 mg/kg) led to weight loss, the kidney index of the mice increased, and creatinine (CRE) and blood urea nitrogen (BUN) levels in mice sharply increased. Continuous administration of R-Rg3 at doses of 10 and 20 mg/kg for 10 days could significantly alleviate this symptom. Similarly, R-Rg3 treatment reduced oxidative stress damage caused by cisplatin. Moreover, R-Rg3 could observably reduce the apoptosis and inflammatory infiltration of renal tubular cells induced by cisplatin. We used western blotting analysis to demonstrate that R-Rg3 restored cisplatin-induced AKI might be related to PI3K/AKT and NF-[Formula: see text]B mediated apoptosis and inflammation pathways. In the meantime, we also verified that R-Rg3 could activate different sites of p53 to control renal cell apoptosis induced by cisplatin without affecting its antitumor effect.

Ginsenosides in vascular remodeling: Cellular and molecular mechanisms of their therapeutic action

Evidence is mounting that abnormal vascular remodeling (VR) is a vital pathological event that precedes many cardiovascular diseases (CVD). This provides us with a new research perspective that VR can be a pivotal target for CVD treatment and prevention. However, the current drugs for treating CVD do not fundamentally reverse VR and repair vascular function. The reason may be that a complicated regulatory network is formed between the various signaling pathways involved in VR. Recently, ginsenoside, the main active substance of ginseng, has become increasingly the focus of many researchers for its multiple targets, multiple pathways, and few side effects. Several data have revealed that ginsenosides can improve VR caused by vasodilation dysfunction, abnormal vascular structure and blood pressure. This review is intended to discuss the therapeutic effects and mechanisms of ginsenosides in some diseases involved in VR. Besides, we herein also give a new and contradictory insight into intracellular and molecular signaling of ginsenosides in all kinds of vascular cells. Most importantly, we also discuss the feasibility of ginsenosides Rb1/Rg1/Rg3 in drug development by combining the pharmacodynamics and pharmacokinetics of ginsenosides, and provide a pharmacological basis for the development of ginsenosides in clinical applications.

Anti-Angiogenic Properties of Ginsenoside Rg3

Ginsenoside Rg3 (Rg3) is a member of the ginsenoside family of chemicals extracted from Panax ginseng. Like other ginsenosides, Rg3 has two epimers: 20(S)-ginsenoside Rg3 (SRg3) and 20(R)-ginsenoside Rg3 (RRg3). Rg3 is an intriguing molecule due to its anti-cancer properties. One facet of the anti-cancer properties of Rg3 is the anti-angiogenic action. This review describes the controversies on the effects and effective dose range of Rg3, summarizes the evidence on the efficacy of Rg3 on angiogenesis, and raises the possibility that Rg3 is a prodrug.

Stereoselective pharmacokinetic study of epiprogoitrin and progoitrin in rats with UHPLC-MS/MS method

An accurate and precise liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method was developed and validated for the pharmacokinetic study of epiprogoitrin and progoitrin, a pair of epimers that can be deglycosylated to epigoitrin and goitrin, respectively. These analytes were administered intravenously or intragastrically to male Sprague-Dawley rats, and the influence of 3(R/S)-configuration on the pharmacokinetics of both epimers in rat plasma was elucidated. The analytes and an internal standard (i.e., sinigrin) were resolved by LC-MS/MS on a reverse-phase ACQUITY UPLC™ HSS T3 column equilibrated and eluted with acetonitrile and water (0.1 % formic acid) at a flow rate of 0.3 mL/min. Quantitation was achieved by applying the multiple reaction monitoring mode, in the negative ion mode, at transitions of m/z 388 → 97 and m/z 358 → 97 for the epimers and sinigrin, respectively. The method demonstrated good linearity over the concentration range of 2-5000 ng/mL (r > 0.996). The lower limit of quantification for epiprogoitrin and progoitrin was 2 ng/mL. The interday and intraday accuracy and precision were within ±15 %. The extraction recovery, stability, and matrix effect were demonstrated to be within acceptable limits. The validated method was thus successfully applied for the pharmacokinetic study of both the epimers. After the rats received the same oral dose of the epimers, the pharmacokinetic profiles were similar. The maximum plasma concentration (C_max) and AUC values of epiprogoitrin were a bit higher than those of progoitrin, whereas the pharmacokinetic behaviours of the epimers were obviously different upon intravenous administration. The C_max and AUC values of epiprogoitrin were approximately three-fold higher than those of progoitrin, and the half-life of progoitrin was much shorter than that of epiprogoitrin. The oral bioavailability of progoitrin was 20.1 %-34.1 %, which is three times higher than that of epiprogoitrin.

Advances in the chemistry, pharmacological diversity, and metabolism of 20(R)-ginseng saponins

Ginseng has been used as a popular herbal medicine in East Asia for at least two millennia. However, 20(R)-ginseng saponins, one class of important rare ginsenosides, are rare in natural products. 20(R)-ginseng saponins are generally prepared by chemical epimerization and microbial transformation from 20(S)-isomers. The C20 configuration of 20(R)-ginseng saponins are usually determined by 13C NMR and X-ray single-crystal diffraction. 20(R)-ginseng saponins have antitumor, antioxidative, antifatigue, neuroprotective, and osteoclastogenesis inhibitory effects, among others. Owing to the chemical structure and pharmacological and stereoselective properties, 20(R)-ginseng saponins have attracted a great deal of attention in recent years. In this study, the discovery, identification, chemical epimerization, microbial transformation, pharmacological activities, and metabolism of 20(R)-ginseng saponins are summarized.

Dose-dependent exposure profile and metabolic characterization of notoginsenoside R1 in rat plasma by ultra-fast liquid chromatography-electrospray ionization-tandem mass spectrometry

Notoginsenoside R₁ (NGR₁ ), a diagnostic protopanaxatriol-type (ppt-type) saponin in Panax notoginseng, possesses potent biological activities including antithrombotic, anti-inflammatory, neuron protection and improvement of microcirculation, yet its pharmacokinetics and metabolic characterization as an individual compound remain unclear. The aim of this study was to investigate the exposure profile of NGR₁ in rats after oral and intravenous administration and to explore the metabolic characterization of NGR₁ . A simple and sensitive ultra-fast liquid chromatographic-tandem mass spectrometric method was developed and validated for the quantitative determination of NGR₁ and its major metabolites, and for characterization of its metabolic profile in rat plasma. The blood samples were precipitated with methanol, quantified in a negative multiple reaction monitoring mode and analyzed within 6.0 min. Validation parameters (linearity, precision and accuracy, recovery and matrix effect, stability) were within acceptable ranges. After oral administration, NGR₁ exhibited dose-independent exposure behaviors with t_1/2 over 8.0 h and oral bioavailability of 0.25-0.29%. A total of seven metabolites were characterized, including two pairs of epimers, 20(R)-notoginsenoside R₂ /20(S)-notoginsenoside R₂ and 20(R)-ginsenoside Rh₁ /20(S)-ginsenoside Rh₁ , with the 20(R) form of saponins identified for the first time in rat plasma. Five deglycometabolites were quantitatively determined, among which 20(S)-notoginsenoside R₂ , ginsenoside Rg₁ , ginsenoside F₁ and protopanaxatriol displayed relatively high exploration, which may partly explain the pharmacodynamic diversity of ginsenosides after oral dose.

Pharmacokinetics, tissue distribution and excretion of saponins after intravenous administration of ShenMai Injection in rats

ShenMai Injection (SMI) is a traditional Chinese medicine that has been extensively applied in the treatment of coronary artery disease and tumor for many years. However, there is still lack of deep research on the behaviors of SMI in vivo. In this study, a reliable, specific, and sensitive method was developed for simultaneous determination of sixteen saponins found in SMI using liquid chromatography tandem mass spectrometry (LC-MS/MS). This method was successfully applied to investigate the pharmacokinetics, tissue distribution and excretion of sixteen active compounds after a single intravenous administration of SMI. These compounds included seven protopapaxdiol (PPD-type) ginsenosides (ginsenosides Rb₁, Rb₂, Rb₃, Rc, Rd, S-Rg₃, R-Rg₃), six protopapaxtriol (PPT-type) ginsenosides (notoginsenoside R₁, ginsenosides Re, Rf, Rg₁, S-Rg₂, R-Rg₂), one oleanolic acid type ginsenoside (ginsenoside Ro) and two ophiopogonins (ophiopogonin D (MD-D) and ophiopogonin D' (MD-D')). Connection of the C-20 hydroxyl group to the glycoside and the chiral configuration of C-20 might significantly impact the pharmacokinetic behaviors in vivo of ginsenosides, particularly PPD-type ginsenosides. PPD-type ginsenosides were usually eliminated slowly in serum and tissues, but S/R-Rg₃ bearing a free hydroxyl group at C-20 exhibited quick elimination, and R-Rg₃ underwent quicker elimination than S-Rg₃. The PPT-type ginsenosides, oleanolic acid type ginsenoside and ophiopogonins underwent a fast elimination from serum and tissues. There were 10 ginsenosides that could penetrate the blood-brain barrier. In contrast to other saponins, the distributions of S-Rg₂, R-Rg₂, S-Rg₃, R-Rg₃, MD-D and MD-D' in liver were higher than in kidney. Several PPD-type ginsenosides were found to have a long-term accumulation risk in some tissues, especially Rd in kidney. In the excretion study, Rg₁, S-Rg₂ and MD-D were mainly excreted in a prototype and other saponins were mainly excreted in the form of metabolites. Prototypes of S-Rg₂, R-Rg₂, S-Rg₃, R-Rg₃, MD-D and MD-D' exhibited higher distribution in the liver than kidney, were excreted mainly in the feces, whereas prototypes of the remaining saponins were primarily excreted via urine. To best our knowledge, this is the first study to quantitatively evaluate the tissue distribution and excretion of SMI in rats. Our research provides novel insight into the behaviors in vivo of PPD-type ginsenosides and delivers valuable information for further drug development of SMI.

Non-clinical pharmacokinetic behavior of ginsenosides

Ginsenosides, the major active ingredients of ginseng and other plants of the genus Panax, have been used as natural medicines in the East for a long time; in addition, their popularity in the West has increased owing to their various beneficial pharmacological effects. There is therefore a wealth of literature regarding the pharmacological effects of ginsenosides. In contrast, there are few comprehensive studies that investigate their pharmacokinetic behaviors. This is because ginseng contains the complicated mixture of herbal materials as well as thousands of constituents with complex chemical properties, and ginsenosides undergo multiple biotransformation processes after administration. This is a significant issue as pharmacokinetic studies provide crucial data regarding the efficacy and safety of compounds. Moreover, there have been many difficulties in the development of the optimal dosage regimens of ginsenosides and the evaluation of their interactions with other drugs. Therefore, this review details the pharmacokinetic properties and profiles of ginsenosides determined in various animal models administered through different routes of administration. Such information is valuable for designing specialized delivery systems and determining optimal dosing strategies for ginsenosides.

Pharmacokinetic Characteristics of Steamed Notoginseng by an Efficient LC-MS/MS Method for Simultaneously Quantifying Twenty-three Triterpenoids

Steamed Panax notoginseng (SNG) has been widely used as a restorative medicine instead of the raw one, but its pharmacokinetic profile is entirely unknown. To address this, we've developed an LC-MS/MS method with high efficiency and sensitivity for simultaneous quantification of 23 triterpenoids (notoginsenosides Fa, Fc, R₁, 20( S)-R₂, 20( R)-R₂, ginsenosides F₄, Rb₁, Rg₁, Rd, Re, Rb₂, 20( S)-Rh₁, 20( R)-Rh₁, Rh₄, R k₁, R k₃, 20( S)-Rg₂, 20( S)-Rg₃, 20( R)-Rg₃, Rg₅, C-K, 20( S)-PPT, 20( S)-PPD) from SNG in rat plasma. This validated approach exhibits great linearity, precision, accuracy, recovery, and stability for all analytes. Furthermore, we, for the first time, applied this method to the pharmacokinetic study of SNG and proposed Rb₁, Fa, Rd, R k₁, Rg₅, R k₃, Rh₄, and 20( S)-PPD to be suitable pharmacokinetic markers of SNG due to their high exposure levels of systemic plasma. Hence, this developed approach would be a powerful tool for future in vivo investigation of various sources of notoginseng-related samples.

Stereoisomers of Saponins in Panax notoginseng (Sanqi): A Review

Panax notoginseng (Sanqi), a traditional Chinese medical drug which has been applied to medical use for over four centuries, contains high content of dammarane-type tetracyclic triterpenoid saponins. A number of stereoisomeric dammarane-type saponins exist in this precious herb, and some are particularly regarded as “biomarkers” in processed notoginseng. Contemporary researches have indicated that some saponin stereoisomers may show stereospecific pharmacological activities, such as anti-tumor, antioxidative, anti-photoaging, anti-inflammatory, antidiabetic, and neuro-protective activities, as well as stereoselective effects on ion channel current regulation, cardiovascular system, and immune system. The current review provides a comprehensive overview of chemical compositions of raw and processed P. notoginseng with a particular emphasis on saponin stereoisomers. Besides, the pharmacological and pharmacokinetic researches, as well as determination and biotechnological preparation methods of stereoisomeric saponins in notoginseng are discussed extensively.

Pharmacokinetic Comparison of 20(R)- and 20(S)-Ginsenoside Rh1 and 20(R)- and 20(S)-Ginsenoside Rg3 in Rat Plasma following Oral Administration of Radix Ginseng Rubra and Sheng-Mai-San Extracts

Ginsenosides Rh1 and Rg3, as the main bioactive components from Ginseng, are effective for prevention and treatment of cardiovascular diseases. Sheng-Mai-San (SMS), a classical complex prescription of traditional Chinese medicines, is composed of Radix Ginseng Rubra, Fructus Schisandrae, and Radix Ophiopogonis. In this research, a sensitive and specific liquid chromatography-mass spectrometric method was developed and validated for stereoselective determination and pharmacokinetic studies of 20(R)- and 20(S)-ginsenoside Rh1 and 20(R)- and 20(S)-ginsenoside Rg3 epimers in rat plasma after oral administration of Radix Ginseng Rubra or SMS extracts. The main pharmacokinetic parameters including T_max, C_max, t_1/2, and AUC were calculated by noncompartment model. Compared with Radix Ginseng Rubra, SMS could significantly increase the content of ginsenosides Rh1 and Rg3 in the decocting process. Ginsenosides Rh1 and Rg3 following SMS treatment displayed higher C_max, AUC_(0–t), and AUC_(0–∞) and longer t_1/2 and t_max except for 20(R)-Rh1 in rat plasma. The results indicated SMS compound compatibility could influence the dissolution in vitro and the pharmacokinetic behaviors in vivo of ginsenosides Rh1 and Rg3, suggesting pharmacokinetic drug-drug interactions between ginsenosides Rh1 and Rg3 and other ingredients from Fructus Schisandrae and Radix Ophiopogonis. This study would provide valuable information for drug development and clinical application of SMS.

Stereoselective pharmacokinetics of 25-methoxyl-dammarane-3β,12β,20-triol and its active demethyl-metabolite epimers in rats after oral and intravenous administration

Stereoselectivity of ginsenosides produced from the stereogenic carbon-20 has been proved to be closely related to drug action including pharmacodynamics and pharmacokinetics. 25-Methoxydammarane-3,12,20-triol (25-OCH₃-PPD) and 25-hydoxyprotopanaxadiol (25-OH-PPD) are novel protopanaxadiol-type (PPD) sapogenins. 25-OH-PPD was also the in vivo bioactive demethyl-metabolite of 25-OCH₃-PPD. The study aimed to investigate the influence of 20(R/S)-configuration on the pharmacokinetics of 20(R/S)-25-OCH₃-PPD epimers and 20(R/S)-25-OH-PPD epimers. When rats were given 20(R/S)-25-OCH₃-PPD epimers intravenously, the pharmacokinetic profiles of both epimers of 25-OCH₃-PPD were similar, while the pharmacokinetic behaviors of their demethyl-metabolites were obviously different. After rats received an oral dose of 20(R/S)-25-OCH₃-PPD epimers, the C_max and AUC values of 20(S)-25-OCH₃-PPD were at least 100 times higher than those of 20(R)-25-OCH₃-PPD. Stereoselective pharmacokinetics of 25-OH-PPD was observed in rats after i.v. and i.g. administration of 20(R/S)-25-OH-PPD epimers. In vitro metabolic kinetics results indicated that faster hepatic metabolism of R-epimer should be one of the crucial factors accounting for the stereospecific pharmacokinetics of 25-OCH₃-PPD and 25-OH-PPD epimers.