Enhancement of oral bioavailability of 20(S)-ginsenoside Rh2 through improved understanding of its absorption and efflux mechanisms

Methods on improvements of the poor oral bioavailability of ginsenosides: Pre-processing, structural modification, drug combination, and micro- or nano- delivery system

Panax ginseng Meyer is a traditional Chinese medicine that is widely used as tonic in Asia. The main pharmacologically active components of ginseng are the dammarane-type ginsenosides, which have been shown to have anti-cancer, anti-inflammatory, immunoregulatory, neuroprotective, and metabolic regulatory activities. Moreover, some of ginsenosides (eg, Rh2 and Rg3) have been developed into nutraceuticals. However, the utilization of ginsenosides in clinic is restrictive due to poor permeability in cells and low bioavailability in human body. Obviously, the dammarane skeleton and glycosyls of ginsenosides are responsible for these limitations. Therefore, improving the oral bioavailability of ginsenosides has become a pressing issue. Here, based on the structures of ginsenosides, we summarized the understanding of the factors affecting the oral bioavailability of ginsenosides, introduced the methods to enhance the oral bioavailability and proposed the future perspectives on improving the oral bioavailability of ginsenosides.

The roles of natural triterpenoid saponins against Alzheimer's disease

The aging of the world population and increasing stress levels in life are the major cause of the increased incidence of neurological disorders. Alzheimer's disease (AD) creates a huge burden on the lives and health of individuals and has become a big concern for society. Triterpenoid saponins (TS), representative natural product components, have a wide range of pharmacological bioactivities such as anti-inflammation, antioxidation, antiapoptosis, hormone-like, and gut microbiota regulation. Notably, some natural TS exhibited promising neuroprotective activity that can intervene in AD progress, especially in the early stage. Recently, studies have indicated that TS play a pronounced positive role in the prevention and treatment of AD. This review discusses the recent research on the neuroprotection of TS and proceeds to detail the action mechanisms of TS against AD, hoping to provide a reference for drug development for anti-AD.

Evaluation of the Anti-Inflammatory Pain Effect of Ginsenoside-Conjugated O-Carboxymethyl Chitosan Particles

Nanoparticle delivery of functional molecules or vaccines is an effective method for the treatment of many diseases. This study aims to design ginsenoside Rh2-conjugated O-carboxymethyl chitosan (O-CMC/Rh2) as a drug delivery system and explore its anti-nociceptive effects. O-CMC/Rh2 was synthesized with an esterification reaction, and its chemical composition and morphology were evaluated using proton nuclear magnetic resonance (1H NMR), the attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscopy (SEM). In addition, the in vitro cumulative release of Rh2 from the O-CMC/Rh2 was also evaluated under different pH conditions. The results showed that the ginsenoside Rh2 was successfully conjugated to the O-CMC matrix and exhibited a highly porous structure after conjugation, facilitating the release of Rh2 from O-CMC. Complete Freund's adjuvant (CFA) and burn injury-induced pain models were used to evaluate the anti-nociceptive effects of O-CMC/Rh2 on inflammatory pain. O-CMC/Rh2 reduced CFA-induced pain hypersensitivity in a dose-dependent manner and had a longer analgesic effect than Rh2. In addition, O-CMC/Rh2 also relieved the chronic pain induced by bury injury. These results indicated that O-CMC/Rh2 could be useful in reducing inflammatory pain, thus possessing a potential medicinal application in pain therapy.

A comprehensive and systemic review of ginseng-based nanomaterials: Synthesis, targeted delivery, and biomedical applications

Among 17 Panax species identified across the world, Panax ginseng (Korean ginseng), Panax quinquefolius (American ginseng), and Panax notoginseng (Chinese ginseng) are highly recognized for the presence of bioactive compound, ginsenosides and their pharmacological effects. P. ginseng is widely used for synthesis of different types of nanoparticles compared to P. quinquefolius and P. notoginseng. The use of nano-ginseng could increase the oral bioavailability, membrane permeability, and thus provide effective delivery of ginsenosides to the target sites through transport system. In this review, we explore the synthesis of ginseng nanoparticles using plant extracts from various organs, microbes, and polymers, as well as their biomedical applications. Furthermore, we highlight transporters involved in transport of ginsenoside nanoparticles to the target sites. Size, zeta potential, temperature, and pH are also discussed as the critical parameters affecting the quality of ginseng nanoparticles synthesis.

The preventive role of the red gingeng ginsenoside Rg3 in the treatment of lung tumorigenesis induced by benzo(a)pyrene

Red ginseng has been used in traditional medicine for centuries in Asia. In this study, we evaluated four types of red ginseng grown in different areas (Chinese red ginseng, Korean red ginseng A, Korean red ginseng B, and Korean red ginseng C) for their ability to inhibit lung tumor formation and growth induced by the carcinogen benzo(a)pyrene (B(a)P) in A/J mice and found that Korean red ginseng B was the most effective at lowering the tumor load among the four red ginseng varieties. Moreover, we analyzed the levels of various ginsenosides (Rg1, Re, Rc, Rb2, Rb3, Rb1, Rh1, Rd, Rg3, Rh2, F1, Rk1, and Rg5) in four kinds of red ginseng extract and found that Korean red ginseng B had the highest level of ginsenoside Rg3 (G-Rg3), which suggested that G-Rg3 may play an important role in its therapeutic efficacy. This work revealed that the bioavailability of G-Rg3 was relatively poor. However, when G-Rg3 was coadministered with verapamil, a P-glycoprotein inhibitor, the G-Rg3 efflux in Caco-2 cells was lowered, the small intestinal absorption rate of G-Rg3 in the rat models was increased, the concentration levels of G-Rg3 were elevated in the intestine and plasma, and its tumor-preventive abilities in the tumorigenesis rat model induced by B(a)P were also augmented. We also found that G-Rg3 reduced B(a)P-induced cytotoxicity and DNA adduct formation in human lung cells and rescued phase II enzyme expression and activity through Nrf2 pathways, which may be the potential mechanisms underlying the inhibitory effects of G-Rg3 on lung tumorigenesis. Our study showed a potentially vital role of G-Rg3 in targeting lung tumors in murine models. The oral bioavailability of this ginsenoside was augmented by targeting P-glycoprotein, which allowed the molecule to exert its anticancer effects.

Chinese medicinal herbs as potential prodrugs for obesity

Obesity is a leading worldwide health threat with ever-growing prevalence, it promotes the incidence of various diseases, particularly cardiovascular disease, metabolic syndrome, diabetes, hypertension, and certain cancers. Traditional Chinese Medicine (TCM) has been used to control body weight and treat obesity for thousands of years, Chinese medicinal herbs provide a rich natural source of effective agents against obesity. However, some problems such as complex active ingredients, poor quality control, and unclear therapeutic mechanisms still need to be investigated and resolved. Prodrugs provide a path forward to overcome TCM deficiencies such as absorption, distribution, metabolism, excretion (ADME) properties, and toxicity. This article aimed to review the possible prodrugs from various medicinal plants that demonstrate beneficial effects on obesity and seek to offer insights on prodrug design as well as a solution to the global obesity issues.

Cytostatic effects of structurally different ginsenosides on yeast cells with altered sterol biosynthesis and transport

Triterpene glycosides are a diverse group of plant secondary metabolites, consisting of a sterol-like aglycon and one or several sugar groups. A number of triterpene glycosides show membranolytic activity, and, therefore, are considered to be promising antimicrobial drugs. However, the interrelation between their structure, biological activities, and target membrane lipid composition remains elusive. Here we studied the antifungal effects of four Panax triterpene glycosides (ginsenosides) with sugar moieties at the C-3 (ginsenosides Rg3, Rh2), C-20 (compound K), and both (ginsenoside F2) positions in Saccharomyces cerevisiae mutants with altered sterol plasma membrane composition. We observed reduced cytostatic activity of the Rg3 and compound K in the UPC2-1 strain with high membrane sterol content. Moreover, LAM gene deletion reduced yeast resistance to Rg3 and digitonin, another saponin with glycosylated aglycon in the C-3 position. LAM genes encode plasma membrane-anchored StARkin superfamily-member sterol transporters. We also showed that the deletion of the ERG6 gene that inhibits ergosterol biosynthesis at the stage of zymosterol increased the cytostatic effects of Rg3 and Rh2, but not the other two tested ginsenosides. At the same time, in silico simulation revealed that the substitution of ergosterol with zymosterol in the membrane changes the spatial orientation of Rg3 and Rh2 in the membranes. These results imply that the plasma membrane sterol composition defines its interaction with triterpene glycoside depending on their glycoside group position. Our results also suggest that the biological role of membrane-anchored StARkin family protein is to protect eukaryotic cells from triterpenes glycosylated at the C-3 position.

Ginsenosides emerging as both bifunctional drugs and nanocarriers for enhanced antitumor therapies

Ginsenosides, the main components isolated from Panax ginseng, can play a therapeutic role by inducing tumor cell apoptosis and reducing proliferation, invasion, metastasis; by enhancing immune regulation; and by reversing tumor cell multidrug resistance. However, clinical applications have been limited because of ginsenosides' physical and chemical properties such as low solubility and poor stability, as well as their short half-life, easy elimination, degradation, and other pharmacokinetic properties in vivo. In recent years, developing a ginsenoside delivery system for bifunctional drugs or carriers has attracted much attention from researchers. To create a precise treatment strategy for cancer, a variety of nano delivery systems and preparation technologies based on ginsenosides have been conducted (e.g., polymer nanoparticles [NPs], liposomes, micelles, microemulsions, protein NPs, metals and inorganic NPs, biomimetic NPs). It is desirable to design a targeted delivery system to achieve antitumor efficacy that can not only cross various barriers but also can enhance immune regulation, eventually converting to a clinical application. Therefore, this review focused on the latest research about delivery systems encapsulated or modified with ginsenosides, and unification of medicines and excipients based on ginsenosides for improving drug bioavailability and targeting ability. In addition, challenges and new treatment methods were discussed to support the development of these new tumor therapeutic agents for use in clinical treatment.

Pharmaceutical Formulations with P-Glycoprotein Inhibitory Effect as Promising Approaches for Enhancing Oral Drug Absorption and Bioavailability

P-glycoprotein (P-gp) is crucial in the active transport of various substrates with diverse structures out of cells, resulting in poor intestinal permeation and limited bioavailability following oral administration. P-gp inhibitors, including small molecule drugs, natural constituents, and pharmaceutically inert excipients, have been exploited to overcome P-gp efflux and enhance the oral absorption and bioavailability of many P-gp substrates. The co-administration of small molecule P-gp inhibitors with P-gp substrates can result in drug–drug interactions and increased side effects due to the pharmacological activity of these molecules. On the other hand, pharmaceutically inert excipients, including polymers, surfactants, and lipid-based excipients, are safe, pharmaceutically acceptable, and are not absorbed from the gut. Notably, they can be incorporated in pharmaceutical formulations to enhance drug solubility, absorption, and bioavailability due to the formulation itself and the P-gp inhibitory effects of the excipients. Different formulations with inherent P-gp inhibitory activity have been developed. These include micelles, emulsions, liposomes, solid lipid nanoparticles, polymeric nanoparticles, microspheres, dendrimers, and solid dispersions. They can bypass P-gp by different mechanisms related to their properties. In this review, we briefly introduce P-gp and P-gp inhibitors, and we extensively summarize the current development of oral drug delivery systems that can bypass and inhibit P-gp to improve the oral absorption and bioavailability of P-gp substrates. Since many drugs are limited by P-gp-mediated efflux, this review is helpful for designing suitable formulations of P-gp substrates to enhance their oral absorption and bioavailability.

Physical, chemical, and biological characterization of ginsenoside F1 incorporated in nanostructured lipid carrier

This study was aimed to determine the physical property and thermodynamic stability of nanostructured lipid carrier suspension incorporating ginsenoside F1 (GF1_NLC), and to evaluate its transport and antioxidant properties. GF1_NLC suspension possessed spherical particles with an average size of 98.9 nm, and the encapsulation efficiency reached approximately 90%. There was a good compatibility between ginsenoside F1 (GF1) and the nanostructured lipid carrier (NLC) formulation, giving no contribution to the changes in the structural organization and crystallization behavior of lipid particles. However, the incorporation of GF1 reduced the thermodynamic stability of the lipid particles. The permeability of GF1_NLC (39.2%) across Caco-2 cell monolayer was higher than that of free GF1 (26.0%); however, no significant differences were observed in the radical scavenging activity (84.1% and 85.5%, respectively). In conclusion, NLC could be a potential candidate for the delivery of GF1 into the living body due to its small particle size, high encapsulation efficiency, and improved permeability. PRACTICAL APPLICATIONS: Poor water solubility in an aqueous solution and low absorption rate of ginsenoside F1 in the intestinal track limit its practical application in food systems. In this study, ginsenoside F1 was encapsulated in nanostructured lipid carrier to enhance its water solubility and absorption rate. The results of the encapsulated ginsenoside F1 showed high encapsulation efficiency of 90% with fine particle size of 98.9 nm that could correspond to the enhancement of water solubility in an aqueous solution and permeability across Caco-2 cell monolayer. The results may encourage the food industry to utilize this encapsulation technique for the enhancement of the functional properties of poorly water-soluble bioactive compounds.

The Anti-Tumor Effect and Underlying Apoptotic Mechanism of Ginsenoside Rk1 and Rg5 in Human Liver Cancer Cells

Ginsenoside Rk1 and Rg5 are minor ginseng saponins that have received more attention recently because of their high oral bioavailability. Each of them can effectively inhibit the survival and proliferation of human liver cancer cells, but the underlying mechanism remains largely unknown. Network pharmacology and bioinformatics analysis demonstrated that G-Rk1 and G-Rg5 yielded 142 potential targets, and shared 44 putative targets associated with hepatocellular carcinoma. Enrichment analysis of the overlapped genes showed that G-Rk1 and G-Rg5 may induce apoptosis of liver cancer cells through inhibition of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signal pathways. Methyl thiazolyl tetrazolium (MTT) assay was used to confirm the inhibition of cell viability with G-Rk1 or G-Rg5 in highly metastatic human cancer MHCC-97H cells. We evaluated the apoptosis of MHCC-97H cells by using flow cytometry and 4′,6-diamidino-2-phenylindole (DAPI) staining. The translocation of Bax/Bak led to the depolarization of mitochondrial membrane potential and release of cytochrome c and Smac. A sequential activation of caspase-9 and caspase-3 and the cleavage of poly(ADP-ribose) polymerase (PARP) were observed after that. The levels of anti-apoptotic proteins were decreased after treatment of G-Rk1 or G-Rg5 in MHCC-97H cells. Taken together, G-Rk1 and G-Rg5 promoted the endogenous apoptotic pathway in MHCC-97H cells by targeting and regulating some critical liver cancer related genes that are involved in the signal pathways associated with cell survival and proliferation.

Saponins in Cancer Treatment: Current Progress and Future Prospects

Saponins are steroidal or triterpenoid glycoside that is distinguished by the soap-forming nature. Different saponins have been characterized and purified and are gaining attention in cancer chemotherapy. Saponins possess high structural diversity, which is linked to the anticancer activities. Several studies have reported the role of saponins in cancer and the mechanism of actions, including cell-cycle arrest, antioxidant activity, cellular invasion inhibition, induction of apoptosis and autophagy. Despite the extensive research and significant anticancer effects of saponins, there are currently no known FDA-approved saponin-based anticancer drugs. This can be attributed to a number of limitations, including toxicities and drug-likeness properties. Recent studies have explored options such as combination therapy and drug delivery systems to ensure increased efficacy and decreased toxicity in saponin. This review discusses the current knowledge on different saponins, their anticancer activity and mechanisms of action, as well as promising research within the last two decades and recommendations for future studies.

Anticancer Effects of Ginsenoside Rh2: A Systematic Review

BACKGROUND

As one of the effective pharmacological constituents of Ginseng Radix et Rhizoma, ginsenoside Rh2 (Rh2) exerts a remarkable anticancer effect on various cancer cell lines in vitro and strongly inhibits tumor growth in vivo without severe toxicity.

OBJECTIVE

This article reviewed existing evidence supporting the anticancer effects of Rh2 to classify and conclude previous and current knowledge on the mechanisms and therapeutic effects of Rh2, as well as to promote the clinical application of this natural product.

CONCLUSION

This article reviewed the anticancer efficacies and mechanisms of Rh2, including the induction of cell cycle arrest and programmed cell death, repression of metastasis, alleviation of drug resistance, and regulation of the immune system. Finally, this paper discussed the research and application prospects of Rh2.

Specific Interaction With Human Serum Albumin Reduces Ginsenoside Cytotoxicity in Human Umbilical Vein Endothelial Cells

Human serum albumin (HSA) is an important component of plasma, which has the functions of maintaining colloid osmotic pressure and capillary membrane stability, promoting blood circulation, and anti-oxidation. Three-dimensional structure of HSA determines its ability to bind and transport hormones and other substances. In this study we examined the interactions between HSA and ginsenoside Rg3, Rg5, Rk1, Rh2, and Rh4, which are the main cytotoxic ginsenosides extracted from red ginseng. Heat transfer generated by the specific interaction between HSA and each ginsenoside was measured using isothermal titration calorimetry (ITC) assay, which demonstrated that all these 5 ginsenosides bound to HSA with binding constants of 3.25, 1.89, 6.04, 2.07, and 5.17 × 10⁵ M⁻¹, respectively. Molecular docking also displayed that these ginsenosides interact with HSA at different sites of the HSA surface. Importantly, cell viability assay showed that the cytotoxicity of these ginsenosides reduced significantly at the presence of HSA in human vascular endothelial cells (HUVEC). Taken together, this study reveals the mechanism by which these ginsenosides are transported in vivo by not causing damage in vascular endothelium, and also suggests HSA might be an ideal carrier help to transport and execute these ginsenoside functions in human body.

Molecular Insight into Stereoselective ADME Characteristics of C20-24 Epimeric Epoxides of Protopanaxadiol by Docking Analysis

Chirality is a common phenomenon, and it is meaningful to explore interactions between stereoselective bio-macromolecules and chiral small molecules with preclinical and clinical significance. Protopanaxadiol-type ginsenosides are main effective ingredients in ginseng and are prone to biotransformation into a pair of ocotillol C20-24 epoxide epimers, namely, (20S,24S)-epoxy-dammarane-3,12,25-triol (24S-PDQ) and (20S,24R)-epoxy dammarane-3,12,25-triol (24R-PDQ) that display stereoselective fate in vivo. However, possible molecular mechanisms involved are still unclear. The present study aimed to investigate stereoselective ADME (absorption, distribution, metabolism and excretion) characteristics of PDQ epimers based on molecular docking analysis of their interaction with some vital proteins responsible for drug disposal. Homology modeling was performed to obtain 3D-structure of the human isoenzyme UGT1A8, while calculation of docking score and binding free energy and ligand-protein interaction pattern analysis were achieved by using the Schrödinger package. Stereoselective interaction was found for both UGT1A8 and CYP3A4, demonstrating that 24S-PDQ was more susceptible to glucuronidation, whereas 24R-PDQ was more prone to oxidation catalyzed by CYP3A4. However, both epimers displayed similarly strong interaction with P-gp, a protein with energy-dependent drug-pump function, suggesting an effect of the dammarane skeleton but not C-24 stereo-configuration. These findings provide an insight into stereo-selectivity of ginsenosides, as well as a support the rational development of ginseng products.

In Vitro and In Situ Characterization of the Intestinal Absorption of Capilliposide B and Capilliposide C from Lysimachia capillipes Hemsl

The goal of this investigation was to determine the processes and mechanism of intestinal absorption for capilliposide B (CAPB) and capilliposide C (CAPC) from the Chinese herb, Lysimachia capillipes Hemsl. An analysis of basic parameters, such as drug concentrations, time, and behavior in different intestinal segments was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS). The susceptibility of CAPB and CAPC to various inhibitors such as P-glycoprotein (P-gp) inhibitor (verapamil); multidrug resistance-associated protein 2 (MRP2) inhibitor (indomethacin); cytochrome P450 protein 3A4 (CYP3A4) inhibitor (ketoconazole); and the co-inhibitor of P-gp, MRP2 and CYP3A4 (cyclosporine A) were assessed using both caco-2 cell monolayer and single-pass intestinal perfusion (SPIP) models. As a result, CAPB and CAPC are both poorly absorbed in the intestines and exhibited segment-dependent permeability. The intestinal permeability of CAPB and CAPC were significantly increased by the co-treatment of verapamil, indomethacin. In addition, the intestinal permeability of CAPB was also enhanced by ketoconazole and cyclosporine A. It can be concluded that the intestinal absorption mechanisms of CAPB and CAPC involve processes such as facilitated passive diffusion, efflux transporters, and enzyme-mediated metabolism. Both CAPB and CAPC are suggested to be substrates of P-gp and MRP2. However, CAPB may interact with the CYP3A4 system.

Identification and quantitative investigation of the effects of intestinal microflora on the metabolism and pharmacokinetics of notoginsenoside Fc assayed by liquid chromatography with electrospray ionization tandem mass spectrometry

Notoginsenoside Fc, which is a protopanaxdiol-type saponin isolated from the leaves of Panax notoginseng, exhibits an exceptional antiplatelet aggregatory effect. To study the modulating effect of gastrointestinal contents on the metabolic profile and pharmacokinetics, pseudo germ-free rats were used to study the influence of the bacterial community structure on the metabolic profile. Glycosidase activities were measured using the spectrophotometric method. Biotransformations of notoginsenoside Fc in normal and pseudo germ-free rat intestinal microflora were systematically investigated using ultra high performance liquid chromatography with tandem quadrupole/time-of-flight mass spectrometry. Moreover, a liquid chromatography with tandem mass spectrometry method was established for simultaneous determination of the notoginsenoside Fc prototype and its degradation products. Through an in vivo pharmacokinetic study, the pharmacokinetic characteristics were compared between normal rats and pseudo germ-free rats. During the in vitro biotransformation, seven deglycosylated products were detected and identified after incubation in the intestinal bacteria of normal rats. In pseudo germ-free rats, glycosidase activities were significantly decreased, and no obvious degradation occurred. In an in vivo study, the systemic exposure was significantly increased 40%, as evidenced by the area under the blood concentration-time curve from time zero to infinity value and half-life value, which were prolonged more in the pseudo germ-free group than in normal rats. The results demonstrate that patients who use intestinal bacteria-metabolized herbs, such as panax notoginseng, should understand the profile of intestinal bacteria to ensure therapeutic efficacy.

Preparation and evaluation of self-microemulsions for improved bioavailability of ginsenoside-Rh1 and Rh2

Due to intestinal cytochrome P450 (CYP450)-mediated metabolism and P-glycoprotein (P-gp) efflux, poor oral bioavailability hinders ginsenoside-Rh1 (Rh1) and ginsenoside-Rh2 (Rh2) from clinical application. In this study, Rh1 and Rh2 were incorporated into two self-microemulsions (SME-1 and SME-2) to improve oral bioavailability. SME-1 contained both CYP450 and P-gp inhibitory excipients while SME-2 only consisted of P-gp inhibitory excipients. Results for release, cellular uptake, transport, and lymph node distribution demonstrated no significant difference between either self-microemulsions in vivo, but were elevated significantly in comparison to the free drug. The pharmaceutical profiles in vivo showed that the bioavailability of Rh1 in SME-1 (33.25%) was significantly higher than that in either SME-2 (21.28%) or free drug (12.92%). There was no significant difference in bioavailability for Rh2 between SME-1 (48.69%) or SME-2 (41.73%), although they both had remarkable increase in comparison to free drug (15.02%). We confirmed that SME containing CYP450 and P-gp inhibitory excipient could distinctively improve the oral availabilities of Rh1 compared to free drug or SME containing P-gp inhibitory excipient. No notable increase was observed between either SME for Rh2, suggesting that Rh2 undergoes P-gp-mediated efflux, but may not undergo distinct CYP450-mediated metabolism.

Chemical and Absorption Signatures of Xiao Chai Hu Tang

RATIONALE

Xiao Chai Hu Tang (XCHT, Sho-saiko-to in Japanese) is a well-known medicine formula used in Asia for centuries. However, the quality control and the absorption of XCHT components are the major remaining concerns.. The study was to develop a sensitive and robust method to characterize the chemical components in XCHT and evaluate their absorptions.

METHODS

An ultra-high pressure liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC-ESI-QTOF MS/MS) was used to identify the compounds in XCHT. The Caco-2 cell culture model was employed to determine the absorption of the identified components.

RESULTS

The results showed that 109 compounds were identified including organic acids, flavonoids, saikosaponins, ginsenosides, licoricesaponins and gingerols. The absorption study showed that among those identified, 33 compounds have decent absorption permerbilities ranging from 1.46 ± 0.24×10-7 to 3.10±0.61×10-5 cm/sec. These compounds were classified as classes II and IV in the biopharmaceutical classification system (BCS).

CONCLUSIONS

These identified compounds could be used to characterize quality of XCHT and those absorbed compounds with decent permreabiliteis are the potential active components in XCHT. Future pharmacodynamics studies should focus on these absorbed compounds.

New generation of drug delivery systems based on ginsenoside Rh2-, Lysine- and Arginine-treated highly porous graphene for improving anticancer activity

In this study, Rh2-treated graphene oxide (GO-Rh2), lysine-treated highly porous graphene (Gr-Lys), arginine-treated Gr (Gr-Arg), Rh2-treated Gr-Lys (Gr-Lys-Rh2) and Rh2-treated Gr-Arg (Gr-Arg-Rh2) were synthesized. MTT assay was used for evaluation of cytotoxicity of samples on ovarian cancer (OVCAR3), breast cancer (MDA-MB), Human melanoma (A375) and human mesenchymal stem cells (MSCs) cell lines. The percentage of apoptotic cells was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. The hemolysis and blood coagulation activity of nanostructures were performed. Interestingly, Gr-Arg, Gr-Lys, Gr-Arg-Rh2, and Gr-Lys-Rh2 were more active against cancer cell lines in comparison with their cytotoxic activity against normal cell lines (MSCs) with IC50 values higher than 100 μg/ml. The results of TUNEL assay indicates a significant increase in the rates of TUNEL positive cells by increasing the concentrations of nanomaterials. Results were also shown that aggregation and changes of RBCs morphology were occurred in the presence of GO, GO-Rh2, Gr-Arg, Gr-Lys, Gr-Arg-Rh2, and Gr-Lys-Rh2. Note that all the samples had effect on blood coagulation system, especially on PTT. All nanostrucure act as antitumor drug so that binding of drugs to a nostructures is irresolvable and the whole structure enter to the cell as a drug.

Transporter-mediated natural product-drug interactions for the treatment of cardiovascular diseases

The growing use of natural products in cardiovascular (CV) patients has been greatly raising the concerns about potential natural product–CV drug interactions. Some of these may lead to unexpected cardiovascular adverse effects and it is, therefore, essential to identify or predict potential natural product–CV drug interactions, and to understand the underlying mechanisms. Drug transporters are important determinants for the pharmacokinetics of drugs and alterations of drug transport has been recognized as one of the major causes of natural product–drug interactions. In last two decades, many CV drugs (e.g., angiotensin II receptor blockers, beta-blockers and statins) have been identified to be substrates and inhibitors of the solute carrier (SLC) transporters and the ATP-binding cassette (ABC) transporters, which are two major transporter superfamilies. Meanwhile, in vitro and in vivo studies indicate that a growing number of natural products showed cardioprotective effects (e.g., gingko biloba, danshen and their active ingredients) are also substrates and inhibitors of drug transporters. Thus, to understand transporter-mediated natural product–CV drug interactions is important and some transporter-mediated interactions have already shown to have clinical relevance. In this review, we review the current knowledge on the role of ABC and SLC transporters in CV therapy, as well as transporter modulation by natural products used in CV diseases and their induced natural product–CV drug interactions through alterations of drug transport. We hope our review will aid in a comprehensive summary of transporter-mediated natural product–CV drug interactions and help public and physicians understand these type of interactions.

The interaction of serum albumin with ginsenoside Rh2 resulted in the downregulation of ginsenoside Rh2 cytotoxicity

Background

Ginsenoside Rh2 (G-Rh2) is a ginseng saponin that is widely investigated because of its remarkable antitumor activity. However, the molecular mechanism by which (20S) G-Rh2 triggers its functions and how target animals avoid its cytotoxic action remains largely unknown.

Methods

Phage display was used to screen the human targets of (20S) G-Rh2. Fluorescence spectroscopy and UV-visible absorption spectroscopy were used to confirm the interaction of candidate target proteins and (20S) G-Rh2. Molecular docking was utilized to calculate the estimated free energy of binding and to structurally visualize their interactions. MTT assay and immunoblotting were used to assess whether human serum albumin (HSA), bovine serum albumin (BSA), and bovine serum can reduce the cytotoxic activity of (20S) G-Rh2 in HepG2 cells.

Results

In phage display, (20S) G-Rh2-beads and (20R) G-Rh2-beads were combined with numerous kinds of phages, and a total of 111 different human complementary DNAs (cDNA) were identified, including HSA which had the highest rate. The binding constant and number of binding site in the interaction between (20S)-Rh2 and HSA were 3.5 × 10⁵ M⁻¹ and 1, and those in the interaction between (20S) G-Rh2 and BSA were 1.4 × 10⁵ M⁻¹ and 1. The quenching mechanism is static quenching. HSA, BSA and bovine serum significantly reduced the proapoptotic effect of (20S) G-Rh2.

Conclusion

HSA and BSA interact with (20S) G-Rh2. Serum inhibited the activity of (20S) G-Rh2 mainly due to the interaction between (20S) G-Rh2 and serum albumin (SA). This study proposes that HSA may enhance (20S) G-Rh2 water solubility, and thus might be used as nanoparticles in the (20S) G-Rh2 delivery process.

Finding and Producing Probiotic Glycosylases for the Biocatalysis of Ginsenosides: A Mini Review

Various microorganisms have been widely applied in nutraceutical industries for the processing of phytochemical conversion. Specifically, in the Asian food industry and academia, notable attention is paid to the biocatalytic process of ginsenosides (ginseng saponins) using probiotic bacteria that produce high levels of glycosyl-hydrolases. Multiple groups have conducted experiments in order to determine the best conditions to produce more active and stable enzymes, which can be applicable to produce diverse types of ginsenosides for commercial applications. In this sense, there are various reviews that cover the biofunctional effects of multiple types of ginsenosides and the pathways of ginsenoside deglycosylation. However, little work has been published on the production methods of probiotic enzymes, which is a critical component of ginsenoside processing. This review aims to investigate current preparation methods, results on the discovery of new glycosylases, the application potential of probiotic enzymes and their use for biocatalysis of ginsenosides in the nutraceutical industry.

Effect of B-complex vitamins on the antifatigue activity and bioavailability of ginsenoside Re after oral administration

Background

Both ginsenoside Re and B-complex vitamins are widely used as nutritional supplements. They are often taken together so as to fully utilize their antifatigue and refreshing effects, respectively. Whether actually a drug–nutrient interaction exists between ginsenoside Re and B-complex vitamins is still unknown. The objective of this study was to simultaneously investigate the effect of B-complex vitamins on the antifatigue activity and bioavailability of ginsenoside Re after their oral administration. The study results will provide valuable theoretical guidance for the combined utilization of ginseng and B-complex vitamins.

Methods

Ginsenoside Re with or without B-complex vitamins was orally administered to mice to evaluate its antifatigue effects and to rats to evaluate its bioavailability. The antifatigue activity was evaluated by the weight-loaded swimming test and biochemical parameters, including hepatic glycogen, plasma urea nitrogen, and blood lactic acid. The concentration of ginsenoside Re in plasma was determined by liquid chromatography–tandem mass spectrometry.

Results

No antifatigue effect of ginsenoside Re was noted when ginsenoside Re in combination with B-complex vitamins was orally administered to mice. B-complex vitamins caused to a reduction in the bioavailability of ginsenoside Re with the area under the concentration–time curve from zero to infinity markedly decreasing from 11,830.85 ± 2,366.47 h·ng/mL to 890.55 ± 372.94 h·ng/mL.

Conclusion

The results suggested that there were pharmacokinetic and pharmacodynamic drug–nutrient interactions between ginsenoside Re and B-complex vitamins. B-complex vitamins can significantly weaken the antifatigue effect and decrease the bioavailability of ginsenoside Re when simultaneously administered orally.

Miconazole-loaded solid lipid nanoparticles: formulation and evaluation of a novel formula with high bioavailability and antifungal activity

Background and objective

Miconazole is a broad-spectrum antifungal drug that has poor aqueous solubility (<1 µg/mL); as a result, a reduction in its therapeutic efficacy has been reported. The aim of this study was to formulate and evaluate miconazole-loaded solid lipid nanoparticles (MN-SLNs) for oral administration to find an innovative way to alleviate the disadvantages associated with commercially available capsules.

Methods

MN-SLNs were prepared by hot homogenization/ultrasonication. The solubility of miconazole in different solid lipids was measured. The effect of process variables, such as surfactant types, homogenization and ultrasonication times, and the charge-inducing agent on the particle size, zeta potential, and encapsulation efficiency were determined. Furthermore, in vitro drug release, antifungal activity against Candida albicans, and in vivo pharmacokinetics were studied in rabbits.

Results

The MN-SLN, consisting of 1.5% miconazole, 2% Precirol ATO5, 2.5% Cremophor RH40, 0.5% Lecinol, and 0.1% Dicetylphosphate, had an average diameter of 23 nm with a 90.2% entrapment efficiency. Furthermore, the formulation of MN-SLNs enhanced the antifungal activity compared with miconazole capsules. An in vivo pharmacokinetic study revealed that the bioavailability was enhanced by >2.5-fold.

Conclusion

MN-SLN was more efficient in the treatment of candidiasis with enhanced oral bioavailability and could be a promising carrier for the oral delivery of miconazole.

Enhancement of oral bioavailability of akebia saponin D by destroying self-micelles and inhibiting multidrug resistance-associated protein mediated efflux

Akebia saponin D (ASD), a triterpenoid saponin with numerous pharmacological activities, is isolated from the rhizome of Dipsacus asper Wall.

Characterization of oxygenated metabolites of ginsenoside Rb1 in plasma and urine of rat

Oxygenated metabolites have been suggested as the major circulating metabolites of ginsenosides. In the current study, 10 oxygenated metabolites of ginsenoside Rb1 in plasma and urine of rat following iv dose were characterized by comparison with chemically synthesized authentic compounds as quinquenoside L16 (M1 and M2), notoginsenoside A (M3), ginsenoside V (M4 and M7), epoxyginsenoside Rb1 (M5 and M9), notoginsenoside K (M6), and notoginsenoside C (M8 and M10), 9 of which were detected as in vivo metabolites for the first time. After oral administration of ginsenoside Rb1, M3, M4, and M7 were observed as major circulating metabolites and presented in the bloodstream of rat for 24 h. Characterization of the exact chemical structures of these circulating metabolites could contribute greatly to our understanding of chemical exposure of ginsenosides after consumption of ginseng products and provide valuable information for explaining multiple bioactivities of ginseng products.

Development and validation of an UPLC-MS/MS method for the quantification of ethoxzolamide in blood, brain tissue, and bioequivalent buffers: applications to absorption, brain distribution, and pharmacokinetic studies

The purpose of this study is to develop and validate an UPLC-MS/MS method to quantify ethoxzolamide in plasma (EZ) and apply the method to absorption, brain distribution, as well as pharmacokinetic studies. A C₁₈ column was used with 0.1% of formic acid in acetonitrile and 0.1% of formic acid in water as the mobile phases to resolve EZ. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode. The results show that the linear range of EZ is 4.88–10,000.00 nM. The intra-day variance is less than 12.43 % and the accuracy is between 88.88–08.00 %. The inter-day variance is less than 12.87 % and accuracy is between 89.27–115.89 %. Protein precipitation was performed using methanol to extract EZ from plasma and brain tissues. Only 40 µL of plasma is needed for analysis due to the high sensitivity of this method, which could be completed in less than three minutes. This method was used to study the pharmacokinetics of EZ in SD rats, and the transport of EZ in Caco-2 and MDCK-MDR1 overexpressing cell culture models. Our data show that EZ is not a substrate for p-glycoprotein (P-gp) and its entry into the brain may not limited by the blood-brain barrier.

Solid lipid nanoparticles loaded with iron to overcome barriers for treatment of iron deficiency anemia

According to the World Health Organization, 46% of the world’s children suffer from anemia, which is usually treated with iron supplements such as ferrous sulfate. The aim of this study was to prepare iron as solid lipid nanoparticles, in order to find an innovative way for alleviating the disadvantages associated with commercially available tablets. These limitations include adverse effects on the digestive system resulting in constipation and blood in the stool. The second drawback is the high variability in the absorption of iron and thus in its bioavailability. Iron solid lipid nanoparticles (Fe-SLNs) were prepared by hot homogenization/ultrasonication. Solubility of ferrous sulfate in different solid lipids was measured, and effects of process variables such as the surfactant type and concentration, homogenization and ultrasonication times, and charge-inducing agent on the particle size, zeta potential, and encapsulation efficiency were determined. Furthermore, in vitro drug release and in vivo pharmacokinetics were studied in rabbits. Results indicated that Fe-SLNs consisted of 3% Compritol 888 ATO, 1% Lecithin, 3% Poloxamer 188, and 0.2% dicetylphosphate, with an average particle size of 25 nm with 92.3% entrapment efficiency. In vivo pharmacokinetic study revealed more than fourfold enhanced bioavailability. In conclusion, Fe-SLNs could be a promising carrier for iron with enhanced oral bioavailability.

The melanogenesis-inhibitory effect and the percutaneous formulation of ginsenoside Rb1

Ginsenoside Rb1 (Rb1) is the most predominant ginsenoside isolated from the roots of ginseng (Panax ginseng C. A. Meyer). This compound is active in various human biological pathways that are involved in human collagen synthesis and inhibition of cell apoptosis. In this study, the skin-whitening effects of Rb1 were investigated in B16 melanoma cells. Our results showed that Rb1 inhibited melanogenesis in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16 cells in a dose-dependent manner, which collectively indicated that Rb1 may have skin-whitening effects and may be formulated into skin-whitening products for skin care. Accordingly, a ginsenoside collagen transdermal patch was developed as a vehicle to topically deliver Rb1 into pig skin. The percutaneous permeation, retention within skin, and release in vitro of Rb1 from seven transdermal patch formulas were studied. It was determined that the best formula for ginsenoside collagen transdermal patch is made of protein collagen hydrolysate powder (PCHP) 2.0% (w/w), methyl cellulose (MC) 0.5% (w/w), polyethyleneglycol 6000 (PEG6000) 0.5% (w/w), ginsenoside 0.036% (w/w), azone 0.4% (v/w), menthol 0.20% (w/w), and water.

Transformation of ginsenosides from notoginseng by artificial gastric juice can increase cytotoxicity toward cancer cells

Multicomponent metabolic profile of notoginseng saponins in artificial gastric juice was qualitatively and quantitatively investigated, showing that ginsenosides were transformed via multiple pathways including deglycosylation, dehydration, hydration, and oxygenation. A total of 83 metabolites was identified by using UPLC-Q-TOF-MS, among which 16 new dammarane glycosides were further characterized by comparing with synthesized authentic compounds. Transformation time-course of notoginseng saponins in artificial gastric juice was quantitatively measured for the first time, showing rapid degradation of primary ginsenosides and concomitant formation of deglycosylation, hydration, and dehydration products. It was further demonstrated that the resultant metabolites exhibited enhanced cytotoxicity toward cancer cells. The extensive metabolism of ginsenosides within a transit time span in stomach, together with the formation of metabolites with diversified chemical structures possessing enhanced biological activities, indicated an important role of transformation in gastric juice in the systematic effects of ginsenosides.

Esterification enhanced intestinal absorption of ginsenoside Rh2 in Caco-2 cells without impacts on its protective effects against H₂O₂-induced cell injury in human umbilical vein endothelial cells (HUVECs)

Ginsenoside Rh2 and its octyl ester derivative (Rh2-O) were investigated for their transcellular transport in the Caco-2 cell system and their protective effect against oxidative stress in human umbilical vein endothelial cells (HUVECs). Results showed that the transport rates for apical-to-basolateral (AP-BL) flux of Rh2 (0.21 × 10⁻⁶ cm/s) was enhanced by the synthesis of its esterified derivative Rh2-O (1.93 × 10⁻⁶ cm/s) over the concentrations of 10-50 μM. In addition, both Rh2 and its esterified derivative Rh2-O exhibited similar protective effects against oxidative damage induced by H₂O₂. Pretreatment of Rh2 and Rh2-O significantly decreased the activation of caspase-3 known to play a key role in H₂O₂-induced cell apoptosis. These results were consistent with that of a flow cytometry assay analyzing HUVECs apoptosis. The present study demonstrated that the absorption of ginsenoside Rh2 in vitro can be significantly enhanced by synthesis of its ester derivative. Meanwhile, no significant discrepancy between Rh2 and Rh2-O on their bioactivities against the oxidative damage induced by H₂O₂ was observed, which means that esterification of Rh2 might have a higher bioavailability than Rh2 in vitro without impacts on pharmaceutical actions.

Ginsenoside Rh2-B1 stimulates cell proliferation and IFN-γ production by activating the p38 MAPK and ERK-dependent signaling pathways in CTLL-2 cells

CONTEXT

Ginsenoside Rh2, an active component of ginseng, exhibits immunoregulatory and anti-inflammatory properties. Rh2-B1, a sulfated derivative, was prepared to enhance its water solubility. We studied the effect of Rh2-B1 on CTLL-2, a CD8⁺ cytotoxic T cell line that was known for protecting against viral infection.

OBJECTIVE

We aimed to investigate the effect of Rh2-B1 on interferon (IFN)-γ production and cell proliferation and its possible mechanism.

MATERIALS AND METHODS

Enzyme-linked immunosorbent assay (ELISA) was employed to analyze the IFN-γ concentration of the whole blood and the supernatant of CTLL-2 cell culture. Cell proliferation assay was conducted using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Western blots were used to evaluate changes in signal transduction pathways in CTLL-2 cells.

RESULTS

Rh2-B1 was able to enhance IFN-γ production from whole blood culture of Balb/c mice. We then evaluated the effect of Rh2-B1 on a cytotoxic T cell line, CTLL-2 for cell proliferation, IFN-γ production and its molecular mechanism. Rh2-B1 promoted cell proliferation and IFN-γ production of CTLL-2 cells. It also induced activation of p38 mitogen-activated protein kinase (MAPK) and extracellular-signal-regulated kinases (ERK), but inhibited p56 Lck and transducer and activator of transcription 5 (STAT5) expression. The effect was blocked by the specific p38 MAPK inhibitor SB203580 and ERK inhibitor U0126.

CONCLUSION

Rh2-B1 could stimulate cell proliferation and IFN-γ production by activating the p38 MAPK- and ERK-dependent signaling pathways in cytotoxic T cells. This may be a novel medicine for treatment of viral infections.

In vitro characterization of ABC transporters involved in the absorption and distribution of liensinine and its analogs

ETHNOPHARMACOLOGICAL RELEVANCE

Lotus plumule, the dried young cotyledon and radicle of the Nelumbo nucifera Gaertn. (Fam. Nymphaeaceae) ripe seed, is a famous Traditional Chinese Medicine to remove heat from the heart, anchor the mind, improve seminal emission, and arrest bleeding for centuries in China. Liensinine and its analogs neferine and isoliensinine are the major active components in lotus plumule. Aim of the study is to investigate the association of liensinine, neferine, and isoliensinine with efflux transporters.

MATERIALS AND METHODS

Caco-2, MDCK, MDCK-MDR1, and MDCK-MRP2 were used as cell models for the transcellular transport and accumulation studies.

RESULTS

The results obtained in Caco-2 cells suggested that P-glycoprotein (P-gp) might be involved in transcellular transport. Cellular accumulation and transport experiments were further performed in MDCK-MDR1 cells. GF120918 and cyclosporine A were found to completely inhibit the efflux, and the net efflux ratios of these alkaloids exhibited saturation over the concentration range. No significant differences in liensinine accumulation and transport were observed between MDCK and MDCK-MRP2 cells.

CONCLUSIONS

These results demonstrated that liensinine, neferine, and isoliensinine are substrates of P-gp, whereas MRP2 is not involved in the transport process, suggesting that P-gp might be responsible for the absorption and distribution of the 3 alkaloids.