Biotransformation of ginsenoside Rb1 via the gypenoside pathway by human gut bacteria

Compound K Production: Achievements and Perspectives

Compound K (CK) is one of the major metabolites found in mammalian blood and organs following oral administration of Panax plants. CK, also known as minor ginsenoside, can be absorbed in the systemic circulation. It has garnered significant attention in healthcare and medical products due to its pharmacological activities, such as antioxidation, anticancer, antiproliferation, antidiabetics, neuroprotection, and anti-atherogenic activities. However, CK is not found in natural ginseng plants but in traditional chemical synthesis, which uses toxic solvents and leads to environmental pollution during the harvest process. Moreover, enzymatic reactions are impractical for industrial CK production due to low yield and high costs. Although CK could be generated from major ginsenosides, most ginsenosides, including protopanaxatriol-oleanane and ocotillol-type, are not converted into CK by catalyzing β-glucosidase. Therefore, microbial cell systems have been used as a promising solution, providing a safe and efficient approach to CK production. This review provides a summary of various approaches for the production of CK, including chemical and enzymatic reactions, biotransformation by the human intestinal bacteria and endophytes as well as engineered microbes. Moreover, the approaches for CK production have been discussed to improve the productivity of target compounds.

Shengmai san-derived compound prescriptions: A review on chemical constituents, pharmacokinetic studies, quality control, and pharmacological properties

BACKGROUND

Shengmai San Formula (SMS), composed of Ginseng Radix et Rhizoma, Ophiopogon Radix and Schisandra chinensis Fructus, was a famous formula in Tradition Chinese Medicine (TCM). With the expansion of clinical applications, SMS was developed to different dosage forms, including Shengmai Yin Oral liquid (SMY), Shengmai Capsule (SMC), Shengmai Granule (SMG), Shengmai Injection (SMI) and Dengzhan Shengmai Capsule (DZSMC). These above SMS-derived compound prescriptions (SSCPs) play an important role in the clinical treatment. This review is aimed to providing a comprehensive perspective of SSCP.

METHODS

The relevant literatures were collected from classical TCM books and a variety of databases, including PubMed, Google Scholar, Science Direct, Springer Link, Web of Science, China National Knowledge Infrastructure, and Wanfang Data.

RESULTS

The chemical constituents of SSCPs, arrived from the individual medicinal materials including Ginseng Radix et Rhizoma, Ophiopogon Radix, Schisandra chinensis Fructus, Erigerontis Herba, were firstly summarized respectively. Then the pharmacokinetics studies, quality control, and pharmacological properties of SSCPs were all reviewed. The active compounds, pharmacokinetics characterizes, quality control markers, the effects and mechanisms of pharmacology of the different dosage forms of SSCPs were summarized. Furthermore, the research deficiencies of SSCPs and an innovative research paradigm for Chinese materia medica (CMM) formula were proposed.

CONCLUSIONS

SMS, as a famous CMM formula, has great values in drug research and in clinical treatment especially for cardiocerebrovascular diseases. This article firstly make a comprehensive and systematic review on SMS.

Differential Metabolic Profiles of Ginsenosides in Artificial Gastric Juice Using ultra-high-pressure Liquid Chromatography Coupled with Linear ion trap-Orbitrap Mass Spectrometry

Ginsenosides have poor bioavailability of oral administration and undergo rapid biologic transformation in the complex gastrointestinal environment. Most studies on the metabolism of ginsenosides has focused on gut bacteria, yet gastric juice remains as a non-negligible factor. Metabolic profiles of ginsenoside monomers formed in artificial gastric juice were separately investigated and qualitatively identified by UHPLC-LTQ-Orbitrap MSⁿ . A common pattern of their metabolic pathways was established, showing that ginsenosides were transformed via deglycosylation, hydration and dehydration pathways. Two major structure types, PPTs and PPDs, basically shared similar transformation pathways and yielded deglycosylated, hydrated and dehydrated products. Fragmentation patterns of major ginsenosides were also discussed. Consequently, gastric juice, as the primary link in ginsenoside metabolism and as important as the intestinal flora, produces considerable amount of degraded ginsenosides, providing a partial explanation for the low bioavailabilities of primary ginsenosides.

Gut microbiota: An emerging therapeutic approach of herbal medicine for prevention of colorectal cancer

The gut dysbiosis has emerged as a prominent player in the pathogenesis and development of colorectal cancer (CRC), which in turn intensifies dysregulated gut microbiota composition and inflammation. Since most drugs are given orally, this dysbiosis directly and indirectly impinges the absorption and metabolism of drugs in the gastrointestinal tract, and subsequently affects the clinical outcome of patients with CRC. Herbal medicine, including the natural bioactive products, have been used traditionally for centuries and can be considered as novel medicinal sources for anticancer drug discovery. Due to their various structures and pharmacological effects, natural products have been found to improve microbiota composition, repair intestinal barrier and reduce inflammation in human and animal models of CRC. This review summarizes the chemo-preventive effects of extracts and/or compounds derived from natural herbs as the promising antineoplastic agents against CRC, and will provide innovative strategies to counteract dysregulated microbiota and improve the lives of CRC patients.

Visual Sensing of β-Glucosidase From Intestinal Fungus in the Generation of Cytotoxic Icarisid II

β-Glucosidase (β-Glc) is an enzyme capable of the selective hydrolysis of the β-glycosidic bond of glycosides and glycans containing glucose. β-Glc expressed by intestinal microbiota has attracted increasing levels of interest, due to their important roles for the metabolism of exogenous substances in the gut. Using the 2-((6-hydroxy-2,3-dihydro-1H-xanthen-4-yl)methylene)malononitrile fluorophore (DXM-OH, λ_em 636 nm) and the recognition group β-Glucose, an enzymatic activatable turn-on fluorescent probe (DXM-Glc) was developed for the selective and sensitive sensing of β-Glc. In addition, DXM-Glc could be used to sense endogenous β-Glc in living fungal cells. Using DXM-Glc, Pichia terricola M2 was identified as a functional intestinal fungus with β-Glc expression. P. terricola M2 could transform the flavone glycoside Icariin to Icariside Ⅱ efficiently, which confirmed the metabolism of glycosides in the gut mediated by fungi. Furthermore, Icariside Ⅱ could inhibit the proliferation of human endometrial cancer cells (RL 95-2 and ishikawa) significantly, suggesting the metabolic activation of Icariin by intestinal fungi in vivo. Therefore, DXM-Glc as a probe for β-Glc provided a novel technique for the investigation of the metabolism of bioactive substances by intestinal microbiota.

Insights into Recent Studies on Biotransformation and Pharmacological Activities of Ginsenoside Rd

It is well known that ginsenosides—major bioactive constituents of Panax ginseng—are attracting more attention due to their beneficial pharmacological activities. Ginsenoside Rd, belonging to protopanaxadiol (PPD)-type ginsenosides, exhibits diverse and powerful pharmacological activities. In recent decades, nearly 300 studies on the pharmacological activities of Rd—as a potential treatment for a variety of diseases—have been published. However, no specific, comprehensive reviews have been documented to date. The present review not only summarizes the in vitro and in vivo studies on the health benefits of Rd, including anti-cancer, anti-diabetic, anti-inflammatory, neuroprotective, cardioprotective, ischemic stroke, immunoregulation, and other pharmacological effects, it also delves into the inclusion of potential molecular mechanisms, providing an overview of future prospects for the use of Rd in the treatment of chronic metabolic diseases and neurodegenerative disorders. Although biotransformation, pharmacokinetics, and clinical studies of Rd have also been reviewed, clinical trial data of Rd are limited; the only data available are for its treatment of acute ischemic stroke. Therefore, clinical evidence of Rd should be considered in future studies.

Ginsenoside Rb1 ameliorates Glycemic Disorder in Mice With High Fat Diet-Induced Obesity via Regulating Gut Microbiota and Amino Acid Metabolism

Accumulating evidences suggested an association between gut microbiome dysbiosis and impaired glycemic control. Ginsenoside Rb1 (Rb1) is a biologically active substance of ginseng, which serves anti-diabetic effects. However, its working mechanism especially interaction with gut microbes remains elusive in detail. In this study, we investigated the impact of Rb1 oral supplementation on high fat diet (HFD) induced obesity mice, and explored its mechanism in regulating blood glucose. The results showed that higher liver weight and lower cecum weight were observed in HFD fed mice, which was maintained by Rb1 administration. In addition, Rb1 ameliorated HFD induced blood lipid abnormality and improved insulin sensitivity. Several mRNA expressions in the liver were measured by quantitative real-time PCR, of which UCP2, Nr1H4, and Fiaf were reversed by Rb1 treatment. 16S rRNA sequencing analysis indicated that Rb1 significantly altered gut microbiota composition and increased the abundance of mucin-degrading bacterium Akkermansia spp. compared to HFD mice. As suggested via functional prediction, amino acid metabolism was modulated by Rb1 supplementation. Subsequent serum amino acids investigation indicated that several diabetes associated amino acids, like branched-chain amino acids, tryptophan and alanine, were altered in company with Rb1 supplementation. Moreover, correlation analysis firstly implied that the circulation level of alanine was related to Akkermansia spp.. In summary, Rb1 supplementation improved HFD induced insulin resistance in mice, and was associated with profound changes in microbial composition and amino acid metabolism.

Development and evaluation of phytosome-loaded microsphere system for delivery of ginseng extract

The current research work focuses mainly on evolving a delivery system for ginseng extract (GE), which in turn will ameliorate the neuroprotective potential through enhancing the Ginsenoside Rb1(GRb1) bioavailability (BA). Phytosome complexes (F1, F2, and F3) were prepared by reacting GE with phospholipids in disparate ratios. F3 was chosen for preparing the phytosomes powder (PP) and phytosomes-loaded microspheres (PMs). Extract microspheres (EMs) were prepared by the addition of extract directly into the same polymer mixture. F3 gave enhanced entrapment efficiency (50.61%, w/w) along with spherical-shaped particle size (42.58 ± 1.4 nm) with the least polydispersity index (0.193 ± 0.01). PM showed an enhanced relative bioavailability (157.94%) of GRb1. It also showed a greater neuroprotective potential exhibiting significant (p < 0.05) augmentation in the nociceptive threshold. It was concluded that the PM system might be an optimistic and feasible strategy to enhance the delivery of GE for the effectual treatment of neuropathy.

Production of minor ginsenosides by combining Stereum hirsutum and cellulase

Minor ginsenosides (MGs) (include ginsenoside F2, Compound K, PPT, etc), which are generally not produced by ginseng plants naturally, are obtained by deglycosylation of major ginsenosides. However, the conventional processes used to produce deglycosylated ginsenosides focus on the use of intestinal microorganisms for transformation. In this study, an edible and medicinal mushroom Stereum hirsutum JE0512 was screened from 161 β-glucosidase-producing soil microorganisms sourced from wild ginseng using the plate coloration method. Furthermore, JE0512 was used for the production of CK from ginseng extracts (GE) in solid-state fermentation (SSF) using 20 g corn bran as substrate, 4 g GE, and 20% inoculation volume, and the results showed that the highest CK content was 29.13 mg/g. After combining S. hirsutum JE0512 with cellulase (Aspergillus niger), the MGs (F2, CK, and PPT) content increased from 1.66 to 130.79 mg/g in the final products. Our results indicate that the Stereum genus has the potential to biotransform GE into CK and the combination of S. hirsutum JE0512 and cellulase could pave the way for the production of MGs from GE.

Qualitatively and quantitatively investigating the metabolism of 20(S)-protopanaxadiol-type ginsenosides by gut microbiota of different species

Ginsenosides Rb1, Rb2, Rb3 and Rc, four major protopanaxadiol (PPD)-type ginsenosides, can be metabolized by gut microbiota. The composition of gut microbiota varies in different species. Existing publications have reported the metabolite fates of ginsenosides by gut microbiota from single species. However, their microbiota-related metabolic species differences have not been evaluated yet. In current study, in vitro anaerobic incubations of PPD-type ginsenosides with gut microbiota from humans, rabbits and rats were conducted. The metabolites of each ginsenoside were then identified by LC-MS. A total of 15 metabolites from the four ginsenosides were identified. The major metabolic pathways were stepwise removals of the C-20 and C-3 sugar moieties to obtain aglycone PPD. The results showed that the hydrolysis rate of C-20 terminal β-D-glucopyranosyl was significantly higher than those of α-L-arabinopyranosyl, β-D-xylopyranosyl and α-L-arabinofuranosyl in different species. The activity of β-glucosidase, the metabolic rates of parent compounds and the formation rates of their metabolites were significantly higher in gut microbiota from rabbits than from humans and rats. Our research draws researchers' attention to the species differences of microbiota-related drug metabolism.

Evolution of the adaptogenic concept from traditional use to medical systems: Pharmacology of stress- and aging-related diseases

Adaptogens comprise a category of herbal medicinal and nutritional products promoting adaptability, resilience, and survival of living organisms in stress. The aim of this review was to summarize the growing knowledge about common adaptogenic plants used in various traditional medical systems (TMS) and conventional medicine and to provide a modern rationale for their use in the treatment of stress-induced and aging-related disorders. Adaptogens have pharmacologically pleiotropic effects on the neuroendocrine-immune system, which explain their traditional use for the treatment of a wide range of conditions. They exhibit a biphasic dose-effect response: at low doses they function as mild stress-mimetics, which activate the adaptive stress-response signaling pathways to cope with severe stress. That is in line with their traditional use for preventing premature aging and to maintain good health and vitality. However, the potential of adaptogens remains poorly explored. Treatment of stress and aging-related diseases require novel approaches. Some combinations of adaptogenic plants provide unique effects due to their synergistic interactions in organisms not obtainable by any ingredient independently. Further progress in this field needs to focus on discovering new combinations of adaptogens based on traditional medical concepts. Robust and rigorous approaches including network pharmacology and systems pharmacology could help in analyzing potential synergistic effects and, more broadly, future uses of adaptogens. In conclusion, the evolution of the adaptogenic concept has led back to basics of TMS and a new level of understanding of holistic approach. It provides a rationale for their use in stress-induced and aging-related diseases.

Chemical components of ginseng, their biotransformation products and their potential as treatment of hypertension

Ginseng is an ancient perennial herb belonging to the family Araliaceae and genus Panax which has been used for medical therapeutics for thousands of years, particularly in China and other Asian cultures although increasing interest in ginseng has recently emerged in western societies. Ginseng is a complex substance containing dozens of bioactive and potentially effective therapeutic compounds. Among the most studied are the ginsenosides, which are triterpene saponins possessing a wide array of potential therapeutic effects for many conditions. The quantity and type of ginsenoside vary greatly depending on ginseng species and their relative quantity in a given ginseng species is greatly affected by extraction processes as well as by subjecting ginseng to various procedures such as heating. Adding to the complexity of ginsenosides is their ability to undergo biotransformation to bioactive metabolites such as compound K by enteric bacteria following ingestion. Many ginsenosides exert vasodilatating effects making them potential candidates for the treatment of hypertension. Their vascular effects are likely dependent on eNOS activation resulting in the increased production of NO. One proposed end-mechanism involves the activation of calcium-activated potassium channels in vascular smooth cells resulting in reduced calcium influx and a vasodilatating effect, although other mechanisms have been proposed as discussed in this review.

How Does Ginsenoside Rh2 Mitigate Adipogenesis in Cultured Cells and Obese Mice?

Ginsenoside Rh2, an intermediate metabolite of ginseng, but not naturally occurring, has recently drawn attention because of its anticancer effect. However, it is not clear if and how Rh2 inhibits preadipocytes differentiation. In the present study, we hypothesized that ginsenoside Rh2 attenuates adipogenesis through regulating the peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway both in cells and obese mice. Different concentrations of Rh2 were applied both in 3T3-L1 cells and human primary preadipocytes to determine if Rh2 inhibits cell differentiation. Dietary Rh2 was administered to obese mice to determine if Rh2 prevents obesity in vivo. The mRNA and protein expression of PPAR-γ pathway molecules in cells and tissues were measured by real-time polymerase chain reaction (RT-PCR) and Western blot, respectively. Our results show that Rh2 dose-dependently (30-60 μM) inhibited cell differentiation in 3T3-L1 cells (44.5% ± 7.8% of control at 60 μM). This inhibitory effect is accompanied by the attenuation of the protein and/or mRNA expression of adipogenic markers including PPAR-γ and CCAAT/enhancer binding protein alpha, fatty acid synthase, fatty acid binding protein 4, and perilipin significantly (p < 0.05). Moreover, Rh2 significantly (p < 0.05) inhibited differentiation in human primary preadipocytes at much lower concentrations (5-15 μM). Furthermore, dietary intake of Rh2 (0.1 g Rh2/kg diet, w/w for eight weeks) significantly (p < 0.05) reduced protein PPAR-γ expression in liver and hepatic glutathione reductase and lowered fasting blood glucose. These results suggest that ginsenoside Rh2 dose-dependently inhibits adipogenesis through down-regulating the PPAR-γ pathway, and Rh2 may be a potential agent in preventing obesity in vivo.

Microbial Conversion of Protopanaxadiol-Type Ginsenosides by the Edible and Medicinal Mushroom Schizophyllum commune: A Green Biotransformation Strategy

Previous studies have shown that many kinds of microorganisms, including bacteria, yeasts, and filamentous fungi, can convert parent ginsenosides into minor ginsenosides. However, most microorganisms used for ginsenoside transformations may not be safe for food consumption and drug development. In this study, 24 edible and medicinal mushrooms were screened by high-performance liquid chromatography analyses for their ability to microbiologically transform protopanaxadiol (PPD)-type ginsenosides. We observed that the degradation of ginsenosides by Schizophyllum commune was inhibited by high concentrations of sugar in the culture medium. However, the inhibition was avoided by maintaining sugar concentration below 15 g L^-1. S. commune showed a strong ability to convert PPD-type ginsenosides (Rb₁, Rc, Rb₂, and Rd) into minor ginsenosides (F₂, C-O, C-Y, C-Mc₁, C-Mc, and C-K). The production and bioconversion rates of minor ginsenosides were significantly higher than those previously reported by food microorganisms. The fermentation process is efficient, nontoxic, eco-friendly, and economical, and the required biotransformation systems are readily available. This is the first report about the biotransformation of major ginsenosides into minor ginsenosides through fermentation by edible and medicinal mushrooms. Our results provide a green biodegradation strategy in transformation of ginsenosides using edible and medicinal mushrooms.

Gut microbial transformation, a potential improving factor in the therapeutic activities of four groups of natural compounds isolated from herbal medicines

Herbal medicines (HMs) have attracted widespread attention because of their significant contributions to the prevention and treatment of many human diseases. Recently, gut microbiota has become an important frontier to understand the therapeutic mechanisms of medicines. Gut microbiota-mediated transformation is a microbial metabolic form after oral administrations of HMs compounds. A great number of studies showed that gut microbiota could transform some HMs compounds by the variation of chemical structures into several active metabolites, which exerted better bioavailabilities and therapeutic activities than their parent compounds. Among these HMs compounds, alkaloids, flavonoids, polyphenols and terpenoids were the representative ones. However, there is no systemic review focusing on the potential improved therapeutic activities of these natural compounds caused by gut microbial transformation. Here, this review summarizes the therapeutic activities that are more potent in microbial transformed metabolites than in their parent compounds (alkaloids, flavonoids, polyphenols and terpenoids) from HMs. We hope this review will be conducive to deepening the understanding of the relationship between gut microbial transformation and therapeutic activities of HMs compounds.

Recent Advances in Biotransformation of Saponins

Saponins are a class of glycosides whose aglycones can be either triterpenes or helical spirostanes. It is commonly recognized that these active ingredients are widely found in various kinds of advanced plants. Rare saponins, a special type of the saponins class, are able to enhance bidirectional immune regulation and memory, and have anti-lipid oxidation, anticancer, and antifatigue capabilities, but they are infrequent in nature. Moreover, the in vivo absorption rate of saponins is exceedingly low, which restricts their functions. Under such circumstances, the biotransformation of these ingredients from normal saponins—which are not be easily adsorbed by human bodies—is preferred nowadays. This process has multiple advantages, including strong specificity, mild conditions, and fewer byproducts. In this paper, the biotransformation of natural saponins—such as ginsenoside, gypenoside, glycyrrhizin, saikosaponin, dioscin, timosaponin, astragaloside and ardipusilloside—through microorganisms (Aspergillus sp., lactic acid bacteria, bacilli, and intestinal microbes) will be reviewed and prospected.

Reductive soil disinfestation effectively alleviates the replant failure of Sanqi ginseng through allelochemical degradation and pathogen suppression

Replant failure has threatened the production of Sanqi ginseng (Panax notoginseng) mainly due to the accumulation of soil-borne pathogens and allelochemicals. Reductive soil disinfestation (RSD) is an effective practice used to eliminate soil-borne pathogens; however, the potential impact of RSD on the degradation of allelochemicals and the growth of replant Sanqi ginseng seedlings remain poorly understood. In this study, RSD was conducted on a Sanqi ginseng monoculture system (SGMS) and a maize-Sanqi ginseng system (MSGS), defined as SGMS_RSD and MSGS_RSD, respectively. The aim was to investigate the impact of RSD on allelochemicals, soil microbiomes, and survival rates of replant seedlings. Both short-term maize planting and RSD treatment significantly degraded the ginsenosides in Sanqi ginseng-cultivated soils, with the degradation rate being higher in the RSD treatment. The population of Fusarium oxysporum and the relative abundance of genus Fusarium were dramatically suppressed by RSD treatment. Furthermore, the RSD treatment, but not maize planting, markedly alleviated the replant failure of Sanqi ginseng, with the seedling survival rate being 52.7-70.7% 6 months after transplanting. Interestingly, RSD followed by short-term maize planting promoted microbial activity restoration, ginsenoside degradation, and ultimately alleviated the replant failure much better than RSD treatment alone (70.7% vs. 52.7%). Collectively, these results indicate that RSD treatment could considerably reduce the obstacles and might also act as a potential agriculture regime for overcoming the replant failure of Sanqi ginseng. Additional practices, such as crop rotation, beneficial microorganism inoculation, etc. may also still be needed to ensure the long-term efficacy of seedling survival.

Herb-drug interaction: A case study of effects and involved mechanisms of cisplatin on the pharmacokinetics of ginsenoside Rb1 in tumor-bearing mice

Ginseng is often prescribed together with cisplatin for treatment of cancer, but the interaction between ginseng and cisplatin is still unknown. This study employed ginsenoside Rb1 (Rb1), one of the major components in ginseng, to explore the effects and involved mechanisms of cisplatin on the pharmacokinetics of ginseng. The effects of cisplatin on the pharmacokinetics of Rb1 and its bioactive metabolites Rd, Rg3, and F2 were investigated by using A549-bearing mice with and without cisplatin intervention. Our data showed that cisplatin could significantly decrease the AUC_(0-t) and C_max of Rd, Rg3, and F2, except Rb1. To evaluate the involved mechanisms, feces and intestinal mucosa were collected to explore the effects of cisplatin on the gut metabolism of Rb1 in vitro; meanwhile, Caco-2 cell model and small intestine histological characters were examined to evaluate the effects of cisplatin on the gut absorptive areas and permeability. The mechanisms involved may be mainly related to the comprehensive contributions of inhibited intestinal bacteria and mucosa metabolisms, narrowed intestinal absorptive area, increased efflux ratio of intestinal absorption and enhanced intestinal permeability. All these findings suggested that the dosage of ginseng traditionally used for health protection should be adjusted when it was prescribed together with cisplatin in the treatment of cancer.

Biopharmaceutical characters and bioavailability improving strategies of ginsenosides

Deglycosylation is the most important gastrointestinal metabolism in which ginsenosides are split off from glycosyl moieties by the enzymes secreted from intestinal microflora, and two possible metabolic pathways of protopanaxdiol-type ginsenosides (PPD-type ginsenosides) and protopanaxtriol-type ginsenosides (PPT-type ginsenosides) have been concluded. The former is deglycosylated at C-3 and/or C-20, and transformed to protopanaxdiol (PPD). By comparison, the latter is deglycosylated at C-6 and/or C-20, and eventually transformed to protopanaxtriol (PPT) instead. The pharmacokinetic behavior of PPD-type ginsenosides and PPT-type ginsenosides is different, mainly in a faster absorption and elimination rate of PPT-type ginsenosides, but almost all of ginsenosides have a low oral bioavailability, which is relevant to the properties, the stability in the gastrointestinal tract, membrane permeability and the intestinal and hepatic first-pass effect of ginsenosides. Fortunately, its bioavailability can be improved by means of pharmaceutical strategies, including nanoparticles, liposomes, emulsions, micelles, etc. These drug delivery systems can significantly increase the bioavailability of ginsenosides, as well as controlling or targeting drug release. Ginsenosides are widely used in the treatment of various diseases, the most famous one is the Shen Yi capsule, which is the world's first clinical application of tumor neovascularization inhibitors. Hence, this article aims to draw people's attention on ocotillol-type ginsenosides, which have prominent anti-Alzheimer's disease activity, but have been overlooked previously, such as its representative compound-Pseudoginsenoside F11(PF11), and then provide a reference for the druggability and further developments of ocotillol-type ginsenosides by utilizing the homogeneous structure between dammarane-type ginsenosides and ocotillol-type ginsenosides.

Pharmacokinetics of Chinese medicines: strategies and perspectives

The modernization and internationalization of Chinese medicines (CMs) are hampered by increasing concerns on the safety and the efficacy. Pharmacokinetic (PK) study is indispensable to establish concentration-activity/toxicity relationship and facilitate target identification and new drug discovery from CMs. To cope with tremendous challenges rooted from chemical complexity of CMs, the classic PK strategies have evolved rapidly from PK study focusing on marker/main drug components to PK-PD correlation study adopting metabolomics approaches to characterize associations between disposition of global drug-related components and host metabolic network shifts. However, the majority of PK studies of CMs have adopted the approaches tailored for western medicines and focused on the systemic exposures of drug-related components, most of which were found to be too low to account for the holistic benefits of CMs. With an area under concentration-time curve- or activity-weighted approach, integral PK attempts to understand the PK-PD relevance with the integrated PK profile of multiple co-existing structural analogs (prototyes/metabolites). Cellular PK-PD complements traditional PK-PD when drug targets localize inside the cells, instead of at the surface of cell membrane or extracellular space. Considering the validated clinical benefits of CMs, reverse pharmacology-based reverse PK strategy was proposed to facilitate target identification and new drug discovery. Recently, gut microbiota have demonstrated multifaceted roles in drug efficacy/toxicity. In traditional oral intake, the presystemic interactions of CMs with gut microbiota seem inevitable, which can contribute to the holistic benefits of CMs through biotransforming CMs components, acting as the peripheral target, and regulating host drug disposition. Hence, we propose a global PK-PD approach which includes the presystemic interaction of CMs with gut microbiota and combines omics with physiologically based pharmacokinetic modeling to offer a comprehensive understanding of the PK-PD relationship of CMs. Moreover, validated clinical benefits of CMs and poor translational potential of animal PK data urge more research efforts in human PK study.

Ginseng polysaccharides enhanced ginsenoside Rb1 and microbial metabolites exposure through enhancing intestinal absorption and affecting gut microbial metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Polysaccharides and small molecules commonly co-exist in decoctions of traditional Chinese medicines (TCMs). Our previous study outlined that ginseng polysaccharides (GP) could interact with co-existing ginsenosides to produce synergistic effect in an over-fatigue and acute cold stress model via gut microbiota involved mechanisms.

AIM OF THE STUDY

This study aimed to verify the interactions by examining the impact of GP on oral pharmacokinetics of ginsenoside Rb1 (Rb1), the dominant protopanoxadiol (PPD)-type ginsenoside in Ginseng, on a dextran sulphate sodium (DSS) induced experimental colitis model which was characterized by gut dysbiosis, and to delineate the underlying mechanisms in vitro.

MATERIALS AND METHODS

Rats received drinking water (normal group), 5% DSS (UC group), or 5% DSS plus daily oral administration of GP (GP group) for 7 days and fecal samples were collected on day -3, 0 and 6. On day 7 all animals received an oral dosage of Rb1 and blood samples were withdrawn for pharmacokinetic study. The in vitro metabolism study of Rb1 in gut microbiota from normal and UC rats and the transport study of Rb1 across Caco-2 cell monolayer were carried out in presence/absence of GP. Rb1 and its bacterial metabolites ginsenoside Rd (Rd), ginsenoside F2 (F2), Compound K (CK) and PPD were determined using LC-MS/MS. Total and target bacteria in fecal samples were determined by using 16S rRNA-based RT-PCR. β-Glucosidase activity was determined by measuring 4-nitrophenol formed from 4-nitrophenyl-β-D-glucopyranoside hydrolysis.

RESULTS

DSS induction did not alter AUC_0-t and C_max of Rb1, which, however, were doubled together with elevated AUC_0-t of the metabolites, in particular Rd and CK, in GP group. GP influenced the microbial composition and showed a prebiotic-like effect. Accordingly, GP treatment could partially restore the β-glucosidase activity which was reduced by DSS induction. The presence of GP resulted in quicker microbial metabolism of Rb1 and higher Rd formation in first 8 h of incubation, while the impact on F2 and CK formation/conversion became obvious after 8 h. More interestingly, GP slightly stimulated Caco-2 cell growth and facilitated Rb1 transport across the Caco-2 monolayer in both directions, increasing the P_app of Rb1 from 10^-7 cm/s to 10^-6 cm/s.

CONCLUSIONS

GP alleviated DSS-induced colitis-like symptoms and enhanced the systemic exposure of Rb1 through enhancing microbial deglycosylation and intestinal epithelial absorption of Rb1. These findings further demonstrated the important role of gut microbiota in the multifaceted action of polysaccharides in the holistic actions of traditional decoction of TCMs.

Metabolic analysis of Panax notoginseng saponins with gut microbiota-mediated biotransformation by HPLC-DAD-Q-TOF-MS/MS

Saponins such as notoginsenosides and ginsenosides from Panax notoginseng are responsible for the herb's clinical applications. Unfortunately, there is poor oral bioavailability of saponins. However, gut microbiota can transform saponins to yield the metabolites that are potential bioactive substances. In this study, we aimed to characterize the metabolic profiles of P. notoginseng saponins (PNS) by incubating them with human gut microbiota. The notoginsenosides, ginsenosides and related metabolites were separated and identified using a highly sensitive and selective high-performance liquid chromatography coupled with diode array detection/quadrupole tandem time-of-flight mass spectrometry (HPLC-DAD-Q-TOF-MS/MS). The results showed that the most abundant metabolites, ginsenoside F₁, protopanaxatriol (PPT), ginsenoside Rh₂, ginsenoside compound K (GCK) and protopanaxadiol (PPD), were reported to possess stronger related pharmacological activities when compared with parent ginsenosides. These metabolites were identified among a total of 45 other metabolites. Furthermore, it was elucidated that deglycosylation is the main metabolic pathway which saponins are split off from glycosyl moieties by the enzymes secreted from gut microbiota. The gut microbiota may play a significant role in mediating the bioactivities of PNS.

Biotransformation of Panax ginseng extract by rat intestinal microflora: identification and quantification of metabolites using liquid chromatography-tandem mass spectrometry

BACKGROUND

In general, after Panax ginseng is administered orally, intestinal microbes play a crucial role in its degradation and metabolization process. Studies on the metabolism of P. ginseng by microflora are important for obtaining a better understanding of their biological effects.

METHODS

In vitro biotransformation of P. ginseng extract by rat intestinal microflora was investigated at 37°C for 24 h, and the simultaneous determination of the metabolites and metabolic profile of P. ginseng saponins by rat intestinal microflora was achieved using LC-MS/MS.

RESULTS

A total of seven ginsenosides were detected in the P. ginseng extract, including ginsenosides Rg1, Re, Rf, Rb1, Rc, Rb2, and Rd. In the transformed P. ginseng samples, considerable amounts of deglycosylated metabolite compound K and Rh1 were detected. In addition, minimal amounts of deglycosylated metabolites (ginsenosides Rg2, F1, F2, Rg3, and protopanaxatriol-type ginsenosides) and untransformed ginsenosides Re, Rg1, and Rd were detected at 24 h. The results indicated that the primary metabolites are compound K and Rh1, and the protopanaxadiol-type ginsenosides were more easily metabolized than protopanaxatriol-type ginsenosides.

CONCLUSION

This is the first report of the identification and quantification of the metabolism and metabolic profile of P. ginseng extract in rat intestinal microflora using LC-MS/MS. The current study provided new insights for studying the metabolism and active metabolites of P. ginseng.

Qualitatively and quantitatively investigating the regulation of intestinal microbiota on the metabolism of panax notoginseng saponins

ETHNOPHARMACOLOGICAL RELEVANCE

Intestinal microflora plays crucial roles in modulating pharmacokinetic characteristics and pharmacological actions of active ingredients in traditional Chinese medicines (TCMs). However, the exact impact of altered intestinal microflora affecting the biotransformation of TCMs remains poorly understood.

AIMS OF THE STUDY

This study aimed to reveal the specific enterobacteria which dominate the metabolism of panax notoginseng saponins (PNSs) via exploring the relationship between bacterial community structures and the metabolic profiles of PNSs.

MATERIALS AND METHODS

2, 4, 6-Trinitrobenzenesulphonic acid (TNBS)-challenged and pseudo germ-free (pseudo GF) rats, which prepared by treating TNBS and antibiotic cocktail, respectively, were employed to investigate the influence of intestinal microflora on the PNS metabolic profiles. Firstly, the bacterial community structures of the conventional, TNBS-challenged and pseudo GF rat intestinal microflora were compared via 16S rDNA amplicon sequencing technique. Then, the biotransformation of protopanaxadiol-type PNSs (ginsenoside Rb1, Rb2 and Rd), protopanaxatriol-type PNSs (ginsenoside Re, Rf, Rg1 and notoginsenoside R1) and Panax notoginseng extract (PNE) in conventional, TNBS-challenged and pseudo GF rat intestinal microbiota was systematically studied from qualitative and quantitative angles based on LC-triple-TOF/MS system. Besides, glycosidases (β-glucosidase and β-xylosidase), predominant enzymes responsible for the deglycosylation of PNSs, were measured by the glycosidases assay kits.

RESULTS

Significant differences in the bacterial community structure on phylum, class, order, family, and genera levels were observed among the conventional, TNBS-challenged and pseudo GF rats. Most of the metabolites in TNBS-challenged rat intestinal microflora were identified as the deglycosylation products, and had slightly lower exposure levels than those in the conventional rats. In the pseudo GF group, the peak area of metabolites formed by loss of glucose, xylose and rhamnose was significantly lower than that in the conventional group. Importantly, the exposure levels of the deglycosylated metabolites were found have a high correlation with the alteration of glycosidase activities and proteobacteria population. Several other metabolites, which formed by oxidation, dehydrogenation, demethylation, etc, had higher relative exposure in pseudo GF group, which implicated that the up-regulation of Bacteroidetes could enhance the activities of some redox enzymes in intestinal microbiota.

CONCLUSION

The metabolism of PNSs was greatly influenced by intestinal microflora. Proteobacteria may affect the deglycosylated metabolism of PNSs via regulating the activities of glycosidases. Besides, up-regulation of Bacteroidetes was likely to promote the redox metabolism of PNSs via improving the activities of redox metabolic enzymes in intestinal microflora.

Evaluation of ginsenoside bioconversion of lactic acid bacteria isolated from kimchi

Background

Panax ginseng is a physiologically active plant widely used in traditional medicine that is characterized by the presence of ginsenosides. Rb1, a major ginsenoside, is used as the starting material for producing ginsenoside derivatives with enhanced pharmaceutical potentials through chemical, enzymatic, or microbial transformation.

Methods

To investigate the bioconversion of ginsenoside Rb1, we prepared kimchi originated bacterial strains Leuconostoc mensenteroides WiKim19, Pediococcus pentosaceus WiKim20, Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49 and analyzed bioconversion products using LC-MS/MS mass spectrometer.

Results

L. mesenteroides WiKim19 and Pediococcus pentosaceus WiKim20 converted ginsenoside Rb1 into the ginsenoside Rg3 approximately five times more than Lactobacillus brevis WiKim47, Leuconostoc lactis WiKim48, and Lactobacillus sakei WiKim49. L mesenteroides WIKim19 showed positive correlation with β-glucosidase activity and higher transformation ability of ginsenoside Rb1 into Rg3 than the other strains whereas, P. pentosaceus WiKim20 showed an elevated production of Rb3 even with lack of β-glucosidase activity but have the highest acidity among the five lactic acid bacteria (LAB).

Conclusion

Ginsenoside Rg5 concentration of five LABs have ranged from ∼2.6 μg/mL to 6.5 μg/mL and increased in accordance with the incubation periods. Our results indicate that the enzymatic activity along with acidic condition contribute to the production of minor ginsenoside from lactic acid bacteria.

Screening of Intestinal Bacterial Metabolites of Platycodin D Using Ultra-Performance Liquid Chromatography/Quadrupole Time-of-Flight Mass Spectrometry

Platycodin D (PD), a bioactive triterpenoid saponin isolated from Platycodi Radix (PR), possesses a vast range of biological activities. Although the pharmacological activities and pharmacokinetics of PD have been well demonstrated, information regarding the intestinal metabolisms of PD is very limited. In this study, human and rat fecal microflora were prepared and anaerobically incubated with PD at 37[Formula: see text]C for 48[Formula: see text]h, respectively. A highly sensitive and specific ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) was developed for the analysis of PD and related metabolites in the reaction samples. A Liquid-liquid extraction method was used for sample pretreatment and the chromatographic separation was performed on a 1.7 [Formula: see text]m particle size Syncronis C[Formula: see text] column using gradient elution system. Finally, a total of seven metabolites were detected and tentatively identified, such as the demethylation metabolite (M1), deoxidation metabolites (M3, M7) and hydrolysis at the C-28 oligosaccharide metabolites (M5, M6), which were first discovered in this experiment. The results indicate that hydrolysis, demethylation, dehydroxylation, and acetylation were the major metabolic pathways of PDin vitro. Additionally, four bacterial strains from human feces including Enterococcus sp.41, Bacillus sp.46, Escherichia sp.49 A and Escherichia sp.64 were detected and further identified with 16S rRNA gene sequencing due to their relatively strong metabolic capacity toward PD. The present study provides important information about the metabolism of PD, which will help elucidate the impact of intestinal bacteria on this active component.

Cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry for screening bioactive capilliposide C metabolites generated by rat intestinal microflora

Many plant-derived glycosides are used as medications. It is common that these glycosides show poor intestinal absorption but their metabolites generated by intestinal microflora demonstrate strong bioactivity. Hence, it is crucial to develop a method for the identification and characterization of the metabolites, and consequently reveal the pathway in which the glycosides are processed in gut. In this study, cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) were developed for rapid discovery and evaluation of the metabolites of a glycoside compound, capilliposide C (LC-C). 92.7% of LC-C was biotransformed by rat intestinal microflora after 36-h incubation at 37°C. Human cancer cell lines HepG2, PC-3 and A549 was treated with metabolites pool, respectively, which was followed by cell viability assays and characterization of metabolites using UHPLC-QTOF-MS/MS. As a result, significant cytotoxicity was observed for the metabolites pool, from which six metabolites were identified. Based on the metabolites identified, deglycosylation and esterolysis were proposed as the major metabolic pathways of LC-C in rat intestinal microflora. In addition, M4, an esterolysis product of LC-C, was obtained and evaluated for its bioactivity in vitro. As a result, M4 exhibited a reduction in cell viability in HepG2 with an IC50 value of 17.46±1.55μg/mL.

Intestinal, portal, and peripheral profiles of daikenchuto (TU-100)'s active ingredients after oral administration

A pharmaceutical grade Japanese traditional medicine, daikenchuto (TU-100), consisting of Japanese pepper, processed ginger, and ginseng, has been widely used for various intestinal disorders in Japan and now under development as a new therapeutic drug in the US. It is suggested that TU-100 ingredients exert pharmacological effects on intestines via two routes, from the luminal side before absorption and the peripheral blood stream after absorption. Therefore, in order to fully understand the pharmacological actions of TU-100, it is critically important to know the intraluminal amounts and forms of ingested TU-100 ingredients. In the present study, after administrating TU-100 to rats, the concentrations of TU-100 ingredients and their conjugates in the peripheral and portal blood and ileal contents were determined by LC-MS/MS. Next, TU-100 was administered to patients with ileostomy bags, but whose small intestines are diagnosed as healthy, and the ingredients/conjugates in the ileal effluent were analyzed. The results suggest that: (1) Pepper ingredients hydroxysanshools are rapidly absorbed and enter systemic circulation, (2) Ginseng ingredients ginsenosides are transported to the colon with the least absorption, (3) Ginger ingredients gingerols are absorbed and some conjugated in the small intestine and transported via the portal vein. While only a small amount of gingerols/gingerol conjugates enter systemic circulation, considerable amounts reappear in the small intestine. Thus, the effect of TU-100 on the intestines is believed to be a composite of multiple actions by multiple compounds supplied via multiple routes.

Classification of glycosidases that hydrolyze the specific positions and types of sugar moieties in ginsenosides

Ginsenosides are the main compounds with pharmacological activities in ginseng. Deglycosylated ginsenosides, which are more pharmacologically active than glycosylated ginsenosides, can be produced by the specific or nonspecific hydrolysis of the sugar moieties in glycosylated ginsenosides using glycosidases. The enzymes that hydrolyze specifically ginsenosides with different types can be classified according to the enzymatic activity on the positions, inner and outer residues and types of sugar moieties in ginsenosides. Glycosylated ginsenosides are also hydrolyzed to deglycosylated ginsenosides with different hydrolytic pathways by cell conversion or fermentation. The biochemical properties of glycosidases involved in ginsenoside hydrolysis - ginsenosidases - were newly arranged and reviewed in accordance with different types. The combination of different-type ginsenosidases is suggested herein as an efficient tool to produce industrially important ginsenosides.

In Silico and In Vitro Analysis of Bacoside A Aglycones and Its Derivatives as the Constituents Responsible for the Cognitive Effects of Bacopa monnieri

Bacopa monnieri has been used in Ayurvedic medicine to improve memory and cognition. The active constituent responsible for its pharmacological effects is bacoside A, a mixture of dammarane-type triterpenoid saponins containing sugar chains linked to a steroid aglycone skeleton. Triterpenoid saponins have been reported to be transformed in vivo to metabolites that give better biological activity and pharmacokinetic characteristics. Thus, the activities of the parent compounds (bacosides), aglycones (jujubogenin and pseudojujubogenin) and their derivatives (ebelin lactone and bacogenin A1) were compared using a combination of in silico and in vitro screening methods. The compounds were docked into 5-HT1A, 5-HT2A, D1, D2, M1 receptors and acetylcholinesterase (AChE) using AutoDock and their central nervous system (CNS) drug-like properties were determined using Discovery Studio molecular properties and ADMET descriptors. The compounds were screened in vitro using radioligand receptor binding and AChE inhibition assays. In silico studies showed that the parent bacosides were not able to dock into the chosen CNS targets and had poor molecular properties as a CNS drug. In contrast, the aglycones and their derivatives showed better binding affinity and good CNS drug-like properties, were well absorbed through the intestines and had good blood brain barrier (BBB) penetration. Among the compounds tested in vitro, ebelin lactone showed binding affinity towards M1 (Ki = 0.45 μM) and 5-HT2A (4.21 μM) receptors. Bacoside A and bacopaside X (9.06 μM) showed binding affinity towards the D1 receptor. None of the compounds showed any inhibitory activity against AChE. Since the stimulation of M1 and 5-HT2A receptors has been implicated in memory and cognition and ebelin lactone was shown to have the strongest binding energy, highest BBB penetration and binding affinity towards M1 and 5-HT2A receptors, we suggest that B. monnieri constituents may be transformed in vivo to the active form before exerting their pharmacological activity.

Identification of the metabolites of myricitrin produced by human intestinal bacteria in vitro using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

OBJECTIVE

To investigate the metabolic routes and metabolites of myricitrin, an important active ingredient of traditional herbal medicine, yielded by the isolated human intestinal bacteria, which have not been reported previously.

METHODS

Fresh human fecal samples were collected from a healthy female volunteer and about 100 different bacterial colonies were isolated. Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry technique combined with Metabolynx™ software was used for analysis of the metabolic profile of myricitrin by the isolated human intestinal bacteria.

RESULTS

One hundred different bacterial colonies, which developed on plates, were picked up, and four of them were further identified by using the technique of 16S rRNA gene sequencing due to their relatively strong metabolic capacity toward myricitrin. Most of them belong to Escherichia. Parent compound and three metabolites (quercetin-3-O-rhamnoside, myricetin and quercetin) were detected in the isolated bacterial samples compared with blank samples. The metabolic pathways of myricitrin included deglycosylation and dehydroxylation.

CONCLUSIONS

These metabolites suggested that myricitrin was first dehydroxylated to quercetin-3-O-rhamnoside and subsequently deglycosylated to quercetin. Additionally, myricitrin could also be deglycosylated to the aglycon myricetin. Moreover, those metabolites might influence the biological effect of myricitrin in vivo, which led to affect the clinical effects of the medicinal plants and traditional herb medicines.