Metabolism of kalopanaxsaponin B and H by human intestinal bacteria and antidiabetic activity of their metabolites

A Comprehensive Review on Biotransformation, Interaction, and Health of Gut Microbiota and Bioactive Components

BACKGROUND

The relationship between gut microbiota and bioactive components has become the research focus in the world. We attempted to clarify the relationship between biotransformation and metabolites of gut microbiota and bioactive components, and explore the metabolic pathway and mechanism of bioactive ingredients in vivo, which will provide an important theoretical basis for the clinical research of bioactive ingredients and rationality of drugs, and also provide an important reference for the development of new drugs with high bioavailability.

METHODS

The related references of this review on microbiota and bioactive components were collected from both online and offline databases, such as ScienceDirect, PubMed, Elsevier, Willy, SciFinder, Google Scholar, Web of Science, Baidu Scholar, SciHub, Scopus, and CNKI.

RESULTS

This review summarized the biotransformation of bioactive components under the action of gut microbiota, including flavonoids, terpenoids, phenylpropanoids, alkaloids, steroids, and other compounds. The interaction of bioactive components and gut microbiota is a key link for drug efficacy. Relevant research is crucial to clarify bioactive components and their mechanisms, which involve the complex interaction among bioactive components, gut microbiota, and intestinal epithelial cells. This review also summarized the individualized, precise, and targeted intervention of gut microbiota in the field of intestinal microorganisms from the aspects of dietary fiber, microecological agents, fecal microbiota transplantation, and postbiotics. It will provide an important reference for intestinal microecology in the field of nutrition and health for people.

CONCLUSION

To sum up, the importance of human gut microbiota in the research of bioactive components metabolism and transformation has attracted the attention of scholars all over the world. It is believed that with the deepening of research, human gut microbiota will be more widely used in the pharmacodynamic basis, drug toxicity relationship, new drug discovery, drug absorption mechanism, and drug transport mechanism in the future.

A mini-review: mechanism of antimicrobial action and application of surfactin

Surfactin, an antibacterial lipopeptide produced by different strains of Bacillus subtilis, is a powerful biosurfactant. It also has multiple biological activities including antiviral, anti-mycoplasma and antiprotozoal activities, in addition to the broad-spectrum antimicrobial activities against Gram-positive bacteria, Gram-negative bacteria and fungi. Surfactin may be one of the promising alternatives to antibiotics. Surfactin's chemical structure and physicochemical properties are briefly discussed in this mini-review. Surfactin's antibacterial mechanism is mainly outlined as follows: (1) attacking pathogenic bacteria's cell membrane, causing cell membrane disintegration or osmotic pressure imbalance; (2) inhibiting pathogenic bacteria's protein synthesis, preventing cell reproduction; (3) inhibiting pathogenic bacteria's enzyme activity, affecting normal cell metabolism. This provides basis for the further research and application of surfactin. Finally, the application of surfactin in food and its prospect are summarized in brief.

Kalopanaxsaponin A induces reactive oxygen species mediated mitochondrial dysfunction and cell membrane destruction in Candida albicans

Candidiasis causes high morbidity and mortality among immunocompromised patients. Antifungal drug resistance and cytotoxicity highlight the need of effective antifungal therapeutics. In this study, we found that kalopanaxsaponin A (KPA), a triterpenoid saponin natural product, could inhibit the proliferation of various Candida species, and exerted a fungicidal effect against C. albicans. To further explore its antifungal action mode, spectrofluorophotometer, fluorescence microscopy and transmission electron microscopy were performed, showing that KPA treatment induced the accumulation of intracellular reactive oxygen species (ROS), resulting in mitochondrial dysfunction. Meanwhile, KPA treatment also broke down the membrane barrier of C. albicans causing the leakage of intracellular trehalose, the entrance of extracellular impermeable substance and the decrease of ergosterol content. Both ROS accumulation and membrane destruction contributed to the death of C. albicans cells. Our work preliminarily elucidated the potential mechanisms of KPA against C. albicans on a cellular level, and might provide a potential option for the treatment of clinical candidiasis.

Study protocol for daiobotanpito combined with antibiotic therapy for treatment of acute diverticulitis: a study protocol for a randomized controlled trial

BACKGROUND

Colonic diverticular disease has been increasing in prevalence due to the rapidly aging global population, but standard treatment has not changed dramatically in recent years. Daiobotanpito (DBT; Da Huang Mu Dan Tang in Chinese) has been used in medical treatment of acute abdominal abscesses, such as appendicitis or diverticulitis in traditional Japanese (Kampo) medicine for many years, based on more than 3000 years of experience. Prior to this study, a retrospective open-label trial was conducted to compare patients with acute diverticulitis who received oral DBT combined with intravenous antibiotics with those who received intravenous antibiotic alone; it showed a positive effect of DBT on acute diverticulitis. We aim to investigate whether moderate to severe acute diverticulitis shows greater improvement with intravenous antibiotics plus orally administered DBT compared with intravenous antibiotics plus placebo.

METHODS

This is a two-group, randomized, double-blind, placebo-controlled, multi-center trial, which is designed to evaluate the efficacy and safety of DBT in patients with moderate to severe diverticulitis treated with intravenous antibiotics. Eligible participants will be randomized to either a treatment group receiving a 10-day oral DBT regimen plus conventional therapy or a control group receiving a 10-day placebo regimen plus conventional therapy. The primary outcome will be success in treating diverticulitis: the success rate will be defined as elimination of abdominal pain within 4 days in all patients, and in patients with fever (body temperature ≧ 37.5 °C) on inclusion into this study, fever relief with reduction in body temperature to < 37.5 °C within 3 days. Secondary endpoints will include the number of hospitalization days, changes in inflammatory response (C-reactive protein (CRP), white blood cell (WBC) and neutrophil counts), fever type, number of days before beginning food intake, recurrence rate (observation for 1 year after registration), and adverse event expression rate. Assessments will be performed at baseline and on the day of discharge. The recurrence rate will be recorded at 1 year after registration.

DISCUSSION

This study is expected to provide evidence to support the clinical benefits of DBT in the treatment of acute diverticulitis. It may also provide evidence on the efficacy and safety of DBT in the recurrence of acute diverticulitis.

TRIAL REGISTRATION

UMIN-CTR: UMIN000027381. Registered on 27 April 2017. https://upload.umin.ac.jp/cgi-bin/ctr/ctr_view_reg.cgi?recptno=R000031377, and changed to jRCTs041180063, registered on 30 July 2019; as a result of the revision of the domestic law in 2018 in Japan.

Anticandidal Activity of Kalopanaxsaponin A: Effect on Proliferation, Cell Morphology, and Key Virulence Attributes of Candida albicans

Background

The pathogenicity of Candida albicans is attributed to various virulence factors including adhesion to the surface of epithelial cells or mucosa, germ tube formation, hyphal morphogenesis, development of drug resistant biofilms, and so on. The objective of this study was to investigate the effects of Kalopanaxsaponin A (KPA) on the virulence of C. albicans.

Methods

The effect of KPA on the virulence of C. albicans was characterized by an XTT reduction assay and fluorescent microscopic observation. The action mechanism was further explored using GC/MS system and BioTek Synergy2 spectrofluorophotometry. The cytotoxicity and therapeutic effect of KPA were evaluated by the Caenorhabditis elegans-C. albicans infection model in vivo.

Results

The minimum inhibitory concentration (MIC) of KPA was 8∼16 μg/mL for various genotypes of C. albicans. The compound was identified as having remarkable effect on the adhesion, morphological transition and biofilm formation of C. albicans. The results of fluorescent microscopy and GC/MS system suggested that KPA could promote the secretion of farnesol by regulating the expression of Dpp3 and decrease the intracellular cAMP level, which together inhibited morphological transition and biofilm formation. Notably, KPA showed low toxicity in vivo and a low possibility of developing resistance.

Conclusion

Our results demonstrated that KPA had remarkable efficacy against C. albicans pathogenicity, suggesting that it could be a potential option for the clinical treatment of candidiasis.

Current knowledge and development of hederagenin as a promising medicinal agent: a comprehensive review

Hederagenin (HG) is a pentacyclic triterpenoid that exists in many plants in the form(s) of sapogenin or saponins. This review highlights the pharmacokinetics, pharmacological activities, mechanisms of action, and safety of HG using literature and patents from the last 50 years to collate information on this compound as a promising medicinal agent. This review also looks at the development of related derivatives of HG with increased efficacy and lower toxicity. HG is quickly absorbed in the gastrointestinal tract with a short elimination half-life, and can cross the blood-brain barrier and rapidly distribute into cerebrospinal fluid. HG has been shown to possess a wide range of pharmacological activities, including anti-tumor, anti-inflammatory, anti-depressant, anti-neurodegenerative, anti-hyperlipidemia, anti-diabetic, anti-leishmanial, and anti-viral activity. In particular, the extensive anti-tumor activity indicates that HG has the potential to be a highly effective chemotherapy agent. Recently, in the search for more active compounds as potential pharmaceuticals, structural modification of the triterpene scaffold of HG at the C-3, C-12, C-13, C-23, and C-28 positions, has resulted in compounds that exhibited greater potency than HG itself. However, the low bioavailability and moderate hemolysis effect of HG may limit its clinical application. The cause of the observed toxic effects in some animals, including dogs, cats, cattle, goats, and horses also needs to be explained. Future studies of HG focusing on extending the half-life, improving bioavailability, enhancing pharmacological activity, as well as decreasing or avoiding hemolysis by structural modification or formulation design could potentially accelerate HG from the preclinical to clinical research phase.

Comparative metabolites in plasma and urine of normal and type 2 diabetic rats after oral administration of the traditional Chinese scutellaria-coptis herb couple by ultra performance liquid chromatography-tandem mass spectrometry

Scutellaria-coptis herb couple is widely used traditional Chinese medicine (TCM) in treating type 2 diabetes; however, the in vivo integrated metabolism of its main bioactive components in type 2 diabetic rats remains unknown. In this paper, ultra-performance liquid chromatography (UPLC) coupled to quadrupole time-of-flight (Q-TOF) and the MetaboLynx™ software combined with mass defect filtering (MDF) together provided unique high throughput capabilities for drug metabolism study with excellent MS mass accuracy and enhanced MS(E) data acquisition. This rapid automated analysis method was successfully applied for screening and identification of the absorbed and metabolized constituents after oral administration of scutellaria-coptis extract to rats. The results showed that a total of 14 metabolites of two parent compounds were detected and tentatively identified in vivo based on the characteristics of their protonated ions. Main parent components of scutellaria-coptis extract such as baicalin and berberine were absorbed into the blood circulation of the rats. Differences of metabolite classes were not observed between normal and type 2 diabetic rat plasma and urine samples. However, the concentrations of baicalin and methylated berberine in type 2 diabetic rat plasma were much higher than those in normal sample. While, the concentrations of these two compounds in type 2 diabetic rat urine were remarkably lower than those in normal sample. This helped maintain a high blood drug concentration which might be beneficial for the treatment of type 2 diabetes. Additionally, the developed method was simple and reliable, revealing that it could be used to rapid screen and propose the structures of active components responsible for pharmacological effects of scutellaria-coptis and to better clarify its action mechanism. This work suggests that the integrative metabolism approach makes a useful template for drug metabolism research of TCMs.

Application of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry to determine the metabolites of orientin produced by human intestinal bacteria

An ultra performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) with MetaboLynx™ software combined with mass defect filtering (MDF) method were provided for orientin metabolism study. The chromatographic separation was performed on a 1.7μm particle size Syncronis C18 column using gradient elution system. The components were identified and confirmed according to the mass spectrometric fragmentation mechanisms, MS/MS fragment ions and relevant literature by means of electrospray ionization mass spectrometry in negative ion mode. With this method, a total of three metabolites were identified based on retention time and MS/MS data. The results illustrated that deglycosylation, dehydroxylation and acetylation were the major metabolic pathways of orientin in vitro by human intestinal bacteria. Additionally, colonic bacteria were screened for bacteria involved in the conversion of orientin. A gram-negative anaerobic bacterium, strain 45, was newly isolated from healthy human feces. This strain, which was able to cleave the C-glycoside of orientin to produce luteolin and generate some other metabolites, had the similarity of 95.44% with Enterococcus casseliflavus and was named Enterococcus sp. 45 based on 16S rRNA sequence analysis. In this paper, the metabolic routes, metabolites of oreintin produced by the intestinal bacteria and the Enterococcus sp. 45 were investigated for the first time.

Effectiveness of traditional Japanese herbal (kampo) medicine, daiobotanpito, in combination with antibiotic therapy in the treatment of acute diverticulitis: a preliminary study

In traditional Japanese herbal (Kampo) medicine, daiobotanpito (DBT) or Da Huang Mu Dan Tang in Chinese has been used in medical treatment of acute diverticulitis for many years based on the experience. Our aim was to investigate whether the treatment of acute diverticulitis can be treated with intravenous antibiotics plus orally administrated DBT than intravenous antibiotics alone. A retrospective nonrandomized open-label trial was established to compare patients with acute diverticulitis who received oral DBT associated with intravenous antibiotics with those who received intravenous antibiotic alone. We included 34 patients, eleven patients in group 1 with DBT and 23 patients in group 2 without DBT. Both groups were comparable in patient demographics and clinical characteristics. There was a significantly better outcome in the group treated with DBT than in the group without DBT when comparing duration of fever, abdominal pain, and antibiotics administration. A trend toward a day shorter mean hospital stay and fasting was seen in group 1, although this did not reach statistical significance. In conclusion, most patients with acute diverticulitis can be managed safely with oral DBT. Although randomized, double-blind study must be done, we could show the possibility to use daiobotanpito as an additional option in treating acute diverticulitis.

An in vitro metabolic system of gut flora and the metabolism of ginsenoside Rg3 and cholic acid

For orally administered drugs, the metabolism of a drug by the gut flora plays an important role in the bioavailability, activation and disposition of the drug in vivo. However, no in vitro system is currently available to evaluate the metabolism of a drug by the gut flora before the drug is absorbed into the body. This paper presents an in vitro metabolic system in an anaerobic environment that could be used to evaluate the metabolism of an endogenous compound, cholic acid, and a xenobiotic compound, ginsenoside Rg3. We showed that the proliferation of the anaerobic bacteria of the gut content of hamsters produced a similar composition of gut flora in a culture medium for yeast to that in vivo. Incubation of ginsenoside Rg3 and cholic acid in the anaerobic in vitro system efficiently produced the metabolites Rh2 and deoxycholic acid, respectively, similar to those seen in the gut content in vivo. In comparison with in vivo analysis, this anaerobic in vitro metabolic system is convenient, reproducible, economic and animal saving, and can easily be applied to assess the transformation and disposition of a drug before it enters into the circulatory system.

Microbial diversity analysis of fermented mung beans (Lu-Doh-Huang) by using pyrosequencing and culture methods

In Taiwanese alternative medicine Lu-doh-huang (also called Pracparatum mungo), mung beans are mixed with various herbal medicines and undergo a 4-stage process of anaerobic fermentation. Here we used high-throughput sequencing of the 16S rRNA gene to profile the bacterial community structure of Lu-doh-huang samples. Pyrosequencing of samples obtained at 7 points during fermentation revealed 9 phyla, 264 genera, and 586 species of bacteria. While mung beans were inside bamboo sections (stages 1 and 2 of the fermentation process), family Lactobacillaceae and genus Lactobacillus emerged in highest abundance; Lactobacillus plantarum was broadly distributed among these samples. During stage 3, the bacterial distribution shifted to family Porphyromonadaceae, and Butyricimonas virosa became the predominant microbial component. Thereafter, bacterial counts decreased dramatically, and organisms were too few to be detected during stage 4. In addition, the microbial compositions of the liquids used for soaking bamboo sections were dramatically different: Exiguobacterium mexicanum predominated in the fermented soybean solution whereas B. virosa was predominant in running spring water. Furthermore, our results from pyrosequencing paralleled those we obtained by using the traditional culture method, which targets lactic acid bacteria. In conclusion, the microbial communities during Lu-doh-huang fermentation were markedly diverse, and pyrosequencing revealed a complete picture of the microbial consortium.

Cloud-point extraction combined with liquid chromatography for the determination of ergosterol, a natural product with diuretic activity, in rat plasma, urine, and faeces

Ergosterol from many medicinal fungi has been demonstrated to possess a variety of pharmacological activities in vivo and in vitro. A new method based on cloud-point extraction has been developed, optimized and validated for the determination of ergosterol in rat plasma, urine and faeces by liquid chromatography. The non-ionic surfactant Triton X-114 was chosen as the extract solvent. The chromatographic separation was performed on an Inertsil ODS-3 analytical column with a mobile phase consisting of methanol and water (98 : 2, v/v) at a flow rate of 1 mL/min. The methodology was validated completely. The results indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. The method was successfully applied to the pharmacokinetic studies of ergosterol in rats. The results indicate that the ergosterol levels in feces are much higher than those in plasma and urine of the rat.

Novel PI3K/Akt inhibitors screened by the cytoprotective function of human immunodeficiency virus type 1 Tat

The PI3K/Akt pathway regulates various stress-related cellular responses such as cell survival, cell proliferation, metabolism and protein synthesis. Many cancer cell types display the activation of this pathway, and compounds inhibiting this cell survival pathway have been extensively evaluated as anti-cancer agents. In addition to cancers, several human viruses, such as HTLV, HPV, HCV and HIV-1, also modulate this pathway, presumably in order to extend the life span of the infected target cells for productive viral replication. The expression of HIV-1 Tat protein exhibited the cytoprotective effect in macrophages and a human microglial cell line by inhibiting the negative regulator of this pathway, PTEN. This cytoprotective effect of HIV-1 appears to contribute to the long-term survival and persistent HIV-1 production in human macrophage reservoirs. In this study we exploited the PI3K/Akt dependent cytoprotective effect of Tat-expressing CHME5 cells. We screened a collection of compounds known to modulate inflammation, and identified three novel compounds: Lancemaside A, Compound K and Arctigenin that abolished the cytoprotective phenotype of Tat-expressing CHME5 cells. All three compounds antagonized the kinase activity of Akt. Further detailed signaling studies revealed that each of these three compounds targeted different steps of the PI3K/Akt pathway. Arctigenin regulates the upstream PI3K enzyme from converting PIP2 to PIP3. Lancemaside A1 inhibited the movement of Akt to the plasma membrane, a critical step for Akt activation. Compound K inhibited Akt phosphorylation. This study supports that Tat-expressing CHME5 cells are an effective model system for screening novel PI3K/Akt inhibitors.

Inhibitory effects of glycitein on hydrogen peroxide induced cell damage by scavenging reactive oxygen species and inhibiting c-Jun N-terminal kinase

The present study investigated the cytoprotective properties of glycitein, a metabolite formed by the transformation of glycitin by intestinal microflora, against oxidative stress. Glycitein was found to scavenge intracellular reactive oxygen species (ROS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and thereby preventing lipid peroxidation and DNA damage. Glycitein inhibited apoptosis of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H(2)O(2)) via radical scavenging activity. Glycitein abrogated the activation of c-Jun N-terminal kinase (JNK) induced by H(2)O(2) treatment and inhibited DNA binding activity of activator protein-1 (AP-1), a downstream transcription factor of JNK. Taken together, these findings suggest that glycitein protected H(2)O(2) induced cell death in V79-4 cells by inhibiting ROS generation and JNK activation.

11beta-Hydroxysteroid dehydrogenase type 1 inhibitors with oleanan and ursan scaffolds

The enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts cortisone to the active glucocorticoid cortisol, thereby acting as a cellular switch to mediate glucocorticoid action in many tissues. Several studies have indicated that 11beta-HSD1 plays a crucial role in the onset of type 2 diabetes and central obesity. As a consequence, selective inhibition of 11beta-HSD1 in humans might become a new and promising approach for lowering blood glucose concentrations and for counteracting the accumulation of visceral fat and its related metabolic abnormalities in type 2 diabetes. In this study, we present the synthesis and the biological evaluation of ursan or oleanan type triterpenoids which may act as selective 11beta-HSD1 inhibitors in liver as well as in peripheral tissues, like adipocytes and muscle cells. In order to rationalise the outcomes of the inhibition data, docking simulations of the ligands were performed on the experimentally determined structure of 11beta-HSD1. Furthermore, we discuss the structural determinants that confer enzymatic specificity. From our investigation, valuable information has been obtained to design selective 11beta-HSD1 blockers based on the oleanan and ursan scaffold.

Rhapontigenin from Rheum undulatum protects against oxidative-stress-induced cell damage through antioxidant activity

The antioxidant properties of rhapontigenin and rhaponticin isolated from Rheum undulatum were investigated. Rhapontigenin was found to scavenge intracellular reactive oxygen species (ROS), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and hydrogen peroxide (H2O2). The radical scavenging effect of rhapontigenin was more effective than rhaponticin. Rhapontigenin protected against H2O2-induced membrane lipid peroxidation and cellular DNA damage, which are the main targets of oxidative stress-induced cellular damage. The radical scavenging activity of rhapontigenin protected Chinese hamster lung fibroblast (V79-4) cells exposed to H2O2 by inhibiting apoptosis. Rhapontigenin inhibited cell damage induced by serum starvation and was also found to increase the activity of catalase and its protein expression. Further, rhapontigenin increased phosphorylation of extracellular signal-regulated kinase (ERK) and inhibited the activity of activator protein 1 (AP-1), a redox-sensitive transcription factor. In summary, these results suggest that rhapontigenin protects V79-4 cells against oxidative damage by enhancing the cellular antioxidant activity and modulating cellular signal pathways.

Cytoprotective effect of tectorigenin, a metabolite formed by transformation of tectoridin by intestinal microflora, on oxidative stress induced by hydrogen peroxide

In the present study, the antioxidative properties of tectorigenin, a metabolite formed by transformation of tectoridin by intestinal microflora, were investigated. Tectorigenin was found to scavenge intracellular reactive oxygen species, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, and thus prevented lipid peroxidation. The radical scavenging activity of tectorigenin protected the viability of Chinese hamster lung fibroblast (V79-4) cells exposed to hydrogen peroxide (H2O2) via activation of extracellular signal regulated kinase (ERK) pathway. Furthermore, tectorigenin reduced the apoptotic cells formation and cell cycle arrest at G2/M phase induced by H2O2. Tectorigenin increased the activities of cellular antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase, and also increased their protein level. Taken together, these findings suggest that tectorigenin protected V79-4 cells against H2O2 damage, by enhancing the antioxidative activity and by activating ERK pathway.

19Alpha-hydroxyursane-type triterpenoids: antinociceptive anti-inflammatory principles of the roots of Rosa rugosa

To search for antiinflammtory 19alpha-hydroxyursane-type triterpenoids, the MeOH extract of the roots of Rosa rugosa (Rosaceae) was fractionated. The active fraction of the EtOAc extract was hydrolyzed in alkaline solution to give a hydrolyzed fraction. Both extracts showed antiinflammatory/antinociceptive action in acetic acid-induced writhing and hot plate testing and in a carrageenan-induced paw edema model in mice and rats. Repeated chromatography of the EtOAc extract on both silica gel and octadecylsilane columns led to the isolation of kaji-ichigoside F1 (1, euscaphic acid 28-O-glucoside) and rosamultin (2, tormentic acid 28-O-glucoside). The hydrolyzed fraction was also subjected to silica gel column and octadecylsilane column chromatography to produce euscaphic acid (3) and tormentic acid (4). The potencies were observed in the following order: 4>3>2>1. These results suggest that 19alpha-hydroxyursane-type triterpenoids are responsible for the antiinflammatory/antinociceptive action of R. rugosa roots.

Antiinflammatory effects of chiisanoside and chiisanogenin obtained from the leaves of Acanthopanax chiisanensis in the carrageenan- and Freund's complete adjuvant-induced rats

To find the antiinflammtory constituents of Acanthopanax chiisanensis (Araliaceae) leaves, phytochemical isolation procedures were performed by activity-guided fractionation in carrageenan- and Freund's complete adjuvant (FCA) reagent-induced rat models, respectively. In the two assay system, the MeOH extract (100 and 250 mg/kg, p.o.) showed significant antiinflammtory effects. Since BuOH extract among the fractionated extracts exhibited the most potent effect, it was subjected to column chromatography to yield a main triterpene glycoside, chiisanoside (1). This compound was hydrolyzed in alkaline solution to find the biological activity of produced aglycone, chiisanogenin (1a). Oral treatment with compounds 1 and 1a produced significant antiinflammtory effects at 10 and 30 mg/kg dose, and 1a was more potent than 1. The antiiflammtory effects of the two compounds were supported by the reduction of carrageenan-induced lipid peroxidation and hydroxy radical in serum. Furthermore, treatment with 1 and 1a significantly reduced rheumatoid arthritis (RA) and C-reactive protein (CRP) factors in the rat induced by Freund's complete adjuvant reagent. Compounds, 1 and 1a, inhibited xanthine oxidase activity and increased superoxide dismutase (SOD), glutathione peroxidase and catalase indicating that both compounds scavenged reactive oxygen species (ROS).

Structure-activity relationship of oleanane disaccharides isolated from Akebia quinata versus cytotoxicity against cancer cells and NO inhibition

In order to further determine the nature of structure-activity relationship on the cytotoxicities of saponins with 1-->2 and 1-->3 linkages of disaccharides, we isolated guaianin N, collinsonidin, kalopanaxsaponin A and hederoside D(2) as disaccharides, and patrinia glycoside B-II as a trisaccharide, from the n-BuOH extract of Akebia quinata (Lardizabalaceae). Complete acid hydrolysis of the extract afforded oleanolic acid (1) and hederagenin (2). By sulforhodamine B (SRB) assay, kalopanaxsaponin A containing an alpha-L-rhap-(1-->2)-alpha-L-arap moiety exhibited distinctly higher cytotoxicity (IC(50) 1.8-2.7 microg/ml) against all of the tested cell lines than the other saponins (IC(50), 4-8 microg/ml). These results suggest that the alpha-L-rhap-(1-->2)-alpha-L-arap moiety has a unique structural significance in terms of its cell biochemistry, compared to those oleanane glycosides with other sugar linkages. On the other hand, kalopanaxsaponin A exhibited a significant inhibitory effect on nitric oxide production by lipopolysaccharide (LPS)-activated macrophage 264.7, whereas other saponins had weaker activities.

Passive Cutaneous Anaphylaxis-Inhibitory Action of Tectorigenin, a Metabolite of Tectoridin by Intestinal Microflora

Tectoridin isolated from the flowers of Pueraria thunbergiana (Leguminosae) are metabolized to tectorigenin by human intestinal microflora. When tectoridin was orally administered to rats, tectorigenin, but not tectoridin, was detected in urine after beta-glucuronidase hydrolysis. The main metabolite tectorigenin potently inhibited the passive cutaneous anaphylaxis reaction and inhibited in vitro the release of beta-hexosaminidase from RBL-2H3 cells induced by IgE. These results suggest that tectoridin is a prodrug, which can be transformed into the active agent tectorigenin by human intestinal bacteria and can be a candidate for antiallergic agent.

Antiinflammatory activity of alpha-hederin methyl ester from the alkaline hydrolysate of the butanol fraction of Kalopanax pictus bark extract

Three antiinflammatory saponin components were isolated from the alkaline hydrolysate of a butanol-soluble portion of Kalopanax pictus bark extract through an in vivo activity-guided fractionation procedure. The hydrolysate showed inhibition of adjuvant induced arthritis in rats. After further fractionation, the ethyl acetate fraction exhibited antiarthritic activity, which resulted in the isolation of alpha-hederin, alpha-hederin methyl ester, and kalopanaxsaponin I. All compounds showed inhibition of vascular permeability in mice, but only alpha-hederin methyl ester showed anticarrageenan activity in rats and antiarthritic activity in rats and mice.

Antithrombotic and antiallergic activities of rhaponticin from Rhei Rhizoma are activated by human intestinal bacteria

To evaluate the antithrombotic and antiallergic properties of rhaponticin extracted from Rhei Rhizoma, the in vitro and ex vivo inhibitory activities of rhaponticin and its metabolite, rhapontigenin, were measured. These compounds inhibited in vitro ADP- and collagen-induced platelet aggregation. Rhapontigenin was more potent, with IC50 values of 4 and 70 microg/ml, respectively. In ex vivo ADP- and collagen-induced rat platelet aggregation, these compounds also exhibited a potent inhibitory effect. The antiplatelet aggregation effects of rhaponticin and rhapontigenin were more potent than those of aspirin. Rhapontigenin showed significant protection from death due to pulmonary thrombosis in mice. Rhapontigenin also showed the strongest inhibitory activity against beta-hexosaminidase release induced by DNP-BSA. These compounds inhibited PCA reaction in mice. Rhapontigenin intraperitoneally administered showed the strongest inhibitory activity and significantly inhibited PCA at doses of 25 and 50 mg/kg, with inhibitory activities of 48 and 85%, respectively. The inhibitory activity of orally administered rhaponticin was stronger than that of intraperitoneally administered rhaponticin. These results suggest that rhaponticin, in the rhizome of Rhei Rhizoma, is a prodrug that has extensive antiallergic and antithrombotic properties.

Potent antimutagenic and their anti-lipid peroxidative effect of kaikasaponin III and tectorigenin from the flower of Pueraria thunbergiana

The MeOH extract of Pueraria thunbergiana (Leguminosae) flowers and its fractions were subjected to Ames test to test the antimutagenicity. EtOAc fraction (1 mg/plate) decreased the number of revertants of Salmonella typhymurium TA100 by 95% against aflatoxin B, (AFB1). Phytochemical isolation of the EtOAc fraction afforded four isoflavonoids (tectorigenin, glycitein, tectoridin and glycitin) and one saponin (kaikasaponin III). Though the three isoflavonoids other than tectoridin showed significant antimutagenicity, the activity of kaikasaponin III was the most potent. Kaikasaponin III (1 mg/plate) decreased the number of revertants of S. typhymurium TA100 by 99% against AFB, but by 75% against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Tectorigenin (1 mg/plate) inhibited the AFB1-induced mutagenicity by 90% and MNNG-induced one by 76%. Glycitein and glycitin were less active than tectorigenin and kaikasaponin III. This result suggested that kaikasponin III prevents the metabolic activation of AFB1 and scavenge electrophilic intermediate capable of mutation. The two components with potent activities, tectorigenin and kaikasaonin III, significantly prevented the malondialdehyde formation caused by bromobenzene in the rat.

Anti-rheumatoid arthritis effect of the Kochia scoparia fruits and activity comparison of momordin lc, its prosapogenin and sapogenin

MeOH extract of Kochia scoparia was fractionated into CHCl3-, EtOAc- and BuOH extracts and the last fraction were hydrolyzed by 3%-NaOH (MeOH-H2O) to compare the bioactivities on antinociceptive and anti-inflammatory effects. Silica gel column chromatography of BuOH fraction afforded a large amount of 3-O-beta-D-xylopyranosyl (1-->3)-beta-D-glucuronopyranosyl oleanolic acid (momordin lc, 4) and that of acid hydrolysate of BuOH fraction gave 3-O-beta-D-glucuronopyranosyl oleanolic acid (momordin lb, 3), its 6'-O-methyl ester (2) and oleanolic acid (1). Silica gel column chromatography of alkaline hydrolysate afforded a large amount of 4. MeOH extract and both EtOAc- and BuOH fractions were active in the rheumatoidal rat induced Freund's complete adjuvant reagent (FCA) whereas CHCl3 fraction was inactive. Compound 1 and 4 showed significant activities in the same assay but oleanolic acid 3-O-glucuronopyranoside (3) showed no activity. These fashions were also observed in carrageenan-induced edema of the rat and in the antinociceptive activity tests undertaken in hot plate- and writhing methods. These results suggest that momordin lc and its aglycone, oleanolic acid, could be active principles for rheumatoid arthritis.

In vitro antiinflammatory activity of kalopanaxsaponin A isolated from Kalopanax pictus in murine macrophage RAW 264.7 cells

In the present study, effects of various hederagenin monodesmosides isolated from the stem bark of Kalopanax pictus Nakai, such as hederagenin, 5-hederin, kalopanaxsaponin A, kalopanaxsaponin 1, and sapindoside C, have been evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO), prostaglandin E2 (PGE2) and tumor necrosis factor-alpha (TNF-alpha) release by the macrophage cell line RAW 264.7. Among the tested monodesmosides, kalopanxsaponin A was the most potent inhibitor of NO production, and it also significantly decreased PGE2 and TNF-alpha release. Consistent with these observations, the expression level of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 enzyme was inhibited by kalopanxsaponin A in a concentration-dependent manner. Thus, this study suggests that kalopanaxsaponin A-mediated inhibition of iNOS, COX-2 expression, and TNF-alpha release may be one of the mechanisms responsible for the anti-inflammatory effects of the stem bark of Kalopanax pictus Nakai.

Fecal metabolic activities of herbal components to bioactive compounds

The herbal components should be transformed to bioactive compounds by the intestinal bacteria and then expressed the pharmacological action of herbal medicines. Human fecal enzyme activities related to the metabolism of herbal components were measured. The metabolic activities of puerarin, poncirin, glycyrrhizin, ginsenoside Rb1 and ginsenoside Rb2 to their bioactive compounds were 3.5 +/- 1.18, 333.1 +/-183.64, 95.7 +/- 107.1, 28.6 +/- 10.32 and 20.8 +/- 13.3 micromol/ h/g, respectively. The profile of these metabolic activities of glycyrrhizin and ginsenosides were not changed even if herbal extracts, water extract of Glycyrrhizae Radix and Ginseng Radix, instead of the isolated compounds were used. All the enzyme activities tested were not different between male and female, and between ages. However, the difference of these enzyme activities in individuals was significant. These results suggest that the metabolic activity of herbal components to bioactive compounds may be a factor of constitutional classification, and could be available for constitutional classifications, if the constitutional herbal medicines were used.

Antinociceptive and anti-rheumatoidal effects of Kalopanax pictus extract and its saponin components in experimental animals

In the present study, we have attempted to elucidate the active components for rheumatoidal arthritis using chloroform (CHCl(3)), ethylacetate (EtOAc) and n-butanol (BuOH) fractions of the methanol extract (MeOH) of Kalopanax pictus. Kalopanaxsaponin-A and -I (KPS-A and -I, hederagenin monodesmoside) were isolated from EtOAc fraction and kalopanaxsaponin-B, -H and -K (KPS-B, -H and -K, hederagenin bisdesmosides) obtained from BuOH fraction, respectively. MeOH extract, EtOAc fraction (250, 500 mg/kg, p.o.) and KPS-A and -I (5, 10, 20 mg/kg, i.p.) exhibited significant antinociceptive effects, which were determined by acetic acid-induced writhing test and hot plate test. On Freund's complete adjuvant reagent-induced rheumatoidal arthritis in rats, the administration of EtOAc fraction and KPS-A and -I inhibited edema, agglutination, vascular permeability and trypsin inhibitor. In addition, LD(50) of the MeOH extract was shown to be 4.033 mg/kg. These results suggest that anti-rheumatoidal effects of KPS-A and -I contribute to the inhibition of kinin formation by suppression of trypsin inhibitor activity.

Kalopanaxsaponin A from Kalopanax pictus, a potent antioxidant in the rheumatoidal rat treated with Freund's complete adjuvant reagent

The stem bark of Kalopanax pictus is an anti-rheumatoidal arthritis drug in Oriental medicine. In the rheumatoidal rat, induced by Freund's complete adjuvant (FCA) reagent, we investigated the effects of hederagenin monodesmosides of K. pictus on oxidative stress and hepatic drug-metabolizing enzymes. Kalopanaxsaponin-A (KPS-A) significantly decreased malondialdehyde formation and the activities of xanthine oxidase and aldehyde oxidase of hepatic non-microsomal systems in FCA reagent-treated rats. In addition, increased activity levels of superoxide dismutase, catalase and glutathione peroxidase were also observed. The effects of KPS-A were more potent than the effects of KPS-I. These results suggested that KPS-A, extracted from K. pictus, could reduce rheumatoidal syndromes through antioxidative mechanisms.

Metabolism of kalopanaxsaponin K by human intestinal bacteria and antirheumatoid arthritis activity of their metabolites

When kalopanaxsaponin K (KPK) from Kalopanax pictus was incubated for 24 h at 37 degrees C with human intestinal microflora, KPK was mainly metabolized to kalopanaxsaponin I (KPI) via kalopanaxsaponin H (KPH) rather than via kalopanaxsaponin J (KPJ), and then transformed to kalopanaxsaponin A (KPA) and hederagenin. Bacteroides sp., and Bifidobacterium sp. and Fusobacterium sp. transformed KPK to KPI and KPA and hederagenin via KPH or KPJ. However, Lactobacillus sp. and Streptococcus sp. transformed KPK to KPI, KPA, and hederagenin only via KPJ. The metabolite KPA of KPK showed potent antirheumatoid arthritis activity.

Metabolism of 20(S)- and 20(R)-ginsenoside Rg3 by human intestinal bacteria and its relation to in vitro biological activities

When ginsenoside Rg3 was anaerobically incubated with human fecal microflora, all specimens metabolized ginsenoside Rg3 to ginsenoside Rh2 and protopanaxadiol. The main metabolite was ginsenoside Rh2. 20(S)-ginsenoside Rg3 was quickly transformed to 20(S)-ginsenoside Rh2 or 20(S)-protopanaxadiol in an amount 19-fold that compared with the transformation of 20(R)-ginsenoside Rg3 to 20(R)-ginsenoside Rh2 or 20(R)-protopanaxadiol. Among the bacteria isolated from human fecal microflora, Bacteroides sp., Eubacterium sp., and Bifidobacterium sp. metabolized ginsenoside Rg3 to protopanaxadiol via ginsenoside Rh2. However, Fusobacterium sp. metabolized ginsenoside Rg3 to ginsenoside Rh2 alone. Among ginsenoside Rg3 and its metabolites, 20(S)-protopanaxadiol and 20(S)-ginsenoside Rh2 exhibited the most potent cytotoxicity against tumor cell lines, 20(S)- and 20(R)-protopanaxadiols potently inhibited the growth of Helicobacter pylori, and 20(S)-ginsenoside Rh2 inhibited H+/K+ ATPase of rat stomach.

Anti-lipid peroxidative principles from the stem bark of Kalopanax pictus Nakai

Hepatic lipid peroxide contents were examined in bromobenzene-treated rats firstly after the oral administration of MeOH extract of Kalopanax pictus stem barks, its n-BuOH fraction, EtOAc fraction and an alkaline hydrolysate of the n-BuOH fraction, and secondly after the intraperitoneal administration of hederagenin monodesmosides and bisdesmosides. Two hederagenin monodesmosides, kalopanaxsaponin A (KPS-A) and sapindoside C, exhibited significant anti-lipid peroxidation effects after intraperitoneal administration at doses of 10-30 micromole/kg, whereas their bisdesmosides did not exhibit any significant activity. These results suggest that it is the hederagenin monodesmosides that are responsible for anti-lipid peroxidation in vivo. The activity of KPS-A was established by the observation of decreased aminopyrine N-demethylase activity and increased epoxide hydrolase activity.

Metabolism of chiisanoside from Acanthopanax divaricatus var. albeofructus by human intestinal bacteria and its relation to some biological activities

The metabolic pathway of chiisanoside isolated from leaves of Acanthopanax divaricatus var. albeofructus (Araliaceae) by human intestinal bacteria and by the protein fraction of leaves of this plant were investigated, and the cytotoxic and anti-rotaviral activities of chiisanoside and its metabolite, chiisanogenin, were assayed. Chiisanogenin was produced as a main metabolite, when chiisanoside were incubated for 15 h with human intestinal bacteria. This metabolic pathway proceeded more potently with the protein fraction than with human intestinal bacteria. The in vitro cytotoxicity of chiisanogenin was superior to that of chiisanoside. H+/K+ ATPase was more potently inhibited by chiisanogenin than by chiisanoside. However, the anti-rotaviral activity of chiisanoside was more potent than that of chiisanogenin.

The bioactivity of saponins: triterpenoid and steroidal glycosides

Triterpenoid and steroidal glycosides, referred to collectively as saponins, are bioactive compounds present naturally in many plants. They have considerable potential as pharmaceutical and/or nutraceutical agents in natural or synthetic form. Saponins, from a variety of sources, have been shown to have hypocholesterolemic, anti-coagulant, anticarcinogenic, hepatoprotective, hypoglycemic, immunomodulatory, neuroprotective, anti-inflammatory and anti-oxidant activity. This paper reviews saponin research of the last decade, focussing on developments in understanding their mechanism of action and structure-activity relationships. Virtually all of this work has used animal and in vitro models. To date there are very few human data.