Vascular Protective Effects of Malus toringoides (Rehd.) Hughes Extracts and their Mechanism in Diabetic Rats and HUVECs.

Malus toringoides (Rehd.) Hughes (Rosaceae) is used as a traditional folk medicine in the Tibet autonomous region of China to treat hypertension, hyperglycemia, and hyperlipidemia. However, few modern pharmacological data on the use of this plant against diabetic syndrome are available. In this study, we examined the vascular protection provided by a 70% ethanol extract of M. toringoides (EMT) in human umbilical vein endothelial cells (HUVECs) grown in high-glucose medium and in a high-fat diet/streptozotocin-induced rat diabetes model. EMT significantly suppressed the expression of cell adhesion molecules in both HUVECs and diabetic rats. EMT also inhibited activation of the CX3CL1/CX3CR1 axis and the nuclear factor kappa B (NF-κB) signaling pathway in vivo and in vitro. The results provide a significant information on the vasoprotective properties of M. toringoides that may contribute to the development and application of related herbal medicines.

Anti-Inflammatory Effects of Compounds from Cudrania tricuspidata in HaCaT Human Keratinocytes.

The root bark of Cudrania tricuspidata has been reported to have anti-sclerotic, anti-inflammatory, antioxidant, neuroprotective, hepatoprotective, and cytotoxic activities. In the present study, the effect of 16 compounds from C. tricuspidata on tumor necrosis factor-α+interferon-γ-treated HaCaT cells were investigated. Among these 16 compounds, 11 decreased IL-6 production and 15 decreased IL-8 production. The six most effective compounds, namely, steppogenin (2), cudraflavone C (6), macluraxanthone B (12), 1,6,7-trihydroxy-2-(1,1-dimethyl-2-propenyl)-3- methoxyxanthone (13), cudraflavanone B (4), and cudratricusxanthone L (14), were selected for further experiments. These six compounds decreased the expression levels of chemokines, such as regulated on activation, normal T cell expressed and secreted (RANTES) and thymus and activation-regulated chemokine (TARC), and downregulated the protein expression levels of intercellular adhesion molecule-1. Compounds 2, 6, 12, 4, and 14 inhibited nuclear factor-kappa B p65 translocation to the nucleus; however, compound 13 showed no significant effects. In addition, extracellular signal regulatory kinase-1/2 phosphorylation was only inhibited by compound 14, whereas p38 phosphorylation was inhibited by compounds 13 and 4. Taken together, the compounds from C. tricuspidata showed potential to be further developed as therapeutic agents to suppress inflammation in skin cells.

Anti-Neuroinflammatory and Anti-Inflammatory Activities of Phenylheptatriyne Isolated from the Flowers of Coreopsis lanceolata L. via NF-κB Inhibition and HO-1 Expression in BV2 and RAW264.7 Cells.

Aging is associated with immune disregulation and oxidative stress which lead to inflammation and neurodegenerative diseases. We have tried to identify the anti-neuroinflammatory and anti-inflammatory components of Coreopsis lanceolata L. The dried flowers of C. lanceolata were extracted with 70% EtOH, and the obtained extract was divided into CH2Cl2, EtOAc, n-BuOH, and H2O fractions. The CH2Cl2 fraction was separated using silica gel and C-18 column chromatography to yield phenylheptatriyne (1), 2'-hydroxy-3,4,4'-trimethoxychalcone (2), and 4',7-dimethoxyflavanone (3). Additionally, the EtOAc fraction was subjected to silica gel, C-18, and Sephadex LH-20 column chromatography to yield 8-methoxybutin (4) and leptosidin (5). All the compounds isolated from C. lanceolata inhibited the production of nitric oxide (NO) in LPS-induced BV2 and RAW264.7 cells. In addition, phenylheptatriyne and 4',7-dimethoxyflavanone reduced the secretion of inflammatory cytokines, tumor necrosis factor alpha (TNF-α), and interleukin (IL)-6. Among them, phenylheptatriyne was significantly downregulated in the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2). Subsequently, phenylheptatriyne also effectively inhibited nuclear factor-kappa B (NF-κB) activation in LPS-stimulated BV2 and RAW264.7 cells. Based on these results, the anti-neuroinflammatory effect of phenylheptatriyne isolated from C. lanceolata was confirmed, which may exert a therapeutic effect in treatment of neuroinflammation-related diseases.

Apigenin promotes antibacterial activity via regulation of nitric oxide and superoxide anion production.

Apigenin is a naturally occurring flavone isolated from the medicinal herb, Aster yomena. The present study was designed to elucidate the apoptosis-like antibacterial mechanism of apigenin in Escherichia coli. Administration of apigenin resulted in a rapid increase in intracellular calcium accompanied by an increase in reactive nitrogen species (RNS) and nitric oxide (NO) levels. Furthermore, apigenin increases reactive oxygen species (ROS), superoxide anion (O2 - ) which left E. coli with no ability to activate superoxide dismutase. Finally, we found that perturbance of the membrane lipid bilayer leading to glutathione oxidation and formation 8-hydroxy-2'-deoxyguanosine occurred during the process and apoptosis-like death hallmarks were further observed. Furthermore, we applied the NO synthase inhibitor ( l-NAME) and the O2 - scavenger (Tiron) and observed attenuation in apoptotic markers under their presence. Taken together, these results suggest that apigenin induces bacterial apoptosis via activation of cellular oxidative pathways dependent on the production and accumulation of RNS/ROS.

Neuroprotective and Anti-Inflammatory Effects of Kuwanon C from Cudrania tricuspidata Are Mediated by Heme Oxygenase-1 in HT22 Hippocampal Cells, RAW264.7 Macrophage, and BV2 Microglia.

Heme oxygenase (HO)-1 is a detoxifying phase II enzyme that plays a role in both inflammatory and oxidative stress responses. Curdrania tricuspidata is widespread throughout East Asia and is used as a therapeutic agent in traditional medicine. We investigated whether treatment with sixteen flavonoid or xanthone compounds from C. tricuspidata could induce HO-1 expression in HT22 hippocampal cells, RAW264.7 macrophage, and BV2 microglia. In these compounds, kuwanon C showed the most remarkable HO-1 expression effects. In addition, treatment with kuwanon C reduced cytoplasmic nuclear erythroid 2-related factor (Nrf2) expression and increased Nrf2 expression in the nucleus. Significant inhibition of glutamate-induced oxidative injury and induction of reactive oxygen species (ROS) occurred when HT22 hippocampal cells were pretreated with kuwanon C. The levels of inflammatory mediator and cytokine, which increased following lipopolysaccharide (LPS) stimulation, were suppressed in RAW264.7 macrophage and BV2 microglia after kuwanon C pretreatment. Kuwanon C also attenuated p65 DNA binding and translocation into the nucleus in LPS-induced RAW264.7 and BV2 cells. The anti-inflammatory, anti-neuroinflammatory, and neuroprotective effects of kuwanon C were reversed when co-treatment with HO-1 inhibitor of tin protoporphyrin-IX (SnPP). These results suggest that the neuroprotective and anti-inflammatory effects of kuwanon C are regulated by HO-1 expression.

Standardized microwave extract of Sappan Lignum exerts anti­inflammatory effects through inhibition of NF­κB activation via regulation of heme oxygenase­1 expression.

The extract of Sappan Lignum, the heartwood of Caesalpinia sappan L., has been used in medicine to improve blood circulation. Recently, the application of microwave extraction methods has been a major focus of research into the extraction of components from natural sources. In this experiment, we compared the anti­inflammatory effects of Sappan Lignum prepared by heat­70% EtOH extraction (CSE­H­70E) and microwave­70% EtOH extraction (CSE­MW­70E). High­performance liquid chromatography analysis was used to identify the compounds in these extracts. The heat­70% EtOH and microwave­70% EtOH extracts of Sappan Lignum had different chromatograms. CSE­MW­70E significantly inhibited the protein expression of iNOS and COX­2, PGE2, TNF­α, and reduced NO and IL­1ß production in macrophages exposed to LPS, whereas, only high concentrations of CSE­H­70E (20 µg/ml) resulted in any effects. Furthermore, CSE­MW­70E upregulated heme oxygenase­1 (HO­1) expression. In addition, the use of tin protoporphyrin, an inhibitor of HO­1, confirmed the inhibitory effects of CSE­MW­70E on pro­inflammatory mediators. These results suggested that the CSE­MW­70E­mediated upregulation of HO­1 played an important role in the anti­inflammatory effects of macrophages. Therefore, these findings showed that microwave extraction can be utilized to improve the extraction efficiency and biological activity of Sappan Lignum.

Effect of apigenin isolated from Aster yomena against Candida albicans: apigenin-triggered apoptotic pathway regulated by mitochondrial calcium signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Aster yomena, a perennial herb that grows mainly in South Korea, has been employed in the traditional temple food for antibiotic efficacy. Recently, it was reported that apigenin isolated from A. yomena has a physical antifungal mechanism targeting membrane against Candida albicans. AIM OF THE STUDY: Our study aimed to investigate the biochemical responses underlying the antifungal activity of apigenin isolated from A. yomena due to lack studies reporting the investigation of intracellular responses of apigenin in C. albicans. MATERIALS AND METHODS: Apigenin was isolated from the aerial parts of A. yomena. To evaluate apigenin-induced inhibitory effects and membrane damages, the measurement of the cell viability assay and the flux of cytosolic components were performed with at various concentrations. Intracellular external potassium and calcium levels were assayed by an ion-selective electrode meter, Fura2-AM and Rhod2-AM, respectively. Mitochondrial dysfunctions were analyzed by using JC-1, Mitotracker Green FM, and MitoSOX Red dye. H2DCFDA, glutathione, and MDA assay were used to detect oxidative damage. Also, flow cytometry was carried out to detect apoptotic hallmarks using Annexin V-PI, TUNEL, and FITC-VAD-FMK staining. Tetraethylammoniumchloride (TEA), Ruthenium red (RR), and N-acetylcysteine (NAC) were used as a potassium channel blocker, mitochondrial calcium uptake inhibitor, and reactive oxygen species (ROS) scavenger, respectively. RESULTS: We confirmed that there was no decrease of cell survival percentages in crude extracts of A. yomena treatment, however, only isolated apigenin has the antifungal effect in C. albicans. Apigenin triggered a dose-dependent mitochondrial calcium uptake followed by mitochondrial dysfunction, loss of the membrane potential and an increase in the mitochondrial mass and ROS. Apigenin also induced intracellular redox imbalance as indicated by the ROS accumulation, glutathione oxidation, and lipid peroxidation. Interestingly, NAC failed the restore the mitochondrial calcium levels and thus alleviate the mitochondrial damages, however, RR reduced the apigenin-induced redox imbalance. Furthermore, apigenin induced apoptosis activation marked by the phosphatidylserine exposure, DNA fragmentation, and caspase activation. The pro-apoptotic effect of apigenin was counteracted by RR and NAC pretreatment. In particular, RR significantly reduced the pro-apoptotic responses. CONCLUSIONS: Apigenin isolated from A. yomena induced mitochondrial-mediated apoptotic pathway, and mitochondrial calcium signaling is main factor in its pathway in C. albicans.

Effect of isoquercitrin on membrane dynamics and apoptosis-like death in Escherichia coli.

Minimum inhibitory concentration (MIC) is defined as the lowest concentration of a compound that completely inhibits microbial growth. Antibacterial mechanisms of compounds have been investigated at their sub-MICs as well as at their MIC. In this study, the effects of sub-MIC and MIC of isoquercitrin on Escherichia coli were investigated. The antibacterial effect of isoquercitrin was tested using the microdilution method. Sub-MICs of isoquercitrin induced the production of reactive oxygen species and depletion of glutathione. The oxidative effects induced by sub-MICs of isoquercitrin could be prolonged, finally resulting in apoptosis-like death. DNA fragmentation and phosphatidylserine externalization, which are regarded as the hallmarks of apoptosis, were evaluated using the TUNEL assay and Annexin V staining, respectively. Furthermore, isoquercitrin induced the peroxidation of membrane lipids and inner membrane permeabilization at both its sub-MIC and MIC. This suggested membrane damage in response to lipid oxidation. The uptake of membrane impermeable dyes, propidium iodide and calcein, demonstrated that isoquercitrin damaged the cell membrane at concentrations higher than its MIC. Thus, isoquercitrin induced apoptosis-like death and dysregulation of cell membrane dynamics.

Acerogenin C from Acer nikoense exhibits a neuroprotective effect in mouse hippocampal HT22 cell lines through the upregulation of Nrf-2/HO-1 signaling pathways.

Oxidative stress contributes to neuronal death in the brain, and neuronal death can cause aging or neurodegenerative disease. Heme oxygenase 1 (HO-1) serves a vital role in the regulation of biological reactions, including oxidative stress associated with reactive oxygen species. In the present study, acerogenin C isolated from the Aceraceae plant Acer nikoense, which is used as a Japanese folk medicine for hepatic disorders and eye diseases. However, there have been no studies on the mechanisms underlying the antineurodegenerative biological activities of acerogenin C. In the present study, acerogenin C demonstrated neuroprotective action against glutamate­induced cell death in hippocampal HT22 cells through the upregulation of HO­1 expression. These effects were also associated with nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the activation of phosphoinositide 3­kinase/protein kinase B. Taken together of the efficacy researches, this study determines that the Nrf2/HO­1 pathways denotes a biological mark and that acerogenin C might contribute to prevention of neurodegenerative disorders.

Oleanane triterpenoids from Akebiae Caulis exhibit inhibitory effects on Aß42 induced fibrillogenesis.

Previous phytochemical investigations of Akebiae Caulis resulted in the isolation of triterpenes, triterpene glycosides, phenylethanoid glycosides and megastigmane glycoside. Amyloid beta (Aß), the main component of the senile plaques detected in Alzheimer's disease, induces cell death. However, only a limited number of studies have addressed the biological and pharmacological effects of Akebiae Caulis. In particular, the inhibitory activity of Akebiae Caulis against Aß42 fibrillogenesis remains unclear. Herein, a new triterpene glycoside, akequintoside F (1), along with nine known compounds pulsatilla saponin A (2), collinsonidin (3), akebonic acid (4), hederagenin (5), 1-(3',4'-dihydroxycinnamoyl) cyclopentane-2,3-diol (6), asperosaponin C (7), leontoside A (8), quinatic acid (9), and quinatoside A (10) were isolated from Akebiae Caulis using repeated column chromatography with silica gel, LiChroprep RP-18, and MCI gel. The chemical structures of compounds 1-10 were illustrated based on 1D and 2D NMR spectroscopy, including 1H-1H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compound 1 a novel compound and known compounds 6 and 7 were isolated for the first time from this plant. Among these compounds, 1, 3, 4, 5 and 7 displayed significant inhibitory effects on Aß42 induced fibrillogenesis. We present the first report of new compound 1 and the inhibitory effects of components from Akebiae Caulis on Aß42 fibrillogenesis.

Antibacterial Activity of Hibicuslide C on Multidrug-Resistant Pseudomonas aeruginosa Isolates.

Pseudomonas aeruginosa is a gram-negative bacterium that is frequently related to natural resistance to many drugs. In this work, the inhibition of growth against P. aeruginosa and multidrug-resistant P. aeruginosa (MDRPA) isolated from patients at Kyungpook National University was confirmed for hibicuslide C, essential oil components from Abutilon theophrasti. Hibicuslide C has antifungal activity with membrane disruption and apoptotic response against Candida albicans. However, its antibacterial activity was not reported yet. Cells treated with hibicuslide C was showed that its antipseudomonal activity is related to gDNA fragmentation and damage by TUNEL and gDNA electrophoresis. Furthermore, hibicuslide C worked synergistically with fluoroquinolones and rifampicin against MDRPA regardless of the ATP-associated mechanism. The antibiofilm activity possessed sole-resulting tissue culture plate method; besides that, the antibiofilm activity of other antibiotics was supported in particular MDRPA. The essential oil components like hibicuslide C may have antipseudomonal activity and, furthermore, increase in bacterial antibiotic susceptibility.

Chemical constituents on the aerial parts of Artemisia selengensis and their IL-6 inhibitory activity.

Ten compounds, 1',3'-propanediol,2'-amino-1'-(1,3-benzodioxol-5-yl) (1), artanomaloide (2), canin (3), eupatilin (4), quercetin-3-O-ß-D-glucoside-7-O-α-L-rhamnoside (5), 1,3-di-O-caffeoylquinic acid (6), isoquercitrin (7), pinoresinol-4-O-ß-D-glucoside (8), scopolin (9), and isofraxidin-7-O-ß-D-glucopyranoside (10) were isolated from the aerial parts of A. selengensis. The structures of compounds (1-10) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Among them, compound 1 was isolated from this plant for the first time as a naturally occurring compound. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

Fungicidal effect of isoquercitrin via inducing membrane disturbance.

Isoquercitrin is a flavonoid isolated from Aster yomena, which has been used as a traditional medicinal herb. In the present study, we investigated the antifungal activity and the underlying mechanism of isoquercitrin. Isoquercitrin had a potent effect in the susceptibility test against pathogenic fungi and almost no hemolysis. Propidium iodide and potassium release assays were conducted in Candida albicans, and these studies confirmed that isoquercitrin induced membrane damage, thereby, increasing permeability. Membrane potential was analyzed using 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)], and the transition of membrane potential was indicated by an increased fluorescence intensity. To further analyze these results using model membranes, giant unilamellar vesicles and large unilamellar vesicles that encapsulated calcein were prepared and the detection of calcein leakage from liposomes indicated that membrane was disturbed. We further verified membrane disturbance by observing the disordered status of the lipid bilayer with 1,6-diphenyl-1,3,5-hexatriene fluorescence. Moreover, changes in size and granularity of the cell were revealed in flow cytometric analysis. All these results suggested the membrane disturbance and the degree of disturbance was estimated to be within a range of 2.3 nm to 3.3 nm by fluorescein isothiocyanate-dextran analysis. Taken together, isoquercitrin exerts its fungicidal effect by disturbing the membrane of cells.

A new megastigmane glycoside from Akebia quinata.

A new megastigmane glycoside, 8S*,9R*-megastigman-3-one-4,6-diene-8,9-diol-9-O-ß-D-glucopyranoside, named akequintoside D (1), as well as six known compounds, roseoside II (2), 3-O-caffeoylquinic acid (3), methyl-3-O-caffeoylquinate (4), 3,4,5-trimethoxyphenyl-ß-D-glucopyranoside (5), cuneataside D (6), 3,4-dimethoxyphenyl-6-O-(α-L-rhamnopyranosyl)-ß-D-glucopyranoside (7) were isolated from the stem of Akebia quinata. The structures of compounds (1-7) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in TNF-α stimulated MG-63 cells was also examined.

Effects of Morus alba L. and Natural Products Including Morusin on In Vivo Secretion and In Vitro Production of Airway MUC5AC Mucin.

BACKGROUND: It is valuable to find the potential activity of regulating the excessive mucin secretion by the compounds derived from various medicinal plants. We investigated whether aqueous extract of the root bark of Morus alba L. (AMA), kuwanon E, kuwanon G, mulberrofuran G, and morusin significantly affect the secretion and production of airway mucin using in vivo and in vitro experimental models. METHODS: Effect of AMA was examined on hypersecretion of airway mucin in sulfur dioxide-induced acute bronchitis in rats. Confluent NCI-H292 cells were pretreated with ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G, or morusin for 30 minutes and then stimulated with phorbol 12-myristate 13-acetate (PMA) for 24 hours. The MUC5AC mucin secretion and production were measured by enzyme-linked immunosorbent assay. RESULTS: AMA stimulated the secretion of airway mucin in sulfur dioxide-induced bronchitis rat model; aqueous extract, ethanolic extract, kuwanon E, kuwanon G, mulberrofuran G and morusin inhibited the production of MUC5AC mucin induced by PMA from NCI-H292 cells, respectively. CONCLUSION: These results suggest that extract of the root bark and the natural products derived from Morus alba L. can regulate the secretion and production of airway mucin and, at least in part, explains the folk use of extract of Morus alba L. as mucoregulators in diverse inflammatory pulmonary diseases.

Effect of Kuwanon G isolated from the root bark of Morus alba on ovalbumin-induced allergic response in a mouse model of asthma.

The root bark of Morus alba L. (Mori Cortex Radicis; MCR) is traditionally used in Korean medicine for upper respiratory diseases. In this study, we investigated the antiasthmatic effect of kuwanon G isolated from MCR on ovalbumin (OVA)-induced allergic asthma in mice. Kuwanon G (1 and 10 mg/kg) was administered orally in mice once a day for 7 days during OVA airway challenge. We measured the levels of OVA-specific IgE and Th2 cytokines (IL-4, IL-5, and IL-13) in the sera or bronchoalveolar lavage (BAL) fluids and also counted the immune cells in BAL fluids. Histopathological changes in the lung tissues were analyzed. Kuwanon G significantly decreased the levels of OVA-specific IgE and IL-4, IL-5, and IL-13 in the sera and BAL fluids of asthma mice. Kuwanon G reduced the numbers of inflammatory cells in the BAL fluids of asthma mice. Furthermore, the pathological feature of lungs including infiltration of inflammatory cells, thickened epithelium of bronchioles, mucus, and collagen accumulation was inhibited by kuwanon G. These results indicate that kuwanon G prevents the pathological progression of allergic asthma through the inhibition of lung destruction by inflammation and immune stimulation.

Three new lignan glycosides with IL-6 inhibitory activity from Akebia quinata.

Three new lignan glycosides, akeqintoside A [(7S,8S)-7,8-dihydro-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-benzofuranpropanol 2'-O-ß-D-glucopyranoside] (1), akeqintoside B [(7R,8R)-7,8-dihydro-8-hydroxymethyl-7-(4-hydroxy-3-methoxyphenyl)-1'-(9'-methoxy-7'-propenyl) benzofuran 2'-O-ß-D-glucopyranoside] (2), and akequintoside C [7R*,8R*-dihydroxy-7-(4-hydroxy-3-methoxyphenyl)-glycerol 9-O-ß-D-(6'-O-caffeoyl)-glucopyranoside] (3) were isolated from Akebia quinata along with five known compounds, syringin (4), vanilloloside (5), salidroside (6), 3,4-dihydroxyphenylethyl alcohol 8-O-ß-D-glucopyranoside (7), and calceolarioside B (8). The structures of the compounds were identified based on one dimensional (1D)- and 2D-NMR, including (1)H-(1)H correlation spectroscopy (COSY), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond connectivity (HMBC) and nuclear Overhauser effect spectroscopy (NOESY) spectroscopic analyses. The inhibitory activity of these isolated compounds against interleukin-6 (IL-6) production in tumor necrosis factor-alpha (TNF-α) stimulated MG-63 cells was also examined.

Antifungal effect and mode of action of glochidioboside against Candida albicans membranes.

Glochidioboside was obtained from Sambucus williamsii and its biological effect has not been reported. Its antifungal activity against pathogenic fungi and the mode of action involved in its effect were examined. Glochidioboside exerted antifungal effect with almost no hemolytic effect against human erythrocytes. To understand its antifungal mechanisms, membrane studies were done. Using two dyes, 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] and propidium iodide, membrane depolarization and permeabilization by glochidioboside were confirmed. Furthermore, the membrane-active mechanism was proven by synthesizing a model membrane, calcein-encapsulating large unilamellar vesicles (LUVs), and also by observing the influx of different sized fluorescent dyes, such as calcein, FD4 and FD10, into the fungal cells. The membrane-active action was pore-forming action with radii between 1.4 and 2.3 nm. Finally, three dimensional (3D) flow cytometric analysis showed the shrinkage of the fungal cells from the membrane damage. In conclusion, this study suggests that glochidioboside exerts an antifungal activity through a membrane-disruptive mechanism.

Phenolic compounds with IL-6 inhibitory activity from Aster yomena.

A new biflavonoid, named asteryomenin (1), as well as six known phenolic compounds, esculetin (2), 4-O-ß-D-glucopyranoside-3-hydroxy methyl benzoate (3), caffeic acid (4), isoquercitrin (5), isorhamnetin-3-O-glucoside (6), and apigenin (7) were isolated from the aerial parts of Aster yomena. The structures of compounds (1-7) were identified based on 1D and 2D NMR, including (1)H-(1)H COSY, HSQC, HMBC and NOESY spectroscopic analyses. Compounds 2-7 were isolated from this plant for the first time. For these isolates, the inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell was examined. Among these isolates, compounds 4 and 7 appeared to have potent inhibitory activity of IL-6 production in the TNF-α stimulated MG-63 cell, while compounds 1-3 and 5-6 showed moderate activity.

Antifungal property of hibicuslide C and its membrane-active mechanism in Candida albicans.

In this study, the antifungal activity and mode of action(s) of hibicuslide C derived from Abutilon theophrasti were investigated. Antifungal susceptibility testing showed that hibicuslide C possessed potent activities toward various fungal strains and less hemolytic activity than amphotericin B. To understand the antifungal mechanism(s) of hibicuslide C in Candida albicans, flow cytometric analysis with propidium iodide was done. The results showed that hibicuslide C perturbed the plasma membrane of the C. albicans. The analysis of the transmembrane electrical potential with 3,3'-dipropylthiacarbocyanine iodide [DiSC3(5)] indicated that hibicuslide C induced membrane depolarization. Furthermore, model membrane studies were performed with calcein encapsulating large unilamellar vesicles (LUVs) and FITC-dextran (FD) loaded LUVs. These results demonstrated that the antifungal effects of hibicuslide C on the fungal plasma membrane were through the formation of pores with radii between 2.3 nm and 3.3 nm. Finally, in three dimensional flow cytometric contour plots, a reduced cell sizes by the pore-forming action of hibicuslide C were observed. Therefore, the present study suggests that hibicuslide C exerts its antifungal effect by membrane-active mechanism.