Dool-Ri Oh

Protective effect of polygoni cuspidati radix and emodin on Vibrio vulnificus cytotoxicity and infection

Vibrio vulnificus, a good model organism of bacterial septicemia, causes fatal septicemia manifesting a fulminating course and a high mortality rate within days. In order to identify new natural substances preventing V. vulnificus infection, a plant library was screened for inhibiting cytotoxicity to host cells by using Trypan blue staining and LDH assay. We found that Polygoni Cuspidati Radix potently suppressed the acute death of HeLa and RAW264.7 cells in a dose dependent manner. Further studies revealed that Polygoni Cuspidati Radix inhibited V. vulnificus growth and survival in HI broth and seawater, respectively. We confirmed that Polygoni Cuspidati Radix contained high level of emodin by thin layer chromatography (TLC). Emodin showed direct antibacterial activity against V. vulnificus. In addition, emodin prevented the morphologic damages and acute death of HeLa cells caused from V. vulnificus. The safety of Polygoni Cuspidati Radix and emodin to host cells was confirmed by MTT assay. Polygoni Cuspidati Radix and emodin protected mice from V. vulnificus infection.

Dammarane triterpenes from the leaves of Panax ginseng enhance cellular immunity.

In our search for immune stimulating materials from natural source, bioassay-guided fractionation of a methanol extract of Panax ginseng leaves led to the isolation of three dammarane triterpenes (1-3), including two previously unknown compounds 27-demethyl-(E,E)-20(22),23-dien-3β,6α,12β-trihydroxydammar-25-one (1) and 3β,20(S)-dihydroxydammar-24-en-12β,23β-epoxy-20-O-β-D-glucopyranoside (2). Their structures were elucidated on the basis of spectroscopic methods, chemical transformation, and by the comparison with those of literature data. Compounds 1-3 significantly increased interleukin-12 expression in LPS-activated mouse peritoneal macrophage at a concentration of 100 ng/mL. Furthermore, compound 1 strongly increased the Th1 response-mediated cytokine IL-2, and decreased Th2 response-mediated cytokines IL-4 and IL-6 expression at 100 ng/mL on ConA-activated splenocytes. This study indicated that compound 1 showed a better effect on cellular immunity, and provided new chemical entities as promising lead compounds for the treatment of cellular immunity-related diseases.

Resveratrol modulates RTX toxin-induced cytotoxicity through interference in adhesion and toxin production.

Host-parasite contact is a prerequisite for the acute cytotoxicity of Vibrio vulnificus, which is mediated primarily by RtxA1, a repeat in toxin (RTX) toxin. We found that resveratrol (at 10 or 30 microM), a natural polyphenol, protected HeLa cells from V. vulnificus cytotoxicity. To further characterize the underlying mechanism, the effect of resveratrol was investigated at the level of the host-microbe interactions. We studied the effects of resveratrol on adhesion, motility, cytotoxicity, and RtxA1 toxin expression of V. vulnificus. In addition, the effect of resveratrol on mouse mortality caused by V. vulnificus was investigated. Resveratrol inhibited V. vulnificus motility and the microbe adhesion to host cells, critical virulence traits for many bacteria. Resveratrol also down-regulated the expression of RtxA1 toxin at the transcriptional level and thereby protected the host cells from becoming rounded and damaged. In addition, resveratrol (20mg/kg) protected CD-1 mice from V. vulnificus infection. Taken together, these results suggest that resveratrol, a modulator of host-microbe interactions, has potential for development as a new paradigm drug to treat infectious diseases.

Genistein inhibits Vibrio vulnificus adhesion and cytotoxicity to HeLa cells

Vibrio vulnificus (V. vulnificus) is a useful model for bacterial septicemia as the bacterial infection generates a wide pathogenic spectrum in addition to a high mortality rate. This study was aimed at investigating the effects of genistein on the growth, cytotoxicity, adhesion, and the mouse mortality caused by V. vulnificus. The results of our study indicated that genistein (50 or 100 mg/L) effectively minimized the morphologic damages and inhibited acute death of HeLa cells by V. vulnificus. Strikingly, genistein significantly inhibited the adhesion of V. vulnificus to HeLa cells. This report confirmed that genistein showed bacteriostatic activity against V. vulnificus, but it did not exhibit any bactericidal activity. Nevertheless, genistein (20 mg/kg) effectively decreased CD-1 mice mortality caused by V. vulnificus infection.

Antidepressant-Like Effects of Vaccinium bracteatum in Chronic Restraint Stress Mice: Functional Actions and Mechanism Explorations

The fruit of Vaccinium bracteatum Thunb. (VBF) is commonly known as the oriental blueberry in Korea. The aim of this study was to evaluate the antidepressant-like effects of water VBF extract (VBFW) in a mouse model of chronic restraint stress (CRS) and to identify the underlying mechanisms of its action. The behavioral effects of VBFW were assessed in the forced swim test (FST) and open field test (OFT). The levels of serum corticosterone (CORT), brain monoamines, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway were evaluated. VBFW treatment significantly reduced the immobility time and increased swimming time in FST without altering the locomotor activity in unstressed mice. Furthermore, CRS mice treated with VBFW exhibited a significantly decreased immobility time in FST and serum CORT, increased locomotor activity in OFT, and enhanced brain monoamine neurotransmitters. Similarly, VBFW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and PFC. In addition, VBFW may reverse CORT-induced cell death by enhancing cyclic AMP-responsive element-binding protein expression through the up-regulation of ERKs/Akt signaling pathways. In addition, VBFW showed the strong antagonistic effect of the 5-HT[Formula: see text] receptor by inhibiting 5-HT-induced intracellular Ca[Formula: see text] and ERK1/2 phosphorylation. Our study provides evidence that antidepressant-like effects of VBFW might be mediated by the regulation of monoaminergic systems and glucocorticoids, which is possibly associated with neuroprotective effects and antagonism of 5-HT[Formula: see text] receptor.

PMA Induces Vaccine Adjuvant Activity by the Modulation of TLR Signaling Pathway

Toll-like receptor (TLR) ligands are being developed for use as vaccine adjuvants and as immunomodulators because of their ability to stimulate innate and adaptive immune responses. Flagellin, a TLR5 ligand, was reported to show potent mucosal vaccine adjuvant activity. To identify ligands that potentiate the adjuvant activity of flagellin, we screened a plant library using HEK293T cells transiently cotransfected with phTLR5 and pNF-κB-SEAP plasmids. The 90% EtOH extract from Croton tiglium showed significant NF-κB transactivation in a TLR5-independent manner along with the increase of a flagellin activity. We have studied to characterize an active component from Croton tiglium and to elucidate the action mechanisms. Phorbol 12-myristate 13-acetate (PMA) was isolated as an active component of Croton tiglium by activity-guided fractionation, column chromatography, HPLC, NMR, and MS. PMA at a range of nM induced PKC-dependent NF-κB activation and IL-8 production in both TLR5− and TLR5+ assay systems. In in vivo mouse vaccination model, PMA induced antigen-specific IgG and IgA antibody responses and increased IL-12 production corresponding to T cell responses in spleen lymphocytes. These results suggest that PMA would serve as an efficacious mucosal vaccine adjuvant.

Vaccinium bracteatum Leaf Extract Reverses Chronic Restraint Stress-Induced Depression-Like Behavior in Mice: Regulation of Hypothalamic-Pituitary-Adrenal Axis, Serotonin Turnover Systems, and ERK/Akt Phosphorylation

The leaves of Vaccinium bracteatum Thunb. are a source of traditional herbal medicines found in East Asia. The present study aimed to evaluate the mechanisms underlying the antidepressant-like effects of water extract of V. bracteatum Thunb. leaves (VBLW) in a mouse model of chronic restraint stress (CRS) and to identify the possible molecular in vitro mechanisms of the neuroprotective effects. The CRS-exposed mice were orally administered VBLW (100 and 200 mg/kg) daily for 21 days consecutively. The behavioral effects of VBLW were assessed through the forced swim test (FST) and the open field test (OFT). The levels of serum corticosterone (CORT), corticotropin releasing hormone (CRH), and adrenocorticotropin hormone (ACTH), brain monoamines, such as serotonin, dopamine, and norepinephrine, and serotonin turnover by tryptophan hydroxylase 2 (TPH2), serotonin reuptake (SERT), and monoamine oxidase A (MAO-A) were evaluated, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway. CRS-exposed mice treated with VBLW (100 and 200 mg/kg) showed significantly reduced immobility time and increased swimming and climbing times in the FST, and increased locomotor activity in the OFT. Moreover, CRS mice treated with VBLW exhibited significantly decreased CORT and ACTH, but enhanced brain monoamine neurotransmitters. In addition, CRS mice treated with VBLW had dramatically decreased protein levels of MAO-A and SERT, but increased TPH2 protein levels in the hippocampus and the PFC. Similarly, VBLW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and the PFC. Furthermore, VBLW showed neuroprotective effects via increased CREB phosphorylation in CORT-induced cell injury that were mediated through the ERK/Akt/mTOR signaling pathways. These results suggested that the antidepressant-like effects of VBLW might be mediated by the regulation of the HPA axis, glucocorticoids, and serotonin turnover, such as TPH2, SERT, and MAO-A, as well as the concentration of monoamine neurotransmitters, and the activities of ERK and Akt phosphorylation, which were possibly associated with neuroprotective effects.

Effect of Aqueous Extract of Dendropanax morbifera Leaf on Sexual Behavior in Male Rats

Sexual function in an important of the quality of life and subjective well-being in humans. Successful treatment of sexual dysfunction may improve not only sexual relationships, but also overall quality of life. The objective of this study was to determine the effects of Dendropanax morbifera (DM) Lev. leaf extracts on sexual behavior and testosterone levels in male rats. Three different doses of DM (50, 100, and 200 mg/kg/day) were administered orally for 28 days. On day 28 (final day of the sample treatment period) and day 42 (after 2 weeks of sample withdrawal period following 28 days of sample treatment), serum testosterone levels and sexual behavior of rats were determined, including mount frequency (MF), intromission frequency, mount latency (ML, the time from introduction of the female to the male to the first mount), intromission latency (IL), and post-ejaculatory interval (PEI). ML significantly reduced, whereas MF increased in the DM group. The DM group also had a reduced PEI. The oral administration of DM significantly increased serum testosterone levels compared with those in the control group. The results of this study demonstrate that an aqueous extract of DM represents a useful natural resource for the management of sexual function.

Quantitative Determination of Caffeine of Green Tea Seed Ethanol Extract on Anti-obesity in C57BL/6 Mice Fed a High-fat Diet and 3T3-L1 Cells

The study was carried out to examine the anti-obesity effects of 40% ethanol extract from green tea seed (GS) and quantitative determination of caffeine as its major compound. The specificity was satisfied with retention time and UV spectrum by analysis of caffeine using HPLC and comparison with standard compound. It showed a high linearity in the calibration curve with a coefficient of correlation (R 2 ) of 0.9974. The amount of caffeine in GS was about 4.649 mg/g (0.465%) in the three times analysis, and relative standard deviation (RSD) was less than 0.452% by the validated method. The anti-obesity effects of GS were evaluated by using Oil Red O staining in 3T3-L1 adipocytes and body weight, visceral fat and lipid profiles in high fat diet (HFD)-induced C57BL/6 obese mice. Our results indicated that treatment with GS dose-dependently decreased lipid accumulation contents (p<0.001). Moreover, after oral administration for 30 days feeding with HFD-induced obses mice, GS (100 and 300 mg/kg/day) produced a significant decrease in serum total cholesterol (TC), glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT) and visceral fat. Thus, the result of this study indicate that the GS may be a useful resource for the management of obesity.

Multifunctional antistress effects of standardized aqueous extracts from Hippophae rhamnoides L.

ABSTRACT This study aims to screen and identify the multi-mechanism antistress effects of an extract of Hippophae rhamnoides L. (HR) leaves on corticosterone (CORT)-induced injury, N-methyl-d-aspartate (NMDA) receptor and serotonin 6 (5-hydroxytryptamine 6, 5-HT6) receptor activity tests (in vitro), electric foot shock and forced swimming tests (FSTs) (in vivo), and tests for hippocampal CORT and monoamine levels (ex vivo), in search of active principles and underlying mechanisms of action. We confirmed that the water extract of HR (HRW) and various ethanol extracts of HR confer protective effects against CORT-induced impairments in SH-SY5Y cells and antagonistic effects on NMDA receptors and the 5-HT6 receptor by using primary cultured rat hippocampal neurons and a stable 5-HT6 receptor-expressing cell line, respectively. In addition, we confirmed the antistress effects of HRW in an electric foot shock stress model in mice and explored the underlying mechanisms of its action. We observed that HRW treatment significantly reversed the reduction in immobility times and increased climbing times in FSTs induced by electric foot shocks in the stress model. The levels of CORT, dopamine, and norepinephrine were increased, and the level of serotonin in the hippocampus was decreased in the electric foot shock stress model. The standardized HRW effectively restored abnormal CORT and monoamine levels in the hippocampus that were induced by stress. The results of the present study demonstrate that the standardized HRW produces novel multifunctional antistress effects.