Seon-Pyo Hong

Extracts from Citrus unshiu promote immune-mediated inhibition of tumor growth in a murine renal cell carcinoma model.

AIM OF THIS STUDY Citrus unshiu (Satsuma mandarin, SM) is a citrus fruit the peel of which has been used as a traditional Chinese medicine to treat common cold, relieve exhaustion, and cancer. In this study, we examined how effectively the content and peel extracts of SM can suppress cancer growth. The mechanism underlying cancer-suppressing properties of SM was investigated in tumor-bearing mice with renal carcinoma cell, Renca. MATERIALS AND METHODS Effectiveness of SM in tumor suppression was evaluated by measuring size of tumor mass in tumor-bearing mice treated with various doses of SM content and peel extracts. Proliferation of tumor cells and splenocytes was determined by MTT assay and [³H]TdR uptake, respectively. Relevant immunological mechanisms were chased by assaying cytokines including TGF-β, IL-6, IFN-γ, and TNF-α by ELISA. RESULTS The content and peel extracts of SM inhibited the growth of tumor cells in tumor-bearing mice. Especially, average tumor volume of two groups treated with 3 and 30 mg peel extracts per mouse weight (kg) were significantly decreased to 52.32% (p<0.05) and 68.72% (p<0.01), respectively. To identify tumor regression mechanism, anti-tumor cytokines measured in Con A-activated splenocytes from tumor-bearing mice. IFN-γ was increased in both of the peel extract-treated groups, while TNF-α, which had been decreased by tumor growth, was rescued to the normal level in SM content and peel extracts-treated groups. However, SM content and peel extracts did not inhibit proliferation and tumor-proliferative cytokines including TGF-β and IL-6 production of tumor cells. CONCLUSION These results indicate that SM content and peel extracts have anti-tumor properties in the tumor-bearing murine model. The mechanism underlying the anti-tumor effects of SM extracts is strongly suggested to be via boosting cytokines such as IFN-γ and TNF-α, enhancing immune-mediated anti-tumor properties.

A reversed-phase high-performance liquid chromatography method with pulsed amperometric detection for the determination of glycosides.

We have developed a reversed-phase high-performance liquid chromatography pulsed amperometric detection (RP-HPLC-PAD) method for the determination of glycosides. It is sensitive, repeatable, and selective without the pretreatment step. Ginsenosides were separated completely in 50 min using an water-acetonitrile gradient as the eluent and detected by PAD under NaOH alkaline conditions. The ginsenoside detection limit (S/N=3) was 0.02-0.07 ng and the quantification limit (S/N=10) was 0.1-0.2 ng. The coefficient of linear regression was 0.9984-0.9998 for concentrations between 1 and 50 microg/mL. The intra- and inter-day precision (RSD) was less than 6.35% in Ginseng Radix and Shy-jiun-tzyy-tang extracts. The average recoveries from Ginseng Radix and Shy-jiun-tzyy-tang extracts were 98.19-105.45% and 96.89-102.22%, respectively.

α-Cyperone, isolated from the rhizomes of Cyperus rotundus, inhibits LPS-induced COX-2 expression and PGE2 production through the negative regulation of NFκB signalling in RAW 264.7 cells

ETHNOPHARMACOLOGICAL RELEVANCE The rhizomes of Cyperus rotundus (Cyperaceae) have been used in Asian traditional medicine for the treatment of several inflammatory diseases. However, the anti-inflammatory effects of α-cyperone, a major active compound of Cyperus rotundus, are poorly understood. MATERIALS AND METHODS PGE2 and cytokines released from cells were measured using an EIA assay kit. The expression of iNOS, COX-2, TNF-α, and IL-6 was measured by real-time RT-PCR and/or Western blot analysis. A luciferase assay was performed to measure the effect of α-cyperone on NFκB activity. RESULTS The n-hexane fraction of the 80% EtOH extract from the rhizomes of Cyperus rotundus was found to inhibit both NO and PGE2 production in RAW 264.7 cells. α-Cyperone isolated from the n-hexane fraction significantly inhibited PGE2 production by suppressing the LPS-induced expression of inducible COX-2 at both the mRNA and the protein levels. In contrast, α-cyperone had little effect on NO production and iNOS expression. Additionally, α-cyperone downregulated the production and mRNA expression of the inflammatory cytokine IL-6. Moreover, treatment with α-cyperone suppressed the transcriptional activity of NFκB and the nuclear translocation of the p65 NFκB subunit in LPS-induced RAW 264.7 cells. CONCLUSION The anti-inflammatory activity of α-cyperone is associated with the down-regulation of COX-2 and IL-6 via the negative regulation of the NFκB pathway in LPS-stimulated RAW 264.7 cells.

Effects of the root bark of Paeonia suffruticosa on mitochondria-mediated neuroprotection in an MPTP-induced model of Parkinson’s disease

Parkinsons disease (PD) is generally characterized by the progressive loss of dopaminergic neurons projecting from the substantia nigra pars compacta (SNpc) to the striatum that results in movement dysfunction, but also entails mitochondrial dysfunction. The purpose of this study is to evaluate the protective effects of Moutan Cortex Radicis (MCE, Moutan peony) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD-like symptoms and to elucidate the underlying mechanisms of action, with a focus on mitochondrial function. In a rat primary mesencephalic culture system, MCE significantly protected dopaminergic neurons from the neurotoxic effects of 1-methyl-4-phenylpyridinium (MPP(+)), an active form of MPTP. Additionally, in a subacute mouse model of MPTP-induced PD, MCE resulted in enhanced recovery from PD-like motor symptoms, including increased locomotor activity and reduced bradykinesia. MCE increased dopamine availability and protected against MPTP-induced dopaminergic neuronal damage. Moreover, MCE inhibited MPTP-induced mitochondrial dysfunction and resulted in increased expression of phosphorylated Akt, ND9, mitochondrial transcription factor A, and H2AX in the SNpc. Mitochondria-mediated apoptosis was also inhibited, via the regulation of B-cell lymphoma family proteins and the inhibition of cytochrome C release and caspase-3 activation. These results indicate that MCE has neuroprotective effects in PD models and may be useful for preventing or treating PD.

TNF-α and LPS activate angiogenesis via VEGF and SIRT1 signalling in human dental pulp cells.

AIM To assess whether SIRT1 and VEGF are responsible for tumour necrosis factor-α (TNF-α) and lipopolysaccharide (LPS)-induced angiogenesis and to examine the molecular mechanism(s) of action in human dental pulp cells (HDPCs). METHODOLOGY Immortalized HDPCs obtained from Prof. Takashi Takata (Hiroshima University, Japan) were treated with LPS (1 μg mL(-1) ) and TNF-α (10 ng mL(-1) ) for 24 h. mRNA and protein levels were examined by RT-PCR and Western blotting, respectively. Migration and tube formation were examined in human umbilical vein endothelial cells (HUVECs). The data were analysed by one-way anova. Statistical analysis was performed at α = 0.05. RESULTS LPS and TNF-α upregulated VEGF and SIRT1 mRNA and protein levels. Inhibition of SIRT1 activity by sirtinol and SIRT1 siRNA or inhibition of the VEGF receptor by CBO-P11 significantly attenuated LPS + TNF-α-stimulated MMPs production in HDPCs, as well as migration and tube formation in HUVECs (P < 0.05). Furthermore, sirtinol, SIRT1 siRNA and CBO-P11 attenuated phosphorylation of Akt, extracellular signal-regulated kinase (ERK), p38 and c-Jun N-terminal kinase (JNK) and the nuclear translocation of NF-κB p65. Pre-treatment with inhibitors of p38, ERK, JNK, PI3K and NF-κB decreased LPS + TNF-α-induced VEGF and SIRT1 expression, MMPs activity in HDPCs and angiogenesis (P < 0.05) in HUVECs. CONCLUSIONS TNF-α and LPS led to upregulation of VEGF and SIRT1, and subsequent upregulation of MMP-2 and MMP-9 production, and promote angiogenesis via pathways involving PI3K, p38, ERK, JNK and NF-κB. The results suggest that inhibition of SIRT1 and VEGF might attenuate pro-inflammatory mediator-induced pulpal disease.

Chiral separation of β-blockers after derivatization with (-)-α-Methoxy-α-(trifluoromethyl)phenylacetyl chloride by gas chromatography

Gas chromatographic method was investigated for the chiral separation of several β-block-ers(atenolol, betaxolol, bisoprolol, metoprolol and pindolol) using (-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride as a chiral derivatizing agent for amino group. Prior to N-acylation, hydroxyl group was converted intoO-silyl ethers by react withN-methyl-N-(tri-methylsilyl)trifluoroacetamide. The reaction was selective and rapid and the diastereomeric derivatives were well separated by capillary gas chromatography. (R)-isomers were eluted faster than (S)-isomers when (-)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride was used as the chiral derivatizing agent. But in the opposite sequence when (+)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride was used. No racemization was found during the reaction.

Reversed-phase high performance liquid chromatographic separation of the enantiomers of terbutaline by derivatization with 2,3,4,6-tetra-o-acetyl-β-D-glucopyranosyl isothiocyanate

The enantiomers of the bronchodilator terbutaline were separated by reversed-phase high performance liquid chromatography after derivatization with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate(GITC) reagent. The derivatization proceeded quantitatively within 1 h at room temperature. The corresponding diastereomeric thiourea derivatives were well resolved on an ODS column with acetonitrile-acetate buffer as a mobile phase. Elution orders of the diastereomers were confirmed by derivatization of R-(−)-terbutaline and S-(+)-terbutaline which were collected by semi-preparative chiral HPLC using Sumichiral OA-4700 column. The native fluorescence of terbutaline was quenched by derivatization with GITC. The detection limit was 25ng when monitored at UV 278 nm.

Comparative study of naphthalene-2,3-dicarboxaldehyde and o-phthalaldehyde fluorogenic reagents for chromatographic detection of sphingoid bases.

Naphthalene-2,3-dialdehyde (NDA) was developed as a precolumn labeling reagent for the fluorescent determination in a HPLC system of bioactive sphingoid bases, including sphingosine, sphinganine, and C20-sphinganine. Cellular sphingoid bases generally exist in the range of 10 to approximately 100 pmol/10(6) cells in a wide variety of cell types and tissues. This study aimed to obtain stable fluorescent derivatives of sphingoid bases and to increase their detectability at low concentrations. Sphingoid bases were reacted with NDA in the presence of cyanide ion to readily make an intensely fluorescent structure, 1-cyano-2-alkyl-benz[f]isoindole (CBI) and were then eluted separately on a reversed-phase C18 column with a simple mobile phase of 90% acetonitrile. For evaluating the NDA method, we compared the fluorescent intensity, elution profile, stability, and detectability of NDA derivatives with those of corresponding o-phthalaldehyde (OPA) derivatives. By monitoring the fluorescent intensity at the excitation wavelength of 252 nm and emission wavelength of 483 nm, NDA derivatives were sensitively determined at concentrations below 1.0 pmol of sphingoid bases in 1 x 10(5) U937 cells and were more stable than OPA derivatives. Linear calibration plots were obtained in the range studied (0.5 to approximately 500 nM). The limit of detection for NDA derivatives of sphingoid bases was approximately 0.1 pmol (S/N=3). The method successfully measured the accumulation of sphingosine in U937 cells following N,N-dimethylsphingosine treatment, and of sphinganine following fumonisin B1 treatment.

Chiral separation of β2-agonists by capillary electrophoresis using hydroxypropyl-α-cyclodextrin as a chiral selector

Enantiomers of five racemic β2-agonists were investigated by capillary electrophoresis employing a hydroxypropyl-β-cyclodextrin (HP-β-CD). The effects of the concentration of HP-β-CD added to the background electrolyte and of the pH of the buffer on the effective mobility and resolution of the studied compounds were examined. Very good resolution was achieved for terbutaline and clenbuterol; salbutamol and bambuterol was able to be partially resolved. Enantioselectivity and resolution were influenced by the concentration of the HP-β-CD, buffer composition and pH.

Chiral separation of the enantiomers of metoprolol and its metabolites by high performance liquid chromatography

Abstract(1′R, 2R)-, (1′R, 2S)-, (1′S, 2R)- and (1′S, 2S)-α-hydroxymetoprolol; (2R)- and (2S)-O-desmethylmetoprolol; and (2R)- and (2S)-metoprolol acid are major metabolites of (2R)-and (2S)-metoprolol, β-adrenergic antagonist. The focus of most chiral separation methods until now has been on determination of the enantiomeric parent drug. However, it is just as important to be able to follow the metabolism of the enantiomers and their possible chiral metabolites. Therefore, for the study of stereoselective metabolism and pharmacokinetic of metoprolol, the chiral separation of the enantiomers of metoprolol and its metabolites has been investigated using four chiral stationary phases, i.e., Chiralcel OD, Chiral-AGP, Cyclobond I and Sumichiral OA-4900 columns. Metoprolol acid was resolved only by Sumichiral OA-4900. Chiralcel OD provided the highest separation factor and resolution value for metoprolol and O-desmethylmetoprolol and partially resolved the four stereoisomers of α-hydroxymetoprolol. Diastereomeric α-hydroxymetoprolols were resolved using the coupled column chromatographic system of two chiral stationary phases, Sumichiral OA-4900 column and Chiralcel OD column.