Synthesis, Odour Characteristics, and Antimicrobial Activity of Optically Active (Z)-7-Decen-4-olide and Its Derivatives.

Six optically active (Z)-7-decen-4-olide derivatives (1a-1f) were synthesized in 99% enantiomeric excess using diastereomeric resolution. The odour properties of the racemic and optically active 1a-1f were evaluated in terms of their orthonasal aromas. All of the stereoisomers had different odour characteristics and thresholds. Decen-4-olides (1a-1c) had a strong fruity note, whereas undecen-4-olide (1d and 1e) and dodecen-4-olide (1f) had a strong green note. For 7-alken-4-olides (1a, 1d, and 1f), the (R)-enantiomer had a lower odour threshold than the (S)-enantiomer. In contrast, no difference in the odour threshold was observed for the enantiomers of the 8-alken-4-olides (1b and 1e). Furthermore, the antimicrobial activity against Escherichia coli (E. coli; ATCC 25922) and Staphylococcus aureus (S. aureus; ATCC 29213) were investigated. Although the no differences in the antimicrobial activity of the stereoisomers was observed, 1d and 1e showed slight antimicrobial activity against E. coli, whereas only 1f showed antimicrobial activity against S. aureus. No antimicrobial activity was exhibited by (R)-1f, whereas (S)-1f exhibited strong antimicrobial activity.

A basic charge cluster near the C-terminus of the cytoplasmic tail contributes to the molecular stability of human herpesvirus 8 E3 ubiquitin ligases.

Human herpesvirus 8 (HHV8; also known as Kaposi's sarcoma-associated herpesvirus [KSHV]) utilizes the viral E3 ubiquitin ligase family members K3 and K5 for immune evasion. Both K3 and K5 mediate the ubiquitination of host MHC class I (MHC-I) molecules, which play a key role in antigen presentation to cytotoxic T lymphocytes (CTLs). Because ubiquitinated MHC-I is immediately down-regulated from the cell surface, HHV8-infected cells can escape surveillance by CTLs. K3 and K5 have similar domain structures and topologies. They contain an N-terminal RINGv ubiquitin ligase domain, two transmembrane helices, and an intrinsically disordered cytoplasmic tail at the C-terminus. The cytoplasmic tail contains a membrane-proximal "conserved region" involved in ligase activity. On the other hand, the role of the membrane-distal region of the cytoplasmic tail, termed the "C-tail" in this study, remains unclear. Here, we demonstrate that the C-tail contributes to the protein expression of both K3 and K5. The C-tail-truncated K3 and K5 mutants were rapidly reduced in cells. The recombinant C-tail proteins bind to acidic lipids via a basic charge cluster located near the C-terminus of the C-tails. Similar to the C-tail-truncated mutants, the basic charge cluster-substituting mutants showed decreased protein expression of K3 and K5. These findings suggest that the basic charge cluster near the C-terminus of the cytoplasmic tail contributes to the molecular stability of K3 and K5.

Importance of accessibility to the extracellular juxtamembrane stalk region of membrane protein for substrate recognition by viral ubiquitin ligase K5.

Kaposi's sarcoma-associated herpesvirus (KSHV) is a carcinogenic virus that latently infects B cells and causes malignant tumors in immunocompromised patients. KSHV utilizes two viral E3 ubiquitin ligases, K3 and K5, in KSHV-infected cells to mediate the polyubiquitination-dependent down-regulation of several host membrane proteins involved in the immune system. Although K3 and K5 are members of the same family and have similar structural topologies, K3 and K5 have different substrate specificities. Hence, K5 may have a different substrate recognition mode than K3; however, the molecular basis of substrate recognition remains unclear. Here, we investigated the reason why human CD8α, which is known not to be a substrate for both K3 and K5, is not recognized by them, to obtain an understanding for molecular basis of substrate specificity. CD8α forms a disulfide-linked homodimer under experimental conditions to evaluate the viral ligase-mediated down-regulation. It is known that two interchain disulfide linkages in the stalk region between each CD8α monomer (Cys164-Cys164 and Cys181-Cys181) mediate homodimerization. When the interchain disulfide linkage of Cys181-Cys181 was eliminated, CD8α was down-regulated by K5 with a functional RING variant (RINGv) domain via polyubiquitination at the cytoplasmic tail. Aspartic acid, located at the stalk/transmembrane interface of CD8α, was essential for K5-mediated down-regulation of the CD8α mutant without a Cys181-Cys181 linkage. These results suggest that disulfide linkage near the stalk/transmembrane interface critically inhibits substrate targeting by K5. Accessibility to the extracellular juxtamembrane stalk region of membrane proteins may be important for substrate recognition by the viral ubiquitin ligase K5.

Kaposi's sarcoma-associated herpesvirus ubiquitin ligases downregulate cell surface expression of l-selectin.

Kaposi's sarcoma-associated herpesvirus (KSHV) is an oncogenic etiological factor for Kaposi's sarcoma and primary effusion lymphoma in immunocompromised patients. KSHV utilizes two immune evasion E3 ubiquitin ligases, namely K3 and K5, to downregulate the expression of antigen-presenting molecules and ligands of natural killer (NK) cells in the host cells through an ubiquitin-dependent endocytic mechanism. This allows the infected cells to evade surveillance and elimination by cytotoxic lymphocytes and NK cells. The number of host cell molecular substrates reported for these ubiquitin ligases is limited. The identification of novel substrates for these ligases will aid in elucidating the mechanism underlying immune evasion of KSHV. This study demonstrated that K5 downregulated the cell surface expression of l-selectin, a C-type lectin-like adhesion receptor expressed in the lymphocytes. Tryptophan residue located at the centre of the E2-binding site in the K5 RINGv domain was essential to downregulate l-selectin expression. Additionally, the lysine residues located at the cytoplasmic tail of l-selectin were required for the K5-mediated downregulation of l-selectin. K5 promoted the degradation of l-selectin through polyubiquitination. These results suggest that K5 downregulates l-selectin expression on the cell surface by promoting polyubiquitination and ubiquitin-dependent endocytosis, which indicated that l-selectin is a novel substrate for K5. Additionally, K3 downregulated l-selectin expression. The findings of this study will aid in the elucidation of a novel immune evasion mechanism in KSHV.

Lignosulfonate Rapidly Inactivates Human Immunodeficiency and Herpes Simplex Viruses.

Background: Very few studies of the antiviral potential of lignosulfonates have been published. With the aim of oral application, among various groups of natural products, the relative antiviral potency of lignosulfonate and its ability to rapidly inactivate viruses were investigated. Methods: As target cells, MT-4 cells in suspension and attached Vero cells were used for infections with human immunodeficiency virus (HIV) and human herpes simplex type-1 virus (HSV). Mock- or virus-infected cells were incubated for 3-5 days with various concentrations of test samples, and the viable cell number was determined with the MTT method. For the shorter exposure experiments, higher titers of HIV or HSV were exposed to test samples for 10 or 3 min, diluted to a normal multiplicity of infection (MOI), and applied to the cells. Antiviral activity was quantified by using the chemotherapy index. Results: In the long-exposure system, lignosulfonates showed comparable anti-HIV activity with those of AZT, ddC, and sulfated polysaccharides, and it exceeded those of hundreds of tannins and flavonoids. When the exposure time was shortened, the chemotherapeutic index of the lignosulfonates for HIV was increased 27-fold. At a physiological pH, lignosulfonate showed higher anti-HIV activity than commercial alkali-lignin, dealkali-lignin, and humic acid, possibly due to the higher solubility and purity. Conclusions: With their rapid virus-inactivation capabilities, lignosulfonates may be useful for the prevention or treatment of virally induced oral diseases.

Re-Evaluation of Chemotherapeutic Potential of Pyoktanin Blue.

Background: Pyoktanin blue (PB) is used for staining tissues and cells, and it is applied in photodynamic therapy due to its potent bactericidal activity. However, clinical application of PB as an antiviral and antitumor agent has been limited due to its potent toxicity. For clinical application, the antitumor and antiviral activity as well as the neurotoxicity of PB were re-evaluated with a chemotherapeutic index. Methods: Tumor-specificity (TS) was determined by the ratio of CC50 against normal oral cells/oral squamous cell carcinoma (OSCC); neurotoxicity by that of normal oral/neuronal cells; antiviral activity by that of mock-infected/virus-infected cells; and potency-selectivity expression (PSE) by dividing TS by CC50 (OSCC). Results: Antitumor activity of PB (assessed by TS and PSE) was comparable with that of DXR and much higher than that of 5-FU and melphalan. PB induced caspase-3 activation and subG1 cell accumulation in an OSCC cell line (Ca9-22). PB and anticancer drugs showed comparable cytotoxicity against both neuronal cells and OSCC cell lines. PB showed no detectable anti-HIV/HSV activity, in contrast to reverse transferase inhibitors, sulfated glucans, and alkaline extract of leaves of S.P. Conclusions: PB showed first-class anticancer activity and neurotoxicity, suggesting the importance of establishing the safe treatment schedule.

Elucidation of anti-HIV mechanism of sulfated cellobiose-polylysine dendrimers.

Three new spherical sulfated cellobiose-polylysine dendrimers of increasing generations bearing negatively charged sulfate groups were prepared by sulfating the corresponding cellobiose-polylysine dendrimers. The first, second, and third-generation derivatives exhibited potent anti-HIV activity with EC50 values of 3.7, 0.6, and 1.5 µg/mL, respectively, in constant to sulfated oligosaccharides with low anti-HIV activity, while the second-generation sulfated dendrimer was the most active. Surface plasmon resonance measurements with poly-l-lysine bearing positively charged amino acids as a model of the HIV surface glycoprotein gp120, indicated that the second-generation dendrimer had the lowest dissociation constant (KD = 1.86 × 10-12 M). Both the particle size and ζ potential increased in the presence of poly-l-lysine. It was proven that the moderate distance between the terminal sulfated cellobiose units in the second-generation dendrimer favored the high anti-HIV activity, owing to the electrostatic interactions developed due to the cluster effect.

Interaction between sulfated 3-O-octadecyl-α-(1→6)-d-glucan and liposomes analyzed by surface plasmon resonance.

To elucidate the role of long alkyl group in sulfated poly- and oligosaccharides on anti-HIV activity, the interaction between sulfated 3-O-octadecyl-(1→6)-α-d-glucopyranan with potent anti-HIV activity and liposomes with diameters of 58 ± 20 nm and 107 ± 28 nm as models of HIV were investigated. SPR measurements of sulfated 3-O-octadecyl-(1→6)-α-d-glucopyranans bearing 2.8 mol% of the octadecyl group and the liposome (diameter = 58 ± 20.0 nm and ζ=0 mV) resulted in an apparent association- ka = 6 × 105 1/M, a dissociation-rate kd = 4 × 10-4 1/s, and a dissociation constants KD = 8 × 10-10 M. The particle size of the sulfated 3-O-octadecyl-(1→6)-α-d-glucopyranan (67 ± 14 nm) measured by DLS increased to 104 ± 25 nm, whereas the ζ potential (-29 mV) was unchanged (-33 mV). For dextran sulfate without an alkyl group, no interaction was observed. These results suggest that the long octadecyl group penetrated into the liposome and sulfated glucopyranan was covered on the liposome to increase the anti-HIV activity. The 107 nm liposome exhibited similar results.

Analysis of interaction between sulfated polysaccharides and HIV oligopeptides by surface plasmon resonance.

This study aims to quantitatively investigate the interaction between sulfated polysaccharides with potent anti-HIV activity, dextran and curdlan sulfates with negatively charged sulfate groups, and poly-L-lysine as a model protein and oligopeptides from a HIV surface glycoprotein gp120 with positively charged amino acids using surface plasmon resonance (SPR) and dynamic light scattering (DLS) to elucidate the anti-HIV mechanism of sulfated polysaccharides. The apparent association- (ka) and dissociation rate (kd) constants of dextran and curdlan sulfates against poly-L-lysine were ka = 6.92 × 104-2.17 × 106 1/Ms and kd = 4.29 × 10-5-2.22 × 10-4 1/s; these kinetic constants were dependent on the molecular weights and degree of sulfation of sulfated polysaccharides. For interaction, the three oligopeptides from the HIV gp120 were peptide A 297TRPNNNTRKRIRIQRGPGRA316 with several lysine (K) and arginine (R) in the V3 loop region, peptide B 493PLGVAPTKAKRRVVQREKR511 with several K and R in the C-terminus region, and oligopeptide C 362KQSSGGDPEIVTHSFNCGG380 with few basic amino acids in the CD4 binding domain. Sulfated polysaccharides exhibited strong interaction against oligopeptides A and B, (ka = 5.48 × 104-2.96 × 106 1/Ms. and kd = 1.74 × 10-4-6.24 × 10-3 1/s), no interaction was noted against oligopeptide C. Moreover, the particle size and zeta potential by DLS indicated the interaction between sulfated polysaccharides and oligopeptides A and B, suggesting the anti-HIV mechanism of sulfated polysaccharides to be the electrostatic interaction of negatively charged sulfated polysaccharides and HIV at the positively charged amino acid regions.

Antimicrobial Susceptibilities of Oral Isolates of Abiotrophia and Granulicatella According to the Consensus Guidelines for Fastidious Bacteria.

Background: The genera Abiotrophia and Granulicatella, previously known as nutritionally variant streptococci (NVS), are fastidious bacteria requiring vitamin B6 analogs for growth. They are members of human normal oral microbiota, and are supposed to be one of the important pathogens for so-called "culture-negative" endocarditis. Methods: The type strains and oral isolates identified, by using both phenotypic profiles and the DNA⁻DNA hybridization method, were examined for susceptibilities to 15 antimicrobial agents including penicillin (benzylpenicillin, ampicillin, amoxicillin, and piperacillin), cephem (cefazolin, ceftazidime, ceftriaxone, and cefaclor), carbapenem (imipenem), aminoglycoside (gentamicin), macrolide (erythromycin), quinolone (ciprofloxacin), tetracycline (minocycline), glycopeptide (vancomycin), and trimethoprim-sulfamethoxazole complex. The minimum inhibitory concentration and susceptibility criterion were determined, according to the consensus guideline from the Clinical and Laboratory Standards Institute. Results: Isolates of Abiotrophia defectiva were susceptible to ampicillin, amoxicillin ceftriaxone, cefaclor, imipenem, ciprofloxacin, and vancomycin. Isolates of Granulicatella adiacens were mostly susceptible to benzylpenicillin, ampicillin, amoxicillin, cefazolin, ceftriaxone, imipenem, minocycline, and vancomycin. The susceptibility profile of Granulicatella elegans was similar to that of G. adiacens, and the susceptibility rate was higher than that of G. adiacens. Conclusions: Although Abiotrophia and Granulicatella strains are hardly distinguishable by their phenotypic characteristics, their susceptibility profiles to the antimicrobial agents were different among the species. Species-related differences in susceptibility of antibiotics should be considered in the clinical treatment for NVS related infections.

Exploring the Impact of Food on the Gut Ecosystem Based on the Combination of Machine Learning and Network Visualization.

Prebiotics and probiotics strongly impact the gut ecosystem by changing the composition and/or metabolism of the microbiota to improve the health of the host. However, the composition of the microbiota constantly changes due to the intake of daily diet. This shift in the microbiota composition has a considerable impact; however, non-pre/probiotic foods that have a low impact are ignored because of the lack of a highly sensitive evaluation method. We performed comprehensive acquisition of data using existing measurements (nuclear magnetic resonance, next-generation DNA sequencing, and inductively coupled plasma-optical emission spectroscopy) and analyses based on a combination of machine learning and network visualization, which extracted important factors by the Random Forest approach, and applied these factors to a network module. We used two pteridophytes, Pteridium aquilinum and Matteuccia struthiopteris, for the representative daily diet. This novel analytical method could detect the impact of a small but significant shift associated with Matteuccia struthiopteris but not Pteridium aquilinum intake, using the functional network module. In this study, we proposed a novel method that is useful to explore a new valuable food to improve the health of the host as pre/probiotics.

Quantitative Structure-Cytotoxicity Relationship of Newly Synthesized Piperic Acid Esters.

BACKGROUND/AIM: Eleven piperic acid esters were subjected to quantitative structure-activity relationship (QSAR) analysis based on their cytotoxicity and tumor-specificity, in order to find their new biological activities. MATERIALS AND METHODS: Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral normal mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC50) against normal cells to that against tumor cell lines. Potency-selectivity expression (PSE) value was calculated by dividing the TS value by CC50 against tumor cells. Apoptosis markers were detected by western blot analysis. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization. RESULTS: One phenylmethyl ester and five phenylethyl esters showed relatively higher cytotoxicity and tumor specificity, that were significantly modified by introduction of hydroxyl and methoxy groups. On the other hand, phenylpropyl ester, phenylbutyl ester and decyl ester were essentially inactive. (2E,4E)-5-(3,4-methylenedioxyphenyl)-2,4-pentadienoic acid 2-(3,4-dihydroxyphenyl)ethyl ester [4] had the highest TS and PSE values. This compound also stimulated the cleavage of caspase-3, suggesting the induction of apoptosis. TS values were correlated with molecular size, ionization potential, molecular shape, ionization potential and electronegativity. None of the compounds had any anti-HIV activity. CONCLUSION: Chemical modification of the lead compound may be a potential choice for designing a new type of anticancer drugs.

In situ depot formation of anti-HIV fusion-inhibitor peptide in recombinant protein polymer hydrogel.

Most peptide drugs have short half-lives, necessitating frequent injections that may induce skin sensitivity reactions; therefore, versatile prolonged-release delivery platforms are urgently needed. Here, we focused on an oxidatively and thermally responsive recombinant elastin-like polypeptide with periodic cysteine residues (cELP), which can rapidly and reversibly form a disulfide cross-linked network in which peptide can be physically incorporated. As a model for proof of concept, we used enfuvirtide, an antiretroviral fusion-inhibitor peptide approved for treatment of human immunodeficiency virus (HIV) infection. cELP was mixed with enfuvirtide and a small amount of hydrogen peroxide (to promote cross-linking), and the soluble mixture was injected subcutaneously. The oxidative cross-linking generates a network structure, causing the mixture to form a hydrogel in situ that serves as an enfuvirtide depot. We fabricated a series of enfuvirtide-containing hydrogels and examined their stability, enfuvirtide-releasing profile and anti-HIV potency in vitro. Among them, hydrophobic cELP hydrogel provided effective concentrations of enfuvirtide in blood of rats for up to 8 h, and the initial concentration peak was suppressed compared with that after injection of enfuvirtide alone. cELP hydrogels should be readily adaptable as platforms to provide effective depot systems for delivery of other anti-HIV peptides besides enfuvirtide. STATEMENT OF SIGNIFICANCE: In this paper, we present an anti-HIV peptide delivery system using oxidatively and thermally responsive polypeptides that contain multiple periodic cysteine residues as an injectable biomaterial capable of in situ self-gelation, and we demonstrate its utility as an injectable depot capable of sustained release of anti-HIV peptides. The novelty of this work stems from the platform employed to provide the depot encapsulating the peptide drugs (without chemical conjugation), which consists of rationally designed, genetically engineered polypeptides that enable the release rate of the peptide drugs to be precisely controlled.

Evaluation of Biological Activity of Mastic Extracts Based on Chemotherapeutic Indices.

BACKGROUND: Most previous mastic investigators have not considered its potent cytotoxicity that may significantly affect the interpretation of obtained data. In the present study, we re-evaluated several biological activities of mastic extracts, based on chemotherapeutic indexes. MATERIALS AND METHODS: Pulverized mastic gum was extracted with n-hexane and then with ethyl acetate or independently with methanol or n-butanol. Tumor specificity (TS) of the extracts was determined by their cytotoxicity against human malignant and non-malignant cells. Antibacterial activity was determined by their cytotoxicity against bacteria and normal oral cells. Antiviral activity was determined by their protection of viral infection and cytotoxic activity. Cytochrome P-450 (CYP) 3A4 activity was measured by ß-hydroxylation of testosterone. RESULTS: Ethyl acetate extract showed slightly higher tumor specificity (TS=2.6) and one order higher antibacterial activity (selectivity index (SI)=0.813) than other extracts (TS=1.4-2.5; SI=0.030-0.063). All extracts showed no anti-human immunodeficiency virus (HIV) activity, but some anti-herpes simplex virus (HSV) activity, which was masked by potent cytotoxicity. They showed strong inhibitory activity against CYP3A4. CONCLUSION: Ethyl acetate extraction following the removal of cytotoxic and CYP3A4 inhibitory substances by n-hexane can enhance antitumor and antibacterial activity of mastic.

Quantitative Structure-Cytotoxicity Relationship of Chalcones.

BACKGROUND: Fifteen chalcones were subjected to quantitative structure-activity relationship (QSAR) analysis based on their cytotoxicity and tumor specificity, in order to find their new biological activities. MATERIALS AND METHODS: Cytotoxicity against four human oral squamous cell carcinoma cell lines and three oral mesenchymal cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Tumor specificity (TS) was evaluated by the ratio of the mean 50% cytotoxic concentration (CC50) against normal cells to that against tumor cell lines. Potency-selectivity expression (PSE) value was calculated by dividing TS by CC50 against tumor cells. Apoptosis markers were detected by western blot analysis. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by force-field minimization. RESULTS: Among 15 chalcone derivatives, (2E)-1-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-2-propen-1-one had the highest TS and PSE values, comparable with those of doxorubicin and methotrexate, respectively. This compound also stimulated the cleavage of poly(ADP-ribose) polymerase and caspase-3. Chalone TS values were correlated with molecular shape and polarization rather than the types of substituted groups. None of the compounds had any anti-HIV activity. CONCLUSION: Chemical modification of the lead compound may be a potential choice for designing new types of anticancer drugs.

Antiviral and Antitumor Activity of Licorice Root Extracts.

BACKGROUND: In the search for anti-viral and antitumor substances from natural resources, antiviral and antitumor activities of licorice root extract and purified ingredients were investigated. MATERIALS AND METHODS: Viability of cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Antiviral activity was quantified by the selectivity index, defined as the ratio of the 50% cytotoxic concentration (CC50) to the 50% effective concentration against human immunodeficiency virus (HIV) or herpes simplex virus (HSV)-infected cells (EC50). The tumor specificity was calculated by the ratio of CC50 against human normal oral cells to that against human oral squamous cell carcinoma cell lines. Licorice flavonoids and lower molecular polyphenols were subjected to quantitative structure-activity relationship analysis. RESULTS: Alkaline extract of licorice root had higher anti-HIV activity than did water extracts, confirming our previous reports. On the other hand, water extract, especially the flavonoid-rich fraction, had higher anti-HSV activity than did the alkaline extract. The flavonoid-rich fraction was more cytotoxic against human oral squamous cell carcinoma cell lines compared to normal oral cells, suggesting their tumor-specific cytotoxicity. CONCLUSION: The present study suggests that water and alkaline extracts of licorice root exert different mechanisms of actions against these two viruses. Physicochemical properties, rather than the category of compounds, may be important in determining their anti-HSV activity.

Synergism of Alkaline Extract of the Leaves of Sasa senanensis Rehder and Antiviral Agents.

BACKGROUND: Previous studies have shown a much greater antiviral activity of alkaline extract of the leaves of Sasa senanensis Rehder (SE) against human immunodeficiency virus (HIV), compared to lignin precursors, tannins and flavonoids, suggesting its possible application to oral diseases. Systematic comparative study with herpes simplex virus (HSV) has been limited compared to that with HIV. In the present study, we investigated whether combination of SE with other popular antiviral agents further enhances their individual activity. MATERIALS AND METHODS: Cell viability of mock-infected, HIV-infected and HSV-infected cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The antiviral activity was evaluated by the selectivity index, defined as the ratio of 50% cytotoxic concentration to 50% effective concentration. Synergy between SE and antiviral agents was evaluated by MacSynerg and CompuSyn software. RESULTS: SE showed potent anti-HIV activity, although its activity was two-orders lower than that of azidothymidine, 2',3'-dideoxycytidine dextran sulfate and curdlan sulfate. Combination of SE with these antiviral agents produced synergistic effects. Using a newly established MTT assay system for anti-HSV activity, SE and acyclovir were found to have synergistic anti-HSV activity. CONCLUSION: The present study suggests the possible efficacy of the clinical application of SE combined with antiviral agents.

Chemically sulfated natural galactomannans with specific antiviral and anticoagulant activities.

Naturally occurring galactomannans were sulfated to give sulfated galactomannans with degrees of substitution of 0.7-1.4 per sugar unit and molecular weights of M¯n=0.6×10(4)-2.4×10(4). Sulfated galactomannans were found to have specific biological activities in vitro such as anticoagulant, anti-HIV and anti-Dengue virus activities. The biological activities were compared with those of standard dextran and curdlan sulfates, which are polysaccharides with potent antiviral activity and low cytotoxicity. It was found that sulfated galactomannans had moderate to high anticoagulant activity, 13.4-36.6unit/mg, compared to that of dextran and curdlan sulfates, 22.7 and 10.0unit/mg, and high anti-HIV and anti-Dengue virus activities, 0.04-0.8µg/mL and 0.2-1.1µg/mL, compared to those curdlan sulfates, 0.1µg/mL, respectively. The cytotoxicity on MT-4 and LCC-MK2 cells was low. Surface plasmon resonance (SPR) of sulfated galactomannans revealed strong interaction with poly-l-lysine as a model compound of virus proteins, and suggested that the specific biological activities might originate in the electrostatic interaction of negatively charged sulfate groups of sulfated galactomannans and positively charged amino groups of surface proteins of viruses. These results suggest that sulfated galactomannans effectively prevented the infection of cells by viruses and the degree of substitution and molecular weights played important roles in the biological activities.

Isolation and antiviral activity of water-soluble Cynomorium songaricum Rupr. polysaccharides.

The plant, Cynomorium songaricum Rupr., is used as a traditional medicine in China and Mongolia. In the present study, two new water-soluble polysaccharides isolated from C. songaricum Rupr. were purified by successive Sephadex G-75 and G-50 column chromatographies and then characterized by high resolution NMR and IR spectroscopies. The molecular weights of two polysaccharides were determined by an aqueous GPC to be [Formula: see text] = 3.7 × 10(4) and 1.0 × 10(4), respectively. In addition, it was found that the polysaccharide with the larger molecular weight was an acidic polysaccharide. It was found that the iodine-starch reaction of both isolated polysaccharides was negative and the methylation analysis gave 2, 4, 6-tri-O-methyl alditol acetate as a main product. NMR and IR measurements and sugar analysis revealed that both polysaccharides had a (1 â†’ 3)-α-d-glucopyranosidic main chain with a small number of branches. After sulfation, the sulfated C. songaricum Rupr. polysaccharides were found to have a potent inhibitory effect on HIV infection of MT-4 cells at a 50% effective concentration of 0.3-0.4 µg/ml, a concentration that has almost the same high activity as standard dextran and curdlan sulfates, EC50 = 0.35 and 0.14 µg/ml, respectively. The 50% cytotoxic concentration was low, CC50>1000 µg/ml. In addition, the interaction between the sulfated polysaccharides and poly-l-lysine as a model protein compound was investigated by a surface plasmon resonance to reveal the anti-HIV mechanism.

Quantitative Structure-Cytotoxicity Relationship of 3-Styryl-2H-chromenes.

BACKGROUND: Sixteen 3-styryl-2H-chromenes were subjected to quantitative structure-activity relationship analysis based on their cytotoxicity, tumor selectivity and anti-HIV activity, in order to find their new biological activities. MATERIALS AND METHODS: Cytotoxicity against four human oral squamous cell carcinoma (OSCC) cell lines, three mesenchymal and two epithelial normal oral cells was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Tumor-selectivity (TS) was evaluated by the ratio of the mean CC50 (50% cytotoxic concentration) against normal human oral cells to that against OSCC cell lines. Anti-HIV activity was evaluated by the ratio of CC50 to EC50 (50% cytoprotective concentration from HIV infection). Potency-selectivity expression (PSE) was determined by the ratio of TS/CC50 against OSCC. Physicochemical, structural and quantum-chemical parameters were calculated based on the conformations optimized by the LowModeMD method. RESULTS: All 3-styryl-2H-chromene derivatives showed relatively high tumor selectivity. Especially, the compound that has a methoxy group at 7-position of the chromene ring and chlorine at 4'-position of phenyl group in styryl moiety [ 12: ] showed the highest TS and PSE values, exceeding those of resveratrol, doxorubicin and 5-FU. All compounds showed no anti-HIV activity. Among 330 chemical descriptors, 8, 74 and 16 descriptors significantly correlated to the cytotoxicity of normal and tumor cells, and tumor-specificity, respectively. CONCLUSION: Multivariate statistics with chemical descriptors for molecular shape and flatness may be useful for the evaluation of tumor-specificity of 3-styryl-2H-chromenes.