Anti-herpesvirus activities of Pseudomonas sp. S-17 rhamnolipid and its complex with alginate

The rhamnolipid biosurfactant PS-17 and its complex with the polysaccharide alginate, both produced by the Pseudomonas sp. S-17 strain, were studied for their antiviral activity against herpes simplex virus (HSV) types 1 and 2. They significantly inhibited the herpesvirus cytopathic effect (CPE) in the Madin-Darby bovine kidney (MDBK) cell line. The investigations were carried out according to the CPE inhibition assay protocol. The suppressive effect of the compounds on HSV replication was dose-dependent and occurred at concentrations lower than the critical micelle concentration of the surfactant. The 50% inhibitory concentration (IC50) of rhamnolipid PS-17 was 14.5 microg/ml against HSV-1 and 13 microg/ml against HSV-2. The IC50 values of the complex were 435 microg/ml for HSV-1 and 482 microg/ml for HSV-2. The inhibitory effects of the substances were confirmed by measuring the infectious virus yields with the multicycle virus growth experimental design as well: deltalog CCID50 of 1.84-2.0 against the two types of herpes simplex viruses by rhamnolipid PS-17 (20 microg/ml), and a strong reduction of the HSV-2 virus yield under the effect of the alginate complex at a concentration of 450 microg/ml. The results indicate that rhamnolipid PS-17 and its alginate complex may be considered as promising substances for the development of anti-herpetic compounds.     

The in vitro antiviral activity of an aliphatic nitro compound from Heteropteris aphrodisiaca

We investigated the antiviral activity of an aliphatic nitro compound (NC) isolated from Heteropteris aphrodisiaca O. Mach. (Malpighiaceae), a Brazilian medicinal plant. The NC was tested for its antiviral activity against poliovirus type 1 (PV-1) and bovine herpes virus type 1 (BHV-1) by plaque reduction assay in cell culture. The NC showed a moderate antiviral activity against PV-1 and BHV-1 in HEp-2 cells, and the 50% inhibitory concentration (IC50) were 22.01 microg/ml (selectivity index (SI)=2.83) and 21.10 microg/ml (SI=2.95), respectively. At the highest concentration of the drug (40 microg/ml) a reduction of approximately 80% in plaque assay was observed for both viruses. The treatment of cells or virus prior to infection did not inhibit the replication of virus strains.     

Anti-herpes simplex virus activity of sulfated galactans from the red seaweeds Gymnogongrus griffithsiae and Cryptonemia crenulata

This study presents the chemical composition and antiviral activity against herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) of sulfated galactan crude extracts and main fractions obtained from two red seaweeds collected in Brazil, Gymnogongrus griffithsiae and Cryptonemia crenulata. Most of the eighteen tested products, including homogeneous kappa/iota/nu carrageenan and DL-galactan hybrid, exhibited antiherpetic activity with inhibitory concentration 50% (IC50) values in the range 0.5-5.6 microg/ml, as determined in a virus plaque reduction assay in Vero cells. The galactans lacked cytotoxic effects and showed a broad spectrum of antiviral activity against HSV-1 and HSV-2. No direct virus inactivation was observed after virion treatment with the galactans. The mode of action of these compounds could be mainly ascribed to an inhibitory effect on virus adsorption. Most importantly, a significant protection against a murine vaginal infection with HSV-2 was afforded by topical treatment with the sulfated galactans.     

Anti-herpetic activity of a sulfated xylomannan from Scinaia hatei

Many viruses display affinity for cell surface heparan sulfate proteoglycans with biological relevance in virus entry. This raises the possibility of the application of sulfated polysaccharides in antiviral therapy. In this study we have analyzed polysaccharide fractions isolated from Scinaia hatei. The crude water extract (ShWE) as well as one fraction (F1) obtained by size exclusion chromatography had potent anti-HSV activity. Their inhibitory concentration 50% (IC50) values ranging from 0.5 to 4.6 microg/ml were much lower than the cytotoxic concentration 50% (CC50) values (1000 microg/ml). These fractions had very low anticoagulant activity. Furthermore, they had a weak inactivating effect on virions in a virucidal assay at concentrations in the range of 60-100 microg/ml. Chemical, chromatographic and spectroscopic methods showed that the major polysaccharide, which had 0.4 sulfate group per monomer unit and an apparent molecular mass of 160 kDa, contained a backbone of alpha-(1-->3)-linked D-mannopyranosyl residues substituted at C-6, C-4 and C-2 with single stub of beta-d-xylopyranosyl residues. Sulfate groups, when present, are located at C-4 of alpha-(1-->3)-linked D-mannopyranosyl units, and appeared to be very important for the anti-herpetic activity of this polymer.     

Synthesis and anti-herpes simplex viral activity of monoglycosyl diglycerides

Based on the discovery of antiviral beta-galactosyl diglycerides from Clinacanthus nutans leaves, 19 monoglycosyl diglycerides were synthesized and examined for inhibitory effect on herpes simplex virus types 1 and 2 (HSV-1, HSV-2). A study of the structure-activity relationships of the synthetic monoglycosyl diglycerides indicated that the fatty acyl moieties were critical for inhibitory action with higher activity displayed as the acyl groups became more olefinic in character. The sugar moiety was also important for anti-HSV action; however, the type of sugar (glucose or galactose) did not affect activity. The stereochemistry at C-2 of the glycerol backbone displayed no significant effect on anti-HSV activity. Among the compounds synthesized, 1,2-O-dilinolenoyl-3-O-beta-D-glucopyranosyl-sn-glycerol showed the highest inhibitory activity against HSV-1 and HSV-2 with IC50 values of 12.5+/-0.5 and 18.5+/-1.5 microg/ml, respectively.     

Structure–Activity Relationships for Six Ketolide Antibiotics

Six structurally related 3-keto-substituted macrolide antibiotics (ketolides) were compared for concentration-dependent inhibitory effects on growth rate, viable cell number, and protein synthesis rates in Staphylococcus aureus cells. Inhibitory effects on 50S ribosomal subunit formation were also examined, as this is a second target for these antibiotics. A concentration range of 0.01 to 0.1 microg/ml was tested. An IC50 for inhibition of translation and 50S synthesis was measured for each compound, to relate structural features to inhibitory activity. ABT-773 was the most effective of the six compounds tested with an IC50 = 0.035 microg/ml. HMR 3004 was almost as effective with an IC50 = 0.05 microg/ml. Two 2-fluoroketolides (HMR 3562 and HMR 3787) were equivalent in their inhibitory activity with an IC50 = 0.06 microg/ml. Telithromycin (HMR 3647) had an IC50 = 0.08 microg/ml, and HMR 3832 was least effective with an IC50 = 0.11 microg/ml. Each antibiotic had an equivalent inhibitory effect on translation and 50S subunit formation. These results indicate specific structural features of these antimicrobial agents, which contribute to defined inhibitory activities against susceptible organisms.     

The effect of betel nut extract on cell growth and prostaglandin endoperoxide synthase in human epidermoid carcinoma cells

The objective of this study was to find out whether prostaglandin endoperoxide synthase (PHS) involves the action of betel nut extract (BNE) on the growth of oral cancers. Therefore, growth and PHS activity were examined in two human oral carcinoma cell lines (OEC-M1 and KB) and one normal fibroblast cell line (NF) in the presence of increasing BNE concentration. BNE at concentrations above 50 microg/ml significantly inhibited the cell growth of OEC-M1 after 72 h in culture, of KB and NF after 48 h in culture. The IC50 of BNE in OEC-M1, KB and NF at 24 h in culture was about 406, 37.5 and 140 microg/ml respectively. PHS activity in OEC-M1 was significantly increased by low BNE concentrations (50 microg/ml, 114%; 100 microg/ml, 33%; 150 microg/ml, 30%) but significantly reduced at higher BNE concentrations (300 microg/ml, 33%; 500 microg/ml, 61%). The PHS activity in KB was significantly inhibited by BNE and this effect was intensified as concentrations increased (50 microg/ml, 31%; 100 microg/ml, 24%; 150 microg/ml, 43%; 300 microg/ml, 60%; 500 microg/ml, 92%). Similar to that in OEC-M1, the PHS activity in NF was significantly increased at low BNE concentrations (50 microg/ml, 139%; 100 microg/ml, 87%;150 microg/ml, 77%) but reduced at higher concentrations (300 microg/ml, 55%; 500 microg/ml, 72%). The PHS activity in all cell lines was almost completely blocked by indomethacin (5 x 10(-6) M). We conclude that these findings suggest that PHS may be an important biochemical mediator of the effect of BNE on the growth of two human oral carcinoma cell lines.     

Inhibition of type 1 and type 2 5alpha-reductase activity by free fatty acids,active ingredients of Permixon

In different cell systems, the lipido-sterolic extract of Serenoa repens (LSESr, Permixon inhibits both type 1 and type 2 5alpha-reductase activity (5alphaR1 and 5alphaR2). LSESr is mainly constituted of fatty acids (90+/-5%) essentially as free fatty acids (80%). Among these free fatty acids, the main components are oleic and lauric acids which represent 65% and linoleic and myristic acids 15%.To evaluate the inhibitory effect of the different components of LSESr on 5alphaR1 or 5alphaR2 activity, the corresponding type 1 and type 2 human genes have been cloned and expressed in the baculovirus-directed insect cell expression system Sf9. The cells were incubated at pH 5.5 (5alphaR2) and pH 7.4 (5alphaR1) with 1 or 3nM testosterone in presence or absence of various concentrations of LSESr or of its different components. Dihydrotestosterone formation was measured with an automatic system combining HPLC and an on-line radiodetector.The inhibition of 5alphaR1 and 5alphaR2 activity was only observed with free fatty acids: esterified fatty acids, alcohols as well as sterols assayed were inactive. A specificity of the fatty acids in 5alphaR1 or 5alphaR2 inhibition has been found. Long unsaturated chains (oleic and linolenic) were active (IC(50)=4+/-2 and 13+/-3 microg/ml, respectively) on 5alphaR1 but to a much lesser extent (IC(50)>100 and 35+/-21 microg/ml, respectively) on 5alphaR2. Palmitic and stearic acids were inactive on the two isoforms. Lauric acid was active on 5alphaR1 (IC(50)=17+/-3 microg/ml) and 5alphaR2 (IC(50)=19+/-9 microg/ml). The inhibitory activity of myristic acid was evaluated on 5alphaR2 only and found active on this isoform (IC(50)=4+/-2 microg/ml).The dual inhibitory activity of LSESr on 5alpha-reductase type 1 and type 2 can be attributed to its high content in free fatty acids.     

Inhibition of AIDS virus replication by acemannan in vitro.

Acemannan (ACE-M), a beta-(1,4)-linked acetylated mannan, was evaluated for in vitro activity against human immunodeficiency virus type 1 (HIV-1). Castanospermine (CAS), deoxymannojirimycin (DMN), swainsonine (SWS), azidothymidine (AZT), and dideoxythymidine (DDC) were tested in parallel as control compounds. In vitro antiviral efficacy of ACE-M was evaluated in a variety of cell lines including human peripheral mononuclear, CEM-SS1 and MT-2(2) cells. The virus strain, number of infectious units per cell, and target cell line were important factors in determining the degree of inhibition of viral cytopathic effect in the presence of ACE-M and other control compounds tested. Maximum inhibitory effect was observed in CEM-SS cells infected with the RFII strain of HIV-1. This inhibitory effect was determined to be concentration-dependent. Assay design included primary screening to measure cell viabilities of infected target cells in the presence and absence of test compounds. When tested on HIV-1/RFII-infected CEM-SS cells, the 50% inhibitory effect of CAS (IC50 = 28), an inhibitor of alpha-glucosidase I, was determined to be similar to that observed for ACE-M (IC50 = 45). However, DMN and SWS, inhibitors of mannosidase I and II, tested in parallel to CAS and ACE-M, exhibited no IC50 values. Antiviral potential of ACE-M as an inhibitor of syncytia formation was also explored using CEM-SS cells. Suppression of syncytia formation was observed at an ACE-M concentration of 31.25 micrograms/ml, and complete inhibition was observed at 62.5 micrograms/ml. In addition, HIV-1 RNA levels were studied to establish the antiviral potential of ACE-M in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antiviral isoflavonoid sulfate and steroidal glycosides from the fruits of Solanum torvum

The C-4 sulfated isoflavonoid, torvanol A (1), and the steroidal glycoside, torvoside H (3), together with the known glycoside, torvoside A (2), were isolated from a MeOH extract of Solanum torvum fruits. Upon enzymatic hydrolysis with beta-glucosidase, torvoside A (2) and torvoside H (3) yielded the corresponding acetal derivatives 4 and 5, respectively. Torvanol A (1), torvoside H (3) and compound 5 exhibited antiviral activity (herpes simplex virus type 1) with IC(50) values of 9.6, 23.2 and 17.4 microg/ml, respectively. Compounds 1-5 showed no cytotoxicity (at 50 microg/ml) against BC, KB and Vero cell lines.     

QiHong prevents death in coxsackievirus B3 induced murine myocarditis through inhibition of virus attachment and penetration

Viral myocarditis affects about 5% to 20% of the population. So far, there are not many effective antiviral treatments available. QiHong, the combination of the extracts from Astragali (Huangqi), Rhadiola rosea (Hongjingtian), and Sophora flavescens (Kushen), was developed based on laboratory research. The aim of this study was to investigate the effect and mechanism of QiHong on coxsackievirus B3 (CVB3)-induced myocarditis. The antiviral activity of QiHong in vitro was evaluated on HeLa and Vero cells infected by CVB3. Ribavirin was chosen as positive control. Our results showed that QiHong possessed potent antiviral effects on CVB3 by sodium 3'-[1-(phenylamino-carbonyl)-3, 4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid and plaque-forming assay (50% inhibitory concentrations [IC50] were 7.16 +/- 0.8 microg/ml and 2.63 +/- 0.5 microg/ml, respectively). The 50% cytotoxicity concentration (CC50) was 16-fold higher in QiHong-treated cells than in ribavirin-treated cells. Time course studies demonstrated that the antiviral effect of QiHong was mainly found during 0-4 hrs of infection, and it blocked the attachment and penetration of CVB3 into cells. In vivo 4-week-old male Balb/C mice were used and inoculated intraperitoneally with CVB3 suspension or normal saline. At 48 hrs after inoculation, the infected mice were gavaged with QiHong or ribavirin. On Day 6, myocardial virus titers were significantly lower in the QiHong-treated group than in the viral-infected groups. On Day 14, QiHong significantly ameliorated CVB3-induced myocardium necrosis; on Day 28, QiHong treatment increased survival rate 4-fold compared with CVB3-infected controls (64% vs. 16%; P < 0.05). The results showed that QiHong is a very promising potent antiviral agent with a highly significant favorable effect on survival and pathologic changes in CVB3-induced myocarditis with less toxicity than ribavirin. The antiviral activity of QiHong is at least partially due to an inhibitory effect on virus attachment and penetration.     

Antiviral flavonoids from the root bark of Morus alba L

A prenylated flavonoid, moralbanone, along with seven known compounds kuwanon S, mulberroside C, cyclomorusin, eudraflavone B hydroperoxide, oxydihydromorusin, leachianone G and alpha-acetyl-amyrin were isolated from the root bark of Morus alba L. Leachianone G showed potent antiviral activity (IC(50) = 1.6 microg/ml), whereas mulberroside C showed weak activity (IC(50) = 75.4 microg/ml) against herpes simplex type 1 virus (HSV-1). Their structures were elucidated by spectroscopic methods.     

Novel biologically active bibenzyls from Bauhinia saccocalyx Pierre

Four new bibenzyls, bauhinols A-D (1-4), together with the two known bibenzyls 5 and 6, were isolated from the roots of Bauhinia saccocalyx, and their structures were elucidated by analyses of spectroscopic data. Bauhinol A (1) exhibits significant cytotoxicity towards NCI-H187 (small-cell lung cancer), BC (breast cancer), and KB (oral-cavity cancer) cell lines, with IC50 values of 2.7-4.5 microg/ml. Bauhinol B (2) is cytotoxic against NCI-H187 (IC50 = 1.1 microg/ml) and BC (IC50 = 9.7 microg/ml) cell lines, but inactive toward the KB cell line (at 20 microg/ml). Compound 2 also is mildly antifungal towards Candia albicans (IC50 = 28.9 microg/ml). Bibenzyl 6 is active against NCI-H187 (IC50 = 14.1 microg/ml) and BC (IC50 = 4.0 microg/ml) cells, but inactive (at 20 microg/ml) toward the KB cell line. Compounds 1, 2, and 6 show mild antimycobacterial activities, with MIC values of 25-50 microg/ml, but are inactive at 20 microg/ml against the K1 malarial parasite strain (Plasmodium falciparum). While bauhinol A (1) is inactive against cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2), compounds 2 and 6 inhibit both COX-1 and COX-2, with IC50 values comparable to those of the standard drug, aspirin (Table 3).     

Antileishmanial activity of Eugenol-rich essential oil from Ocimum gratissimum

Leishmaniasis is a group of diseases with a large spectrum of clinical manifestations caused by protozoans of the genus Leishmania. Here we demonstrate the leishmanicidal activity of the essential oil of Ocimum gratissimum as well as its main constituent, eugenol. The eugenol-rich essential oil of O. gratissimum progressively inhibited Leishmania amazonensis growth at concentrations ranging from 100 to 1000 microg/ml. The IC50 (sub-inhibitory concentration) of the essential oil for promastigotes and amastigotes were respectively 135 and 100 microg/ml and the IC50 of eugenol was 80 microg/ml for promastigote forms. L. amazonensis exposed to essential oil at concentrations corresponding to IC50 for promastigotes and for amastigotes underwent considerable ultrastructural alterations, as shown by transmission electron microscopy. Two or more nuclei or flagella were observed in 31% and 23.3% of treated amastigote and promastigote forms, respectively, suggesting interference in cell division. Considerable mitochondrial swelling was observed in essential oil-treated promastigotes and amastigotes, which had the inner mitochondrial membrane altered, with a significant increase in the number of cristae; in some amastigotes the mitochondrial matrix became less electron-dense. The minimum inhibitory concentration for both promastigotes and amastigotes was 150 microg/ml. Pretreatment of mouse peritoneal macrophages with 100 and 150 microg/ml essential oil reduced the indices of association between promastigotes and the macrophages, followed by increased in nitric oxide production by the infected macrophages. The essential oil showed no cytototoxic effects against mammalian cells. This set of results suggests that O. gratissimum essential oil and its compounds could be used as sources for new antileishmanial drugs.     

Antiviral and antimicrobial assessment of some selected flavonoids

In the current study, the results of antibacterial, antifungal, and antiviral activity tests of four flavonoid derivatives, scandenone (1), tiliroside (2), quercetin-3,7-O-alpha-L-dirhamnoside (3), and kaempferol-3,7-O-alpha-L-dirhamnoside (4), are presented. Antibacterial and antifungal activities of these compounds were tested against Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella pneumoniae, Acinetobacter baumannii, Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis, as well as the fungus Candida albicans by a micro-dilution method. On the other hand, both DNA virus Herpes simplex (HSV) and RNA virus Parainfluenza-3 (PI-3) were employed for antiviral assessment of the compounds using Madin-Darby bovine kidney and Vero cell lines. According to our data, all of the compounds tested were found to be quite active against S. aureus and E. faecalis with MIC values of 0.5 microg/ml, followed by E. coli (2 microg/ml), K. pneumoniae (4 microg/ml), A. baumannii (8 micro/g/ml), and B. subtilis (8 microg/ml), while they inhibited C. albicans at 1 microg/ml as potent as ketoconazole. However, only compound 3 displayed an antiviral effect towards PI-3 in the range of 8-32 microg/ml of inhibitory concentration for cytopathogenic effect (CPE).     

Effects of the dietary phytoestrogen biochanin A on cell growth in the mammary carcinoma cell line MCF-7

Studies of the dietary phytoestrogen biochanin A on cell proliferation of the cultured estrogen responsive cells human breast carcinoma MCF-7 showed that biochanin A exhibits biphasic regulation on MCF-7 cells. At concentrations of less than 10 microg/mL, cells respond to biochanin A by increasing cell growth and de novo DNA synthesis. The addition of biochanin A at concentrations of greater than 30 microg/mL significantly inhibited cell growth and DNA synthesis in a dose-dependent fashion, resulting in an IC(50) value of 40 microg/mL. The reversibility of these inhibitory effects by biochanin A appears also to be concentration dependent. Cells previously treated with high concentrations (>60 microg/mL) of biochanin A did not regain normal growth after treatment ceased. Biochanin A was cytostatic at low concentrations (<40 microg/mL) and cytotoxic at higher concentrations. Upon exposure to 100 microg/mL of biochanin A, cell morphology was severely altered, cell volume decreased, and condensation of cell components was clearly noticeable. In addition, biochanin A damaged cell membranes by increasing membrane permeability. These results suggest possible molecular and cellular mechanisms of the action of dietary phytoestrogens on estrogen target cells.     

Antioxidant effects of an aqueous extract of Ilex paraguariensis

In this work we investigate the antioxidant properties of an aqueous extract prepared from an infusion of Ilex paraguariensis (Aquifoliaceae) using free radical-generating systems. The extract inhibited the enzymatic and nonenzymatic lipid peroxidation in rat liver microsomes in a concentration-dependent fashion, with IC(50) values of 18 microg/ml and 28 microg/ml, respectively. The extract also inhibited the H(2)O(2)-induced peroxidation of red blood cell membranes with an IC(50) of 100 microg/ml and exhibited radical scavenging properties toward superoxide anion (IC(50) = 15 microg/ml) and 2,2-diphenyl-1-picrylhydrazyl radical. In the range of concentrations used, the extract was not a scavenger of the hydroxyl radical. Our results suggest that ingestion of extracts of Ilex paraguariensis could contribute to increase the antioxidant defense of an organism against free radicals attack.     

Virucidal effect of peppermint oil on the enveloped viruses herpes simplex virus type 1 and type 2 in vitro

The virucidal effect of peppermint oil, the essential oil of Mentha piperita, against herpes simplex virus was examined. The inhibitory activity against herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) was tested in vitro on RC-37 cells using a plaque reduction assay. The 50% inhibitory concentration (IC50) of peppermint oil for herpes simplex virus plaque formation was determined at 0.002% and 0.0008% for HSV-1 and HSV-2, respectively. Peppermint oil exhibited high levels of virucidal activity against HSV-1 and HSV-2 in viral suspension tests. At noncytotoxic concentrations of the oil, plaque formation was significantly reduced by 82% and 92% for HSV-1 and HSV-2, respectively. Higher concentrations of peppermint oil reduced viral titers of both herpesviruses by more than 90%. A clearly time-dependent activity could be demonstrated, after 3 h of incubation of herpes simplex virus with peppermint oil an antiviral activity of about 99% could be demonstrated. In order to determine the mode of antiviral action of the essential oil, peppermint oil was added at different times to the cells or viruses during infection. Both herpesviruses were significantly inhibited when herpes simplex virus was pretreated with the essential oil prior to adsorption. These results indicate that peppermint oil affected the virus before adsorption, but not after penetration into the host cell. Thus this essential oil is capable to exert a direct virucidal effect on HSV. Peppermint oil is also active against an acyclovir resistant strain of HSV-1 (HSV-1-ACV(res)), plaque formation was significantly reduced by 99%. Considering the lipophilic nature of the oil which enables it to penetrate the skin, peppermint oil might be suitable for topical therapeutic use as virucidal agent in recurrent herpes infection.