Antitumor activity of quaternized chitosan-based electrospun implants against Graffi myeloid tumor.

Nanofibrous implants containing quaternized chitosan (QCh), poly(L-lactide-co-D,L-lactide) (coPLA), and the antitumor drug doxorubicin (DOX) were fabricated by electrospinning. The surface chemical composition and the morphology of the implants were characterized by XPS and SEM. In vitro cell viability studies demonstrated that QCh- and DOX-based implants exhibited high cytotoxicity against Graffi tumor cells. The implants efficiently inhibited the growth of Graffi tumor in hamsters with minimum weight loss. Insertion of QCh/coPLA/DOX implants in the place of removed tumor led to an increase in the animal survival rate and to a decrease in the percentage of recurrences.

Antibacterial and antimycotic activity of a cross-linked electrospun poly(vinyl pyrrolidone)-iodine complex and a poly(ethylene oxide)/poly(vinyl pyrrolidone)-iodine complex.

Photo-cross-linked poly(vinyl pyrrolidone) (PVP) and poly(ethylene oxide)(PEO)/PVP electrospun nanofibrous mats containing complex-bound iodine have been studied. FT-IR spectroscopy analyses have proved that coordination of molecular iodine with carbonyl group and nitrogen atom of pyrrolidone rings of the PVP chains has taken place. The distribution of iodine along the fibers is uniform as revealed by X-ray mapping. The microbiological tests have demonstrated that the iodine complex-containing electrospun mats are highly effective against the Gram-positive bacterium Staphylococcus aureus, the Gram-negative bacterium Escherichia coli and the fungus Candida albicans. Comparison with iodine complex-containing films has shown that the iodine complex-containing nanofibers exhibit a higher killing rate than the films against bacteria E. coli. SEM observations showed that PVP-iodine nanofibrous mats inhibit the adhesion of bacteria S. aureus. These characteristic features make the electrospun iodine-containing nanofibers good candidates for wound-dressing materials.

Isolation of a polysaccharide with antiviral effect from Ulva lactuca.

A polysaccharide from the green marine algae Ulva lactuca has been isolated. The substance has been investigated after acid hydrolysis by thin-layer and gas chromatography. The following carbohydrate components have been found: arabinose-xylose-rhamnose-galactose-mannose-glucose in ratio 1:1:9:5:2.5:16 respectively. One unidentified sugar has been demonstrated too. The polysaccharide has been studied for antiviral activity in vitro against a number of human and avian influenza viruses. A considerable inhibition of the viral reproduction was found. The effect was dose-dependent, strain-specific and selective.

Combined effect of selected antiviral substances of natural and synthetic origin. II. Anti-influenza activity of a combination of a polyphenolic complex isolated from Geranium sanguineum L. and rimantadine in vivo.

The synergistic effect shown by the combination of a natural product, polyphenolic complex (PC) isolated from Geranium sanguineum L., and rimantadine (R) in vitro and in ovo [7], encouraged us to continue these studies by in vivo testing. A marked protective effect in experimental influenza virus A (H3N2) infection in mice was found when PC was applied nasally (i.n.) (1.0 mg/kg) only once 6 h before infection in combination with R applied orally in concentration 10.5 and 2.5 mg/kg 2h before and 2.24 and 48 h after viral inoculation (PI = 72.55%, 55% and 57.8% respectively).

Antiherpes effect of Melissa officinalis L. extracts.

Studies were carried out on the virucidal and antiviral effects of Melissa officinalis L. extracts (M1, M3, M3 and M4) with respect to Herpes simplex virus type 1 (HSV-1). Virucidal effect was registered within 3 and 6 hours of treatment using M4 administered in MTC. The remaining extracts inactivate the virus at the 12th and 24th hour. No significant values of inhibiting activity of M1, M2, and M3 on the same virus in vitro or in vivo were demonstrated. The presence of caffeic, rosmarinic and ferulic acids was demonstrated by thin-layer chromatography. Their role in the antiviral activity of M. officinalis L. is discussed.

Anti-influenza virus effect of some propolis constituents and their analogues (esters of substituted cinnamic acids).

The antiviral activity of six synthetic substances, esters of substituted cinnamic acids, identical with or analogous to some of the constituents of the Et2O fraction of propolis was studied in vitro. One of them, isopentyl ferulate, inhibited significantly the infectious activity of influenza virus A/Hong Kong (H3N2) in vitro and the production of hemagglutinins in ovo. By the use of diverse experimental patterns, it was found that the maximal inhibition of viral reproduction was observed when test substances were present in the medium during the whole infectious process.

Polyphenols from Bulgarian medicinal plants with anti-infectious activity.

Three Bulgarian medicinal plants--Geranium macrorrhizum L. and G. sanguineum L. (Geraniaceae), and Epilobium hirsutum L. (Onagraceae) were analyzed phytochemically. Different polyphenols like flavonoids and tannis have been found to be principal constituents of the plants. A series of water or alcohol extracts was obtained, and their anti-infectious activity was tested. A significant inhibitory effect of water-alcohol extract and of four fractions from the polyphenolic mixture of E. hirsutum on the reproduction of influenza viruses in vitro, in ovo, and in vivo was established. Four extracts from G. macrorrhizum and three extracts from G. sanguineum were studied for in vitro inhibition of the growth of some Gram-negative bacteria (Klebsiella pneumoniae, Proteus vulgaris, Escherichia coli, Pseudomonas aeruginosa), Gram-positive bacterium (Staphylococcus aureus), and fungus (Candida albicans). Some geranium extracts caused a strong increase of the survival rate in an infection with K. pneumoniae in mice. Augmentation of the nonspecific host resistance in relation to the influence of the extracts on the classical complement activation pathway was also studied.

Plant polyphenolic complex inhibits the reproduction of influenza and herpes simplex viruses.

A polyphenolic complex (PC), isolated from the Bulgarian medicinal plant Germanium sanguineum L., inhibited the reproduction of influenza virus types A and B in vitro and in ovo. It protected white mice in an experimental lethal influenza infection. When influenza viruses were treated with a high dose (1 mg/mL), their hemagglutination, neuraminidase and infections activities were reduced completely. It was assumed that the PC-specific inhibitory effect on influenza virus reproduction in tissue cultures (50 micrograms/mL) was mediated by partial inactivation of viral glycoproteins which prevented the initial stages of reproduction. The PC also affected the intracellular stages of viral replication. The effect was dependent on the mode of application, the viral strain, and the biological test system. The PC also inhibited the reproduction of herpes simplex virus in vitro. Infectious titers were reduced and newly synthesized virion with damaged protein envelopes were observed by electron microscopy.

Antiviral activity of Flos verbasci infusion against influenza and Herpes simplex viruses.

The lyophilized infusion from flowers of Verbascum thapsiforme Schrad. (FVI) showed antiviral activity in in vitro studies against Fowl plague virus, several influenza A strains, influenza B strain as well as Herpes simplex virus. Influenza viruses titer decreased by 1-3 log units, while of H. simplex virus by 2.3 log. FVI has shown virucidal activity on H. simplex virus at 300 micrograms/ml, but did not inactivate influenza viruses. Phytochemical investigations of FVI have shown the presence of flavonoids, iridoids, phenolic acids, saponins, amino acids and free sugars.

[The anti-influenza effect of rimantadine and isoprinosine when used in combination in mice]. / Protivogripen efekt na rimantadin i izoprinozin pri kombinirano prilagane u mishki.

The antiviral effect of rimantadine and isoprinosine applied in combination against fowl plague virus (FPV) in cell cultures of chick embryo fibroblasts and in experimental influenza infection in mice has been studied. Isoprinosine does not inhibit the reproduction of FPV when given alone and does not increase the antiviral activity of rimantadine. After oral application of both substances according to an appropriate scheme in mice infected with influenza virus A/Aichi (N3N2), an increase in the antiviral effect with an index of protection by 12% higher than the theoretically calculated one for additive effect was established. The results suggest that the combined effect is synergic.

A study on the antiviral action of a polyphenolic complex isolated from the medicinal plant Geranium sanguineum L. VIII. Inhibitory effect on the reproduction of herpes simplex virus type 1.

The antiviral activity of a polyphenolic complex, isolated from a Bulgarian medicinal plant Geranium sanguineum L., on the reproduction of herpes simplex virus type 1 was studied. The substance inhibited the intracellular stages of viral replication and exhibited a virucidal effect.