M.D. Wigg

Antimicrobial and antiviral activities of polyphenolics from Cocos nucifera Linn. (Palmae) husk fiber extract

The decoction of Cocos nucifera L. husk fiber has been used in northeastern Brazil traditional medicine for treatment of diarrhea and arthritis. Water extract obtained from coconut husk fiber and fractions from adsorption chromatography revealed antimicrobial activity against Staphylococcus aureus. The crude extract and one of the fractions rich in catechin also showed inhibitory activity against acyclovir-resistant herpes simplex virus type 1 (HSV-1-ACVr). All fractions were inactive against the fungi Candida albicans, Fonsecaea pedrosoi and Cryptococcus neoformans. Catechin and epicatechin together with condensed tannins (B-type procyanidins) were demonstrated to be the components of the water extract.

Flavonol monoglycosides isolated from the antiviral fractions of Persea americana (Lauraceae) leaf infusion

An infusion of Persea americana leaves (Lauraceae) strongly inhibited herpes simplex virus type 1 (HSV‐1), Aujeszkys disease virus (ADV) and adenovirus type 3 (AD3) in cell cultures. Its fractionation, guided by anti‐HSV‐1 and ADV assays, allowed the isolation and identification of two new flavonol monoglycosides, kaempferol and quercetin 3‐O‐α‐D‐arabinopyranosides, along with the known kaempferol 3‐O‐α‐L‐rhamnopyranoside (afzelin), quercetin 3‐O‐α‐L‐rhamnopyranoside (quercitrin), quercetin 3‐O‐β‐glucopyranoside and quercetin. The known quercetin 3‐O‐β‐galactopyranoside was identified in a mixture.

Placental pathology in congenital rubella

Summary Two groups of placentae from 18 cases of maternal rubella were examined morphologically and virologically. Placentae in Group I (four cases) had a mean gestational age of 21±1.9 weeks, whilst those in Group 2 (14 cases) had a mean gestational age of 38±2.8 weeks. A tendency to hypoplasia was observed. The microscopic lesions were similar to those found in other viral infections but in each group some specific features were noted. Only placentae of Group 1 showed nodules of villi agglutinated by fibrin. This lesion suggested recent maternal infection. Attention is drawn to the presence of abnormal areas of lobular rarefaction due to dysmaturity of villous stem and terminal villi. This aspect was more diffuse and accentuated in Group 2 placentae. Villitis of reactive, necrotic, proliferative and reparative types was seen only in placentae of Group 2. Devastating villitis was not observed. Inclusions in placental cells suggested rubella infection. The lesions were non-specific and hence stress the need for virological examination of the placenta, immunofluorescence studies and electron microscopy to confirm the diagnosis.

In vitro antiviral effect of flavonoid-rich extracts of Vitex polygama (Verbenaceae) against acyclovir-resistant herpes simplex virus type 1

Extracts and fractions rich in flavonoids from fruits and leaves of Vitex polygama Cham. (Verbenaceae) were tested against acyclovir-resistant herpes simplex virus type 1 (ACV-HSV-1). Both fruit and leaf extracts exhibited a dose-dependent antiviral activity. The extract from the leaves showed intracellular antiviral activity while the extract from the fruits had virucidal effect. A fraction from the ethyl actetate extract of the leaves inhibited virus propagation by blocking HEp-2 cell receptors.

Inhibitory Effect of Extracts of Brazilian Marine Algae on Human T-Cell Lymphotropic Virus Type 1 (HTLV-1)-Induced Syncytium Formation In Vitro

Extracts from four species of Brazilian marine algae collected from the Rio de Janeiro State coast were screened to determine the inhibitory effect on HTLV-1-induced syncytium formation. Before performing the syncytium inhibition assay the 50% cytotoxic dose (CyD50) of the algal extracts was evaluated. The antiviral test was carried out in HeLa cells co-cultured with HTLV-I infected T-cell line (C91/PL cells) in the presence of marine algal extracts in the concentration inferior to that corresponding to the CyD50. It was observed that co-cultured cells exposed to Ulva fasciata extract showed 60.2% syncytium inhibition at a concentration of 2.5%. At 5% concentration, Sargassum vulgare and Vidalia obtusiloba extracts presented 78.8 and 76% syncytium inhibition, respectively. The best inhibitory activity was observed with Laminaria abyssalis that presented 100% syncytium inhibition at a concentration of 2.5%. This work shows that extracts of marine algae, mainly L. abyssalis extract, are able to inhibit the cell-to-cell contact essential for the spreading of the virus and could be useful to prevent the infection.

In vitro activity of extracts of Persea americana leaves on acyclovir-resistant and phosphonoacetic resistant Herpes simplex virus.

The lyophilized aqueous crude extract (LACE) from leaves of Persea americana (Lauraceae) species showed a strong inhibitory effect on acyclovir (ACG(r)4 and dlsp TK mutants) and PAA-resistant (PAA(r)5 mutant) herpes simplex virus. After exhaustive washing of LACE using methanol, the soluble fraction was chromatographed on a reverse-phase column giving 11 fractions that were revealed by thin-layer chromatography. Analysis of the antiviral effect of the fractions showed the extract contained compounds that were able to inhibit extracellular virus and the replication of resistant acyclovir HSV. The virucidal effect was concentrated from fraction 4 up to 8. Fraction 7 mainly contains the flavonoid isoquercitrin, and fraction 8 the flavonoid quercitrin. The flavonoid afzelin that is the major substance present in the fraction 9 showed virustatic effect with no virucidal effect. These results show P. americana is a potential plant extract for treatment of herpes simplex virus infections either alone or associated with acyclovir.

Anti-herpes simplex virus effect of a seed extract from the tropical plant Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae)

Incubation of acyclovir-resistant herpes simplex virus type 1 (ACVr-HSV1), during infection of the HEp-2 cell culture, with an extract prepared from the seeds of Licania tomentosa (Benth.) Fritsch (Chrysobalanaceae) species impaired the productive replication of this virus in a concentration-dependent manner. The extract was able to inhibit extracellular virus (virucidal effect) and also interfered with a very early event of cell infection, at a non-cytotoxic concentration.

Antiviral investigation on the flavonoids of Chamaesyce thymifolia

Flavonoidic extractives from the aerial parts of Chamaesyce thymifolia showed high cytotoxicity on HEp-2 cells and moderate inhibitory activity against HSV-1 and BVDV viruses.

Antioxidant and antiviral properties of Pseudopiptadenia contorta (Leguminosae) and of quebracho (Schinopsis sp.) extracts

Proanthocyanidins from P. contorta leaves and from a commercial quebracho extract were isolated and characterized. Flavonoids, catechins and gallic acid were also identified in the extracts of P. contorta. Compounds were evaluated for their antioxidant properties and for their antiviral activity against an acyclovir-resistant herpes simplex virus type 1 strain. The low molecular weight phenolic derivatives and the proanthocyanidins from P. contorta showed the highest antioxidant activity. Purified proanthocyanidins from both P. contorta and quebracho showed the same maximum non toxic concentrations (25 µg/mL), with 82.2% and 100% of virus inhibition, respectively.

Sulfated fucan from marine alga inhibits HeLa cells infection by HTLV-1 free particles: semi-quantitative analysis

A sulfated fucan from Laminaria abyssalis marine alga prevented the interaction of HTLV-1 particles, purified from the MT-2 cell line, with HeLa cells. The infection obtained using a concentrated virus suspension was detected only by amplification of the newly synthesized HTLV-1 proviral cDNA by the nested-polymerase chain reaction (PCR). The sulfated polysaccharide was not toxic to the cells at a concentration of 100 µg/mL and prevented infection by the viral particles when added to the cell monolayers. The proviral cDNA was only detected when the sulfated polysaccharide was added to the cells three hours post-infection, indicating that the inhibitory activity occurred in the initial stages of virus-cell interaction. Our results demonstrate, for the first time, the ability of a sulfated fucan from marine algae to inhibit virus transmission through free virus particles.