In vitro anti-rotavirus activity of some medicinal plants used in Brazil against diarrhea.

Acute diarrhea, especially in children, is a very common disease with worldwide distribution and with a significant public health impact. Rotaviruses have been recognized as the major agents of diarrhea in infants and young children in developed as well as developing countries. In Brazil, diarrhea is one of the principal causes of death, mainly in the infant population. To fight diarrhea, traditional Brazilian medicine uses a great variety of plants. In this work, 12 medicinal plant species were screened for simian (SA-11) and human (HCR3) rotaviruses inhibition in vitro. At non-cytotoxic concentrations, the extracts from Artocarpus integrifolia L. (Moraceae) bark (480 microg/ml) and Spondias lutea L. (Anacardiaceae) leaves (160 microg/ml) had antiviral activity against both viruses. They showed inhibition of 99.2% and 97%, respectively, for human rotavirus, and 96.4% and 96.2% for simian rotavirus. The extracts from Myristica fragrans Houtt (Myristicaceae) seeds (160 microg/ml) and Spongias lutea bark (40 microg/ml) inhibited human rotavirus (90% and 82.2% inhibition, respectively), whereas the extracts from Anacardium occidentale L. (Anacardiaceae) leaves (4 microg/ml) and Psidium guajava L. (Myrtaceae) leaves (8 microg/ml) showed activity only against simian rotavirus (82.2% and 93.8% inhibition, respectively). Our results indicate that the extracts of Artocarpus integrifolia, Myristica fragrans and Spongias lutea can be useful in the treatment of human diarrhea if the etiologic agent is a rotavirus.

A sulphated fucan from the Laminaria abyssalis inhibits the human T cell lymphotropic virus type 1-induced syncytium formation in HeLa cells.

This work evaluated the effect of a sulphated fucan extracted from the Laminaria abyssalis marine algae on the human T cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation. The experiments were carried out in HeLa cells cocultured with a HTLV-1-infected T cell line (C91/PL cells) in the presence of the sulphated polysaccharide at concentration below that corresponding to the ED50. The sulphated fucan inhibited almost 100% of the syncytium formation at concentration of 100 microg/mI and was still active (>95%) at a concentration of 25 microg/ml. It was also observed that the best inhibition occurred when the compound was added in the first 2 h of the cell-to-cell contact. This is the first report showing that a purified sulphated polysaccharide, extracted from marine algae, is able to inhibit the cell-to-cell contact essential for the spreading of the HTLV-1.

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.

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.

In vitro anti-HIV-1 virucidal activity of tyrosine-conjugated tri- and dihydroxy bile salt derivatives.

The cellular toxicity and anti-human immunodeficiency virus type 1 (HIV-1) virucidal activity of four synthesized tyrosine-conjugated bile salt derivatives with high surfactant activities, namely di-iodo-deoxycholyltyrosine (DIDCT), di-iodo-chenodeoxycholyltyrosine (DICDCT), di-iodo-cholylglycyltyrosine (DICGT) and deoxycholyltyrosine (DCT), were evaluated and compared with either sodium deoxycholate or nonoxynol-9. DIDCT, DICDCT and DCT but not DICGT showed virucidal activity against three different laboratory-adapted strains of HIV-1 (RF, IIIB and MN). All the bile salt derivatives tested excluding DICGT were virucidal at a concentration as low as 10 ng/mL. DCT had the highest anti-HIV-1 virucidal potency, suggesting that monopeptide 7alpha,12alpha dihydroxy bile salt derivatives have the most potent antiviral activity. Complexing of iodine to the bile salt derivative (as in DICGT) decreases virucidal potency.

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.

A multistep procedure for the chemical inactivation of human immunodeficiency virus for use as an experimental vaccine.

The kinetics of inactivation of four different strains of HIV-1 (RF, MN, SF2 and IIIB) by beta-propiolactone (BPL) and binary ethylenimine (BEI) were studied under various conditions. The conditions that would be required for the reduction of virus infectivity by at least 10(20) TCID50 ml-1 were estimated on the basis of the experimental rates of inactivation obtained. A multiple step procedure including treatment with 0.2% BPL, 0.05% sodium cholate, 10 mM BEI and 0.02% formaldehyde was designed to inactivate HIV-1 for use as an experimental vaccine. Complete inactivation of virus infectivity was confirmed by prolonged cell culture. The experimental vaccine preparation was analysed for the presence of HIV-1 proviral DNA utilizing the polymerase chain reaction. After treatment with both BPL and BEI proviral DNA was detected in one of four samples using primers encoding a 244 bp segment of the pol region of the viral genome. Proviral DNA could not be detected in any of the four samples using primers encoding segments of > 400 bp in the gag and reverse transcriptase region.

The in vitro antiviral activity of isoprinosine on simian rotavirus (SA-11).

1. The antiviral effect of isoprinosine on simian rotavirus (SA-11) replication was studied using MA-104 cell cultures from Rhesus monkey fetal kidney. 2. Isoprinosine (N,N-dimethylamino-2-propanol-p-acetamidobenzoate in association with inosine) added after viral infection (therapeutic test) inhibited viral replication by more than 90%. In these experiments, the drug was added to the medium and replaced daily at concentrations varying from 62.5 micrograms/ml to 1 mg/ml. Viral inhibition activity was dependent on drug concentration. No antiviral effect was observed when isoprinosine was tested without replacement (200-500 micrograms/ml). 3. When isoprinosine (1 mg/ml) was added to cell cultures only before viral infection (prophylactic test), inhibition of viral replication occurred but was less than 90%. Inhibition by less than 90% is not considered to be significant in this type of test. 4. Isoprinosine inhibited synthesis of both viral antigen (protein) and viral double-stranded nucleic acid, as monitored by immunofluorescence and acridine orange staining, respectively. Inhibition of synthesis of viral macromolecules increased with drug concentration.

The in vitro antiviral activity of isoprinosine on simian rotavirus (SA-11)

The antiviral effect of isoprinosine on simian rotavirus (SA-11) replication was studied using MA-104 cell cultures from Rhesus monkey fetal kidney. Isoprinosine (N,N-dimethylamino-2-propanol-p-acetamidobenzoate in association with inosine) added after viral infection (therapeutic test) inhibited viral replication by more than 90%. In these experiments, the drug was added to the medium and replaced daily at concentrations varying from 62.5 microng/ml to l mg/ml. Viral inhibition activity was dependent on drug concentration. No antiviral effect was observed when isoprinosine was tested without replacement (200-500 microng/ml). When isoprinosine (l mg/ml) was added to cell cultures only before viral infection (prophylactic test), inhibition of viral replication occurred but was less than 90%. Inhibition by less than 90% is not considered to be significant in this type of test. Isoprinosine inhibited synthesis of both viral antigen (protein) and viral double-stranded nucleic acid, as monitored by immunofluorescence and acridine orange staining, respectively. Inhibiton of synthesis of viral macromolecules increased with drug concentration

Placental pathology in congenital rubella.

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 I 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.