Antiviral activity of south Brazilian medicinal plant extracts.

Brazilian plants are potential sources of useful edible and medicinal plants. Hydromethanolic extracts prepared from 54 medicinal plants used in folk medicine to treat infections were screened for antiviral properties against five different viruses (HSV-1, HSV-2, poliovirus type 2, adenovirus type 2 and VSV). Fifty-two percent of the plant extracts exhibited antiviral against one or more tested viruses. More specifically, 42.6% showed activity against HSV-1 (herpes simplex virus type 1), 42.6% against HSV-2 (herpes simplex virus type 2), 26% against poliovirus and 24% against VSV (vesicular stomatitis virus). None of the extracts was active against adenovirus. Trixis praestans (Vell.) Cabr. and Cunila spicata Benth. extracts were further characterized for antiviral activity.

Mechanism of antiviral activity of triterpenoid saponins.

Triterpenoid saponins are naturally occurring sugar conjugates of triterpenes possessing various biological activities, including antiviral action. Two substances isolated from natural sources were tested against herpes simplex virus type 1 replication. They did not show evidence of cytotoxicity under antiviral test conditions. The triterpenoid saponin, isolated from a Brazilian plant (s21), represents the oleanane group and inhibited herpes simplex virus type 1 DNA synthesis. The triterpenoid saponin, isolated from a Chinese plant (s17), represents the ursane group and seemed to inhibit viral capsid protein synthesis of herpes simplex virus type 1.

Anti-herpes virus activity of aporphine alkaloids.

We evaluated, in cell cultures, the action of a series of 19 aporphine alkaloids against Herpes simplex virus type 1 (HSV-1). On the basis of viral titre reduction, six alkaloids were found to be active. The mode of action of the three most potent inhibitors, oliverine HCl, pachystaudine, and oxostephanine, was studied. These compounds did not have any virucidal or prophylactic effect but they were shown to interfere with the viral replicative cycle. Although DNA synthesis was reduced, their exact target remains to be elucidated. In the discussion, some structure-activity relationships are considered.

Mutagenic and membranal effect of a phytotoxic molecule isolated from olive leaves parasitized by the fungus Cycloconium oleaginum Cast.

A phytotoxic substance (C23H44O3) which is named 'Substance A', was purified from olive leaves infected with Cycloconium oleaginum Cast. The mutagenic effect of this substance was detected using TA 100 and TA 102 strains of Salmonella in the Ames test using Bacillus subtilis strains M45 rec-, H17 rec+ in the rec assay. Another substance manifesting the mutagenic effect was found in the extract from the Cycloconium oleaginum culture. This substance was not detected in the extract from contaminated olive leaves. Substance A increased electrolytes leakage from tissue of olive leaves, thus manifesting its phytotoxicity.

Comparison of the anti-herpes simplex virus activities of propolis and 3-methyl-but-2-enyl caffeate.

The in vitro activity against herpes simplex virus type 1 of 3-methyl-but-2-enyl caffeate isolated from poplar buds or prepared by synthesis was investigated. Under conditions of one or multiple multiplication cycles, this compound, which is a minor constituent of propolis, was found to reduce the viral titer by 3 log10, and viral DNA synthesis by 32-fold.

Search for "in vitro" antiviral activity of a new isoflavonic glycoside from Ulex europaeus.

Extracts from Ulex europaeus L. (Fabaceae) were tested for antiviral activity against HSV-1 and poliovirus. It was found that the n-butanolic extract significantly inhibited the replication of these viruses, as shown by inhibition of cytophathic effects and reduction of plaques; the extract has neither a prophylactic nor a virucidal activity. From this extract has been isolated and identified by chromatographic, chemical, and spectroscopic methods, the 5-O-methylgenistein 7-O-beta D-glucopyranoside. This isoflavonic glycoside has not been previously described and it is responsible at least partially for the antiviral activity.

[Inhibitory effects of some crude and semi-purified extracts of indigenous French plants on the multiplication of human herpesvirus 1 and poliovirus 2 in cell culture]. / Effets inhibiteurs de quelques extraits bruts et semi purifiés de plantes indigènes françaises sur la multiplication de l'herpesvirus humain 1 et du poliovirus humain 2 en culture cellulaire.

Within a valorization program of natural regional resources, 50 ethanolic extracts of 41 indigenous plants have been subjected to chemical tests and antiviral screening. Four plants: Bryonia dioìca, Anthyllis vulneraria, Matricaria chamomilla, and M. inodora inhibit the growth of poliovirus. Furthermore, three (A. vulneraria, M. Chamomilla, and M. inodora) have an antiherpetic effect.