Maryvonne Amoros

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. Copyright

Antipoliovirus Flavonoids from Psiadia Dentata

The search for antiviral agents against vesicular stomatitis virus, herpes simplex virus type 1 and poliovirus type 2 in plants extracts, led to the isolation of two antipoliovirus flavonoids from the medicinal plant Psiadia dentata (Cass.) DC, Asteraceae: 3-methylkaempferol and 3,4′-dimethylkaempferol. The antipoliovirus activity of both compounds was estimated by comparison with 3-methylquercetin, guanidine and Ro-090179. The most potent inhibitor of poliovirus replication was 3-methylkaempferol, and therefore we investigated its mechanism of action. We showed, using the inhibition of [3H]uridine incorporation in viral RNA and performing a dot-blot with one RNA probe specific for the poliovirus genomic strand RNA, that 3-methylkaempferol inhibits the genomic RNA synthesis of poliovirus.

Synthesis and Antiviral Effect against Herpes Simplex Type 1 of 12-substituted Benzo[c]phenanthridinium Salts

The synthesis of benzo[c]phenanthridine alkaloid derivatives is described. In vitro antiviral activity against herpes simplex type 1 (HSV1) has been investigated. Contrary to the natural product fagaronine, which did not have any activity in the HSV1 antiviral tests, four 12-alkoxy derivatives showed good activity demonstrating the importance of the 12-substitution in the structure-activity relationships.

Cytotoxic Activity of Tricholomatales determined with Murine and Human Cancer Cell Lines

The cytotoxic activity of 22 methanol extracts of fresh fruiting bodies of the Tricholomatales order was evaluated with two murine cancer cell lines (L1210 and 3LL). The 8 extracts that inhibited the growth of at least one murine cancer cell line were then evaluated with 4 human cancer cell lines (K-562, U251, DU145, MCF7). Four of them had significant cytotoxic activity (IC 50 =20 ?g/ml) against at least one human cancer cell line. Lepista inversa, with an IC 50 = 20 ?g/ml against the 4 human cancer cell lines tested and an activity either equal to or greater than that of a bark extract from Taxus baccata L., used as positive control, appeared to be the most promising species.

Solid‐phase Synthesis, Antiviral Activity and Cytotoxicity of Some Functionalized Lactones

Thio-substituted γ- and δ-lactones were prepared via a resin-bound epoxide by ring-opening reaction with sodium thiolates and subsequent cleavage. The compounds were ineffective against herpes simplex virus type 1 and poliovirus. However, the cytotoxicity on murine tumour lines of 3,3-dimethyl lactone appeared to be promising.

Expedient method for the solid-phase synthesis of some 4-substituted-4,5-dihydropyridazin-3(2H)-ones

The solid-phase synthesis of some 4-amino-4,5-dihydropyridazin-3(2H)-ones has been realised using regiospecific Michael addition and subsequent cyclorelease reactions.

In-vitro Antiherpetic Activity of Erythroxylon laurifolium (Erythroxylaceae)

Oligomeric and polymeric proanthocyanidins extracts from Erythroxylon laurifolium (Erythroxylaceae) and Krameria triandra (Krameriaceae), were found to have moderate activity against Herpes simplex virus type 1. No notable differences were found between the two types of compounds or plants. Proanthocyanidins did not affect viral attachment or penetration but did affect further events in the replicative cycle. An enzymatic inhibition was suggested. Direct inactivation of virus was found at high concentrations and may partially contribute to the antiviral effect of tannins.