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A. C. Schmitt, A. P. Ravazzolo, and G. L. von Poser,

a) Departamento de Patologia Clínica Veterinária, Laboratório de Virologia Veterinária, Universidade Federal do Rio Grande do Sul, 90540-000, Porto Alegre, RS, Brazil

b) Centro de Biotecnologia, Laboratório de Virologia Molecular, Universidade Federal do Rio Grande do Sul, 91501-970, Porto Alegre, RS, Brazil

c) Laboratorio de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Programa de pós-graduaçáo em Ciêncìas Farmacêuticas, Av. Ipiranga, 2752, 90610-000 Porto Alegre, RS, Brazil

Received 13 February 2001;
revised 11 July 2001;
accepted 17 July 2001.
Available online 29 August 2001.

Abstract

Three plant species, Hypericum connatum, Hypericum caprifoliatum, Hypericum polyanthemum (Guttiferae), growing in Southern of Brazil were chemically investigated and tested for their antiviral activity against feline immunodeficiency virus (FIV). The chemical analysis revealed the presence of polyphenolic compounds such as tannins and flavonoids. Hypericin was not detected in these species. The aqueous extract (AE), the aqueous extract with low tannin concentration (LTCAE) and the methanolic extract (ME) were tested for their cytotoxic properties in concentrations of 50–150 µg/ml. AE was toxic to CRFK for the three species in all concentrations. LTCAE and ME varied between different concentrations being not toxic or allowing 80% of cell growth. LTCAE and ME (10–50 µg/ml) were analyzed for antiviral activity by inhibition of CPE and measuring FIV genome from cell culture supernatant. LTCAE of all species in this work did not cause any inhibition of FIV. Although no difference was seen in CPE, a lower number of viral particles in the supernatant was observed when FIV infected cells were treated with ME of H. connatum. These results suggest that some plants of the genus Hypericum from Southern Brazil contain compounds with potential antiviral activity against lentiviruses.

Author Keywords: Antiviral; Feline immunodeficiency virus; Guttiferae, Hypericum spp; Plant extracts

Fig. 1. Amounts of FIV (ng of RT-hemi-nested-PCR products) in cell culture supernatant treated with LTCAE (A) and ME (B) extracts from H. polyanthemum, H. caprifoliatum and H. connatum using RT-‘hemi-nested’-PCR technique mcg+µg.

Table 1. Cytotoxicity of the plant extracts+: cytotoxicity, -: no cytotoxicity, ±: about 80% of cell culture confluence.

Table 2. Antiviral assay: CPE analysis and detection of FIV genome in cell culture supernatant

CPE, cytophatic effect characterized by sincycia and cell death; CD, cell death; +, presence of FIV genome in supernatant; -, absence of FIV genome in supernatant.

Corresponding author; email: gilsane@farmacia.ufrgs.br