Dengue Antiviral Polycyclic Quinones

The virucidal and antiviral photoactivities of three compounds, hypericin, tetrabromohypericin and gymnochrome B, were evaluated against dengue viruses. All the three products were active, and both the virucidal and antiviral activities were enhanced by light. Gymnochrome B was more potent than hypericin and tetrabromohypericin. The presence of the side chains on the hypericin core of gymnochromes appears to be beneficial for both virucidal and antiviral activities. This enhanced activity is likely to be linked to a complementary mechanism independent of photoactivation. investigated. Antiviral properties of gymnochromes against dengue viruses were previously reported (Laille et al, 1998). Gymnochromes are brominated compounds with an hypericin core obtained from a fossil crinoïd Gymnochrinus richeri (De Riccardis et al, 1991). Hypericin and pseudohypericin are known for their high potency against retroviruses (Meruelo et al, 1988). The virucidal and antiviral photoactivities of hypericin were first demonstrated on inactivated murine cytomegalovirus, Sindbis virus and human immunodeficiency virus type 1 (Hudson et al, 1991). Photosensitization of hypericin is also required for the inactivation of Equine Infectious Anemia Virus (Carpenter and Kraus, 1991). Furthermore, Hudson et al (1999) demonstrated the effect of light exposure on the antiviral activities of hypericin and its brominated derivatives against both Herpes simplex and Influenza viruses. These compounds have extended-electron systems which are responsible for singlet oxygen production upon photoexcitation with visible light. Similarly (Sauviat et al, 2001) showed that photoexcitation of gymnochrome A blocked the background K+ current in frog atrial heart muscle and altered transmembrane currents. The aim of this study was to compare the viruSOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 902 Vol 36 No. 4 July 2005 cidal and antiviral photoactivities of hypericin, tetrabromohypericin and gymnochrome B on dengue virus. MATERIALS AND METHODS