Inactivation of Herpes Simplex Virus by Photosensitizing Anthraquinones Isolated from Heterophyllaea pustulata

Heterophyllaea pustulata is a phototoxic plant from Argentina. Aerial parts extracts, high in photosensitizing anthraquinones, have shown in vitro antiviral activity. The purpose of this study was to study the antiherpetic activity of the main purified anthraquinones, even evaluating their competence as photodynamic sensitizers to photo-stimulate the antiviral effect. In vitro antiviral activity against Herpes Simplex virus type I and the photo-inactivation of viral particle were studied by the Neutral Red uptake test and observation of the cytopathic effect. Rubiadin 1-methyl ether and 5,5′-bisoranjidiol produced a significant effect (≥ 80% inhibition) with minimal damage to host cells (subtoxic concentration). Anthraquinones with poor antiherpetic activity at its maximum noncytotoxic concentration showed an important photo-stimulated effect, such is the case of soranjidiol and 5,5′-bisoranjidiol (28.0 ± 6.3 vs. 81.8 ± 2.1% and 15.5 ± 0.3 vs. 89.8 ± 1.7%, respectively). The study also proved the decrease of viral particles, necessary to reduce infection. Therefore, photosensitizing anthraquinones from natural resources could be proposed to develop new treatments for localized viral lesions with antimicrobial photodynamic therapy.

Activity of carraginanes from red algae for infections caused by the herpes simplex virus

Herpesvirus infections, the incidence of which has increased significantly throughout the world in recent years, are actualizing the search and development of new, more effective drugs and prophylactic drugs. Particular attention of researchers is attracted, in particular, by sulfated polysaccharides — carrageenans obtained from natural sources (red algae of the Sea of Japan), which, as it turned out, have a wide spectrum of biological activity. The aim of this study was to study the antiherpetic activity of three types of carrageenans (K1, K2 and K3), with different polymer chain structure, number of sulfate groups and their location. A study of the cytotoxic activity of these compounds and their effect on the reproduction of herpes simplex virus type 1 (HSV-1) in a transplanted Vero cell culture was evaluated using an MTT assay. It was established that all three carrageenans have a pronounced antiviral activity in vitro, however, the effect of their action is different due to the fact that each of them affects different stages of the life cycle of the virus. When Vero cells were treated with carrageenans before they were infected with the virus, K2 polysaccharide showed the most pronounced antiherpetic activity; with direct treatment of the virus with carrageenans, the most significant antiherpetic effect was demonstrated by polysaccharide K1. The revealed differences in the effect of carrageenans on different stages of HSV-1 replication are apparently related to the structural features of the tested compounds.