Anti HSV-I virus activity

Soyasaponin I and II were studied in vitro against herpes simplex virus type I (HSV-1). Soyasaponin II was more potent than soyasaponin I in the reduction of HSV-1 production. Soyasaponin II was also found to inhibit the replication of human cytomegalovirus, influenza virus, and human immunodeficiency virus type 1. This activity was not due to the inhibition of virus penetration and protein synthesis, but might involve a virucidal effect. When acyclovir and soyasaponin II were evaluated in combination for anti-HSV-1 activity, additive antiviral effects were observed for this virus [160]. Astragaloside II afforded almost 100% protection of T-lymphocytes in vitro against the cytophatic effects of HIV infection. However, the EC50 of ca. 2.5 x 105 molar was difficult to achieve in vivo [98],... 

In order to find new sources of antiviral agents with different mechanisms of action, extracts of marine algae from all over the world were assayed for anti-HSV activity. The first screening of 89 types of seaweed collected from British Columbia, Canada and Korea for antiviral activity was reported by Kim et al. [66]. Analipus japonicus was the most potent anti-herpes algae. Extracts from 13 types of Korean seaweed previously shown to contain antiviral activity were investigated in more detail in order to learn their mechanism of action [14]. Four species, Enteromorpha linza, Colpomenia bullosa, Scytosiphon lomentaria and Undaria pinnatifida were active against HSV. In experiments to determine the site of action of these antiviral extracts, the predominant activity was virucidal (i.e., direct inactivation of virus particles) rather than inhibition of virus replication. 

A variety of mammalian cellular systems have been used as experimental models for documenting the in vitro effects of cannabinoids on immune responsiveness to viruses, bacteria, and amoebae. Blevins and Dumic (1980) indicated that THC had a protective effect against HSV infection in vitro. It was found that both HSV-1 and HSV-2 failed to replicate and produce extensive cytopathic effect (c.p.e.) in human cell monolayer cultures exposed before infection, at infection, or post infection to various concentrations of THC. In contrast, other studies indicate that THC compromises resistance to virus infection. It has been reported that THC inhibits macrophage extrinsic anti-viral activity (Cabral and Vasquez 1991 Cabral and Vdsquez 1992) whereby macrophages normally suppress virus replication in cells to which they attach (Morahan et al. 1980 Stohlman et al. 1982). Noe et al. (1998) reported that a variety of cannabinoid receptor agonists enhanced syncytia formation in human T cell leukemia virus-I (HTLV-I)-transformed human T (MT-2) cells infected with cell free human immunodeficiency virus (HIV-IMN). It was found that CP 55,940, THC, WIN 55,212-2, and WIN 55,212-3 significantly increased syncytia formation, a phenomenon that has been reported to serve as an indicator of HIV infection and cytopathicity. 

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