Virucidal effect

This type of procedure may thus suggest that an unnecessarily high disinfectant concentration (so-called overkill) may be employed in practice to achieve a virucidal effect. 

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],... 

Weber ND, Andersen DO, North JA, et al. In-vitro virucidal effects of allium sativum (garlic) extract and compounds. Planta Med 1992 58 417 -23. 

A number of substances have been identified that have either a specific virucidal effect on HIV or prevent infection of cells in vitro. The virucidal activity of potential topical agents can be assessed against cell-free and cell-associated virus using these assay systems. They allow the measurement of precise contact times between the HIV and virucides, enable the protective effect of preparations to be examined, and allow removal of the virucide from the system prior to assessment of cell viability. 

Suzuki N, Mizumoto I, Itami T, Takahashi Y, Tanaka R, Hatate H, Nomoto T, Kozawa A. Virucidal effect of singlet oxygen on penaeid white spot syndrome virus. Fisheries Science. 2(XX) 66 166-8. 

Numerous studies have investigated effects of UV light inactivation of baculoviruses [12, 32, 34, 70, 84], Generally, the virucidal effects of UV radiation is rapid and has been partly attributed to the adverse affects on DNA or virus-associated structural proteins [42],... 

The virucidal effects of pH have been studied more extensively for baculoviruses. Ignoffo and Garcia [48] observed a significant reduction in virus activity for inclusion bodies exposed at pH 1.2 and pH 12.4. Similar results were reported for HzSNPV at pH 2 and pH 12 [36], Virus inactivation was recorded at 50% and 88% after 30 min and 24 h respectively, suspended at pH 2 in 1.0 M phosphate buffer. Comparatively, vims suspended at pH 12, in 1.0 M phosphate buffer, was inactivated by 40% and 92% after 30 min and 24 h respectively. Similarly, TnNPV in soil exposed to low pH (4.83-5.22) is rapidly inactivated over a month [113],... 

When virus was added to the solution of SDB and incubated for 3 h at 4°C, then assayed in HeLa cells, no significant virucidal effect of the solution against HSV-1 was observed. From these experimental results, the antiviral effect of SDB was suggested not to be attributed to a direct inactivation of the viral particles or inhibition of attachment. The compound was found to interfere with earlier events of HSV-1 replication,... 

Studies on the mechanism of action, suggested that hypericin antiviral effect is directed towards enveloped viruses, while non enveloped viruses, such as adenovirus and poliovirus, are unaffected [4], Hypericin virucidal effect is increased by light, however its antiviral properties against selected viruses [7] have also been documented in the dark. 

De Logu et al. (2000) investigated the inactivation of HSV-1 and HSV-2 and the prevention of cell-to-cell virus spread by the EO of the Asteraceae Santolina insularis. The plaque-reduction assay showed an IC50 values of 0.88 p.g/mL for HSV-1 and 0.7 xg/mL for HSV-2, respectively, whereas another test on Vero cells showed a cytotoxic concentration (CC50) of 112 p.g/mL, which leads to a CC50/IC50 ratio of 127 for HSV-1 and 160 for HSV-2. These findings indicate that the antiviral effect of the EO was caused by direct virucidal effects. There was no antiviral activity detected in a postattachment assay. Dne to attachment assays it was shown that virus adsorption was not reduced. Additionally, the reduction of plaqne formation assay indicated that the EO reduced cell-to-cell transmission of both HSV-1 and HSV-2. 

Schuhmacher, A., J. Reichling, and R Schnitzler, 2003. Virucidal effect of peppermint oil on the enveloped viruses Herpes simplex virus type 1 and type 2 in vitro. Phytomedicine, 10(6-7) 504-510. 

Especially remarkable is the high activity of PCMC against lipophilic, enveloped viruses, such as Herpes, simplex, Hepatitis B or HIV viruses. As other phenolic membrane active agents also PCMC exhibits a weak effect only on naked viruses and resistant bacterial spores (e.g. bacillus spores). However, a fully virucidal effect is achievable by combining PCMC formulations with small concentrations of glutaraldehyde (2.5.). 

Chelating agents with high affinity for zinc can also influence viral repUcation as indicated in Section 10.2.1 [3, 44]. Adjustment of the zinc balance, then, may result in virucidal effects. Zinc salts such as the sulfate have been used in treatment of herpes infections, although the clinical efficacy is still in doubt [45—47]. 

The antiviral activity of a triterpene saponin isolated from angallis arvensis, was studied in vitro against several vimses including HSV-1, adenovirus type 6, vaccinia, vesicular stomatitis and poliovirus (Amoros et al. 1987). The drug was found to inhibit the replication of HSV-1 and poliovirus type 2 as shown by inhibition of cytopathic effect and reduction of virus production. The action was not due to a virucidal effect but might involve inhibition of virus-host cell attachment. Single cycle experiments indicated that saponins interfered with both early and late events of herpes virus replication (Amoros et al. 1987). 

The essential oil from Santolina insularis was also inhibited virus replication against HSV-1 and HSV-2 in vitro (Schnitzler et al. 2008). Its antiviral activity was principally due to direct virucidal effects (De Logu et al. 2000). Lemon balm oil, the essential oil of Melissa officinalis, is capable of exerting a direct antiviral effect on HSV-1 and HSV-2. Considering the lipophilic nature of essential oils, which enable it to penetrate the skin, and a high selectivity index, essential oils might be suitable for topical treatment of herpetic infections (Schnitzler et al. 2008). 

Chrysophanic acid (l,8-dihydroxy-3-methylanthraquinone), isolated from the Australian Aboriginal medicinal plant Dianella longifolia, has been found to inhibit the replication of poliovirus types 2 and 3 (Picornaviridae) in vitro (Fig. 3.7 Semple et al. 2001). The compound inhibited an early stage in the viral replication cycle, but did not have an irreversible virucidal effect on poliovirus particles. Chrysophanic acid did not have significant antiviral activity against five other viruses which were tested Coxsackievirus types A21 and B4, human rhinovirus type 2 (Picornaviridae), and the enveloped viruses Ross River virus (Jogaviridae) and HS V-1 (Herpesviridae). 

Schnitzler P, Schuhmacher A, Astani A et al (2008) Melissa officinalis oil affects infectivity of enveloped herpesviruses. Phytomedicine 15 734-740 Schuhmacher A, ReichUng 1, Schnitzler P (2003) Virucidal effect of peppermint oil on the enveloped viruses herpes simplex virus type 1 and type 2 in vitro. Phytomedicine 10 504-510 Semple SI, Nobbs SF, Pyke SM et al (1999) Antiviral flavonoid from Pterocaulon sphacelatum, an Australian Aboriginal medicine. 1 Ethnopharmacol 68 283-288 Semple SI, Pyke SM, Reynolds GD et al (2001) In vitro antiviral activity of the emthraquinone chrysophanic add agmnst poliovirus. Antiviral Res 49 169-178 Serkedjieva 1 (1997) Antiinfective activity of a plant preparation from Geranium sanguineum L. Pharmazie 52 799-802... 

---