Antiviral Activities Of Water Extract From Cordyceps Sinensis Against HCMV

HCMV(Human Cytomegalovirus) is a kind ofβ-herpes virus, has high prevalence in population. Usually people'infection can not lead to any clinical manifestation, but as AIDS, solid-organ transplantation and other immunocompromised patients, HCMV can be activated, then many diseases are available, such as retinitis, fever, pneumonia, allograft failure. Except these, infection with HCMV is closely related with occurrence of physical and mental defects of new-born, atherosclerosis, colonic diverticulitis.Now few drugs were approved by FDA, Ganciclovir, Valganciclovir, Cidofovir, Foscarnet sodium, and the first antisense drug: Formivirsen. But these drugs have many side effects, nephrotoxicity, anaemia, myelosuppression, resistance to drugs, low oral bioavailability. These limit their use in clinical practice. So it's necessary to find more potent but low toxicity antiviral drugs.Objective: Cordyceps sinensis has been widely used as a tonic food and herbal medicine since ancient times. Numerous reports have been documented for pharmacological and chemical properties of Cordyceps sinensis, These include various nucleosides, polysaccharides, ergosterol, and so on. Different therapeutic effects of Cordyceps sinensis have been also reported for its abilities of stimulating immune response, inhibiting cancer growth, anti-fatigue, anti-stress, the regulation of steroidogenesis, lowering blood glucose, and scavenging free radicals. Based on these considerations, we try to use Cordyceps sinensis for anti-HCMV.In the present study, we show the antiviral activity of Cordyceps sinensis against HCMV.Methods: HCMV need cultured in host cells, firstly, Human foreskin fibroblasts were isolated from infants'foreskin, then high titer HCMV was propagated on fibroblast monolayers, with respect to how to extract active fraction of Cordyceps sinensis effectively, extraction with water is in use. MTT assay was performed for checking cytotoxicity, then plaque reduction assay was on operation determining antiviral role of Cordyceps sinensis. In order to find its antiviral targets, cell viability was tested and western blot was employed.Results: Host cells for HCMV culture, high titer HCMV(2.4×106PFU/ml)and water extract of Cordyceps sinensis were prepared well for investigating antiviral activity of Cordyceps sinensis against HCMV. Cytotoxicity assay discovers that, Cordyceps sinensis has no toxicity towards to fibroblasts, when its concentration is below 0.5mg/ml. By plaque reduction assay, we find Cordyceps sinensis can inhibit HCMV replication effectively, in western blot analysis, Cordyceps sinensis can block IE2/UL84 expression and decrease IE1 expression. Meanwhile, cell viability was tested again, Cordyceps sinensis can decrease cell viability increased by HCMV infection.Conclusions: By plaque reduction assay, we find Cordyceps sinensis can inhibit HCMV replication effectively, in western blot analysis, Cordyceps sinensis can block IE2/UL84 expression and decrease IE1 expression. Meanwhile, cell viability was tested again, Cordyceps sinensis can decrease cell viability increased by HCMV infection, it implies that decreasing cell viability maybe its site of action, but the change of cell viability maybe induced by blocking HCMV early or early late proteins, it need more data to illustrate it.In a word, our research is very important in investigation of antiviral activities of Cordyceps sinensis against HCMV. More research should be performed on isolation, screening, and other assays on antiviral pathway, in order to find prospective drugs.