BackgroundAdenovirus (ADV) causes a number of diseases in human, and to date, no specific antiviral therapy is approved against this virus. Thus, searching for effective anti-ADV agents seems to be an urgent requirement. Many studies have shown that components derived from medicinal plants have antiviral activity. Therefore, the present study was aimed to evaluate in vitro anti-ADV activity and also antioxidant potential and total phenolic compounds of black tea (Camellia sinensis) crude extract. MethodsIn this study, the hydroalchoholic extract of black tea was prepared and its anti-ADV activity was evaluated on HEp2 cell line using MTT [3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay. The 50 % inhibitory concentration (IC50) and 50 % cytotoxicity concentration (CC50) of the extract were determined using regression analysis. Its inhibitory effect on adsorption and/or post-adsorption stages of the virus replication cycle was evaluated. To determine antioxidant activity, total phenol content, and flavonoids content of the extract, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, Folin-Ciocalteu method, and aluminum chloride colorimetric method were used, respectively. ResultsThe CC50 and the IC50 of the extract were 165.95±12.7 and 6.62±1.4 µg/mL, respectively, with the selectivity index (SI) of 25.06. This extract inhibited ADV replication in post-adsorption stage. The IC50 of DPPH radical was 8±1.41 μg/mL, compared with butylated hydroxytoluene, with IC50 of 25.41±1.89 μg/mL. The total phenol and flavonoid contents of the extract were 341.8±4.41 mg gallic acid equivalent per gram and 21.1±2.11 mg/g, respectively. ConclusionsHaving SI value of 25.06 with inhibitory effect on ADV replication, particularly during the post-adsorption period, black tea extract could be considered as a potential anti-ADV agent. The antiviral activity of this extract could be attributed to its phenolic compounds.

Background Adenovirus causes a number of diseases in human, and can cause serious infection in severely immunosuppressed individuals. Despite the seriousness of adenovirus infection, there is no definitely approved anti-adenoviral therapy. Many studies have shown that compounds derived from medicinal plants have antiviral activity. Therefore, this study evaluated in vitro anti-adenoviral activity of ethanol extract, fractions, and main phenolic compounds of pomegranate peel. Methods The ethanol extract of pomegranate peel was prepared with maceration method and fractionated by consecutive liquid/liquid partition. The cytotoxic and anti-adenovirus activities of the extract, fractions, and main phenolic compounds (ellagic acid, punicalagin and gallic acid) were evaluated on Hep-2 cell line using MTT assay. Inhibitory effect on adsorption and post-adsorption phases of the virus replication cycle was also evaluated. Results Pomegranate peel extract had a desirable effect against adenovirus with IC50 of 5.77 µg/mL and selectivity index of 49.9. Among the fractions and compounds, the n-butanol fraction and gallic acid had the highest anti-adenoviral activity with IC50 of 2.16 µg/mL and 4.67 µM and selectivity indices of 122.5 and 10.5, respectively. The crude extract, n-butanol fraction and gallic acid inhibited the virus replication in post-adsorption phase ( p <  0.01). Conclusion Pomegranate peel extract, especially its n-butanol fraction, could serve as a new promising anti-adenovirus agent due to high inhibitory effect against adenovirus replication. The effect of the n-butanol fraction may be related to the synergistic effect or other compounds of this fraction. Further understanding of the bioassay guided isolation of natural compounds of this fraction seems essential.

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The emergence of medicine resistance strains of influenza A viruses to the chemical drogs lead to the development of alternative herbal compounds that inhibit the virus replication. Therefore, the aim of this research was to investigate in vitro anti-influenza A viruses activity, antioxidant potential, total phenolic, and flavonoid content of a total of 12 hydro alcoholic crude extracts obtained from 8 kinds of medicinal plants. Antiinfluenza A viruses activity of the extracts was investigated by the using of MDCK cell line and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) method. Both 50% inhibitory concentration (IC 50 ) and 50% cytotoxicity concentration (CC 50 ) of the extracts were identified using regression analysis. The antioxidant activity, total phenol, and flavonoid content of the extracts were determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, Folin-Ciocalteu method, and aluminum chloride colorimetric method, respectively. The results demonstrated that there was high activity against influenza virus for Peganum harmala L., Equisetum arvense L., and Punica granatum L, extracts with IC 50 value of 9.1 (CI95%:7.3-11.3), 6.45 (CI95%: 4.5-9.23), and 104.5 (CI95%: 82.8-131.8), respectively. DPPH radical scavenging activity showed that both Equisetum arvense L. and Punica granatum L. demonstrated the highest antioxidant activity with IC 50 value of 6.5, 6.8 and 7.7 μg/mL, respectively. According to the results, some of these extracts might be further analyzed to develop effective anti-influenza factors.

This research was aimed to evaluate anti–herpes simplex virus type-1 (anti-HSV-1) activity of crude ethanol extract and 4 corresponding fractions of Quercus brantii acorn in vitro. Crude ethanol extract was prepared and subjected to fractionation with different polarity. Anti-HSV-1 activity was evaluated on baby hamster kidney cell line using MTT assay. The inhibitory effect of the plant materials on adsorption and/or post-adsorption stages of HSV-1 replication cycle were determined. Regression analysis was used to determine 50% inhibitory concentration and 50% cytotoxicity concentration, from which selective index was calculated. Based on our results, the chloroform fraction and the crude extract had the highest effect against HSV-1 with selectivity indices of 53.8 and 48.4, respectively. The n-hexane, n-butanol, and chloroform fractions inhibited HSV-1 replication in postadsorption stage (P < .001). The results obtained indicated that the chloroform fraction of Q brantii acorn with high inhibitory effect against HSV-1 replication could be a new promising anti-HSV-1 agent.