In Vitro Anti-adenovirus Activity, Antioxidant Potential and total Phenolic Compounds of Melissa officinalis L. (Lemon Balm) Extract

Adenovirus causes a number of diseases in Human, and to date, no specific antiviral therapy approved against this virus. Thus, searching for effective anti-adenovirus agents seems to be required. Many studies showed that components derived from medicinal plants had effective antiviral activity. Therefore, the present was aimed to evaluate activity of Melissa officinalis L. extract against adenovirus in vitro. In this study, the hydroalchoholic extract of Melissa officinalis was prepared and its anti-adenovirus activity was evaluated on HEp2 cell line using MTT (3-[4,5-dimethylthiazol–2-yl]-2,5diphenyltetrazolium 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 was used, respectively. The results revealed that the 50% Cytotoxicity Concentration (CC50) on HEp2 cell line and the 50% inhibitory concentration (IC50) on adenovirus of the extract were 294.9±12.7and 15±2.7μg/ml, respectively, with the selectivity index (SI), of 19.66. This extract inhibited adenovirus replication in post-adsorption stage (p<0.05). The IC50 of DPPH radical was 16.8±1.41μg/ml, compare with butylated hydroxytoluene (BHT), with IC50 of 25.41±1.89 μg/ml. The total phenol and Flavonoid contents were 227.6±4.41mgGAE/g and 12.5±2.1mg/g, respectively. We conclude that, having SI value of 19.66 with inhibitory effect on adenovirus replication, particularly during the postadsorption period, Melissa officinalis L. extract could be considered as a potential anti-adenovirus agent.