Antiviral Effects of Aloe vera (L.) Burm.f. and Ruta Graveolens L. Extract on Acyclovir-Resistant Herpes Simplex Virus Type 1

Herpes simplex virus type I (HSV-1) is a causative agent in a wide range of human diseases. With increasing drug resistance to anti-viral drugs, numerous studies are under way, particularly on medicinal plants. In this study, therefore, the effects of Aloe vera (L.) Burm. f. and Ruta graveolens L. (R. graveolens) extracts were evaluated on acyclovir-resistant HSV-1. The toxicity of extracts from A. Vera and R. graveolens, and also acyclovir was evaluated on HeLa cells by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide) assay to obtain the highest non-toxic concentrations of the extracts and acyclovir on the cells. The effects of extracts and acyclovir HSV-1 were examined at different concentrations during a range of times. The virus titers were measured at different stages of the study using the TCID50 method. Minimum cytotoxic concentrations (MCC) of 12000 μg/ml and 125 μg/ml were determined for A. vera and R. graveolens extracts respectively. R. graveolens extract with a SI (Stimulation Index) of 15.33 had a higher antiviral effect than A. vera. extract with 3 log TCID50 in 1 h and R. graveolens extract with 1.9 log TCID50 in 2 h after cell infection reduced the virus titer compared to the control. None of the tested concentrations of acyclovir had inhibitory effects on the virus replication. The extract of both plants had antiviral effects, but the extract of R. graveolens showed a higher antiviral impact on acyclovir-resistant HSV-1 compared to A. vera extract.