Extracts of Salvia officinalis from different growing areas and their antiviral effect against enveloped and non-enveloped viruses

In our study we compared extracts from Salvia officinalis L. (sage), which was grown at two different areas in Germany, for their antiviral effect. Firstly it was cultivated in an dry and hot area (area 1) and secondly in an area with a cooler climate and more rain (area 2). Different extracts were made from both samples with water/ethanol- mixtures in the ratio of 0, 20, 40, 60 and 80% ethanol, respectively. A HPLC analysis of the extracts showed as major components apigenin-7-glucuronide, luteolin- 3-glucuronide and rosmarinic acid. The antiviral effects of these extracts were tested against the enveloped herpes simplex virus type 1 (HSV-1) and the non-enveloped adenovirus type 5. In order to determine the mode of antiviral action, the extracts were added to the cells or viruses at different times during infection. The inhibitory activity against HSV-1 was tested using a plaque reduction assay. Adenoviral GFP reporter gene expression allowed for a flow cytometry-based quantification of infection levels. When HSV-1 was pretreated with the extracts prior to adsorption, plaque formation was reduced by >90%. The best results were shown by the extracts from area 1. In time-response studies over a period of 2 hours, a clearly time-dependent activity for all extracts was demonstrated. Already after 20 minutes of incubation of HSV-1 with the extracts, an antiviral activity of about 70–80% was shown. Pretreatment of adenovirus with the extracts for 1 hour showed an inhibitory effect on adenoviral infection from 20% (80% ethanol) up to 70% (20% ethanol). Therefore the extracts show antiviral activity independent of an envelope.