10.22376/ijpbs.2019.10.1.p1-12 Volume 5 Issue 1 2014 (January - March) Extracts of three different plant species; lessThan i greaterThan Curcuma longa lessThan /i greaterThan L., lessThan i greaterThan Centella asiatica lessThan /i greaterThan L. and lessThan i greaterThan Strobilanthes crispus lessThan /i greaterThan L. which are used widely in Malaysian traditional medicine are investigated for antiviral activity against alpha-herpesvirus (pseudorabies virus). The methanol extract (ME) and aqueous extract (AE) were tested in three cell lines; African Green Monkey Kidney (Vero), Baby Hamster Kidney (BHK) and Rabbit Kidney (RK) cells, at non-cytotoxic concentrations. Assays were developed to determine the characteristics of anti pseudorabies virus (PrV) activities, as anti-viral attachment, anti-prophylactic and /or virucidal. All plant extracts showed marked virucidal ability and considerable prophylactic and anti-viral attachment activities. Plant ME always showed better antiviral activities than plant AE. lessThan i greaterThan Curcuma longa lessThan /i greaterThan L. showed a better virucidal and prophylactic effect (with more than 70% cell viability at 25 µg/ml) for ME and AE. While lessThan i greaterThan Centella asiatica lessThan /i greaterThan L. and lessThan i greaterThan Strobilanthes crispus lessThan /i greaterThan L. were most active as anti-viral attachment agent with percent cell viability up to 60%. It was also found that the anti-viral activities were varies in different cell lines tested. Therefore, the extracts of all three plant species exhibited anti PrV and they could be further investigated for medical purposes. H. HANISA, M.L. MOHD AZMI, M. SUHAILA AND M.N.SOMCHIT Centella asiatica L.; Curcuma longa L.; Strobilanthes crispus L.; In vitro anti-herpesvirus. 42-52