Romanian Biotechnological Letters Vol. 16, No. 6, 2011 Copyright © 2011 University of Bucharest Printed in Romania. All rights reserved ORIGINAL PAPER 6730 Romanian Biotechnological Letters, Vol. 16, No. 6, 2011 Screening of five alcoholic plants extracts effects on the immune status of Romanian EIAV infected horses Received for publication, March 29, 2011 Accepted, June 9, 2011 POMPEI BOLFĂ *1 , CORNEL CĂTOI 1 , ADRIAN GAL 1 , MARIAN TAULESCU 1 , NICODIM FIŢ 2 , GEORGE NADAŞ 2 , MIHAELA NICULAE 3 , MIRCEA TĂMAŞ 4 , COSMINA CUC 1 , MARINA SPÎNU 3 1 Pathology Department, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania 2 Microbiology Department, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania 3 Infectious Disease Department, Faculty of Veterinary Medicine, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania 4 University of Medicine and Farmacy ”Iuliu Haţieganu”, Cluj-Napoca, Faculty of Farmacy * Corresponding author: Bolfă Pompei Florin 1 ; Phone: +40 264 59 63 84, Fax: +40 264 59 37 92; E-mail: pompeibolfa@gmail.com, Present adress: Calea Manastur, 3-5, 400372, Cluj-Napoca, Romania Abstract Classical medicinal treatments tend to be replaced by alternative therapies, in which the natural plant extracts are being used. In the current study we studied the effects of five alcoholic plant extracts (Calendula flos, Echinacea pallida, Echinacea purpurea, Urtica dioica and Aloe vera) on the dynamics of some immune effectors of equine infectious anemia virus (EIAV) infected horses in vitro. The research focused on the effects of plants active principles on the cellular non-specific defence subsystem and on the functional capacity of the T lymphocyte subsystem. Our findings suggest that the stimulatory effect of Urtica dioica alcoholic extract on the phagocytic function in young, recently EIAV infected horses is followed by an inhibitory effect, that could be explained by the possible rapid carbon particle ingestion, and then by increase cell membrane fragility. Although very closed related taxonomically, the two Echinacea extracts studied here don’t share the same effect in vitro, meaning that different principles are responsible for their in vitro effects. Young horses recently infected with EIAV have an overall increased cellular reactivity compared to older animals, due to infection. On the other hand, due to general increased immunoreactivity in younger animals, the immune recovery effects of the used alcoholic extracts is marked in younger equines. Keywords: herbal extracts, immunity, immune competent cells, equines, EIAV Introduction Nowadays prophylaxis primes over therapy in the majority of diseases affecting man or animals. Numerous studies have been conducted so far that offer scientific proofs on the therapeutic benefits of different plant extracts in the treatment or prophylaxis of different diseases, including some rare forms of cancer (TAJIMA & AIDA, 2000 [1]; VICKERS, 2002 [2]). There are herbal plants that have the capacity to modulate different immunologic functions in the pathology of different diseases, but they are also being used as adjutants in the preparation of vaccines (FLORINS et al., 2007 [3]; KAILEH et al., 2007 [4]). The capacity of plant extracts or plant isolated active principles to modulate the immune response has been proven by three different pathways: a non-specific stimulation of the immune system