The present study was conducted to determine the antiviral activity of different Cholistani plants growing in the Cholistan Desert, Pakistan. Methanolic extracts of plants were prepared by dissolving air-dried, powdered plants in methanol and later concentrated in a rotary evaporator. The concentrated extracts were dissolved in distilled water and sterilized through filtration. To asses antiviral potential plant extracts were mixed with an equal concentration of a live virus and propagated for 7-11 days in embryonated eggs with appropriate controls. After 48 hours, the allantoic fluids were harvested and hemagglutination assay (HA) was performed for infectious bronchitis virus (IBV) and indirect haemagglutination assay (IHA) for infectious bursal disease virus (IBDV) to determine both viruses titer, as well as evaluation of the inhibitory effects of various plant extracts.  Almost all selected plant extracts exhibited an antiviral effect varying from plant to plant and manifested through controlling growth of IBV except Solanum surattense. The methanolic extracts of two plants Ochthochloa compressa and Sporobolos icolados, showed a 100% inhibitory effect demonstrated through no viral growth determined by HA assays.  Similarly other plant extracts also showed antiviral activity in the order of HA titer at 8 in case of three plants Haloxylon salicornicum, Neurada procumbens and Salsola baryosma, 16 for Achyranthes aspera, Haloxylon recurvum and Panicum antidotale. The HA values 32 and 64, respectively, for Oxystelma esculentum and Suaeda fruticosa were revealed. In case of anti-IBDV activity, the methanolic extracts of Achyranthes  aspera, Haloxylon  recurvum, Haloxylon  salicornicum, Panicum  antidotale, Salsola  baryosma, Sporobolos  icolados were shown to have the optimal antiviral potential (IHA titer 0). Similarly, extract of Neurada procumbens kept the IHA titer at 2 and Solanum surattense at 4. The extracts of Oxystelma esculentum and Ochthochloa compressa were least effective in controlling multiplication of IBDV and their IHA titer was equal to virus control. Overall, our studies open up new avenues in the development of much needed antivirals, utilizing indigenous resources.

Key words: Antiviral Activity, Cholistan, IBDV, IBV, Medicinal plants