The frogs were acquired in June and July from Toroq dam located south east of Mashhad, Iran. Animals were then transferred to the laboratory and maintained in proper cages and conditions based on the amphibian husbandry resource guide (Poole and Grow, 2008). In order to collect skin secretions, frogs were washed with distilled water and the dorsal part of the frog was then stimulated several times with a 4–6 V electrical current (Heiss et al., 2009). The extracts were collected by washing the dorsal part of body using 5% acetic acid (Sai et al., 1995) and centrifuged at 10,000 rpm for 15 min. The supernatant was freeze-dried, and is hereafter referred to as raw extract (RE). Additionally, skin secretions were ultrafiltrated using a membrane with cutoff 10 kDa. The solution was freeze-dried, and is hereafter referred to as under 10 kDa extract (U10E).