Antibacterial and antioxidant activities, total phenolic content, and protein content of gum tragacanth harvested from different populations of Astragalus gossypinus and Astaragalus parrowianus (Fabaceae) from three provinces in central to southwestern Iran were investigated. Total phenolic amount of aqueous solution of gum tragacanth was determined using Folin-Ciocalteu method. Antioxidant activity of the aqueous solution of gum tragacanth was evaluated by measuring DPPH. The antibacterial activity of the aqueous solution of gum tragacanth against four bacteria was determined by serial dilution assay. Results indicated that there were significant differences in amount of total phenol, antibacterial and antioxidant activities among different populations of two species. The highest amounts of total phenol of gum tragacanth were obtained from the Shahrekord and the Khomeyn populations for A. parrowianus (237 and 235 mg GAE∙g^-1 gum tragacanth, respectively). The highest protein content was obtained from the populations of A. parrowianus and the lowest amount of protein content was obtained from the Shahrekord population of A. gossypinus. The highest antioxidant activity was obtained the Shahrekord population for both species (IC₅₀ = 0.345, and 0.419 mg∙ml^-1), and the Khomeyn population for A. gossypinus (IC₅₀ = 0.511 mg∙ml^-1). The aqueous solutions of the gum tragacanth studied indicated moderate-to-good inhibitory activities (MICs = 0.125 to 0.250 mg∙ml^-1) against four bacteria, especially against Listeria monocytogenes. In conclusion, gum tragacanth from some populations of A. gossypinus and A. parrowianus could be an important dietary source of protein and total phenolic compound with antioxidant capacity and antibacterial activity.

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