Baqiyatallah University of Medical Sciences Journal of Applied Biotechnology Reports 2322-1186 1 2 2014 06 01 The Inhibition Effects of Two Species of Astragalus Extracts on Mushroom Tyrosinase Activity 63 66 68946 EN Azadeh Taherian Department of Biology, School of Science and Agriculture, Payame Noor University of Tehran, Tehran, Iran Alireza Jahangiri Department of Medicinal Chemistry, School of Pharmacy, Ahwaz Jundishapur University of Medical Sciences, Ahwaz, Iran Forogh Namjoyan Department of Pharmacognosy, School of Pharmacy, Ahwaz Jundishapur University of Medical Sciences, Ahwaz, Iran Seyed Reza Hajhosseini Department of Biology, School of Science and Agriculture, Payame Noor University of Tehran, Tehran, Iran Journal Article 2014 03 25 Melanin pigment plays a critical role in camouflage and protection against harmful effects of solar radiation. Melanogenesis is under complex regulatory control by multiple agents. Tyrosinase is a multifunctional, which catalyzes the first two steps in mammalian melanogenesis. In this study, inhibitory effects of <em>Astragalus fasciculifolius</em> and <em>Astragalus gypsicolus</em> on diphenolase activity of mushroom tyrosinase were evaluated. .Ethanol 80% extracts were prepared for screening tests. The IC₅₀, K_i, Km and Vm values of <em>Astragalus fasciculifolius</em> and <em>Astragalus gypsicolus</em> were measured then compared them. We found that Both extracts show mixed type inhibition on mushroom tyrosinase when L-DOPA was used as a substrate. https://www.biotechrep.ir/article_68946_d724408089c39a7576109b8c762ed912.pdf