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چکیده
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The process of melanogenesis is responsible for the pigmentation of the skin, eyes and hair.inhuman. Melanin production is also responsible for the browning of fruits, vegetables and fungi. Melanogenesis begins with the oxidation of L-tyrosine to L-Dopa by tyrosinase .The accumulation of melanin in the skin causes complications such as skin lesions, eczema and melasma in humans .Inhibition of tyrosinase could be effective in tretment those complications. The aim of this study was to determine inhibitory activity on tyrosinase and antioxidant activity of methanolic extract of various aerial parts of Astragalus siliquosus bioss and Verbascum phonicum L. Methanolic extracts of the isolated organs of the plants were prepared using rotary evaporator. Inhibitory effects of the extracts were evaluated in nine concentrations in 96 wells at 492 nm wavelengths using a microplate reader. The antioxidant activity of the extracts was evaluated using DPPH free radicalscavengingindex. The most inhibitory activity of the Astragalus siliquosus Bioss was at 1000 mg/ml concentration of its flower extract (97% inhibition and IC50 = 1.58 mg/ml) and 1500 mg/ml concentration of its stem extract (100 mg / ml and IC50 = 13.225 mg/ml). For Verbuscum phonicum L., the highest inhibitory activity was observed in the 1500 mg/ml concentration of its leaf extract (87% inhibition and IC50 = 155.3 mg/ml).All aerial parts of the Astragalus siliquosus had 100% antioxidant activity with EC50s of 0/089, 1/775, 1.25 mg/ml for its flower, leaf and stem respectively. On the other hand just leaves of the Verbuscum phonicum had a 100% antioxidant activity, with EC50 of 0.129 mg/ml. According to the results of this study, methanolic extracts of flower and leaf organs of Astragalus siliquosus Bioss , and just leaf organ of Verbuscum phonicum L., had a reasonable inhibitory effect on tyrosinase activity. So feature studies could be focused on those organs to separat potential agents with pharmaceutical and food
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