Effects of various extractions of Scrophularia striata to reduce Aflatoxin B1 from Aspergillus flavus on pistachio nut

Today, the use of essential oils and extracts of medicinal plants in food and pharmaceutical industries is growing because of their medicinal, antifungal, antibacterial and antioxidant properties. In this way, the effects of various extracts of Scrophularia striata, a medicine plant, were studied for inhibiting Aspergillus flavus mycelial growth and reducing aflatoxin B1-level in culture liquid potato-dextrose (PDB) as well as the pistachio nut. Aflatoxin B1 (AFB1) was evaluated by high performance thin layer chromatography (HPTLC) method. Application of different concentrations of the extracts (250, 500, 1000, 2000 mg/L) in order to inhibit the growth of Aspergillus flavus and also Aflatoxin B1 production in PDB medium demonstrated that the aqueous extract at a concentration of 2000 mg/L could significantly inhibit the A. flavus growth (41.02% loss in dried weight). Ethyl acetate, methanol and aqueous extracts had amazing effect (92-100%) to inhibit toxin production. The results of AFB1 degradation assay indicated that the application of aqueous and methanolic extracts led to significant degradation of aflatoxin by 33.7 and 29.2%, respectively. It is shown that only aqueous extract at concentrations of 2000 and 4000 mg/L could significantlly inhibit (37.14- 58.91%) fungal sporulation on pistachio nuts, while both  methanol and aqueous extracts showed the strongest impact on inhibiting toxin production and caused a reduction of 96.85% and 75.48%, respectively, in AFB1 content. At the concentration of 2000 mg/L only methanol exract was able to reduce AFB1 (40.35%) on the pistachio nuts. Finally, the use of Scrophularia striata can possibly inhibit the aflatoxin contamination on agricultural products.