EXPLOITATION OF ASPERGILLUS AND CLADOSPORIUM SPECIES FOR BIOLOGICALLY ACTIVE SECONDARY METABOLITES
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Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Center of Biotechnology
Abstract
Aspergillus carbonarius (NRRL–369) and Aspergillus oryzae from Aspergillus genus as well as Cladosporium carrionii and Cladosporium resinae (NRRL–6437) from Cladosporium genus were selected for the present study. Nutrient media were optimized for the growth and production of secondary metabolites. Out of five different media used, A. carbonarius and A. oryzae produced relatively more metabolites in Czapek–dox (Glucose and Starch) broth media (CGSB). Whereas; C. carrionii and C. resinae produced relatively more metabolites in Czapek yeast extracts broth (CYB). To further increase secondary metabolites productivity, two additional chemical compounds (suberoyl anilide hydroxamic acid; SAHA and 5–azacytidine; 5–AZA) were also used as chemical inducers for all fungi except C. carrionii. A dose of 10 μM/100 mL of SAHA resulted in higher secondary metabolites production from Aspergillus species and 15 μM/100 mL of SAHA resulted in higher secondary metabolites production from C. resinae. While a dose 15 μM/100 mL of 5–AZA resulted in higher secondary metabolites production from all the species.
Secondary metabolites produced were then studied for its respective biological activities. In antibacterial assay a dose of 500 μg/mL of ethyl acetate extracted from A. carbonarius inhibited the growth of B. subtilis (64.5%), while for antifungal testing a dose of 1000 μg/mL ethyl acetate extract inhibited the linear growth of C. glabrata (58.5%). Whereas, in cytotoxic activities, dose of 1000 μg/mL of ethyl acetate extract showed 94% mortality against brine shrimps, while for phytotoxic activities, a dose 1000 μg/mL showed 90% mortality against Lemna.