Evaluation of the Antioxidant Activity and Mycochemical Screening of Two <i>Penicillium oxalicum </i>Isolated from Soil and Leaves of <i>Solanum lycopersicum </i>Respectively

Abstract

The purpose of the work was to compare the mycochemical composition and antioxidant properties of acetate extracts of Penicillium oxalicum from two different sources, soil and leaves of Solanum lycopersicum (tomato). After extraction of the metabolites on rice medium, qualitative analyses of the extracts were carried out by colorimetric tests and thin layer chromatography (TLC). The contents of total polyphenols and flavonoids were determined respectively by the Folin-Ciocalteu method and the AlCl 3 method. For antioxidant capacity, the 1,1-diphenyl-2picrylhydrazyl free radical trapping method and the FRAP method were used. Penicillium oxalicum from the soil was characterised by molecular biology. Mycochemical analysis revealed the existence of polyphenols, flavonoids, alkaloids, polyterpenes and sterols and saponosides in the extract of Penicillium oxalicum from soil. Except for saponosides, the other secondary metabolites were present in the endophyte extract but in low quantities. In addition, the contents of total flavonoids and phenols in soil Penicillium oxalicum, which are respectively 11.67 ± 1.03 mg QE/ g extract and 58.36 ± 2.779 mg GAE/ g extract, were higher than those of the endophyte 6.03 ± 0.95 mg QE/ g extract and 36.66 ± 2.01 mg GAE/ g extract. Concerning the antioxidant activity, the IC 50 of Penicillium oxalicum extracts were 67.73 ± 0.58 µg/mL for the soil extract and 2.74 ± 0.33 mg/mL for the endophyte extract. The reducing power of Penicillium oxalicum from the soil is higher than that of the endophyte. It appears that Penicillium oxalicum from soil is rich in secondary metabolites. Also, it showed a better antioxidant activity. This work shows that soil Penicillium oxalicum is the best candidate for the production of antioxidant compounds.