Evaluation the effect of elicitors on antioxidant properties and mycelial secondary metabolites of Stereum hirsutum, Hyphodontia paradoxa and Arthrinium arundinis from Golestan province

The aim of this study was to evaluate the effect of elicitors on antioxidant properties and mycelial secondary metabolites of Arthrinium arundinis, Lichen symbiont, and Hyphodontia paradoxa and Stereum hirsutum hosted by Betula pendula . In the summer of 2016 preliminary sampling was performed from tree barks of Siah-Marzkouh, Golestan province, from an altitude of 2400 m above sea level. Then, fungal purification was achieved. In 2018, biennial mycelial reserves were used to investigate changes in secondary compounds. The following treatments were applied as elicitor: sodium nitrate, nanofibers cellulose and magnesium sulphate. Initial evaluation of triterpenoids was performed by HPLC using standard betulin and betulinic acid, and LC-MS was used to confirm the corresponding peak as triterpenoid. Antioxidant properties in mycelia of these fungi were studied by DPPH method. Based on the results, the highest peak of triterpenoids which are derivatives of betulin was in H. paradoxa treated by nanofibers cellulose, while in S. hirsutum it was by sodium nitrate (6.5 and 6.37 times in comparison to control, respectively). In A. arundinis, elicitors had no effect on triterpenoids amount and significantly reduced it. The antioxidant activity of H. paradoxa in the control treatment was 83.1% and the induction of elicitors had the opposite effect on this activity. The antioxidant activity of A. arundinis decreased from 82.05 to 87.12% with magnesium sulfate elicitor, meanwhile by adding sodium nitrate to the medium it increased from 24.62 to 86.04%.