New adipate esters from Cunninghamella echinulata : isolation, identification, biosynthesis and in silico prediction of potential opioid/anti-opioid and antidiabetic activities.

Metabolites of the fungus Cunninghamella echinulata NRRL 1382 were investigated under the effect of fusidic acid ( 1 ) feeding. In addition to ergosterol ( 2 ) which is a fungal sterol, two novel adipate esters ( 3, 4 ) were isolated, and their structures were fully investigated using various spectroscopic analyses, including 1 D, 2 D NMR and HRESIMS. In silico biological target prediction and molecular docking investigation revealed a potential agonist/antagonist activity for compound 3 by binding to µ opioid receptor and antidiabetic effect by aldose reductase inhibitory activity for compound 4 .