Daldiniaeschsone A, a Rare Tricyclic Polyketide Having a Chromone Unit Fused to a <i>δ</i>-Lactone and Its Symmetrical Biphenyl Dimer, Daldiniaeschsone B, from an Endophytic Fungus <i>Daldinia eschscholtzii</i> SDBR-CMUNKC745

Abstract

Daldiniaeschsone A (1), a rare tricyclic polyketide having a chromone unit fused to a δ-lactone and its symmetrical 6,6′-biphenyl dimer, daldiniaeschsone B (2), together with three known compounds (3−5), were isolated from a plant-derived endophytic fungus, Daldinia eschscholtzii SDBR-CMUNKC745. Their structures were elucidated by extensive 1D and 2D NMR spectroscopic data and HRESIMS. All compounds showed α-glucosidase inhibitory activity with IC50 values ranging from 0.16−0.85 mM and compound 1 was the best α-glucosidase inhibitory activity (IC50 = 0.16 mM).

Keywords

• <i>Daldinia eschscholtzii</i> SDBR-CMUNKC745
• tricyclic polyketide
• biphenyl dimer
• chromone
• <i>α</i>-glucosidase inhibitory activity