Two New a-Glucosidase Inhibitory Depsidones from the Lichen Parmotrema cristiferum (Taylor) Hale

A bioactivity-guided investigation of the lichen Parmotrema cristiferum (Taylor) Hale (Parmeliaceae) led to the isolation of two new depsidones, cristifones A and B (1 and 2). The structures of the isolated compounds were identified by spectroscopic methods and comparison with the literature data. Compound 1 showed the initial combined structures of depsidone and depside cores. The two isolated compounds were then evaluated for alpha-glucosidase inhibition. Compounds 1 and 2 were confirmed as potent, with IC50 values of 21.5 and 18.4 mu M, respectively. Compound 2 was a non-competitive inhibitor against alpha-glucosidase, as indicated by the intersect in the second quadrant of each respective plot.

Automated summary

A bioactivity-guided investigation of lichen Parmotrema cristiferum led to the discovery and identification of two new depsidones, cristifones A and B. The structures of the isolated compounds were determined using spectroscopic methods and comparison with literature data. Both compounds showed potent alpha-glucosidase inhibitory activity, with compound 2 being a non-competitive inhibitor.