New diterpene furanoids from the Antarctic lichen Huea sp

In the course of ongoing research on protein tyrosine phosphatase 1B (PTP1B) inhibitory compounds from Antarctic lichens, four new diterpene furanoids, hueafuranoids A-D (1-4) have been isolated from the MeOH extract of Antarctic lichen Huea sp. by various chromatographic methods. The structures of these compounds were elucidated by analysis of NMR and MS data, and comparing their spectral data with those in the literature. Compound 1 showed inhibitory activity against therapeutically targeted protein, PTP1B with an IC50 value of 13.9 μM. The kinetic analysis of PTP1B inhibition by hueafuranoid A (1) suggested that the diterpene furanoids encountered in this study inhibited PTP1B activity in a non-competitive manner.