Two novel 27-norergostanol steroids,panthogenins A(1) and B(2),possessing unusual rings E and F featuring a ketal moiety at C-25 were isolated from rhizomes of Dioscorea panthaica.Their structures and relative configurations were elucidated by extensive spectroscopic methods including 1D and 2D NMR techniques,and the structure of panthogenin A was further confirmed by X-ray crystallography.Both compounds showed potent in vitro insulin sensitizing activity.
In a novel procedure,human serum albumin functionalized magnetic nanoparticles(HSA-MNPs)were used to selectively extract nine flavonoids in the extract of Ginkgo biloba leaves.The chemical structures of those flavonoids were characterized with high performance liquid chromatography coupled with mass spectrometry(HPLC–MS).The selective extraction with HSA-MNPs coupled with structural elucidation with HPLC–MS shows powerful potential for analysis of bioactive components in traditional Chinese medicines.
