![Sample our Bioscience journals, sign in here to start your access, Latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5925/TOC-Subject-Sample-2021-Bioscience.jpg"})
Abstract
A phytochemical study of Baeckea frutescens afforded a new biflavonoid named as baeckein E (1), along with four known C-methylated flavonols, baeckeins A (2) and B (3), 6-methylquercetin (6) and 6-methylquercetin-4′-O-β-d-glucopyranoside (7), and two known biflavonoids baeckeins C (4) and D (5). The structure of compound 1 was elucidated on the basis of spectroscopic analysis, including HR-ESI-MS, 1D and 2D NMR spectra, and the absolute configurations of C-2 and C-3 for compound 1 were assigned by circular dichroism spectrometry combined with quantum chemical calculations. The antioxidant and cytoprotective activities of compounds 1–7 were also investigated.
Acknowledgements
This work was supported by grants from a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD). The authors appreciate the kind help of Dr C.L. Xu (Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University) and Dr X.B. Wang (Department of Natural Medicinal Chemistry, China Pharmaceutical University) for providing assistance in technology and equipment.