Biological activity of new flavonoids and phenolic compounds from Cirsium italicum (Savi) DC.

Abstract

Cirsium italicum (Savi) DC. was researched for its phytochemicals for the first time. Two new biflavonoids, 5,5'',7''-trihydroxy-3,7-dimethoxy-4'-4'''-O-biflavone (3), (8,3',4',5'-tetrahydroxy-7-O-α-glucosyl isoflavone)-6-8''-(4'''-hydroxy-7''-O-α-glucosyl isoflavone) biflavone (7), a new isoflavone, 6-2'-dihydroxy-5-methoxy isoflavonone-4'-O-α-D-glucopyranoside (5) and a new phenolic compound, ethyl-(2,3-dihydroxy-5,6-dimethoxy-4-acetyl) benzoate (4), together with three known compounds (1), (2) and (6) were isolated from Cirsium italicum. Their structures were elucidated by extensive 1D and 2D NMR, and MS data analyses. All compounds isolated from C. italicum exhibited antioxidant activity. However, the highest activity of the EtOAc extract is considered to be responsible for compounds (1), (2) and (3) being the main compounds.

Graphical Abstract

Keywords:

• Cirsium italicum
• biflavonoids
• isoflavones
• phenolic compounds
• antioxidant activity

Acknowledgements

We would like to thank TUBITAK for financial support of the project (116Z450). The authors thanks to Prof. Dr. A. Orak for his assistance with the statistical evaluations.

Supporting Information Available

Supplementary material relating to this article is available online, alongside Table S1-S3, Figures S1-S24 and Experimental.

Disclosure statement

The authors declare no conflict of interest in this study.