Sesquiterpenes from the roots of Illicium oligandrum

Abstract

Two new sesquiterpenes, oligandrin (1) and oligandric acid (2), together with three analogues, tashironin A (3), tashironin (4), and oplodiol (5), were isolated from the roots of Illicium oligandrum. The structures of new compounds were determined based on 1D and 2D NMR experiments and X-ray diffraction. Compound 1 represents a presumed biosynthetic precursor of seco-prezizaane sesquiterpenes which consists of a novel 6/6/5 tricarbocyclic skeleton. Compound 2 is the first example of chamipinene-type sesquiterpene possessing a 6/4/6 tricyclic system from the genus Illicium. Compounds 1–5 were evaluated in vitro for their activity against coxsackie virus B3 (CVB3), influenza virus A/Hanfang/359/95 (H3N2), and influenza virus A/FM/1/47 (H1N1). Compound 1 showed selective antiviral activity against CVB3 with IC₅₀ value of 11.11 μM.

Keywords::

• Illiciumoligandrum
• Illiciaceae
• sesquiterpene
• antiviral activity
• coxsackie virus

Acknowledgement

The authors are grateful to the Department of Instrumental Analysis at our institute for the UV, IR, NMR, and MS measurements and to the Instrumental Analysis Center of Beijing University of Chemical Technology for X-ray crystallographic measurement and analyses.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by grants from the National Natural Science Foundation of China [grant number 21132009]; the National Science and Technology Project of China [grant number 2012ZX09301002-002], [grant number 2014ZX09507003-006]; and CICSEM (2013-B1).