Prenylated acylphloroglucinols from Hypericum tetrapterum

The genus Hypericum L. (Hypericaceae) comprises about 500 species and is almost spread worldwide, avoiding only zones of extreme aridity, temperature and/or salinity. Acylphloroglucinols are an abundant class of secondary metabolites with hyperforin being a prominent representative occurring in H. perforatum ([Fig. 1]) L. and several other Hypericum species.

Fig. 1 Structures of prenylated acylphloroglucinols from Hypericum tetrapterum Fr.

Besides their antibacterial effects, the extracts of H. perforatum show anti-depressive, antiviral, anti-inflammatory and anti-tumoural activity.

Hypericum tetrapterum Fr. is a perennial herb with a four-winged stem and a congested inflorescence of small yellow flowers. It is native to Europe, Western Asia and North Africa. To date, the chemical profile of the plant, particularly the composition of prenylated acylphloroglucinols is mostly unknown. For the isolation of acylphloroglucinols based on ¹H-NMR-guided fractionation a petroleum ether extract was obtained from the dried aerial parts of H. tetrapterum. The structures of three isolates were elucidated by ¹H-, ¹³C- and 2D NMR (HSQC, HMBC, NOESY, COSY) spectroscopy as well as on data derived from mass spectrometry. Optical characterisation was performed by polarimetry and circular dichroism. The compounds obtained are prenylated bicyclic acylphloroglucinols with furanone skeletons which are described here for the first time. The compounds will be evaluated for anti-bacterial, cytotoxic and anti- angiogenetic activity. Isolation and structure elucidation of further acylphloroglucinols from H. tetrapterum Fr. is in progress.

 

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Publication History

Article published online:
16 November 2023