Novel phenolics in Eriocephalus genus

Eriocephalus africanus is a small fast growing evergreen shrub endemic of South Africa where it is traditionally used in the folk medicine as an analgesic, anti-allergic, antidepressant, antiseptic, antioxidant and anti-inflammatory [1]. Regardless its widespread usage in African countries, little is known about phytochemical composition of the plant. The present study aimed to characterize the phenolic compounds of E. africanus. Stems and leaves of E. africanus were separately extracted with aqueous EtOH (80%, v:v), and the identification of compounds in both extracts were accomplished by reversed-phase high-performance liquid chromatography with DAD and ESI-MSn analysis in negative mode [2]. The HPLC-DAD-MSn analysis allowed the separation and identification of 13 compounds. Caffeoylquinic acid (CQA) and diCQA were the most abundant compounds, representing approximately 90% and 75% of the phenolic compounds in the stems and leaves extracts, respectively. The two compounds showed typical UV spectra, with absorption maxima at 219 and 325nm, and MS fragmentation pattern of m/z 515→353→191, 179 for CQA, and m/z 515→353→191, 135 for diCQA. The leaves contained significant amounts of eriodictyol-O-hexuronide which, together with other eriodictyol derivatives, represented about 18% of the phenols found in this extract. The phenolic compounds were identified for the first time in the genus Eriocephalus.

Acknowledgements: FCT for providing financial support to CERNAS (PEst-OE/AGR/UI0681/2014) and to Center of Chemistry of University of Coimbra (FCT/PTDC/AAC-CLI/118092/2010, PEst-OE/QUI/UI0313/2014).

Keywords: phenolic compounds, mass spectrometry, Eriocephalus, Caffeoylquinic acid

References:

[1] Njenga, E. W. et al. (2006), South African J Bot 72: 637 – 641.

[2] Pereira, O.R. et al. (2012), Food Chem 662 – 659.