6 - Athrixia phylicoides

Abstract

Athrixia phylicoides DC. is an aromatic shrub belonging to the Asteraceae family. The species is mostly referred to as ‘bush tea’ and used throughout South Africa, where it grows abundantly in several provinces. The leaf infusions are taken as beverages and used to treat hypertension, heart disease, headache, infested wounds and skin conditions. A wide range of biological activities has been reported for A. phylicoides including antibacterial, antifungal, antidiabetic, antimalarial, anti-inflammatory and anti-oxidant. Chromatographic quality control protocols for A. phylicoides were developed using semi-automated high-performance thin-layer chromatography (HPTLC), and ultra-performance liquid chromatography coupled to mass spectrometry and photodiode array detection (UPLC-MS-PDA). The chemical profiles of six A. phylicoides samples were obtained for the aerial parts, extracted with methanol. The non-volatile fractions obtained were analysed using HPTLC, HPTLC-MS and UPLC-MS-PDA. The methanol extracts viewed under 366nm radiation after derivatisation, displayed several bands common to all the samples. The HPTLC-MS analysis of some isolated bands revealed the presence of 5,7,5′-trihydroxy-3,6,8,3′,4′-pentamethoxyflavone (m/z 419) and 5,7-dihydroxy-3,6,8,3′,4′,5′-hexamethoxyflavone (m/z 433) as marker compounds in the A. phylicoides extracts. The UPLC-MS-PDA chromatograms enabled the identification of major compounds that include chlorogenic acid, 3-O-dimethyldigicitrin, p-hydroxyphenylpropan-3-ol-coumarate and 5-hydroxy-6,7,8,3′,4′,5′-hexamethoxyflavon-3-ol.