Identification, Isolation and Determination of Biomarkers for Quality Control of Bush Tea (Athrixia phyllicoides)

Athrixia phylicoides, known as "bush tea", grows abundantly in South Africa. An infusion of the leaves is used as a beverage and to treat a multitude of health conditions. The aim of this study was to investigate the chemical variation within A. phylicoides and to identify characteristic compounds for quality control. Samples from 12 locations in South Africa were analysed using ultra-performance liquid chromatography. Hierarchical cluster analysis of the aligned ultra-performance liquid chromatography-time-of-flight mass spectrometry data indicated two groups on the resulting dendrogram, representing 48 samples. Five marker compounds, identified through visual inspection and the construction of a discriminant analysis model, were evident on the ultra-performance liquid chromatography-MS profiles. Four of these compounds were isolated and identified, three as hydroxy methoxyflavones and the fourth as a coumarate, using nuclear magnetic resonance spectroscopy. An ultra-performance liquid chromatography-photodiode array method was developed and validated for the determination of the marker compounds using the isolates as standards. The limits of detection for the four compounds ranged from 0.92 - 2.50 µg/mL. Their recoveries at three concentration levels (1.00, 10.0, and 100 µg/mL) were between 97.0 and 101%, while acceptable intra- and inter-day precision was obtained as reflected by percentage relative standard deviation values below 2.24%. The concentrations of all the marker compounds were found to be higher in samples corresponding to Group 1 of the dendrogram than in those from Group 2. This may be attributable to differences in altitude, climate, and some edaphic factors. Identification of these marker compounds will make a valuable contribution towards the quality control and sustainable commercialisation of bush tea.

[1]  Paul Geladi,et al.  Principal Component Analysis , 1987, Comprehensive Chemometrics.

[2]  A. Viljoen,et al.  Bush tea (Athrixia phylicoides): A review of the traditional uses, bioactivity and phytochemistry , 2017 .

[3]  V. Bagla,et al.  Antifungal and antibacterial activity and chemical composition of polar and non-polar extracts of Athrixia phylicoides determined using bioautography and HPLC , 2013, BMC Complementary and Alternative Medicine.

[4]  J. Ley,et al.  Phytochemical characterization of South African bush tea (Athrixia phylicoides DC.) , 2012 .

[5]  J. Louw,et al.  An in vitro assessment of the effect of Athrixia phylicoides DC. aqueous extract on glucose metabolism. , 2012, Phytomedicine : international journal of phytotherapy and phytopharmacology.

[6]  Jing-Yu Yang,et al.  Density-based hierarchical clustering for streaming data , 2012, Pattern Recognit. Lett..

[7]  F. Mudau,et al.  Effects of chemical composition of wild bush tea (Athrixia phylicoides DC.) growing at locations differing in altitude, climate and edaphic factors , 2012 .

[8]  D. de Beer,et al.  Use of countercurrent chromatography during isolation of 6-hydroxyluteolin-7-O-β-glucoside, a major antioxidant of Athrixia phylicoides. , 2011, Journal of chromatography. A.

[9]  K Ferenczi-Fodor,et al.  Validation of thin layer and high performance thin layer chromatographic methods. , 2011, Journal of chromatography. A.

[10]  N. Lall,et al.  Antioxidant activity and cytotoxicity of three flavonoids from Athrixia phylicoides ethanol extract , 2010 .

[11]  Peter Filzmoser,et al.  Introduction to Multivariate Statistical Analysis in Chemometrics , 2009 .

[12]  P. Soundy,et al.  Seasonal variation of total antioxidant content of wild bush tea , 2008 .

[13]  J. Louw,et al.  A toxicological assessment of Athrixia phylicoides aqueous extract following sub-chronic ingestion in a rat model , 2008, Human & experimental toxicology.

[14]  D. de Beer,et al.  South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides--a review. , 2008, Journal of ethnopharmacology.

[15]  P. Soundy,et al.  Effects of nitrogen, phosphorus, and potassium nutrition on total polyphenol content of bush tea (Athrixia phylicoides L.) leaves in shaded nursery environment , 2007 .

[16]  P. Soundy,et al.  Seasonal variation of tannin content in wild bush tea , 2007 .

[17]  P. Soundy,et al.  Variation in polyphenolic content of Athrixia phylicoides (L.) (bush tea) leaves with season and nitrogen application , 2006 .

[18]  P. Soundy,et al.  A New Flavonol from Athrixia phylicoides (Bush Tea) , 2006 .

[19]  Isaac Olivier Jana Rampedi,et al.  The use and potential commercial development of Athrixia phylicoides , 2005 .

[20]  J. Miller,et al.  Statistics and chemometrics for analytical chemistry , 2005 .

[21]  D. M. Gottlieb,et al.  Multivariate approaches in plant science. , 2004, Phytochemistry.

[22]  O. A. Leistner,et al.  Seed plants of southern Africa: Families and genera , 2001 .

[23]  B.-E. Van Wyk,et al.  People's Plants: A Guide to Useful Plants of Southern Africa , 2000 .

[24]  Randall D. Tobias,et al.  Chemometrics: A Practical Guide , 1998, Technometrics.

[25]  Y. Kawamura,et al.  13C NMR spectral assignment of the A-ring of polyoxygenated flavones , 1998 .

[26]  A. Hutchings,et al.  Zulu Medicinal Plants: An Inventory , 1996 .

[27]  H. Wagner,et al.  Plant drug analysis : a thin layer chromatography atlas , 1996 .

[28]  F. Guéritte-Voegelein,et al.  Antimitotic and cytotoxic flavonols from Zieridium pseudobtusifolium and Acronychia porteri. , 1994, Journal of natural products.

[29]  T. Mabry,et al.  Flavonoids from Gutierrezia grandis , 1985 .

[30]  L. James,et al.  Chemistry of toxic range plants. Highly oxygenated flavonol methyl ethers from Gutierrezia microcephala , 1985 .

[31]  F. W. Fox,et al.  Food from the veld: Edible wild plants of southern Africa botanically identified and described , 1983 .

[32]  F. Bohlmann,et al.  A new seco-labdane derivative from Athrixia elata , 1982 .

[33]  F. Bohlmann,et al.  Neue norkauren- und thymol-derivate aus Athrixia-arten , 1977 .

[34]  J. M. Watt,et al.  The medicinal and poisonous plants of southern and eastern Africa. , 1962 .