Search

Honeybush tea is made from the fynbos plant Cyclopia subternata , which is unique to South Africa. Cultivation takes place in its natural environment, which has a Mediterranean climate with dry summers and wet winters. During the summer, the plant is vulnerable to drought, an abiotic stress factor that is likely to affect its development and yield. This study investigated the effect of drought stress for a short duration on the leaf, as well as the quality of the herbal tea. Protein expression in the leaf was measured to gain insight into possible mechanisms used by the plant to cope with drought stress conditions. Fifteen-month-old C. subternata plants were subjected to three water treatments (control, moderately-stressed (MS), and severely-stressed (SS)) for ten days. Leaves were sampled at regular intervals throughout the treatment period to determine their relative water content (RWC). Leaves were also sampled on the 11th day for untargeted and targeted chemical composition and protein expression analyses. The remaining leaves and stems were processed to obtain the herbal tea. Descriptive sensory analysis of the herbal tea was performed to determine whether drought stress affected product quality. RWC was substantially higher (p < 0.05) in the control plants (100%) than in the MS and SS treated plants (83–90% and 47%, respectively). Untargeted analysis revealed that drought stress considerably altered leaf chemical composition. According to targeted analysis, the proline content of SS treated plants increased more than 40-fold when compared to the control, however, the treatments had no effect on the total carbohydrate and major phenolic compound content of the leaves, nor on the sensory quality of the herbal tea. Differences in the expression of 27 proteins, 24 of which were identified using proteomic analysis, were observed. During drought stress, 17 of these proteins increased, whereas seven decreased. Thirteen of the 24 identified proteins produced statistically significant results based on their Byonic scores. The findings laid the foundation for future research into the functions of drought response genes in Cyclopia species, as well as helping with the identification of stress-tolerant honeybush genotypes. [ABSTRACT FROM AUTHOR]

• Twenty-five year scientometric assessment of 421 rooibos tea publications from Scopus was undertaken. • Research output on rooibos tea displays a steady upward trajectory, with 27.2% average annual growth rate. • South African authors dominated the research landscape, contributing 60% of total publication output. • Research hotspots include - oxidative stress, agronomy, commercialisation, Type 2 diabetes, safety and quality aspects. • Pharmacological activity of rooibos tea metabolites appears to be insufficiently studied. This bibliometric assessment aimed to gain insight into the publication landscape over a 25-year period on one of South Africa's most coveted indigenous plants, Aspalathus linearis , known in commerce as rooibos tea. Despite the growing global market, and acceptance as a refreshing and health-promoting tea, scientific publications on rooibos, have not been subjected to scientometric analyses. A total of 421 relevant documents spanning the period 1994-2018 as indexed in the Scopus database were considered using VOSviewer. The global publication contribution on rooibos tea shows an average annual growth rate of 27.2%, and citation impact averaged 30 per publication. South African authors dominated the research landscape, contributing to approximately 60% of the total publication output. Prominent research themes include oxidative stress and inflammatory process mitigation using rooibos tea extracts, agronomy and fair trade in the rooibos tea industry, metabolic syndrome research, antioxidant activity, toxicity, quality control of rooibos tea and formulated products. More recently, a research focus has developed around bioavailability evaluation of rooibos tea components, green synthesis and nanoparticle formulations with the aim of improving the efficacy and potency of rooibos tea in the treatment of Type 2 Diabetes. We propose that research attention should be devoted to the mechanistic action of rooibos metabolites in mitigation of infectious diseases, diabetes, cardiovascular diseases and obesity which will inevitably lay the foundation for clinical studies to proceed. [ABSTRACT FROM AUTHOR]

Abstract: In the presented work, an insight was made into the polyphenolic composition of intact plant material and in vitro cultures of indigenous South African plant Cyclopia subternata Vogel (honeybush). Ethyl acetate fractions of methanol extracts were separated by means of gravity column chromatography and/or semipreparative HPLC on two serially connected monolithic RP-18 columns. The structures of the isolated compounds were determined by means of 1D and 2D NMR techniques and additionally confirmed by LC-DAD-ESI-MS. Apart from the previously described honeybush components, that is mangiferin (1), scolymoside (2), hesperidin (3) and narirutin (4), three additional compounds: iriflophenone 3-C-β-glucoside (benzophenone) (5), phloretin 3′,5′-di-C-β-glucoside (dihydrochalcone) (6), and isorhoifolin (flavone) (7) were identified for the first time in the herb of C. subternata. Additionally, three isoflavone glucosides, namely calycosin 7-O-β-glucoside (8), rothindin (9) and ononin (10), which had not been previously reported in Cyclopia plants, were identified in the callus of the above species. As far as the authors are concerned, this is the first report on the presence of benzophenone and dihydrochalcone derivatives in Cyclopia genus. [Copyright &y& Elsevier]

Abstract: Honeybush tea (Cyclopia spp.), one of the traditional South African herbal teas with a long history of regional use, remained a cottage industry until the mid-1990s when researchers were instrumental in the development of a formal agricultural and agro-processing industry. It is one of the few indigenous South African plants that made the transition from the wild to a commercial product during the past 100years. Research activities during the past 20years included propagation, production, genetic improvement, processing, composition and the potential for value-adding. The present review provides an up-to-date and comprehensive record of the development of the South African honeybush industry, against the background of the historical highlights in the making of an industry. It provides a blueprint of the processes and actions involved in the development of a new agricultural and agro-processing industry from an herbal plant. Insight into challenges faced by the industry and future research needed to keep it competitive are provided. [Copyright &y& Elsevier]

Abstract: Aspalathus linearis (Burm.f.) Dahlg. (Fabaceae, Tribe Crotalarieae), an endemic South African fynbos species, is cultivated to produce the well-known herbal tea, rooibos. It is currently sold in more than 37 countries with Germany, the Netherlands, the United Kingdom, Japan and the United States of America representing 86% of the export market in 2010. Its caffeine-free and comparatively low tannin status, combined with its potential health-promoting properties, most notably antioxidant activity, contributes to its popularity. First marketed in 1904 in its fermented (oxidised) form, green rooibos is a new product recently on the market. The utilisation of rooibos has also moved beyond a herbal tea to intermediate value-added products such as extracts for the beverage, food, nutraceutical and cosmetic markets. Its potential as a phytopharmaceutical, shown in recent scientific studies, has not yet been exploited. This review focuses on past and current research aimed at enhancing the value of rooibos herbal tea as a specialised, niche product and expanding its value-adding potential against the background of its traditional use and the current market. The focus falls specifically on aspects such as composition, processing, quality and rooibos as food and potential medicine. [Copyright &y& Elsevier]

The commercial value of indigenous South African animal and plant resources can add significantly to the nation's socioeconomic development and contribute towards the achievement of the goals of the African Renaissance. However, very few of the country's many indigenous plants have been successfully commercialised. This article reviews the development phases of one success story: rooibos tea. Its development trajectory offers a useful lesson in the commercialisation of other South African indigenous animal and plant resources. Constraints that hindered the effective commercialisation of the beverage are highlighted, notably the initial over-reliance on a local market and the lack of coordinated broad marketing and quality assurance. These constraints were compounded by international trade restrictions imposed on South Africa prior to the 1994 transition to democracy. While the world moved forward, the rooibos tea sector lagged behind in the development of niche markets. It was only in the late 1990s when a seemingly perfect match between the health-giving properties of rooibos and consumer needs was achieved, thus creating a vibrant niche market for the tea. Since then, production and sales of rooibos tea have increased markedly. Adherence to national and international codes of good manufacturing practice, together with the recognition of the importance of fair trade principles regarding the participation of small-scale cooperatives, are becoming increasingly important parameters for product acceptance. [ABSTRACT FROM AUTHOR]

South Africa has a traditional heritage of using indigenous herbal teas, and the demand for herbal teas motivated by the functional health benefits has far exceeded global supply. This has led to worldwide interest in the sensory characteristics and volatile compound characterisation of herbal drink formulations. The objective of this study was to investigate the descriptive sensory analysis and volatile compounds of bush, special, honeybush and rooibos tea and the blend of bush tea with special, honeybush and rooibos, respectively. The trained sensory panel scored each tea sample for aroma, taste, aftertaste and mouthfeel attributes using sensory evaluation practices. Compound identification was performed by gas chromatography connected to a mass spectrometer (GC-MS). The results of the study demonstrated that rooibos and honeybush tea had an overall sweet-caramel, honey-sweet, perfume floral and woody aroma while bush tea and special tea depicted green-cut grass, dry green herbal and astringent/dry mouth feel. The GC-MS analyses depicted the following compounds 2-furanmethanol, 2-methoxy-4-vinylphenol, D-limonene, dihydroactinidolide, linalool, (E,E)-2,4-heptadienal, and phytol. The blending of bush tea with rooibos and honeybush tea toned down its astringent mouth feel. Compounds identified in this study may be useful markers for potential herbal tea sensory characteristics. [ABSTRACT FROM AUTHOR]

Rooibos and honeybush are popular herbal teas produced from the shrubs of Aspalathus linearis and Cyclopia spp., respectively, which are indigenous to South Africa. Both herbal teas are rich in polyphenols and their consumption is associated with several health benefits, partly ascribed to their phenolic constituents. Quantification of phenolics in extracts and teas for quality control and research purposes is generally performed using HPLC, although dedicated and often species-specific methods are required. CE offers an attractive alternative to HPLC for the analysis of phenolics, with potential benefits in terms of efficiency, speed and operating costs. In this contribution, we report quantitative CZE methods for the analysis of the principal honeybush and rooibos phenolics. Optimal separation for honeybush and rooibos phenolics was achieved in 21 and 32 min, respectively, with good linearity and repeatability. Quantitative data for extracts of "unfermented" and "fermented" rooibos and two honeybush species were statistically comparable with those obtained by HPLC for the majority of compounds. The developed methods demonstrated their utility for the comparison of phenolic contents between different species and as a function of manufacturing processes, thus offering cost effective, although less sensitive and robust, alternatives to HPLC analysis., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)