Phenolic metabolites from rooibos tea (Aspalathus linearis)

Factors promoting marine invasions: A chemoecological approach

“…From the viscera of S. geographica we isolated the known bioactive flavonoids apigenin (5), genkwanin (6), and chrisoeriol (7) (Fig. 2) (27)(28)(29)(30). Syphonoside (1) (21) was also detected as a polar component.…”

“…The extracts were, primarily, analyzed by TLC using two different mobile phases (light petroleum ether/diethyl ether and chloroform/methanol in different ratio) showing identical chromatographic patterns. The diethyl ether extracts were then combined to give 290.1 mg of crude residue, which was fractionated by Sephadex LH-20 chromatography eluted with chloroform/methanol in ratio 1:1 to give a fraction that was further purified on preparative silica gel TLC (90% chloroform/ methanol) affording the known flavones apigenin (5, 2.7 mg), genkwanin (6, 1.0 mg), and chrisoeriol (7, 1.6 mg), all identified by comparison with 1 H and 13 C NMR data described in the literature (27)(28)(29)(30). In each n-butanolic extract, we identified syphonoside (1) by TLC comparison with the standard compound we recently isolated and reported from both S. geographica and H. stipulacea (21).…”

The Occurrence, Fate and Biological Activities ofC-glycosyl Flavonoids in the Human Diet

“…These unusual compounds have received a significant deal of attention, not least because of their abundance in this tisane and the importance of this principal South African export to its home economy. Indeed, the routine quantification of both aspalathin (2 ,3,4,4 ,6 -pentahydroxy-3-C--Dglucopyranosyldihydrochalcone) and the 2 ,4,4 ,6 tetrahydroxylated analogue, nothofagin, has become an accepted measure of rooibos quality, with several publications detailing methodologies for analysis and abundance in material from various processing yards and following several processing protocols (Bramati et al, 2003;Bramati et al, 2002;Joubert, 1996;Joubert and deVilliers, 1997;Joubert et al, 2008;Manley et al, 2006;Pengilly et al, 2008;Rabe et al, 1994;Schulz et al, 2003;Standley et al, 2001;vonGadow et al, 1997). The predominant factor determining the concentration of these two C-glycosyl dihydrochalcones in rooibos tea is the 'fermentation' process.…”

“…This is an important factor in considering the dietary burden of the rooibos C-glycosyl dihydrochalcones, as both unfermented ('green') and fermented (often known as 'redbush') rooibos tea is consumed. Rooibos also contains the flavones orientin and isoorientin, both native to the plant and derived from the pathway of aspalathin oxidation during fermentation via the two aforementioned eriodictyol-C-glucoside isomers (Marais et al, 2000;Rabe et al, 1994). These isomeric compounds are reported to be interconvertable via a Wessely-Moser rearrangement of the flavone structure under heating in an aqueous solution: conditions similar to those that occur during tisane extraction (Koeppen and Roux, 1965).…”

Effect of Rooibos and Honeybush Tea Extracts Against Botrytis cinerea

“…This suggests that the antifungal property of the tested tea extracts may be due to the presence of a specific flavanol or a combination of different flavanoids. Both rooibos and honeybush tea extracts are known to contain different phenolic compounds, including epicatechin gallate and epigallocatechin gallate (Kamara et al, 2003;Kamara et al, 2004;Rabe et al, 1994).…”