The herbal tea called rooibos (pronounced ROY-boss), also sometimes referred to as "red tea", has become quite popular in recent times due to its being marketed as a beverage possessing numerous health benefits due to its high levels of anti-oxidants.
The Rooibos plant (Aspalathus linearis (Burm. f.) Dahlgren, Fabaceae) is a South African flowering shrub used to make a mild-tasting tea that has no caffeine, very little tannin, and significant amounts of polyphenol anti-oxidants. Rooibos tea has been enjoyed in South Africa for generations, and has been produced in the Cedarberg mountain region of South Africa.
International demand for rooibos has been increasing since trade sanctions against South Africa were lifted following the demise of apartheid in the 1990s.
Rooibos tea health benefits are derived from several of the polyphenol anti-oxidants, called 'flavonoids', which combat the proliferation of so-called free radicals that damage the DNA in cells. Free radicals running amuck in one's system can lead to cancer. They can oxidize cholesterol and lead to clogged blood vessels, heart attack, and stroke.
Anti-oxidants from rooibos tea can bind to free radicals before the free radicals cause harm.
A recent analysis of fermented rooibos measured the levels of all the flavonoids listed above except nothofagin. Of the 10 flavonoids measured, the three that occurred in largest amounts were aspalathin, rutin, and orientin, followed by isoorientin and isoquercitrin. Nothofagin was identified by mass spectrometry but was not quantified because a standard was not available.
The amount of nothofagin in fermented and unfermented rooibos was estimated to be about three times less than aspalathin in one study. Aspalathin and nothofagin arepresent in relatively large amounts in unfermented rooibos tea, but some of the aspalathin and nothofagin oxidizes to other substancesduring fermentation; thus, fermented rooibos contains less aspalathin and nothofagin than unfermented rooibos. The change in polyphenol composition is the reason the tea changes color with fermentation.
Currently, rooibos is the only known natural source of aspalathin. Nothofagin is similar in structure to aspalathin and has only been identified in one other natural source besides rooibos: the heartwood of the red beech tree which is native to New Zealand.
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