Journal of Tea Science Research, 2024, Vol.14, No.3, 148-159 http://hortherbpublisher.com/index.php/jtsr 149 This study aims to comprehensively evaluate the antioxidant properties, health impacts, and economic effects of rooibos tea in the global market. By summarizing the current scientific evidence on the antioxidant properties of rooibos tea and its main active compound, aspalathin, we assess the health benefits associated with rooibos tea consumption, including its potential role in the prevention and management of chronic diseases such as cardiovascular disease, diabetes, and cancer. Additionally, this study explores the economic impact of rooibos tea, focusing on its market growth, global demand, and industry challenges. This study provides a more comprehensive understanding of the multifaceted benefits of rooibos tea, highlighting its significance in both health and economic contexts. 2 Phytochemistry and Antioxidant Properties 2.1 Key phytochemicals in rooibos tea Rooibos tea (Aspalathus linearis) is renowned for its rich phytochemical profile, which includes a variety of phenolic compounds. The primary phenolic constituents identified in rooibos tea are flavonoids, tyrosols, and phenolic acids. Among these, aspalathin and nothofagin are particularly notable as they are rare dietary dihydrochalcones found predominantly in rooibos (McKay and Blumberg, 2007; Damiani et al., 2019). Other significant flavonoids include isoorientin, orientin, quercetin-3-O-robinobioside, and phenylpyruvic acid glucoside (Joubert et al., 2012). Additionally, compounds such as isovitexin, vitexin, hyperoside, rutin, ferulic acid, and isoquercitrin are present in varying concentrations (Bramati et al., 2003; Joubert et al., 2012). The presence of these compounds contributes to the tea's antioxidant properties and potential health benefits. Rooibos tea is also rich in phenolic acids, such as 4-hydroxybenzoic acid, protocatechuic acid, and vanillic acid. These phenolic compounds not only contribute to the unique flavor of rooibos tea but also possess significant antioxidant properties. 2.2 Mechanisms of antioxidant action The antioxidant activity of rooibos tea is primarily attributed to its high content of polyphenols, which act through various mechanisms. These include scavenging free radicals, chelating metal ions, and inhibiting oxidative enzymes. Aspalathin, one of the major flavonoids in rooibos, has been shown to exhibit significant radical scavenging activity, particularly against the DPPH radical. Other phenolic compounds such as caffeic acid and quercetin also contribute to the tea's antioxidant capacity by inhibiting lipid peroxidation and enhancing the activity of antioxidant enzymes like superoxide dismutase and catalase (Marnewick et al., 2009; Xiao et al., 2020). The total antioxidant activity (TAA) of unfermented rooibos has been reported to be higher than that of fermented rooibos, indicating that the fermentation process may reduce the antioxidant potential of the tea (Bramati et al., 2003). Notably, aspalathin in rooibos tea not only has strong antioxidant properties but also works synergistically with vitamin C to combat oxidative stress. This synergy enhances the antioxidant effectiveness of rooibos tea, making it an ideal natural antioxidant. 2.3 Comparison with other antioxidant-rich teas When compared to other antioxidant-rich teas such as green and black tea (Camellia sinensis), rooibos tea exhibits a unique phytochemical profile and antioxidant activity. While green and black teas are rich in catechins and theaflavins, respectively, rooibos tea is distinguished by its high levels of aspalathin and nothofagin (McKay and Blumberg, 2007; Xiao et al., 2020). Studies have shown that rooibos tea has comparable, if not superior, antioxidant activities to green and black teas in certain assays. For instance, rooibos tea has been found to significantly increase plasma total antioxidant capacity in humans, similar to the effects observed with green tea (Villaño et al., 2010). Additionally, rooibos tea has demonstrated potent chemoprotective properties against oxidative stress and cancer promotion, which are comparable to those of green and black teas (Marnewick et al., 2009). However, the specific polyphenolic composition and the interactions between these compounds and biological systems may result in different health outcomes.
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