Effect of species variation and processing on phenolic composition and in vitro antioxidant activity of aqueous extracts of Cyclopia spp. (honeybush tea)

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dc.contributor.authorJoubert E.
dc.contributor.authorRichards E.S.
dc.contributor.authorVan Der Merwe J.D.
dc.contributor.authorDe Beer D.
dc.contributor.authorManley M.
dc.contributor.authorGelderblom W.C.A.
dc.date.accessioned2011-05-15T15:56:51Z
dc.date.available2011-05-15T15:56:51Z
dc.date.issued2008
dc.description.abstractThe in vitro antioxidant activity of aqueous extracts prepared from four Cyclopia spp. (unfermented and fermented) was assessed using radical (ABTS •+) scavenging, ferric ion reduction, and inhibition of Fe 2+-induced microsomal lipid peroxidation as criteria. Aqueous extracts of unfermented and fermented Aspalathus linearis (rooibos) and Camellia sinensis teas (green, oolong, and black) were included as reference samples. Qualitative and quantitative differences in phenolic composition were demonstrated for the Cyclopia spp. The xanthone glycoside, a.k.a. mangiferin, was the major monomeric polyphenol present in the Cyclopia extracts, with both unfermented and fermented C. genistoides extracts containing the highest quantities. Fermentation resulted in a significant reduction in extract yields and their total polyphenol and individual polyphenol contents. Unfermented plant material should preferentially be used for preparation of extracts, as fermentation significantly (P < 0.05) lowered antioxidant activity of all species, except in the case of C. genistoides, where the ability to inhibit lipid peroxidation was not affected. Unfermented plant material also retained the highest concentration of mangiferin. Overall, extracts of unfermented Cyclopia were either of similar or lower antioxidant activity as compared to the other teas. However, the presence of high levels of mangiferin merits the use of Cyclopia spp. and, in particular, C. genistoides, as an alternative herbal tea and potential dietary supplement. © 2008 American Chemical Society.
dc.description.versionArticle
dc.identifier.citationJournal of Agricultural and Food Chemistry
dc.identifier.citation56
dc.identifier.citation3
dc.identifier.issn218561
dc.identifier.other10.1021/jf072904a
dc.identifier.urihttp://hdl.handle.net/10019.1/10076
dc.subjectantioxidant
dc.subjectflavonoid
dc.subjectmangiferin
dc.subjectphenol derivative
dc.subjectplant extract
dc.subjectpolyphenols
dc.subjectunclassified drug
dc.subjectxanthone derivative
dc.subjectarticle
dc.subjectbeverage
dc.subjectchemistry
dc.subjectcomparative study
dc.subjectCyclopia plant
dc.subjectfood handling
dc.subjectmethodology
dc.subjectplant
dc.subjectspecies difference
dc.subjectAntioxidants
dc.subjectBeverages
dc.subjectCyclopia Plant
dc.subjectFlavonoids
dc.subjectFood Handling
dc.subjectPhenols
dc.subjectPlant Extracts
dc.subjectPlant Shoots
dc.subjectSpecies Specificity
dc.subjectXanthones
dc.subjectAspalathus
dc.subjectAspalathus linearis
dc.subjectCamellia sinensis
dc.subjectCyclopia genistoides
dc.titleEffect of species variation and processing on phenolic composition and in vitro antioxidant activity of aqueous extracts of Cyclopia spp. (honeybush tea)
dc.typeArticle
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