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Yerba mate is a beverage rich in bioactive compounds popular in South America. Polyphenols and methylxanthines were qualitatively and quantitatively analyzed in four commercial brands of yerba mate, as well as the antioxidant capacity of the beverages. Using LC/MS analysis, 58 polyphenols were observed of which 4-sinapoylquinic acid, di- and tri-methoxycinnamoylquinic acids, two isomers of trimethoxycinnamoylshikimic acid and four isomers of caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosonic acid were identified for the first time in mate. Additionally, 46 polyphenols and 2 methylxanthines were quantified by HPLC-DAD. Hydroxycinnamic acid derivatives and flavonols comprised 90% and 10% of mate phenols, respectively, 3-caffeoylquinic (26.8-28.8%), 5-caffeoylquinic (21.1-22.4%), 4-caffeoylquinic (12.6-14.2%) and 3,5-dicaffeoylquinic acids (9.5-11.3%) along with rutin (7.1-7.8%) were the most abundant polyphenols, whereas caffeine was the main methylxanthine (90%). Ilex paraguariensis is an important source of polyphenols with moderate methylxanthines content; therefore its high antioxidant capacity was mainly associated to its polyphenolic composition.

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Coffee is one of the most consumed beverages in the world, due to its unique aroma and stimulant properties. Although its health effects are controversial, moderate intake seems to be beneficial. The present work deals with the characterization and quantification of polyphenols and methylxanthines in four Arabica green coffee beans from different geographical origins. The antioxidant activity was also evaluated. Forty-three polyphenols (cinnamic acid, cinnamoyl-amide, 5 cinammoyl-glycosides, and 36 cinnamate esters) were identified using LC-MS. Among these, cinnamate esters of six different chemical groups (including two dimethoxycinnamoylquinic acid isomers, three caffeoyl-feruloylquinic acid isomers, caffeoyl-sinapoylquinic acid, p-coumaroyl-feruloylquinic acid, two caffeoylshikimic acid isomers, and trimethoxycinnamoylshikimic acid) in addition to five isomers of cinnamoyl-glycosides called caffeoyl-2,7-anhydro-3-deoxy-2-octulopyranosic acid (CDOA) are described for the first time in Arabica green coffee beans. Moreover, 38 polyphenols (6-7% w/w) and 2 methylxanthines (1.3% w/w) were quantified by HPLC-DAD. Caffeoylquinic was the most abundant group of compounds (up to 85.5%) followed by dicaffeoylquinic and feruloylquinic acids (up to 8 and 7%, respectively) and the newly identified cinnamoyl-glycosides (CDOA) (up to 2.5%). Caffeine was the main methylxanthine (99.8%), with minimal amounts of theobromine (0.2%). African coffees (from Kenya and Ethiopia) showed higher polyphenolic content than American beans (from Brazil and Colombia), whereas methylxanthine contents varied randomly. Both phenols and methylxanthines contributed to the antioxidant capacity associated with green coffee, with a higher contribution of polyphenols. We conclude that green coffee represents an important source of polyphenols and methylxanthines, with high antioxidant capacity.

Regular consumption of the studied beverages provides considerable amounts of antioxidants which are relatively stable after simulated digestion, and thus have the potential to prevent oxidative stress-related disorders. © 2017 Society of Chemical Industry.

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Cardiovascular disease (CVD) is the major cause of morbidity and mortality worldwide.