Chemical characterisation by UPLC-Q-ToF-MS/MS and antibacterial potential of Coffea arabica L. leaves: A coffee by-product.

Coffea arabica L. leaves are considered a by-product of the coffee industry however they are sources of several bioactive compounds. This study aimed to evaluate the chemical composition and the in vitro antibacterial activity of the lyophilised ethanol extract of arabica coffee leaves (EE-CaL). The chemical characterisation of EE-CaL was performed using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q-ToF-MS/MS). The in vitro antibacterial effect of EE-CaL was evaluated using the broth microdilution method and the adapted drop plate agar method to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC), respectively. The chemical analysis of EE-CaL revealed the presence of compounds from the alkaloid class, such as trigonelline and caffeine, in addition to the phenolic compounds such as quinic acid, 5-caffeoylquinic acid, caffeic acid-O-hexoside, mangiferin, (epi)catechin, (epi)catechin monoglucoside and procyanidin trimer. Regarding the antibacterial potential, EE-CaL was active against Gram-positive and Gram-negative bacteria, being more effective against Escherichia coli (ATCC 25922) (MIC = 2500 μg/mL and bactericidal effect). The results of this research suggest that coffee leaves, a by-product, possess compounds with antibacterial properties. Thus, further studies with coffee leaf extracts must be carried out to relate the compounds present in the extract with the antibacterial activity and find the mechanisms of action of this extract against bacteria.

Mesquita Júnior GA ，da Costa YFG ，Mello V ，Costa FF ，Rodarte MP ，Costa JCD ，Alves MS ，Vilela FMP ... -  《-》

Quality and bioactive compounds of blends of Arabica and Robusta spray-dried coffee.

The objective of this study was to develop both a possible process and a spray-dried coffee product with a balanced content of bioactive compounds. Spray-dried coffees were prepared by mixing different ratios of medium-roasted Coffea canephora (R) with green Coffea arabica (A) beans. Overall, quality characteristics of spray-dried coffees were not different. The dominant signals of 1D 1H NMR were identified as trigonelline, caffeine and chlorogenic and organic acids. Principal component analysis explained 81.8% of the total variance. Roasted Robusta spray-dried coffee was clearly distinguished from blended coffees. Forty-two volatile compounds were identified. An increase in green Arabica mixed with roasted Robusta in the blends resulted in an increase in 5-caffeoylquinic acid but a decrease in caffeine contents. Spray-dried coffee prepared from a A35:R65 showed greater total phenolic content and antioxidant activity due to a balance in bioactive compounds. In addition, its coffee brew obtained the highest overall liking score.

Wongsa P ，Khampa N ，Horadee S ，Chaiwarith J ，Rattanapanone N ... -  《-》

Green coffee seed residue: A sustainable source of antioxidant compounds.

Oil extraction from green coffee seeds generates residual mass that is discarded by agribusiness and has not been previously studied. Bioactive secondary metabolites in coffee include antioxidant phenolic compounds, such as chlorogenic acids. Coffee seeds also contain caffeine, a pharmaceutically important methylxanthine. Here, we report the chemical profile, antioxidant activity, and cytotoxicity of hydroethanolic extracts of green Coffea arabica L. seed residue. The extracts of the green seeds and the residue have similar chemical profiles, containing the phenolic compounds chlorogenic acid and caffeine. Five monoacyl and three diacyl esters of trans-cinnamic acids and quinic acid were identified by ultra-performance liquid chromatography/electrospray ionization-quadruple time of flight mass spectrometry. The residue extract showed antioxidant potential in DPPH, ABTS, and pyranine assays and low cytotoxicity. Thus, coffee oil residue has great potential for use as a raw material in dietary supplements, cosmetic and pharmaceutical products, or as a source of bioactive compounds.

Castro ACCM ，Oda FB ，Almeida-Cincotto MGJ ，Davanço MG ，Chiari-Andréo BG ，Cicarelli RMB ，Peccinini RG ，Zocolo GJ ，Ribeiro PRV ，Corrêa MA ，Isaac VLB ，Santos AG ... -  《-》

Nutraceutical compounds: Echinoids, flavonoids, xanthones and caffeine identified and quantitated in the leaves of Coffea arabica trees from three regions of Brazil.

There are relatively few studies concerning the use of coffee leaves for medicinal purposes and the composition of secondary plant substances. Therefore, we identified and quantitated polyphenolic compounds along with caffeine present in methanol extracts of Coffea arabica leaves from three different regions of Brazil (Ceará, Minas Gerais and São Paulo) by HPLC-ESI-MS. In addition, correlations between polyphenolic content of the coffee leaves and antioxidant assays DPPH, FRAP and ORAC were evaluated. Fifteen compounds belonging to three classes of polyphenols (xanthones, chlorogenic acids and flavonoids) along with the alkaloid caffeine were detected. The mean concentration of total polyphenolic compounds in the leaves of C. arabica, harvested from three different regions of Brazil was quite variable. The highest values were detected in the coffee leaves harvested in Minas Gerais (n = 4) at 40.80(13.00) g/kg (SD), followed by coffee leaves harvested in São Paulo (n = 20) at 24.79(20.19) g/kg, and the lowest in coffee leaves harvested in Ceará (n = 11) in the Northeast of Brazil at 10.30(5.61) g/kg. The three classes of polyphenols, all showed excellent correlations in the antioxidant assays. Coffee leaf tea, appears to be an excellent functional beverage, with its high content of polyphenolic compounds, which may render positive biologic effects, when inbibed as part of the normal human diet.

de Almeida RF ，Trevisan MTS ，Thomaziello RA ，Breuer A ，Klika KD ，Ulrich CM ，Owen RW ... -  《-》

UHPLC-ESI-QqTOF-MS/MS characterization of minor chlorogenic acids in roasted Coffea arabica from different geographical origin.

Chlorogenic acids are relevant coffee quality markers, taste, and aroma precursors as well as important bioactive compounds. A number of mono-acyl, di-acyl, and tri-acyl quinic acid isomers were found in green coffee beans, being mono-caffeoyl, mono-feruloyl, mono-p-coumaroyl, and di-caffeoylquinic acid isomers considered as quantitatively major compounds. Roasting process increases the chemical complexity of coffee by inducing the formation of a number of lactones (quinides), shikimates, and other chlorogenic acids derivatives. So far, little attention has been paid in characterizing minor chlorogenic acids and derivatives in roasted Coffea arabica, also known as Arabica. In the present work, roasted C. arabica samples from different geographical origins (Brazil, Colombia, Costa Rica, Ethiopia, Guatemala, and India) were characterized by UHPLC-ESI-QqTOF-MS/MS. Several minor chlorogenic acid isomers were identified. In particular, HR-MS/MS provided putative identification of four dimethoxycinnamoyl-quinic acid derivatives, such as 4-dimethoxycinnamoylquinic acid, 4-dimethoxycinnamoyl-3-caffeoylquinic acid, 3-dimethoxycinnamoyl-4-feruloylquinic acid, 4-dimethoxycinnamoyl-5-feruloylquinic acid, and two caffeoyl, feruloyl quinic acid derivatives (3-caffeoyl-4-feruloylquinic acid and 3-feruloyl-4-caffeoylquinic acid). To our knowledge, these compounds were found in roasted Arabica coffee for the first time, and their presence is independent on the different geographical origins examined.

De Rosso M ，Colomban S ，Flamini R ，Navarini L ... -  《-》