Effects of processing method and age of leaves on phytochemical profiles and bioactivity of coffee leaves.

The use of coffee leaves as a novel beverage has recently received consumer interest, but there is little known about how processing methods affect the quality of final product. We applied tea (white, green, oolong and black tea) processing methods to process coffee leaves and then investigated their effects on phytochemical composition and related antioxidant and anti-inflammatory properties. Using Japanese-style green tea-processing of young leaves, and black tea-processing of mature (BTP-M) coffee leaves, produced contrasting effects on phenolic content, and associated antioxidant activity and nitric oxide (NO) inhibitory activity in IFN-γ and LPS induced Raw 264.7 cells. BTP-M coffee leaves also had significantly (P < .05) higher responses in NO, iNOS, COX-2, as well as a number of cytokines, in non-induced Raw 264.7. Our findings show that the age of coffee leaves and the type of processing method affect phytochemical profiles sufficiently to produce characteristic antioxidant and anti-inflammatory activities.

Chen XM ，Ma Z ，Kitts DD 《-》

Characterization of phytochemical mixtures with inflammatory modulation potential from coffee leaves processed by green and black tea processing methods.

Our previous study reported that different tea processing methods along with the age of coffee leaves affected antioxidant and anti-inflammatory bioactivities; however, identification of phytochemical components or associated mixtures that contribute to the anti-/pro-inflammatory activities was not determined. Herein, we report results of additional experiments designed to characterize the phytochemical composition of fractionated coffee leaf extract, derived from Japanese-style-green-tea-process-young (JGTP-Y) and black-tea-process-mature (BTP-M) leaves and related these data to anti-/pro-inflammatory activities. The aqueous fraction of BTP-M coffee leaves induced nitric oxide (NO), iNOS, COX-2, IL-6 and IL-10 production in Raw 264.7 cells. A 40% methanol fraction possessed greatest anti-inflammatory activities in IFN-γ and LPS treated Raw 264.7 cells (P < 0.05). The anti-inflammatory activities of coffee leaf fractions could not only be attributed to chlorogenic acids, mangiferin, rutin, and caffeine content, but possibly subtle interactions of mixtures of bioactive molecules.

Chen X ，Mu K ，Kitts DD 《-》

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 ... -  《-》

Phytochemical profiles and antioxidant activities of Chinese dark teas obtained by different processing technologies.

Dark teas are rich in secondary metabolites, such as phenolics and flavonoids, which have been suggested to be associated with their health benefits. In this study, the concentrations of tea polyphenols, tea pigments, catechins, flavonoids, alkaloid, and volatile components in 44 dark tea samples, including Pu-erh, Fuzhuan and Liubao teas, were systematically examined. Among the samples tested, Pu-erh tea contained the highest total flavonoid content (5.24±0.05%), followed by Liubao (4.45±0.61%) and Fuzhuan teas (3.33±0.23%). The tea polyphenols levels in the dark teas were approximately 10%, and no statistically significant differences (p>0.05) were found among the different types. Hexadecanoic acid was the most abundant aroma component in the dark teas, accounting for 15-20% of the total volatile oils. Moreover, the antioxidant activities of these dark teas were analyzed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS) assay, ferric reducing antioxidant power (FRAP) assay, and cellular antioxidant activity (CAA) assay (HepG2 cells). The fat metabolism modulation activities (FMMA) of the dark teas were tested using a high-throughput screening method (SMMC-7221 cells). The results indicated that the different dark teas had diverse antioxidant activities, and the variation in the activities was significant. Correlation analysis showed that there was a significant positive correlation between the levels of EGCG and antioxidant activities measured using the ABTS (r=0.916) and FRAP (r=0.853) assays, and the levels of total flavonoids and theabrownins correlated well with the values determined using the CAA (r=0.845 and 0.865, respectively) assay.

Lv HP ，Zhang Y ，Shi J ，Lin Z ... -  《-》

Characterization of kombucha prepared from black tea and coffee leaves: A comparative analysis of physiochemical properties, bioactive components, and bioactivities.

The utilization of coffee leaves in kombucha production has intrigued researchers; however, the lack of understanding regarding the characteristics of coffee leaf kombucha (CK) and its differentiation from black tea kombucha (BK) has impeded its application in the beverage industry. Therefore, this study aimed to characterize and compare the physiochemical properties, phytochemical compositions, antioxidant activity, and α-glucosidase inhibitory ability of kombucha prepared from the leaves of Coffea arabica (CK) and black tea (Camellia sinensis, BK) and their extracts (CT and BT). After fermentation, pH and the contents of total sugars, reducing sugars, and free amino acids of BK and CK were decreased, whereas the levels of total acids and organic acids, such as gluconic, lactic, and acetic acid were increased. Notably, the concentration of vitamin C in CK was 48.9% higher than that in BK. HPLC analysis exhibited that 5-caffeoylquinic acid in CT was significantly decreased by 48.0% in CK, whereas the levels of 3-caffeoylquinic acid and 4-caffeoylquinic acid were significantly increased after fermentation. The content of caffeine was significantly (p < 0.05) reduced by 9.5% and 22.0% in BK and CK, respectively, whereas the theobromine level was significantly increased in CK. Notably, CK has superior total phenolic and flavonoid contents and antioxidant activity than BK, whereas BK possesses higher α-glucosidase inhibitory capacity. Electronic nose analysis demonstrated that sulfur-containing organics were the main volatiles in both kombuchas, and fermentation significantly increased their levels. Our study indicates that coffee leaves are a promising resource for preparing kombucha. PRACTICAL APPLICATION: This article investigates the differences in physicochemical properties, bioactive constituents, antioxidant activity, and α-glucosidase inhibitory activity of kombucha preparation from black tea and coffee leaves. We have found that after fermentation BK had brighter soup color and higher α-glucosidase inhibitory capacity, whereas CK had higher levels of total phenols, flavonoids, vitamin C, and antioxidants and lower contents of sugars. This study provides valuable information for the preparation of CK with high-quality attributes and antioxidant activity.

Huang G ，Huang Y ，Sun Y ，Lu T ，Cao Q ，Chen X ... -  《-》