ABSTRACT
INTRODUCTION: Coffea arabica L. leaves are considered a by-product of the coffee industry however they are sources of several bioactive compounds. OBJECTIVES: 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). MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.
Subject(s)
Alkaloids , Catechin , Coffea , Proanthocyanidins , Agar/pharmacology , Alkaloids/pharmacology , Anti-Bacterial Agents/analysis , Anti-Bacterial Agents/pharmacology , Caffeine/analysis , Caffeine/pharmacology , Coffea/chemistry , Ethanol , Gas Chromatography-Mass Spectrometry , Gram-Negative Bacteria , Gram-Positive Bacteria , Plant Extracts/chemistry , Quinic Acid/analysis , Tandem Mass SpectrometryABSTRACT
Este trabalho objetivou estudar os efeitos da adição de cloreto de cálcio na coalescência dos glóbulos de gordura em sorvetes. Foram preparados sorvetes adicionados ou não de 0,025% deκ-carragena, 0,15% de emulsifi cante (80% de mono e diglicerídeos e 20% de polissorbato 80) e cloreto de cálcio (0, 40 e 80 mM). Partículas coloidais presentes nas gotas do sorvete derretido foram analisadas e seus tamanhos e distribuição medidos, utilizando-seo equipamento Mastersizer 2000. De acordo com os resultados foi possível observar que não houve variação dos valores medidos nas amostras sem adição de cloreto de cálcio. Entretanto, quando se adicionou emulsifi cante ocorreu maior desestabilização dosglóbulos de gordura nas amostras de sorvetes com 40 e 80 mM de cloreto de cálcio e esses valores foram minimizados pela presença de κ-carragena. Os resultados podem ser explicados devido à capacidade de interação dos íons cálcio com os emulsificantes, estabilizantes e as proteínas do leite. Concluiu-se que a adição de cloreto de cálcio é extremamente danosa para aestabilidade de emulsões como sorvetes.