Chlorogenic acid and caffeine contents and anti-inflammatory and antioxidant activities of green beans of conilon and arabica coffees harvested with different degrees of maturation

Abstract

This work aimed at assessing 3-caffeoylquinic acid (chlorogenic acid) and caffeine contents and in vitro anti-inflammatory and antioxidant activities of nine genotypes of conilon coffee, one cultivar of Arabica and one of Robusta, with different degrees of maturation. All genotypes were harvested with three degrees of maturation (60%, 80%, and 100%), accounting 33 samples of green coffee beans. Metabolite contents were quantified by HPLC with a C18 reverse-phase column. Chromatograms were obtained by UV at 274 nm wavelength for caffeine and 325 nm for chlorogenic acid. Antioxidant activity was measured by FRAP, ABTS, and DPPH, and anti-inflammatory activity, by inhibition of production of NO, O2−, and IL-6 and TNF-α cytokines in macrophages culture stimulated with bacterial endotoxin (LPS). Cell viability was evaluated by MTT method. K-means clustering followed principal component analysis (PCA) to check for correlations. The results showed that the degree of maturation significantly affected the levels of chlorogenic acid and caffeine. For both chlorogenic acid and caffeine, all conilon genotypes had higher contents than Arabica coffee. The values found for chlorogenic acid in conilon coffees ranged from 9.1 to 11.7%, while in Arabica coffee it ranged from 8.7 to 9.2%. Among the 33 assessed coffees, C101, C105, and Robusta displayed the best antioxidant profiles, while the genotypes C303, C304, and C306 revealed strong anti-inflammatory responses, with O2− and IL-6 inhibitions close to 100%. Despite the absence of statistical correlation, it is known that the presence of both metabolites contributed to the activities, as chlorogenic acid presented high antioxidant and anti-inflammatory activities and caffeine, elevated anti-inflammatory activity.