Identification of a Phosphodiesterase-Inhibiting Fraction from Roasted Coffee (Coffea arabica) through Activity-Guided Fractionation

Abstract

Recent reports that coffee can significantly inhibit cAMP phosphodiesterases (PDEs) in vitro, as well as in vivo, have described another beneficial effect of coffee consumption. However, the PDE-inhibiting substances remain mostly unknown. We chose activity-guided fractionation and an in vitro test system to identify the coffee components that are responsible for PDE inhibition. This approach indicated that a fraction of melanoidins reveals strong PDE-inhibiting potential (IC = 130 ± 42 μg/mL). These melanoidins were characterized as water-soluble, low-molecular weight melanoidins (<3 kDa) with a nitrogen content of 4.2% and a carbohydrate content lower than those of other melanoidins. Fractions containing known PDE inhibitors such as chlorogenic acids, alkylpyrazines, or trigonelline as well as N-caffeoyl-tryptophan and N-p-coumaroyl-tryptophan did not exert PDE-inhibiting activity. We also observed that the known PDE inhibitor caffeine does not contribute to the PDE-inhibiting effects of coffee.

Inhibition of Cyclic Adenosine Monophosphate-Specific Phosphodiesterase by Various Food Plant-Derived Phytotherapeutic Agents

“…The selective PDE 4 inhibitor rolipram (10 μM) served as a positive control. To compare with previous experiments, test concentrations of extracts and single substances were chosen in a similar range of previous studies (extracts <10 mg/mL, single substances <500 μg/mL) [ 10 , 68 ].…”

“…Caffeine and other methylxanthines, for example, had already been recognized as nonspecific inhibitors at the time of phosphodiesterase discovery [ 6 , 7 ]. Coffee has been shown to have both in-vitro and in-vivo PDE-inhibiting effects [ 8 , 9 , 10 ]. Furthermore, some classes of flavonoids (flavonols, flavones, anthocyanins and anthocyanidins, flavanones, and flavanonols) have shown PDE-inhibiting potential, whereas catechins are not potent PDE inhibitors [ 11 , 12 , 13 , 14 , 15 ].…”

Enhancement of Monascus Azaphilone Pigments Production by Activating the cAMP Signalling Pathway in Monascus Purpureus HJ11

“…Phosphodiesterase activity was determined using a PDE activity assay kit (Colorimetric) following the manufacturer's instructions (Abcam, Cambridge, United Kingdom) with slight modi cation [31]. The PDE activities were determined in puri ed mrPDE and recombinant E. coli lysates.…”

Polyphenol Phase‐II Metabolites are Detectable in Human Plasma after Ingestion of 13C Labeled Spinach—a Pilot Intervention Trial in Young Healthy Adults

“…In vitro, flavonoids exhibit high antioxidant capacity and can, thus, prevent oxidative cell damages . Moreover, polyphenols and metabolites thereof can influence cellular enzyme activities thereby affecting metabolic pathways . In recent years, it became, however, clear that the bioavailability of dietary polyphenols in humans is influenced by several factors, especially the food matrix, food processing, the compound concentration in the food item and the amount ingested .…”

“…[4] Moreover, polyphenols and metabolites thereof can influence cellular enzyme activities thereby affecting metabolic pathways. [5][6][7] In recent years, it became, however, clear that the bioavailability of dietary polyphenols in humans is influenced by several factors, especially the food matrix, food processing, the compound concentration in the food item and the amount ingested. [8] Thus, endogenous extra-and intracellular concentration of potential metabolites may be too low to exhibit measurable effects; the prevailing concept that polyphenols and their metabolites can modulate body cell pathways and prevent oxidative damage should be reassessed.…”