Antioxidant and Anti‐Inflammatory Profiles of Spent Coffee Ground Extracts for the Treatment of Neurodegeneration

Abstract

Spent coffee grounds (SCGs), waste products of coffee beverage production, are rich in organic compounds such as phenols. Different studies have demonstrated phenol beneficial effects in counteracting neurodegenerative diseases. These diseases are associated with oxidative stress and neuroinflammation, which initiates the degeneration of neurons by overactivating microglia. Unfortunately, to date, there are no pharmacological therapies to treat these pathologies. The aim of this study was to evaluate the phenolic content of 4 different SCG extracts and their ability to counteract oxidative stress and neuroinflammation. Caffeine and 5-O-caffeoylquinic acid were the most abundant compounds in all extracts, followed by 3-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. The four extracts demonstrated a different ability to counteract oxidative stress and neuroinflammation in vitro. In particular, the methanol extract was the most effective in protecting neuron-like SH-SY5Y cells against H2O2-induced oxidative stress by upregulating endogenous antioxidant enzymes such as thioredoxin reductase, heme oxygenase 1, NADPH quinone oxidoreductase, and glutathione reductase. The water extract was the most effective in counteracting lipopolysaccharide-induced neuroinflammation in microglial BV-2 cells by strongly reducing the expression of proinflammatory mediators through the modulation of the TLR4/NF-κB pathway. On these bases, SCG extracts could represent valuable nutraceutical sources for the treatment of neurodegeneration.

Antifungal Activity of Spent Coffee Ground Extracts

“…However, our results did not show anti-inflammatory activity of SCG from caffeinated and decaffeinated coffee extracts on the RAW 264.7 cell line. A recent publication reported that the SCG water extracts are more effective than extracts obtained with solvents [ 59 ]. Nevertheless, when considering the antifungal activity of the extracts obtained in this study in fungi agents of human skin infections together with the absence of cytotoxicity on a non-tumoral cell line, it can be anticipated as a possible utilization in the therapy of dermatomycosis.…”

Neuroprotective Effects of Agri-Food By-Products Rich in Phenolic Compounds

“…Additionally, it promoted neuronal differentiation by inducing the expression of neuronal markers from the MAPK signaling pathway, which modulated the growth and stabilization of microtubules in neurites [ 48 ]. Angeloni et al (2021) reported that coffee by-product extract was able to reduce the activity of pro-inflammatory enzymes, such as iNOS and COX-2, and the levels of different pro-inflammatory mediators by reducing NF-kB proteins to basal levels [ 89 ]. In fact, these coffee extracts showed catechin content, in accordance with LSE.…”

“… Main mechanisms through which plant extracts and their phenolic compounds exert their neuroprotective effects, as well as key cell processes involved. Finally, several references in which this information is demonstrated [ 30 , 34 , 41 , 48 , 57 , 58 , 75 , 79 , 80 , 81 , 85 , 86 , 87 , 88 , 89 , 92 , 93 , 95 , 102 , 108 , 110 , 115 , 123 , 130 , 131 ]. …”

Coffee By-Products as Sustainable Novel Foods: Report of the 2nd International Electronic Conference on Foods—“Future Foods and Food Technologies for a Sustainable World”

“…The data showed that caffeine and chlorogenic acids were the most abundant compounds in all samples followed by phenolic acids. Neuroprotective activity of silverskin and spent coffee extracts against H 2 O 2 -induced damage was evaluated for the first time suggesting for methanol and ethanol/water (70:30) extracts a potential role as protective agents against neurodegeneration due to their ability to counteract oxidative stress and maintain cell viability [ 31 , 32 ].…”