Coffee pulp polysaccharides with potential immunomodulatory activity

Abstract

Coffee is one of the most valuable primary products in world trade and its agricultural production and consumption are part of Mexican culture. Coffee pulp is the first byproduct obtained during the wet processing of coffee. This waste is rich in macronutrients and contains considerable amounts of tannins, total pectic substances, sugars, caffeine, chlorogenic acid and caffeic acid. These components have multiple beneficial health properties. This has led to the generation of a line of research for the study of biologically active ingredients such as specific polysaccharides that may present immunostimulatory activity for the treatment of diseases. The following project assessed the immunomodulatory potential of different pectin extracts from coffee pulp. The extraction of polysaccharides that may have an immunomodulatory activity was the main objective of this investigation along with the identification and quantification of phenolic compounds present in the extracts. The interactions between the polysaccharides and phenolic compounds present in the extracts are key for understanding their dual immunomodulatory effect. This could contribute to the treatment and prevention of immunodeficiency diseases. This project was structured in three main stages: extraction of pectin from coffee pulp, separation and quantification of phenolic compounds in the extracts and evaluation of the immunomodulatory potential of the polysaccharides. Dry coffee pulp samples were collected from Tezonapa, Veracruz. Pectin extractions were carried out with different experimental factors, such as the type of solvent (water and acidified water to pH 4 using citric acid at a 1% concentration), pulp: solvent ratio (1:10 and 1:20), agitation (with and without agitation), temperature (90 °C and 70 °C) and washing method (dialysis and ethanol washes). The content of total phenolic compounds, caffeine and caffeic acid of the extracted pectin samples was also evaluated. Finally, cytotoxicity assays in mouse machrophages cell line (RAW264.7) were performed to evaluate the growth induction of the different extracts. LPSinduced inflammatory response of this cell line was also evaluated.