Preliminary Assessment of the In Vitro Immunological Activity of Native Lactobacillus Strains from the Ecuadorian Amazon

Abstract

The isolation and characterization of new Lactobacillus strains from fermented traditional foods is a global trend as it enhances the potential for discovering novel probiotic foods. The fermented cocoa (Theobroma cacao) mucilage is an intriguing substrate for isolating lactic acid bacteria involved in fermentation. This study represents a preliminary investigation into the isolation, quantification, characterization, and immunological activity of Lactobacillus strains derived from cocoa beans sampled from two farmer associations (Kallari and Wiñak) in the Ecuadorian Amazon region. A mother culture was prepared using fermented cocoa pulp, cultivated on selective MRS media. After growth, the isolates were morphologically characterized. A significantly higher bacterial concentration was recorded in Kallari Association samples if compared with Wiñac. A total of 25 strains were isolated, eight of which were rod-shaped and positive to catalase tests and were characterized as Lactobacillus. In vitro, immunological activity was performed on differentiated THP-1 cell lines. Cells were treated with bacterial concentrates, and immunological activity was determined through interleukin-10 expression. Results indicated that W6 strain showed the highest immunological activity. These results indicated that Lactobacillus strains isolated from fermented cocoa pulp in the Ecuadorian Amazon show promise as a new source of probiotics. Keywords: cocoa; lactic acid bacteria; biological activity; isolation; cocoa fermentation; probiotics; cocoa pulp