Search Results (2)

Background/Objectives: The growing demand for functional foods and alternative therapeutic strategies has intensified the search for novel probiotic strains from underexplored ecosystems. This study aimed to isolate and phenotypically characterize lactic acid bacteria (LAB) from spontaneously fermented fruits found in the Legal Amazon (Ananas comosus, Humiria balsamifera, Manilkara zapota, and Platonia insignis) and to perform genome-based analysis of the most promising isolate to evaluate its probiotic potential. Methods: The isolates were identified by MALDI-TOF-MS and screened for tolerance to low pH, bile salts, lysozyme, growth at 39 °C, and antimicrobial activity against five enteric pathogens. The most promising isolate was evaluated by coaggregation and biofilm assays, in silico proteome and CAZyme analysis, bacteriocin cluster mining, and in vivo efficacy testing using Tenebrio molitor larvae. Results: Three isolates from H. balsamifera were identified as Lactiplantibacillus plantarum (M1, M2, M4) by MALDI-TOF-MS. These isolates exhibited high resilience to all tested physiological stressors. Antimicrobial activity was contact-dependent, with no inhibition by cell-free supernatants. M2 showed the strongest pathogen exclusion, moderate biofilm formation, and high coaggregation with S. enterica and E. faecalis. Genome analysis of M2 revealed a 3.40 Mb chromosome, absence of acquired resistance or virulence genes, two plantaricin gene clusters, and 93 CAZymes, including GT families linked to exopolysaccharides biosynthesis. SignalP predicted secretion signals in 10 CAZymes. M2 significantly improved larval survival against E. coli and S. enterica, especially under prophylactic treatment. Conclusions: L. plantarum M2 combines safety, stress tolerance, genomic features, and in vivo efficacy, positioning it as a promising probiotic candidate adapted to tropical niches. These findings highlight H. balsamifera as a reservoir of novel probiotic strains. Full article

Humiria balsamifera (Aubl), commonly known as “mirim”, is a plant of the Humiriaceae family, which consists of 39 species divided between eight genera: Duckesia, Endopleura, Humiria, Humiriastrum, Hylocara, Sacoglottis, Schistostemon, and Vantenea. This study aimed to characterize H. balsamifera extracts by LC-MS/MS and evaluate their antimicrobial potential through in vitro and in vivo assays. The leaves and stem bark of H. balsamifera were collected and dried at room temperature and then ground in a knife mill. The extracts were prepared with organic solvents in order to increase the polarity index (hexane, ethyl acetate, and methanol). The antimicrobial effects of these extracts were evaluated against the following bacterial strains: Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 15313, Salmonella enterica Typhimurium ATCC 14028, and Staphylococcus aureus ATCC 6538. The best activity was observed in the ethyl acetate (EALE = 780 µg/mL), methanol (MLE = 780 µg/mL), and hexane (HLE = 1560 µg/mL) leaf extracts against S. aureus. Considering the results for both antimicrobial and antibiofilm activities, the EALE extract was chosen to proceed to the infection assays, which used Tenebrio molitor larvae. The EALE treatment was able to extend the average lifespan of the larvae (6.5 days) in comparison to S. aureus-infected larvae (1 day). Next, the samples were characterized by High-Performance Liquid Chromatography coupled to a mass spectrometer, allowing the identification of 11 substances, including seven flavonoids, substances whose antimicrobial activity is already well-reported in the literature. The number of bioactive compounds found in the chemical composition of H. balsamifera emphasizes its significance in both traditional medicine and scientific research that studies new treatments based on substances from the Brazilian flora. Full article