CONDITIONED MEDIUM FROM COFFEE LAB LACKS NEUROPROTECTIVE EFFECTS, WHILE CO-CULTURE SHOWS PATHOGEN INHIBITION

Coffee consumption is linked to a reduced risk of Parkinson’s disease (PD), suggesting potential benefits from its fermenting microorganisms. This study evaluated the functional potential of 270 lactic acid bacteria (LAB) isolates from wet-fermented coffee collected from two farms in ES-BR through a PD-focused screening approach. Isolates were screened for gastrointestinal and oxidative stress. Under acidic stress (pH 3), 28/270 showed intermediate growth. At pH 4, 27/270 maintained or exceeded control growth, while at pH 8, this occurred in 126/270 isolates. For bile salt tolerance (1% w/v), only 12/270 showed partial inhibition, which increased to 77/270 when bile concentration was reduced to 0.5%. For oxidative stress, 14/270 and 21/270 isolates were inhibited at 0.5 mM and 1 mM hydrogen peroxide, respectively. None survived 8% NaCl; at 6% NaCl, 63/270 were partially inhibited, and at 4% NaCl, 124/270. All isolates were tested for safety and metabolic activity. None showed hemolytic activity. Regarding amino acid decarboxylation, 11/270 metabolized histidine, 16/270 ornithine, and 25/270 tyrosine, indicating potential to produce PD-associated biogenic amines. The 27 best-performing isolates advanced to further testing. MALDI-TOF identified one isolate as Weissella cibaria and others as Leuconostoc mesenteroides/pseudomesenteroides, species not previously studied in PD; nine remained unidentified. All Weissella and Leuconostoc isolates showed intrinsic resistance to vancomycin. Additionally, 10 isolates resisted at least three antibiotics and four resisted four, including vancomycin, ceftazidime, streptomycin, oxacillin, and ciprofloxacin. In self-aggregation tests, all isolates showed over 60% aggregation at 4°C and 37°C, supporting potential for intestinal colonization. In antioxidant tests, few LAB postbiotics outperformed controls: strain 83 in ABTS (12.36 μmol TE/mL), strains 82 and 36 in DPPH (3.36, 3.01 μmol TE/mL), and strain 16 in FRAP (3.43 μmol TE/mL). Selected LAB strains (n=10) were tested for antagonism against PD-associated pathogens (Staphylococcus aureus, Escherichia coli, Salmonella Typhimurium, Proteus mirabilis, and Klebsiella pneumoniae) using disc diffusion. Strain 82 (Weissella) inhibited S. aureus, while strains 82 and 83 (L. pseudomesenteroides) inhibited all other pathogens. Finally, the effects of pretreating neuroendocrine (STC-1) and hypothalamic (CLU-189) cells with 10% LAB-conditioned media (postbiotics, n=10) were assessed. Cells were pre-treated for 4h, then co-exposed for 20h to neurotoxins 6-hydroxydopamine (80 μM), rotenone (20 μM), and paraquat (100 μM), as sporadic PD models. Despite in vitro antioxidant activity, postbiotics did not improve cell viability under neurotoxic conditions. Overall, findings highlight the potential of live LAB to combat PD-associated pathogens but not to prevent drug-induced cytotoxicity.