A PILOT STUDY TO INVESTIGATE THE ANTIAGING EFFECTS OF THE OLIVE POMACE BY-PRODUCT ON THE BRAIN OF DROSOPHILA MELANOGASTER

Makladissi S^1†, Tomassoni D^2†*, Nardin T³, Bellitto V², Cappelli A², Di Cara F^1‡ and Beghelli D^2‡ | ¹Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada; ²School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, MC, Italy ; ³Chemical Unit Oenological Vines Agri-food - Technology Transfer Centre Foundation Edmund Mach, TN, Italy ^†These authors equally contributed. ^‡These authors share the authorship

Olive pomace (OP), a byproduct of olive oil extraction, retains numerous bioactive compounds (in particular, hydroxytyrosol and tyrosol, but also other beneficial flavonoids, phenols and secoiridoids like luteolin, oleocanthal, and oleuropein) found in extra virgin olive oil, which are recognized for their health-promoting properties, particularly in reducing oxidative stress and inflammation. Recent studies have demonstrated that oleuropein and other polyphenols may exert significant neuroprotective effects contributing to improved cognitive function and reducing neuroinflammation, thereby supporting neuronal health. Furthermore, research suggests that polyphenols can promote neurogenesis and synaptic plasticity, essential processes for maintaining brain function during aging. Dietary supplementation (DS) with OP compounds may positively influence gut microbiota, which interacts with the central nervous system, highlighting the intricate relationship between diet and brain health. Following our observation in a previous study that dietary supplementation with OP significantly increased the half-life in both female and male flies, in the present pilot study, using one of the two OP batches previously employed, we evaluated the effects of dietary supplementation with OP on motor abilities and on the maintenance of brain tissue morphological integrity during aging in female flies. Climbing ability, brain size, and quantitative analyses of vacuole-like degeneration associated with specific brain regions were utilized as indicators of brain functional integrity and neurodegeneration during the aging process. Dietary supplementation commenced at 30 of flies age (w1118 strain), and climbing ability was assessed at the beginning (T0) and after 10 days of OP DS (T1). Brain tissue collections were conducted immediately after the T1 climbing assay. Female flies supplemented with OP exhibited significantly improved climbing activity at T1 (p<0.0188), a trend toward larger brain size (p=0.053) along with a significantly reduced total volume of brain vacuoles compared to flies without DS (p<0.05). The gut microbiota modulation by bioactive compounds has been linked to various health benefits through multiple mechanisms. Understanding how OP-derived polyphenols specifically influence these microbial populations and their functional outputs would provide valuable insights into the neuroprotective and longevity-promoting effects observed in our observations.