Mechanistic Insights into the Metabolic Pathways and Neuroprotective Potential of Pentacyclic Triterpenoids: In-Depth Analysis of Betulin, Betulinic, and Ursolic Acids

Due to their complexity, both genotypic and phenotypic, neurodegenerative diseases are one of the main causes of death globally nowadays. Among phytochemicals of high scientific interest, based on experimental studies, pentacyclic triterpenoids (TTs), including mainly betulin, betulinic, and ursolic acid, became targets of scientific research in recent years, especially in terms of their biological activity and pharmacological potential. Due to their anti-inflammatory and antioxidant properties, as well as their involvement in cellular signal transductions, they have been observed to act as anticancer, chemopreventive, and neuroprotective agents. The aim of this review is to update the reader on the diversity, bioavailability, pharmacological properties, and neuroprotective effects of TTs, as biomolecules that can interfere with metabolic mechanisms related to neurodegeneration and restoring of neuronal integrity. Recent data were analyzed, with a particular focus on mechanistic insights related to their neuroprotective effects. Starting with their biosynthetic pathways, bioavailability, and involvement in specific metabolic pathways, their impact on neurological pathology and benefits as natural neuroprotection agents through specific signaling pathways are presented. Furthermore, emphasis will also be put on current challenges and future strategies that could develop TTs into effective compounds for neuroprotection and personalized medicine.