Acyclic sesquiterpenes nerolidol and farnesol: mechanistic insights into their neuroprotective potential.

Sesquiterpenes are a class of organic compounds found in plants, fungi, and some insects. They are characterized by the presence of three isoprene units, resulting in a molecular formula that typically contains 15 carbon atoms (C₁₅H₂₄). Nerolidol and farnesol are both sesquiterpene alcohols present in the essential oils of numerous plants. They have drawn attention due to their potential neuroprotective properties. Nerolidol and farnesol are structural isomers, specifically geometric isomers, haring the same molecular formula (C₁₅H₂₄O) but differing in the spatial arrangement of their atoms. This variation in structure may contribute to their distinct biological activities. Scientific evidence suggests that nerolidol and farnesol exhibit antioxidant and anti-inflammatory characteristics which are crucial for neuroprotection. Nerolidol has been specifically noted for its ability to alleviate conditions such as Alzheimer's disease, Parkinson's disease, encephalomyelitis, depression, and anxiety by modulating inflammatory and oxidative stress pathways. Moreover, research indicates that both nerolidol and farnesol may modulate the Nrf-2/HO-1 antioxidant signaling pathway to mitigate oxidative stress-induced neurological damage. Activation of Nrf-2/HO-1 signaling cascade promotes cell survival and enhances the brain's ability to resist various insults. Nerolidol has also been reported to alleviate neuroinflammation by inhibiting the TLR-4/NF-κB and COX-2/NF-κB inflammatory signaling pathway. Besides, this nerolidol also modulates BDNF/TrkB/CREB signaling pathway to improve neuronal health. To date, limited research has delved into the anti-inflammatory properties of farnesol concerning neurodegenerative diseases. Further investigation is warranted to comprehensively elucidate the mechanisms underlying its action and potential therapeutic uses in neuroprotection. Initial observations indicate that farnesol exhibits promising prospects as a natural agent for safeguarding brain functions. Henceforth, drawing upon existing literature elucidating the neuroprotective attributes of nerolidol and farnesol, the current review endeavors to provide a detailed analysis of their mechanistic underpinnings in neuroprotection.