VetSRev
Database of veterinary systematic reviews
Database of veterinary systematic reviews
Nutrients (2020) 12:
DOI: 10.3390/nu12020521
BACKGROUND: Several natural products have been reported to elicit beneficial effects against neurodegenerative disorders due to their vitamin E contents. However, the neuroprotective efficacy of palm oil or its tocotrienol-rich fraction (TRF) from the pre-clinical cell and animal studies have not been systematically reviewed. METHODS: The protocol for this systematic review was registered in "PROSPERO" (CRD42019150408). This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The Medical Subject Heading (MeSH) descriptors of PubMed with Boolean operators were used to construct keywords, including ("Palm Oil"[Mesh]) AND "Nervous System"[Mesh], ("Palm Oil"[Mesh]) AND "Neurodegenerative Diseases"[Mesh], ("Palm Oil"[Mesh]) AND "Brain"[Mesh], and ("Palm Oil"[Mesh]) AND "Cognition"[Mesh], to retrieve the pertinent records from PubMed, Scopus, Web of Science and ScienceDirect from 1990 to 2019, while bibliographies, ProQuest and Google Scholar were searched to ensure a comprehensive identification of relevant articles. Two independent investigators were involved at every stage of the systematic review, while discrepancies were resolved through discussion with a third investigator. RESULTS: All of the 18 included studies in this review (10 animal and eight cell studies) showed that palm oil and TRF enhanced the cognitive performance of healthy animals. In diabetes-induced rats, TRF and α-tocotrienol enhanced cognitive function and exerted antioxidant, anti-apoptotic and anti-inflammatory activities, while in a transgenic Alzheimer’s disease (AD) animal model, TRF enhanced the cognitive function and reduced the deposition of β-amyloid by altering the expression of several genes related to AD and neuroprotection. In cell studies, simultaneous treatment with α-tocotrienols and neurotoxins improved the redox status in neuronal cells better than ϒ- and δ-tocotrienols. Both pre-treatment and post-treatment with α-tocotrienol relative to oxidative insults were able to enhance the survival of neuronal cells via increased antioxidant responses. CONCLUSIONS: Palm oil and its TRF enhanced the cognitive functions of healthy animals, while TRF and α-tocotrienol enhanced the cognitive performance with attenuation of oxidative stress, neuroinflammation and apoptosis in diabetes-induced or transgenic AD animal models. In cell studies, TRF and α-tocotrienol exerted prophylactic neuroprotective effects, while α-tocotrienol exerted therapeutic neuroprotective effects that were superior to those of ϒ- and δ-tocotrienol isomers.
Ismail, M., Alsalahi, A., Imam, M. U., Ooi, J., Khaza’ai, H., Aljaberi, M. A., Shamsudin, M. N., & Idrus, Z. (2020). Safety and Neuroprotective Efficacy of Palm Oil and Tocotrienol-Rich Fraction from Palm Oil: A Systematic Review. Nutrients, 12(2). https://doi.org/10.3390/nu12020521 Animals, Disease Models, Animal, Rats, Humans, Mice, Antioxidants, Cells, Cultured, neurodegeneration, Oxidative Stress/*drug effects, neuroprotection, Anti-Inflammatory Agents, *Neuroprotective Agents, Alzheimer Disease/metabolism/*psychology/therapy, Amyloid beta-Peptides/metabolism, Chemical Fractionation, cognition, Cognition/*drug effects, palm oil, Palm Oil/chemistry/*pharmacology/therapeutic use, Phytotherapy, tocotrienol, tocotrienol-rich fraction, Tocotrienols/isolation & purification/*pharmacology/therapeutic use