Molecular Mechanisms of the Protective Effects of Olive Leaf Polyphenols against Alzheimer’s Disease

Abstract

Alzheimer’s Disease (AD) is the cause of around 60–70% of global cases of dementia and approximately 50 million people have been reported to suffer this disease worldwide. The leaves of olive trees (Olea europaea) are the most abundant by-products of the olive grove industry. These by-products have been highlighted due to the wide variety of bioactive compounds such as oleuropein (OLE) and hydroxytyrosol (HT) with demonstrated medicinal properties to fight AD. In particular, the olive leaf (OL), OLE, and HT reduced not only amyloid-β formation but also neurofibrillary tangles formation through amyloid protein precursor processing modulation. Although the isolated olive phytochemicals exerted lower cholinesterase inhibitory activity, OL demonstrated high inhibitory activity in the cholinergic tests evaluated. The mechanisms underlying these protective effects may be associated with decreased neuroinflammation and oxidative stress via NF-κB and Nrf2 modulation, respectively. Despite the limited research, evidence indicates that OL consumption promotes autophagy and restores loss of proteostasis, which was reflected in lower toxic protein aggregation in AD models. Therefore, olive phytochemicals may be a promising tool as an adjuvant in the treatment of AD.

Bioactive Properties of Tagetes erecta Edible Flowers: Polyphenol and Antioxidant Characterization and Therapeutic Activity against Ovarian Tumoral Cells and Caenorhabditis elegans Tauopathy

“…In recent years, the potential impact of certain subproducts/waste products obtained from the food industry on neurodegenerative diseases has grown [ 43 , 44 ], mainly due to their high polyphenol content.…”

Another Use for a Proven Drug: Experimental Evidence for the Potential of Artemisinin and Its Derivatives to Treat Alzheimer’s Disease

“…For instance, some studies have evaluated the roles of flowers, such as rose x hybrida petals [27] and tubalghia volacea petals [28]. Certain by-products, including olive leaves, have also shown promise in combating AD [29]. Moreover, the potential therapeutic effects of honey in the context of AD have been explored (e.g., [30,31]).…”

Kolaviron neuroprotective effect against okadaic acid-provoked cognitive impairment

“…Bioactive compounds in medicinal plants especially their polyphenols have shown potential and promising effects to combat against AD pathophysiological processes [ [13] , [14] , [15] ]. Garcinia kola (Garcinia genus, Clusiaceae family, Malpighiales order), commonly known as the bitter kola, is a dioecious, multifunctional, and agroforestry tree which is found in some tropical African and even in Asian countries [ 16 , 17 ].…”