Protection by extra virgin olive oil against oxidative stress in vitro and in vivo. Chemical and biological studies on the health benefits due to a major component of the Mediterranean diet

Abstract

We report the results of in vivo studies in Caenorhabditis elegans nematodes in which addition of extra virgin olive oil (EVOO) to their diet significantly increased their life span with respect to the control group. Furthermore, when nematodes were exposed to the pesticide paraquat, they started to die after two days, but after the addition of EVOO to their diet, both survival percentage and lifespans of paraquat-exposed nematodes increased. Since paraquat is associated with superoxide radical production, a test for scavenging this radical was performed using cyclovoltammetry and the EVOO efficiently scavenged the superoxide. Thus, a linear correlation (y = -0.0838x +19.73, regression factor = 0.99348) was observed for superoxide presence (y) in the voltaic cell as a function of aliquot (x) additions of EVOO, 10 μL each. The originally generated supoeroxide was approximately halved after 10 aliquots (100 μL total). The superoxide scavenging ability was analyzed, theoretically, using Density Functional Theory for tyrosol and hydroxytyrosol, two components of EVOO and was also confirmed experimentally for the galvinoxyl radical, using Electron Paramagnetic Resonance (EPR) spectroscopy. The galvinoxyl signal disappeared after adding 1 μL of EVOO to the EPR cell in 10 minutes. In addition, EVOO significantly decreased the proliferation of human leukemic THP-1 cells, while it kept the proliferation at about normal levels in rat L6 myoblasts, a non-tumoral skeletal muscle cell line. The protection due to EVOO was also assessed in L6 cells and THP-1 exposed to the radical generator cumene hydroperoxide, in which cell viability was reduced. Also in this case the oxidative stress was ameliorated by EVOO, in line with results obtained with tetrazolium dye reduction assays, cell cycle analysis and reactive oxygen species measurements. We ascribe these beneficial effects to EVOO antioxidant properties and our results are in agreement with a clear health benefit of EVOO use in the Mediterranean diet.

Potential Beneficial Effects of Extra Virgin Olive Oils Characterized by High Content in Minor Polar Compounds in Nephropathic Patients: A Pilot Study

“…This data could be supported by the observed reduction trend of oxidative stress (OS); in fact, the latter plays a key role in the progression of the CKD because OS is related to CKD complications like arterial hypertension, low-grade chronic inflammation, and anemia [ 25 , 26 ]. The OS reduction observed confirms previous studies [ 27 , 28 , 29 , 30 ] such as the CMPs of EVOO play a key role in the mechanisms that favor the induction of antioxidant activity [ 31 , 32 , 33 ].…”

Nutrients in the Prevention of Alzheimer’s Disease

“…One of the main components of the Mediterranean diet, as well as the main source of fat in this diet, is extravirgin olive oil (EVOO), which contains mainly oleic acid and to a lesser extent linoleic acid. In addition, EVOO contains hundreds of bioactive compounds including triterpenes (i.e., squalene), biophenols (hydroxytyrosol, tyrosol, and oleuropein), pigments (carotenoids, xanthophylls, and lutein), and vitamin E (tocopherols), whose beneficial effects have been shown in several studies [98, 99]. The low (and nontoxic) level of oxidized forms of EVOO polyphenols in plasma and tissues can activate the Nrf2 pathway and other adaptive stress response systems leading to the upregulation of the endogenous antioxidant and detoxification enzymes and thus rendering the cells “protected” against more dangerous and chronic oxidative stress stimuli (hormesis) [100].…”

Therapeutic alternative of the ketogenic Mediterranean diet to improve mitochondrial activity in Amyotrophic Lateral Sclerosis (ALS): A Comprehensive Review

“…This evidence may be related to the activity of the total polyphenolic fraction (TPF) and to HT itself, which achieve a powerful in vitro free radical scavenging (improving the redox state by increasing glutathione levels (Kouka et al, 2017). This fact has been observed in Caenorhabditis elegans nematodes, when extra virgin olive oil is included in the Mediterranean diet (Rossi et al, 2017). This fact has been observed in Caenorhabditis elegans nematodes, when extra virgin olive oil is included in the Mediterranean diet (Rossi et al, 2017).…”