Adult‐onset brain tumors and neurodegeneration: Are polyphenols protective?

Abstract

Aging is a primary risk factor for both neurodegenerative disorders (NDs) and tumors such as adult-onset brain tumors. Since NDs and tumors are severe, disabling, progressive and often incurable conditions, they represent a pressing problem in terms of human suffering and economic costs to the healthcare systems. The current challenge for physicians and researchers is to develop new therapeutic strategies in both areas to improve the patients' quality of life. In addition to genetics and environmental stressors, the increase in cellular oxidative stress as one of the potential common etiologies has been reported for both disorders. Recently, the scientific community has focused on the beneficial effects of dietary antioxidant classes, known as nutraceuticals, such as carotenoids, vitamins, and polyphenols. Among these compounds, polyphenols are considered to be one of the most bioactive agents in neurodegeneration and tumor prevention. Despite the beneficial activity of polyphenols, their poor bioavailability and inefficient delivery systems are the main factors limiting their use in medicine and functional food. The development of polymeric nanoparticle-based delivery systems able to encapsulate and preserve polyphenolic compounds may represent a promising tool to enhance their stability, solubility, and cell membrane permeation. In the present review we provide an overview of the main polyphenolic compounds used for ND and brain tumor prevention and treatment that explores their mechanisms of action, recent clinical findings and principal factors limiting their application in medicine.

Bioactive Phenolic Compounds in the Modulation of Central and Peripheral Nervous System Cancers: Facts and Misdeeds

“…Oxidative stress is a common alteration present in adult-onset brain tumors as well as in hereditary cancer of the nervous system, such as Neurofibromatosis type 1 (NF1) and Tuberous Sclerosis (TSC) [22,23]. Since polyphenols show a powerful antioxidant activity, several studies have analyzed their therapeutic potential to counteract tumor progression [23].…”

“…Phenols are "molecules possessing at minimum one aromatic ring with one or more hydroxyl groups attached" [23]. They are subdivided into flavonoids and non-flavonoids [24] (Figure 1).…”

“…Ellagitannins are contained in strawberries (Fragaria ananassa), raspberries (Rubus idaeus), blackberries (Rubus spp), persimmon (Diospyros kaki), pomegranates (Punica granatum), hazelnuts (Corylus avellana), and walnuts (Juglans regia) [24]. Belonging to this class are also: (i) secoiridoids and ligstroside, which are present in olive oil, (ii) stilbenes, whose major representing is resveratrol and is found in wine, and (iii) diferuloylmethanes that include curcumin, a curcuminoid of turmeric (Curcuma longa) [23].…”

“…Glioblastoma multiform (GBM) shows the highest aggressive phenotype (grade IV) representing the 60% of age-related brain tumors [78]. At present there is not definite cure for GBM; thus, researchers are looking at innovative therapeutic strategies [23].…”

Selective Upregulation by Theanine of Slc38a1 Expression in Neural Stem Cell for Brain Wellness

“…In contrast, neuroprotective polyphenols such as catechins are most abundant in green tea with a poor bioavailability for the brain after oral consumption [78][79][80]. Although polymeric nanoparticle-based delivery systems could be useful for the efficient delivery of neuroprotective catechins to the brain [81], such artificial modifications would often lead to severe impairment, dysfunction, and degeneration in a variety of eukaryotic cells in a particular situation. At any rate, we need to establish and develop validated nutraceutical sciences as quickly as possible as done with pharmaceutical sciences for human healthcare [82].…”