Tyrosol as a Neuroprotector: Strong Effects of a "Weak" Antioxidant

The use of neuroprotective agents for stroke is pathogenetically justified, but the translation of the results of preclinical studies of neuroprotectors into clinical practice has been a noticeable failure. One of the leading reasons for these failures is the one-target mechanism of their activity. p-Tyrosol (Tyr), a biophenol, is present in a variety of natural sources, mainly in foods, such as olive oil and wine. Tyr has a wide spectrum of biological activity: antioxidant, stress-protective, anti-inflammatory, anticancer, cardioprotective, neuroprotective and many others. This review analyzes data on the neuroprotective, antioxidant, anti-inflammatory, anti-apoptotic and other kinds of Tyr activity as well as data on the pharmacokinetics of the substance. The data presented in the review substantiate the acceptability of tyr as the basis for the development of a new neuroprotective drug with multitarget activity for the treatment of ischemic stroke. Tyr is a promising molecule for the development of an effective neuroprotective agent for use in ischemic stroke.

Furan, phenolic, and heptelidic acid derivatives produced by Aspergillus oryzae

Eleven compounds, including a new sesquiterpene, were isolated from the culture medium of Aspergillus oryzae incubated with capsaicin. The structure of the new compound was determined to be 1,3,5a,6,7,8,9,9a-octahydro-9-hydroxy-9-(hydroxymethyl)-6-isopropyl-1-oxobenzo[c]oxepine-4- carboxylic acid, a heptelidic acid derivative. In addition, 10 known compounds were identified, namely 5-(hydroxymethyl)-3-furancarboxylic acid (flufuran), 3-hydroxypropanoic acid, 5-(hydroxymethyl)-2- furancarboxylic acid, 2-(4-hydroxyphenyl)-ethanol, 4-hydroxybenzoic acid, vanillic acid, 3,4-dihydroxybenzoic acid, 2-furanol, hydroheptelidic acid, and trichoderonic acid A, using spectroscopic data from nuclear magnetic resonance and electrospray ionization-mass spectroscopy.

Pharmacokinetics of Tyrosol Metabolites in Rats

Tyrosol is considered a potential antioxidant; however, little is known regarding the pharmacokinetics of its metabolites. To study the pharmacokinetics of tyrosol-derived metabolites after oral administration of a single dose of tyrosol, we attempted to identify tyrosol metabolites in rat plasma by using ultra-performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Two tyrosol metabolites (M1 and M2) were detected in the plasma. M1 was identified as tyrosol-4-sulfate (T4S) with an [M − H]⁻ ion at m/z 217. While M2 showed an [M − H]⁻ ion at m/z 151.0, its metabolite was not identified. Pharmacokinetic analysis of T4S and M2 showed rapid uptake after oral administration of tyrosol within 1 h. The metabolites were rapidly distributed in most organs and tissues and eliminated within 4 h. The greatest T4S deposition by tissue weight was observed in the liver, followed by the kidney and spleen, while M2 was most concentrated in the kidney followed by the liver and spleen. These findings indicate that T4S and M2 were distributed mainly in tissues with an abundant blood supply and were rapidly excreted in urine.

Tyrosol, an olive oil polyphenol, inhibits ER stress-induced apoptosis in pancreatic β-cell through JNK signaling

Dysfunction of pancreatic β-cell is a major determinant for the development of type 2 diabetes. Because of the stimulated insulin secretion in metabolic syndrome, endoplasmic reticulum (ER) stress plays a central mediator for β-cell failure. In this study, we investigated whether an antioxidant phenolic compound, tyrosol protects against β-cell dysfunction associated with ER stress. To address this issue, we exposed pancreatic β cells, NIT-1 to tunicamycin with tyrosol. We found tyrosol diminished tunicamycin-induced cell death in a dose-dependent manner. We also detected tyrosol decreased the expressions of apoptosis-related markers. Exposure to tunicamycin evoked UPR response and co-treatment of tyrosol led to reduction of ER stress. These effects of tyrosol were mediated by the phosphorylation of JNK. Moreover, we confirmed supplement of tyrosol ameliorated β-cell loss induced by high fat feeding. Taken together, our study provides a molecular basis for signaling transduction of protective effect of tyrosol against ER stress-induced β-cell death. Therefore, we suggest tyrosol could be a potential therapeutic candidate for amelioration of type 2 diabetes.