Hydroxytyrosol acetate

Antioxidant activity of hydroxytyrosol acetate compared with that of other olive oil polyphenols.[Pubmed: 11368623]

J Agric Food Chem. 2001 May;49(5):2480-5.

Hydroxytyrosol acetate was synthesized, and the antioxidant activity of this olive oil component was assessed in comparison with that of other olive oil components, namely hydroxytyrosol, oleuropein, 3,4-DHPEA-EA, and alpha-tocopherol in bulk oil and oil-in-water emulsions.
METHODS AND RESULTS:
The activity of the compounds was also assessed by scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. Hydroxytyrosol acetate had a weaker DPPH radical scavenging activity than hydroxytyrosol, oleuropein, or 3,4-DHPEA-EA but it had a radical scavenging activity similar to that of alpha-tocopherol. In oil, the antioxidant activity of Hydroxytyrosol acetate was much higher than that of alpha-tocopherol or oleuropein, but in an emulsion 3,4-DHPEA-EA and alpha-tocopherol were more effective as antioxidants than Hydroxytyrosol acetate.
CONCLUSIONS:
The antioxidant activity of Hydroxytyrosol acetate was rather similar to that of hydroxytyrosol in oil and emulsions despite the difference in DPPH radical scavenging activity.

Antibacterial Activity of Hydroxytyrosol Acetate from Olive Leaves (Olea Europaea L.).[Pubmed: 28768425 ]

Nat Prod Res. 2017 Aug 2:1-4.

Vibrio spp. are pathogens of many bacterial diseases which have caused great economic losses in marine aquaculture. The strategy of alternative medical treatment that is utilised by herbalists has expanded in the past decade.
METHODS AND RESULTS:
The aim of our study is to discover the antibacterial molecules against Vibrio spp. Bacterial growth inhibition, membrane permeabilisation assessment and DNA interaction assays, as well as agarose gel electrophoresis, were employed to elucidate the antibacterial activity of Hydroxytyrosol acetate. Results showed that Hydroxytyrosol acetate had antibacterial activity against Vibrio spp. and it played the role via increasing bacterial membrane permeabilisation. The DNA interaction assay and agarose gel electrophoresis revealed that Hydroxytyrosol acetate interacted with DNA. Hydroxytyrosol acetate enhanced the fluorescent intensity of DNA binding molecules and mediated supercoiled DNA relaxation.
CONCLUSIONS:
The present study provides more evidence that Hydroxytyrosol acetate is a novel antibacterial candidate against Vibrio spp.

Neuroprotective effect of hydroxytyrosol and hydroxytyrosol acetate in rat brain slices subjected to hypoxia-reoxygenation.[Pubmed: 18809463 ]

Neurosci Lett. 2008 Dec 3;446(2-3):143-6.

Hydroxytyrosol (HT) and Hydroxytyrosol acetate (HT-AC) are two well-known phenolic compounds with antioxidant properties that are present in virgin olive oil (VOO).
METHODS AND RESULTS:
Because VOO has shown neuroprotective effects in rats, the purpose of the present study was to investigate the possible neuroprotective effect of HT and HT-AC in a model of hypoxia-reoxygenation in rat brain slices after in vitro incubation of these compounds or after 7 days of oral treatment with 5 or 10 mg/kg per day. Lactate dehydrogenase (LDH) efflux to the incubation medium was measured as a marker of brain cell death. HT and HT-AC inhibited LDH efflux in a concentration-dependent manner, with 50% inhibitory concentrations of 77.78 and 28.18 microM, respectively. Other well-known antioxidants such as vitamin E and N-acetyl-cysteine had no neuroprotective effect in this experimental model. After 1 week of treatment, HT (5 and 10 mg/kg per day p.o.) reduced LDH efflux by 37.8% and 52.7%, respectively, and HT-AC reduced LDH efflux by 45.4% and 67.8%.
CONCLUSIONS:
These data are additional evidence of the cytoprotective effect of VOO administration, and provide a preliminary basis for further study of these polyphenols as potential neuroprotective compounds.

Preventive effects of dietary hydroxytyrosol acetate, an extra virgin olive oil polyphenol in murine collagen-induced arthritis[Reference: WebLink]

Molecular Nutrition & Food Research, 2015 , 59 (12) :2537-46.

Hydroxytyrosol acetate (HTy-Ac), an extra virgin olive oil (EVOO) polyphenol, has recently been reported to exhibit antioxidant and anti-inflammatory effects on LPS-stimulated macrophages and ulcerative colitis.
METHODS AND RESULTS:
This study was designed to evaluate dietary HTy-Ac supplementation effects on collagen-induced arthritis (CIA) in mice. HTy-Ac improved the oxidative events and returned pro-inflammatory proteins expression to basal levels probably through JAK/STAT, MAPKs and NF-κB pathways.
CONCLUSIONS:
HTy-Ac supplement might provide a basis for developing a new dietary strategy for the prevention of rheumatoid arthritis.

Effects of hydroxytyrosol and hydroxytyrosol acetate administration to rats on platelet function compared to acetylsalicylic acid.[Pubmed: 18707113 ]

J Agric Food Chem. 2008 Sep 10;56(17):7872-6.

Virgin olive oil (VOO) contains the polyphenols hydroxytyrosol (HT) and Hydroxytyrosol acetate (HT-AC).
METHODS AND RESULTS:
This study investigated the antiplatelet effect of HT and HT-AC in healthy rats and compared their effects to acetylsalicylic acid (ASA). All compounds were administered orally for 7 days. HT and HT-AC inhibited platelet aggregation in whole blood, with a 50% inhibitory dose (ID50) of 48.25 mg/kg per day for HT, 16.05 mg/kg per day for HT-AC, and 2.42 mg/kg per day for ASA. Platelet synthesis of thromboxane B2 was inhibited by up to 30% by HT and 37% by HT-AC; the ID50 of this effect for ASA was 1.09 mg/kg per day. Vascular prostacyclin production was inhibited by up to 27.5% by HT and 32% by HT-AC; the ID50 of this effect for ASA was 6.75 mg/kg per day. Vascular nitric oxide production was increased by up to 34.2% by HT, 66% by HT-AC, and 64% by ASA.
CONCLUSIONS:
We conclude that HT and HT-AC administered orally inhibited platelet aggregation in rats and that a decrease in thromboxane synthesis along with an increase in nitric oxide production contributed to this effect.