Olives and olive oil in cancer prevention.

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Olives and olive oil in cancer prevention (hydroxytyrosol).

JoAnn Guest

Jan 15, 2007 10:56 PST

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Biological properties of phenols present in extra virgin olive oil

(hydroxytyrosol)

C. Galli, F. Visioli, D. Caruso, G. Galli

Department of Pharmacological Sciences,

School of Pharmacy, University of Milan

 

http://www.istitutonutrizionalecarapelli.com/script/page.asp?

lang=en & id=14

 

 

Olives contain phenolic compounds (simple and complex phenols) which

protect the fruit against oxidative stress and other types of

noxiuos conditions.

 

Phenols are partially transferred from olives into the first

pressure (extra virgin) oil. Concentrations of total phenols in the

oil vary within a rather wide range (from 50 to over 500 mg/Kg),

depending on several factors (cultivar, climate, ripening of olives,

harvesting, etc.).

 

 

Q. Raw Cacao Powder (by Nature's First Law) has a high ORAC of 955

per gram. How does that product compare with hydroxytyrosol in olive

oil?

Johan

 

A. Dear Johan,

Hydroxytyrosol has an ORAC value of approximately 25,000 per gram.

 

 

Phenols are responsible of the organoleptic characteristics and of

the stability of the oil, preventing rancidity.

 

The two most important compounds for this type of activity are the

simple phenol Hydroxytyrosol and the complex phenol Oleuropein

aglycone, both characterized by a catecholic structure (orto-

diphenols).

 

Biological activities of phenols - Activities in vitro

 

Studies carried out at the Department of Pharmacological Sciences at

the

University of Milan have shown that these compounds are endowed with

important biological activities in vitro:

 

a. Antioxidant activity against the oxidation of the cholesterol-

rich

low density lipoprotein (LDL), thereby reducing the atherogenic

properties of this lipoprotein.

b. Functional inhibition of cells involved in physiopathological

processes, such as platelet, responsible for thrombogenic events

through

the formation of thromboxane A2 via the cyclo-oxygenase pathway, and

leukocytes, involved in inflammatory processes, through the

formation of

leukotrienes via the lipoxygenase pathway.

 

In addition phenols modulate enzymes that regulate functions: the

synthesis of nitric oxide (NO), a potent vasodilatator, by

macrophages,

is increased, while the production of the free radical anion

superoxide,

by the same type of cell, is reduced.

 

In contrast, these activities are not shown by typical lipophilic

antioxidants (e.g. Vitamin E). Phenols in olive oil share,

therefore, a

broad spectrum of biological activities, in addition to acting

simply as

" antioxidants " .

 

This may be attributed to the chemical characteristics of these

compounds, amphiphilic molecules, i.e. partly lipophilic with the

typical lipid antioxidant activity (like Vitamin E) and partly

hydrophilic, with would allow interactions with enzymes, such as the

oxygenases (such as water soluble compounds).

 

 

Biological activities of phenols - Activities in vivo

In vitro studies on the effects on various biological parameters

represent the basis for the assessment of possible activities of

phenolic compounds in vivo.

 

a. Bioavailability.

Until now, no information about the " bioavailability " of these

compounds

had been available. Bioavailability is a measure of the proportion

of a

compound, taken with food or as a pharmaceutical formulation, that

is

absorbed after oral administration, and is therefore available to

give

biological effects. The bioavailability of a compound can be

evaluated

quantitatively as:

 

1. Total renal excretion of the compound and/or its transformation

products in urines collected for a sufficiently long period of time

(provided that the compound is actually excreted with urine), as a

fraction of the total amount taken.

 

2. Determination of the plasma concentrations of the compound and

metabolites assessed at various time points. Bioavailability can be

calculated from the curve describing the changes in plasma

concentrations at different times after administration (Area Under

the

Curve, AUC with respect to the time). This approach is onehower

difficult to apply for phenols.

 

b. Studies of the bioavailability of olive oil phenols in humans.

A study recently completed at the Department of Pharmacological

Sciences, carried out by administering to healthy subjects constant

quantities of olive oil, but containing different amounts of total

phenols and ortho di phenols, and by evaluating the urinary

excretion of

hydroxytyrosol and its metabolites, has shown that these compounds

are

dose dependently absorbed.

 

In addition, a large proportion of these compounds is excreted as

products of metabolic transformation.

This indicates that hydroxytyrosol enters cellular compartments

(possibly the liver) and interacts with enzymatic systems.

 

These data indicate that olive oil phenols exert antioxidant

activities

in vivo.

 

Altogether the above results provide the basis for studies

specifically

aimed at exploring the activities of such compounds in humans, in

the

prevention and possibly in support of treatment of major diseases

(cardiovascular and degenerative diseases).

 

With this aim in mind, a study was set up in collaboration with the

Department of Pharmaceutical Sciences of Milan University, to

confirm

the antioxidant activity of Phenols in olive oil on humans, already

demonstrated in vitro and in vivo on rats.

 

The administration of samples of oil containing increasingly higher

levels of hydroxytyrosol and oleuropein aglycone (catechols) to

subjects

is linked to decreasing excretion in the urine of isoprostanes

(8-iso-PGF2a) biomarker in vivo of lipidic peroxidation and

therefore of

cellular oxidative stress.

 

Furthermore it was shown that a reduction in excretion in the urine

of

isoprostanes is statistically linked to grater excretion in the

urine of

hydroxytyrosol and of one of its metabolites, homovanillicalcohol,

demonstrating that the antioxidant activity of hydroxytyrosol leads

to

it being absorbed by cells and being metabolically transformed.

 

--

 

Proprietary Hydroxytyrosol: Polyphenol from the Pulp of Organic

Olives

JoAnn Guest

Jan 15, 2007 10:03 PST

 

Proprietary Hydroxytyrosol

The Most Potent Polyphenol from the Pulp of Organic Olives

 

 

 

It is widely accepted among scientists and consumers that extra

virgin

olive oil confers many health benefits, most notably supporting

cardiovascular health and preventing cancer. Harvard-trained medical

doctor turned naturopath Andrew Weil recommends this oil above all

others for cooking and baking. And Dr. Nicholas Perricone, author of

the

 

newly released The Perricone Prescription, dedicates six pages of

his

new book to extolling the virtues of this favored oil of the

Mediterranean.

 

Hydroxytyrosol is a highly potent and protective polyphenol found

mainly

in olives. The term polyphenol refers to the shared chemical

structure

of certain plant compounds containing carbon, hydrogen and oxygen.

Polyphenols are scientifically recognized for their tremendous

antioxidant capacity. Citrus bioflavonoids, proanthocyanidins

and isoflavonoids are all polyphenols.

 

Independent laboratory analyses that measure Oxygen

Radical Absorbance Capacity (ORAC) identifies hydroxytyrosol as the

most

 

potent antioxidant yet discovered. Its pharmacokinetic properties

are

also unsurpassed, meaning hydroxytyrosol is absorbed, distributed

and

metabolized extremely well by the body

 

---

 

 

Olives and olive oil in cancer prevention.

 

Owen, R W 1; Haubner, R 1; Wurtele, G 1; Hull, W E 2; Spiegelhalder,

B

1; Bartsch, H 1

 

Abstract:

 

Epidemiologic studies conducted in the latter part of the twentieth

century demonstrate fairly conclusively that the people of the

Mediterranean basin enjoy a healthy lifestyle with decreased

incidence

of degenerative diseases.

 

The data show that populations within Europe that consume the so-

called

'Mediterranean diet' have lower incidences of major illnesses such

as

cancer and cardiovascular disease.

 

Studies have suggested that the health-conferring benefits of the

Mediterranean diet are due mainly to a high consumption of fibre,

fish,

fruits and vegetables.

 

More recent research has focused on other important factors such as

olives and olive oil. Obviously fibre (especially wholegrain-derived

products), fruits and vegetables supply an important source of

dietary

antioxidants.

 

What is the contribution from olives and olive oil? Apparently the

potential is extremely high but epidemiologic studies rarely

investigate

consumption of these very important products in-depth, perhaps due

to a

lack of exact information on the types and amounts of antioxidants

present.

 

Recent studies have shown that olives and olive oil contain

antioxidants

in abundance. Olives (especially those that have not been subjected

to

the Spanish brining process) contain up to 16 g/kg typified by

acteosides, hydroxytyrosol, tyrosol and phenyl propionic acids.

 

Olive oil, especially extra virgin, contains smaller amounts of

hydroxytyrosol and tyrosol, but also contains secoiridoids and

lignans

in abundance.

 

Both olives and olive oil contain substantial amounts of other

compounds

deemed to be anticancer agents (e.g. squalene and terpenoids) as

well as

the peroxidation-resistant lipid oleic acid.

 

It seems probable that olive and olive oil consumption in southern

Europe represents an important contribution to the beneficial

effects on

health of the Mediterranean diet.

 

European Journal of Cancer Prevention. 13(4):319-326, August 2004.

 

JoAnn Guest

mrsjo-

www.geocities.com/mrsjoguest/Diets