Olive leaf was first used medicinally in Ancient Egypt.

Article Content:

Phytochemicals and Constituents:Mechanisms of olive leaf.

Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image Over a period of more than 30 years since Panizzi et al's isolation of oleuropein, extracts from various parts of the olive tree have been extensively investigated. Oleuropein appears to be present throughout the olive tree, including leaves, buds, fruit, wood, bark and roots. Olive leaves contain around 60~90 mg per gram (dry weight) oleuropein,plus significant levels of a glucosidic ester of elenolic acid and hydroxytyrosol (3,4-dihydrophenylethanol). However, it turns out that oleuropein and the products of its hydrolysis, oleuropein aglycone, elenolic acid, beta-3,4-dihydroxyphenyethyl alcohol and methyl-o-methyl elenolate, are the major molecules of interest biologically.
Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image

Active constituents:

Olive leaf has a wide number of constituents, including oleuropein and several types of flavonoids (e.g., rutin, apigenin, luteolin). While olive leaf is traditionally associated with a wide number of medicinal claims, few of these have been verified by experimental study. In an animal study oleuropein (when given by injection or in intravenous form) was found to decrease blood pressure (e.g., systolic and diastolic) and dilate the coronary arteries surrounding the heart. This ability to lower blood pressure may justify the traditional use of olive leaf in the treatment of mild to moderate hypertension. However, human studies are needed to clearly establish olive leaf as a potential treatment for high blood pressure.

In addition, a test tube study has revealed that oleuropein inhibits the oxidation of LDL cholesterol. LDL oxidation is one part in a series of damaging events that,if left unchecked, can lead to the development of atherosclerosis. This action may provide one clue as to why those consuming a Mediterranean-based diet may lower their risk of developing atherosclerosis.

Oleuropein from olives may also have antibacterial properties. When unheated olives are brined to preserve them, oleuropein is converted into another chemical called elenolic acid. Elenolic acid has shown antibacterial actions against several species of Lactobacilli and Staphylococcus aureus and Bacillus subtilus in a test tube study. Whether or not the oleuropein in the leaf undergoes such a transformation is open to question at this point, raising some question as to its antibacterial effects and potential use for this purpose in humans.
Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image

Olive leaf extracts have been employed experimentally to lower elevated blood-sugar levels in animals with diabetes. These results have not been reproduced in human clinical trials and as such, no clear conclusions can be made from this animal study in the treatment of diabetes.

Hippocrates, the ancient Greek physician prescribed olive oil for ulcers and other ailments, yet it was only in the 1900 that the bitter compound - oleuropein - was isolated from the leaf.

The leaves contain secoiridoids - including oleuropein, as well as ligustroside and oleacein. It further contains triterpenoids (oleanolic acid and uvaol), sterols, flavonoids (chrysoeriol, apigenin and luteolin glycosides) and various other phenolic acids.
Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image

Oleuropein:

Oleuropein, an active constituent of olive oil and olive leaf, was investigated by Coni and coworkers. The researchers conducted an in vivo study that evaluated oleuropein's effects on the serum low density lipoprotein (LDL) levels in rabbits. The study was carried out on the basis of the positive results obtained with in vitro, pilot studies on human LDL. The results of these pilot studies indicated that certain constituents in olive oil inhibited prooxidative processes in human LDL.

The rabbits were fed special diets. Diet A consisted of a standard diet for rabbits. Diet B consisted of the standard diet plus 10% (w/w) extra virgin olive oil, and Diet C consisted of the standard diet plus 10% (w/w) extra virgin olive oil and 7 mg/kg oleuropein. In order to evaluate oleuropein's effect, biochemical parameters identified in the rabbits'blood plasma and LDL were measured before and after copper-induced oxidation.
Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image

The results verified the antioxidant efficacy of extra virgin olive oil's biophenols, particularly oleuropein. In measuring the presence of conjugated dienes in the rabbits' LDL, it was determined that rabbits fed Diet C had a lesser amount of conjugated dienes and therefore of lipid radicals than either rabbits fed Diets A or B. The amounts of conjugated dienes present in the LDL were 51.0 +- 9.3 uM, 25.8 +- 4.1 uM, and 19.8 +- 3.9 uM for rabbits fed Diet A, Diet B, and Diet C, respectively. Similarly, evaluation of other ox-LDL (oxidized LDL) parameters followed the same trend. These results indicate that oleuropein increased the ability of LDL to resist oxidation.

In addition to oleuropein's antioxidant properties, it was determined that Diet C reduced the rabbits plasma levels of total, free, and ester cholesterol by 15%, 12%, and 17%, respectively, compared to rabbits fed Diet B. This reduction caused a redistribution of the lipid components of LDL with an indirect effect on the dimensions.

Oleuropein has also been shown to effect the body's glucose or blood sugar levels, by working independently of insulin to increase metabolic uptake of glucose. However, this activity is believed to be in concert with the glucose-induced insulin release.
Olive Leaf Extract INCI Name Olea Europaea Leaf Extract CAS 84012-27-1 Olea Europaea Leaf Extract Olive Leaves Extract photo picture image

Mechanism of Action:

The cholesterol lowering effects of olive leaf extracts are thought to come from oleuropein, a substance contained within the leaf. Studies on hypercholesterolemic rats have shown that olive leaf extracts are more effective at lowering cholesterol than pure oleuropein. This implies that a synergistic effect occurs between oleuropein and another substance within the leaf. Oleuropein is converted into elenoic acid in the body which may prevent viruses and bacteria from replicating. The antihypertensive and vasodilating effects of olive leaf occurred independently of the integrity of the vascular endothelium. Constituents of olive leaf have been shown to strongly inhibit the complement system, although it is unknown what effect this has on the body. Hypoglycemic activities of olive leaf are attributed to two mechanisms: potentiation of glucose-induced insulin release and increased peripheral uptake of glucose. Hypoglycemic activity is greater in samples collected in the winter months.

Olive leaf extract has been shown to be effective against the following microorganisms: E. coli, Pseudomonas aeruginosa, S. aureus, K. pneumoniae, Trichophyton mentagrophytes, Microsporum canis, T. rubrum and Candida albicans. Anti-HIV properties of Olive leaf extract include up-regulation of the expression of apoptosis inhibitor proteins as well as protein kinase signaling molecules. Few trials in humans are available in the current literature.

Oleuropein works specifically against microbes in the following ways:

Interferes with certain amino acid production processes necessary to keep viruses alive.
Inactivates viruses by interfering with virus shedding, budding or assembly at the cellular membrane.
Penetrates infected host cells and inhibits viral replication.
Stimulates an immune system response, eliminating harmful microorganisms from the body.