Olive leaf extract

The olive tree (Olea europea) has been cultivated in the Mediterranean region for thousands of years. The olive has been widely used as a food, for personal hygiene, for healing purposes, as a lubricant and preservative, for making oil lamps and for sacred services. While the positive properties of the olive fruit and the oil extracted from it are known to most people, the therapeutic effect of its leaves has almost been forgotten. Hildegard von Bingen - for example - treated digestive complaints with a tea made from olive leaves and at the beginning of the 19th century, Spanish wound doctors used a similar tea mixture to cure numerous soldiers suffering from fever during the war. In 1811, Etiene Pallas succeeded in analyzing some of the ingredients of olive leaves for the first time. Some doctors later made use of their antipyretic properties in the fight against malaria.

Systematic scientific research into the ingredients of olive leaves began in the 1960s. And there are now many positive and very encouraging reports from the USA, Hungary, Great Britain and other countries. Olive leaves from the olive tree (Olea europaea L.) mainly contain the bitter substance oleuropein and other secondary plant substances such as flavonoids. The most important ingredients, which are primarily responsible for the virucidal, bactericidal and antioxidant healing effects, include: Oleuropein, oleoside, glycosides, oleosterol and olevanol. Olive leaf extracts - especially in liquid form - are characterized by exceptionally good digestibility and high availability. They have no side effects and can be safely taken as a dietary supplement for longer periods of time.

Mechanisms of action of olive leaf extracts

Olive leaf extracts reduce the expression of genes that promote fat formation: PPARy, lipoprotein lipase, fatty acid binding protein 4 (1).
Olive leaf extracts increase the differentiation of osteoblasts (increased production of osteoblast gene markers RUNXII, Osterix, collagen type 1, osteocalcin and alkaline phosphatase) (1).
Olive leaf extracts stimulate the development of blood vessels VEGF production (2).
Olive leaf extracts normalize MDA and blood glucose levels (3).
Olive leaf extracts lower left ventricular developed and systolic blood pressure and improve stroke volume, ejection fraction and cardiac output, as well as levels of superoxide dismutase and glutathione reductase (4).
Olive leaf extracts prevent an increase in serum levels of malondialdehyde, interleukin-1β, TNF-α, creatine kinase-MB, troponin I and lactate dehydrogenase (4).
Olive leaf extracts increase the production of proteins that prevent cell death (Bcl-2, Bcl-XL, Bim and p53) (5).

Active ingredients

Olive leaves of the olive tree (Olea europaea L.) mainly contain the bitter substance called oleuropein and also secondary plant substances such as flavonoids. It has been scientifically proven that the phenolic compounds of these substances have a positive influence on health: effectively protects LDL cholesterol from oxidation, arteriosclerosis and heart attacks, inhibits the formation of pro-inflammatory substances and the formation of blood clots, serves in the body to strengthen the immune system and fight viruses, bacteria and fungi The 2,5 times higher antioxidant activity of olive leaf extract than vitamins C and E and significant reduction of elevated LDL cholesterol without affecting HDL cholesterol as well as anti-inflammatory, antiviral, antibacterial and antimicrobial properties are due to the synergistic effect between oleuropeosides, flavonoids and substituted phenols.

Olive leaf extracts have the following potential health benefits

Olive leaf extracts are rich in antioxidants

In 2 clinical studies of 62 elderly and 8 healthy adults, both extra virgin olive oil and olives improved overall antioxidant status (6, 7). In a small study of 10 postmenopausal women, olive oil also reduced oxidative damage to DNA (8). Olive oil prevented oxidative processes (measured as reduced LDL oxidation) in 2 clinical studies involving 230 healthy volunteers (9, 10). Hydroxytyrosol, followed by oleuropein and tyrosol, is the phenol in olive leaves that is most effective in neutralizing free radicals (11). Hydroxytyrosol has been shown to improve antioxidant status in several clinical trials involving a total of 144 subjects (11, 12).

The blood sugar-lowering effects of oleuropein are also based on its ability to block the production of free radicals by Nox2, as shown in a small study involving 20 healthy volunteers (13). Oleuropein applied to the skin also reduced damage caused by UV radiation in a study involving 10 volunteers (15). In a study with mice poisoned with arsenic, oleuropein reduced oxidative damage to the blood, liver, kidneys and brain (16). Existing studies suggest that olive leaf extracts have antioxidant properties.

Olive leaf extract has positive effects on cardiovascular health

Olive leaf extracts can lower blood pressure

In a clinical study of 60 men at increased risk of high blood pressure, oleuropein significantly reduced systolic and diastolic blood pressure, blood lipids and cholesterol levels (17). In another study of 232 patients with high blood pressure, 500 mg oleuropein twice daily for 8 weeks was as effective as the diuretic captopril at a dose of 12.5 to 25 mg twice daily in reducing systolic and diastolic blood pressure (18).

The antihypertensive effects of olive leaf extract may be due to its ability to maintain blood vessel function, as observed in a small study of 13 subjects with slightly elevated blood pressure (19). In rats with high blood pressure, an olive leaf extract reduced blood pressure, heart rate and enlargement of the heart and kidneys while improving blood vessel function (20).

Olive leaf extracts can improve blood lipid levels

In a clinical trial involving 200 healthy volunteers, olive oil polyphenols reduced markers of increased risk of heart disease such as cholesterol (both free and bound LDL), triglycerides and oxidative stress (9). In 4 clinical trials involving a total of almost 150 subjects with high blood pressure, olive polyphenols lowered blood lipid levels (total cholesterol, LDL cholesterol and triglycerides (21, 22). A combination of olive extracts and red yeast rice was able to significantly reduce blood lipid levels (especially LDL cholesterol) in 2 clinical studies involving almost 700 subjects at increased risk of heart disease (23, 24).

Olive oil reduced LDL oxidation in 2 small studies with 42 subjects and thus helped to reduce arterial blockages. Hydroxytyrosol had the same effect in another study with 84 subjects (10, 25, 13). Taken together, this evidence suggests that olive leaf extract may help prevent heart disease by lowering blood pressure and preventing arterial blockage.

Olive leaf extract has anti-inflammatory effects

In a small study of 18 healthy volunteers, olive leaf extract (standardized to 51 mg oleuropein and 9 mg hydroxytyrosol) reduced the production of pro-inflammatory cytokines (IL-8) and improved blood vessel function (26). In another clinical study of 45 women with breast cancer, a combination of hydroxytyrosol with omega-3 fatty acids and curcumin reduced inflammation (CRP levels and pain) after one month of use. Hydroxytyrosol also reduced inflammation and pain in a small study of 25 subjects with joint problems (genoarthritis) (28). In intestinal samples isolated from 14 subjects with ulcerative colitis, treatment with an olive leaf extract reduced the production of pro-inflammatory molecules (the enzyme COX-2 and the cytokine IL.17) and the infiltration of immune cells (CD3, CD4 and CD20), resulting in a reduction in inflammatory damage (29).

In a study of mice injected with cisplatin to induce liver damage, oleuropein reduced inflammation and prevented renal cell death (30). In mice with skin lesions, oleuropein reduced inflammation and accelerated wound healing (31). In human brain cells, an olive leaf extract prevented inflammation by reducing COX-2 production (32) The phenolic components of olive leaf extracts also show significant effects against polyarthritis and soft tissue rheumatism and all types of respiratory tract inflammation.

According to various practical experiences, the liquid form of olive leaf extract is rated particularly positively as it allows rapid absorption via the oral mucosa. This is very beneficial, for example, in the case of swallowing difficulties and inflammatory throat infections. As the product is alcohol-free, it is also ideal for children. All in all, scientific studies suggest that olive leaf extracts and their components have anti-inflammatory properties. Further research should confirm these results and establish the optimal way of therapeutic use.

Olive leaf extract could lower blood sugar levels

In a small study of 20 healthy volunteers, oleuropein reduced post-meal blood glucose levels by blocking the production of free radicals by Nox2 (14), and in another study of 46 overweight middle-aged men at increased risk of developing type 2 diabetes, supplementation with olive leaf extract for 12 weeks improved insulin sensitivity and the activity of pancreatic cells that produce insulin (33). In diabetic rabbits, oleuropein reduced blood glucose levels to normal values and reduced markers of oxidative damage (34).

In addition, oleuropein improved insulin sensitivity and increased blood glucose uptake in diabetic mice (35). Olive leaf extract could be useful for the supportive treatment of diabetes mellitus In 1992, the Spanish researcher Gonzales discovered that olive leaf extracts, and in particular the active ingredient oleuropeoside contained therein, have a blood sugar-lowering effect at a concentration of 16 mg/kg body weight. During adjuvant therapy with olive leaf extracts, insulin doses can be significantly reduced.

Olive leaf extract can improve bone health

In a clinical study of 64 women with bone loss (osteoporosis), consumption of olive leaf extract for 12 months maintained bone density and increased markers of blood levels of bone-forming cells (osteocalcin) (36). In female mice whose ovaries had been removed to mimic menopause, both olive oil and oleuropein prevented bone loss (37). In a study with human bone marrow stem cells, it was observed that oleuropein increased bone cell production (1).

Olive leaf extract could counteract infections

In a clinical study with 32 high school athletes, the intake of an olive leaf extract in a dosage equivalent to 20 grams of olive leaves and 100 mg oleuropein for 9 weeks slightly reduced the number of sick days due to upper respiratory tract diseases. However, the extract had no effect on the frequency of the illnesses (38). In addition, oleuropein was able to inhibit toxoplasmosis in mouse kidney cells. Oleuropein was also effective in preventing cell death and tumor formation in the spleen and liver of infected mice (39). Although oleuropein had no antimicrobial effects against lactic acid bacteria, two of its hydrolysis products - aglycone and oleanolic acid - inhibited the growth of four of the species tested (40). In cells infected with a common opportunistic fungus, hydroxytyrosol was able to inhibit fungal growth (41).

Olive leaf extract could support weight loss

Preliminary research suggests that olive leaf extract may help fight obesity by preventing the body from generating more fat cells (42). In rats fed a high-fat diet, oleuropein reduced body weight, adipose tissue mass, liver fat and blood cholesterol levels (43, 35, 44). Oleuropein reduced fat cell production in bone marrow stem cells. In addition, oleuropein and hydroxytyrosol blocked the development of immature fat cells (1, 45).

Olive leaf extract can improve fat metabolism

A study from Milan showed that the daily intake of 1.2 g of olive leaf extract resulted in a significant reduction in excessive cholesterol levels and an improved lipoprotein ratio after just 15 days. LDL levels were reduced and the HDL concentration increased steadily.

Olive leaf extract could counteract neurodegenerative diseases

Amyloid diseases such as Alzheimer's are caused, at least in part, by the build-up of misfolded proteins in tissue, which cause inflammation and tissue damage (46). Olive leaf extracts can prevent these misfolded proteins from reaching the brain. This effectively prevented toxicity and tissue damage in studies conducted with mice (47). Even in advanced stages of Alzheimer's, mice experienced an improvement in brain function after treatment with oleuropein aglycone (47). In rats with Parkinson's disease, an olive extract reduced cell damage and cell death (48). In rats with anesthetic-induced oxidative stress, oleuropein reduced spatial memory impairment and improved cognition (49).

Chronic fatigue

Olive leaf extracts have a stimulating and uplifting effect, so they should not be taken in the evening. An attempt at treatment is also worthwhile for CFS. The improvement in symptoms of chronic fatigue is probably due to the virustatic property of olive leaf extracts.