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Clinical Studies
References
Olive Leaf is used for the treatment of conditions associated with viruses, retroviruses, bacteria, or protozoa including influenza, the common cold, meningitis, Epstein-Barr Virus (EBV), encephalitis, herpes I and II, human herpes virus 6 and 7, shingles, HIV/AIDS, chronic fatigue and hepatitis B. It is also used for pneumonia, tuberculosis, gonorrhoea, malaria, dengue, bacteraemia, severe diarrhoea, blood poisoning and dental, ear, urinary tract and surgical infections. Other uses include hypertension, diabetes, allergic rhinitis, improving renal and digestive function and as a diuretic and antipyretic.
In animal experiments Olive Leaf preparations demonstrate multiple properties including antispasmodic, hypotensive, antiarrhythmic and hypoglycemic, bronchodilator, coronary dilator, antipyretic and diuretic properties. The active constituent oleuropein has bacteriostatic and antioxidant activity.
Olive Leaf may be beneficial in fungus and yeast infections, frequent colds, asthma, vaginal yeast infections, rheumatoid arthritis, diabetes, bacterial infections, herpes, AIDS, chronic fatigue, antioxidant, flu and colds.
Published Clinical Studiesclin
1
Anti-HIV activity of olive leaf extract (OLE) and modulation of host cell gene expression by HIV-1 infection and OLE treatment.
Lee-Huang S, Zhang L, Huang PL, Chang YT, Huang PL.
Department of Biochemistry, New York University School of Medicine, New York, NY 10016, USA. Sylvia.lee-huang@med.nyu.edu
We investigated the antiviral activity of olive leaf extract (OLE) preparations standardized by liquid chromatography-coupled mass spectrometry (LC-MS) against HIV-1 infection and replication. We find that OLE inhibits acute infection and cell-to-cell transmission of HIV-1 as assayed by syncytia formation using uninfected MT2 cells co-cultured with HIV-1-infected H9 T lymphocytes. OLE also inhibits HIV-1 replication as assayed by p24 expression in infected H9 cells. These anti-HIV effects of OLE are dose dependent, with EC(50)s of around 0.2 microg/ml. In the effective dose range, no cytotoxicity on uninfected target cells was detected. The therapeutic index of OLE is above 5000. To identify viral and host targets for OLE, we characterized gene expression profiles associated with HIV-1 infection and OLE treatment using cDNA microarrays. HIV-1 infection modulates the expression patterns of cellular genes involved in apoptosis, stress, cytokine, protein kinase C, and hedgehog signaling. HIV-1 infection up-regulates the expression of the heat-shock proteins hsp27 and hsp90, the DNA damage inducible transcript 1 gadd45, the p53-binding protein mdm2, and the hedgehog signal protein patched 1, while it down-regulates the expression of the anti-apoptotic BCL2-associated X protein Bax. Treatment with OLE reverses many of these HIV-1 infection-associated changes. Treatment of HIV-1-infected cells with OLE also up-regulates the expression of the apoptosis inhibitor proteins IAP1 and 2, as well as the calcium and protein kinase C pathway signaling molecules IL-2, IL-2Ralpha, and ornithine decarboxylase ODC1.
PMID: 12878215 [PubMed - indexed for MEDLINE]
In vitro antimicrobial activity of olive leaves.2
Markin D, Duek L, Berdicevsky I.
Department of Microbiology, Rappaport Faculty of Medicine, Technion-Institute of Technology, Haifa, Israel.
We investigated the antimicrobial effect of olive leaves against bacteria and fungi. The microorganisms tested were inoculated in various concentrations of olive leaf water extract. Olive leaf 0.6% (w/v) water extract killed almost all bacteria tested, within 3 h. Dermatophytes were inhibited by 1.25% (w/v) plant extract following a 3-day exposure whereas Candida albicans was killed following a 24 h incubation in the presence of 15% (w/v) plant extract. Olive leaf extract fractions, obtained by dialysis, that showed antimicrobial activity consisted of particles smaller than 1000 molecular rate cutoffs. Scanning electron microscopic observations of C. albicans, exposed to 40% (w/v) olive leaf extract, showed invaginated and amorphous cells. Escherichia coli cells, subjected to a similar treatment but exposed to only 0.6% (w/v) olive leaf extract showed complete destruction. These findings suggest an antimicrobial potential for olive leaves.
PMID: 12870202 [PubMed - indexed for MEDLINE]
Safety evaluation of olive phenolic compounds as natural antioxidants.3
Farag RS, El-Baroty GS, Basuny AM.
Department of Biochemistry, Faculty of Agriculture, Cairo University, Giza, Egypt.
Free and total polyphenolic compounds were extracted from the fruits and leaves of the Picual cultivar. The safety limits of these compounds were recognized by measuring the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the levels of high-density lipoprotein (HDL) cholesterol and total lipids of rat serum. The free and total phenolic compounds (400, 800, and 1600 ppm) and butylated hydroxy toluene (BHT) (200 ppm) were daily ingested for 7 weeks. The administration of olive total and free phenolic compounds at 400 and 800 ppm did not cause any significant changes on ALT and AST activities and serum total lipids. These compounds at 1600 ppm caused significant increase in ALT and AST activities and the content of total lipids. Both olive phenolic compounds were superior to that of BHT in increasing HDL-cholesterol level. Nutritional experiments demonstrated that BHT at 200 ppm caused an enlargement in the kidney and liver of the rat compared with the administration of total and free olive phenolic compounds at 1200 and 1600 ppm. Microscopical examination of kidney and liver tissues of rats administered free and total phenolic compounds at 1200 ppm had the same histological character as that of control rats, while the administration of BHT (200 ppm) and phenolic compounds (1600 ppm) induced severe damage to the tissues of the rat kidney and liver.
PMID: 12775365 [PubMed - indexed for MEDLINE]
4
Antihypertensive, antiatherosclerotic and antioxidant activity of triterpenoids isolated from Olea europaea, subspecies africana leaves.
Somova LI, Shode FO, Ramnanan P, Nadar A.
Department of Human Physiology, University of Durban-Westville, Private Bag X54001, Durban 4000, South Africa. somova@pixie.udw.ac.za
For the first time a biossay-directed study of triterpenoids isolated from the leaves of Olea europaea from Greece, from wild African olive and from a cultivar of O. europaea grown in Cape Town was reported. The experiment was undertaken since our preliminary analyses showed that the African wild olive leave is rich in triterpenoids and contain only traces of the glycoside oleuropein, which is typical for the European olive leaves. The isolate of the African wild olive leaves (AO) used in the experiments was found to contain 0.27% 1:1 mixture of oleanolic acid and ursolic acid, named oleuafricein. The isolate of Greek olive leaves (GO) was found to contain 0.71% oleanolic acid, and the Cape Town cultivar (CT) contained 2.47% oleanolic acid. No ursolic acid was found in either GO or CT. The antihypertensive, diuretic, antiatherosclerotic, antioxidant and hypoglycemic effects of authentic oleanolic and ursolic acid and the three isolates (GO, AO and CT) were studied on Dahl salt-sensitive (DSS), insulin-resistant rat genetic model of hypertension. All three isolates, in a dose 60 mg/kg b.w. for 6 weeks treatment, prevented the development of severe hypertension and atherosclerosis and improved the insulin resistance of the experimental animals. GO, OA and CT isolates could provide an effective and cheap treatment of this particular, most common type of salt-sensitive hypertension in the African population. Copyright 2002 Elsevier Science Ireland Ltd.
PMID: 12648829 [PubMed - indexed for MEDLINE]
5
Blood pressure lowering effect of an olive leaf extract (Olea europaea) in L-NAME induced hypertension in rats.
Khayyal MT, el-Ghazaly MA, Abdallah DM, Nassar NN, Okpanyi SN, Kreuter MH.
Department of Pharmacology, Faculty of Pharmacy, Cairo University, Cairo, Egypt. mtkhayyal@hotmail.com
A specially prepared olive leaf extract (EFLA 943) has been tested for its blood pressure lowering activity in rats rendered hypertensive by daily oral doses of L-NAME (NG-nitro-L-arginine methyl ester, 50 mg/kg) for at least 4 weeks. Oral administration of the extract at different dose levels at the same time as L-NAME for a period of 8 weeks showed a dose dependent prophylactic effect against the rise in blood pressure induced by L-NAME, best effects being induced by a dose of 100 mg/kg of the extract. In rats previously rendered hypertensive by L-NAME for 6 weeks and then treated with that dose of the extract for a further 6 weeks without discontinuation of L-NAME, normalisation of the blood pressure was observed. The findings confirm previous reports on the hypotensive effects of olive leaf. The special extract, EFLA 943, was shown to give consistent results with little individual variability. The antihypertensive effect of the extract may be related to a variety of factors involving reversal of vascular changes involved in the L-NAME induced hypertension.
PMID: 12489249 [PubMed - indexed for MEDLINE]
Effect of freeze dried extract of Olea europaea on the pituitary-thyroid axis in rats.6
Al-Qarawi AA, Al-Damegh MA, ElMougy SA.
Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, King Saud University, Saudi Arabia.
The effect of an aqueous extract of olive (Olea europaea) leaf on the thyroid activity was studied. The results suggest a stimulatory action of the extract on the thyroid, unrelated to the pituitary.
PMID: 12164280 [PubMed - indexed for MEDLINE]
7
Radioprotective effects in vivo of phenolics extracted from Olea europaea L. leaves against X-ray-induced chromosomal damage: comparative study versus several flavonoids and sulfur-containing compounds.
Benavente-Garcia O, Castillo J, Lorente J, Alcaraz M.
Research and Development Department, Furfural Espanol S.A., Camino Viejo de Pliego s/n, 80320 Alcantarilla, Murcia, Spain. laboratorio@furesa.es
The radioprotective effects of a polyphenolic extract of Olea europaea L. leaves (OL); the flavonoids diosmin and rutin, which are widely used as pharmaceuticals; and the sulfur-containing compounds dimethylsulfoxide (DMSO) and 6-n-propyl-2-thiouracil (PTU) were determined by using the micronucleus test for anticlastogenic activity, evaluating the reduction of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) in bone marrow of mouse before and after X-ray irradiation. With treatment before X-irradiation, the most effective compounds were, in order, rutin > DMSO > OL > PTU > diosmin. These results showed, for the polyphenols studied, a linear correlation (r(2) = 0.965) between anticlastogenic activity and antioxidant capacity. The magnitude of protection with treatment after X-irradiation were lower, and the most effective compounds were, in order, OL > diosmin > rutin; DMSO and PTU lacked radioprotective activity. Therefore, OL is the only substance that showed a significant anticlastogenic activity both before and after X-ray irradiation treatments. Structurally, the free oxygen radicals and lipoperoxyradicals scavenging capacity and, consequently, the anticlastogenic activity of these polyphenolic compounds are based principally on the presence of specific functional groups, mainly catechol groups (rutin, oleuropein, hydroxytyrosol, verbascoside, luteolin), that also increase the stability of the aroxyl-polyphenol radical generated in the above processes.
PMID: 12495584 [PubMed - indexed for MEDLINE]
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