Effects of Olea oleaster leaf extract and purified oleuropein on ethanol-induced gastric ulcer in male Wistar rats.

Objectives: Evaluating the effect of fresh Oleaster leaf extract (OLE) and purified oleuropein (OLR) on ethanol-induced gastric ulcers in rats. HPLC analysis demonstrates the presence of various polyphenol compounds such as ligstroside, luteolin derivative, oleuropein, and comselogoside. Materials and Methods: Gastric ulcer was induced by administration of ethanol by the gastric gavage route. The olive leaf extract was analyzed by HPLC-PDA-ESI-MS, and OLR was purified. These two compounds were given 2 hr before gastric ulcer induction by ethanol. Results: This study verified that OLE and purified OLR protect from ethanol-induced gastric ulceration and damage, evidenced by the significant decrease in gastric ulcer urea (by 74 and 58% respectively) and stomach mucus content (by 169 and 87% respectively). In addition, the ulcer index (UI) and curative index (CI) levels in the stomach of the rats treated with this supplement were also suppressed by 55 and 46%, respectively. OLE and OLR also decreased the gastric myeloperoxidase (MPO) activity and ameliorated the nitric oxide (NO) content. OLE and OL also ingestion suppressed gastric tumor necrosis factor-alpha (TNF-α) and interleukin (IL-6) rates. Macroscopic and histological findings revealed that OLE and OLR protect from gastric hemorrhage, severe disruption of the gastric mucosa, and neutrophil infiltration. Conclusion: Overall, the findings demonstrate that OLE and OLR have both promising potential with regard to the inhibition of gastric hemorrhage and lesions.

Protective effects of melatonin and N-acetyl cysteine against oxidative stress induced by microcystin-LR on cardiac muscle tissue.

Microcystin Leucine-Arginine (MC-LR) is a toxin produced by the cyanobacteria Microcystis aeruginosa. It is the most encountered and toxic type of cyanotoxins. Oxidative stress was shown to play a role in the pathogenesis of microcystin LR by the induction of intracellular reactive oxygen species (ROS) formation that oxidize and damage cellular macromolecules. In the present study we examined the effect of acute MC-LR dose on the cardiac muscle of BALB/c mice. Afterwards, melatonin and N-acetyl cysteine (NAC) were assayed and evaluated as potential protective and antioxidant agents against damages generated by MC-LR. For this purpose, thirty mice were assigned into six groups of five mice each. The effect of MC-LR was first compared to the control group supplied with distilled water, then compared to the other groups supplied with melatonin and NAC. The experiment lasted 10 days after which animals were euthanized. Biomarkers of toxicity such as alkaline phosphatase activity, lipid peroxidation, protein carbonyl content, reduced glutathione content, serum lactate dehydrogenase and serum sorbitol dehydrogenase were assayed. Results showed that toxin treated mice have experienced significant oxidative damage in their myocardial tissue as revealed by noticeable levels of oxidative stress biomarkers and by the reduction in alkaline phosphatase activity. Whereas, melatonin and NAC treated mice manifested lesser oxidative damages. Our findings suggest a potential therapeutic use of melatonin and N-acetyl cysteine as antioxidant protective agents against oxidative damage induced by MC-LR.

Molecular mechanism underlying anti-inflammatory and anti-allergic activities of phytochemicals: an update.

The resort worldwide to edible medicinal plants for medical care has increased significantly during the last few years. Currently, there is a renewed interest in the search for new phytochemicals that could be developed as useful anti-inflammatory and anti-allergic agents to reduce the risk of many diseases. The activation of nuclear transcription factor-kappa B (NF-κB) has now been linked to a variety of inflammatory diseases, while data from numerous studies underline the importance of phytochemicals in inhibiting the pathway that activates this transcription factor. Moreover, the incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. Thus, a good number of plant products with anti-inflammatory and anti-allergic activity have been documented, but very few of these compounds have reached clinical use and there is scant scientific evidence that could explain their mode of action. Therefore, this paper intends to review the most salient recent reports on the anti-inflammatory and anti-allergic properties of phytochemicals and the molecular mechanisms underlying these properties.

Evaluation of the antioxidant activity of three varieties of honey from different botanical and geographical origins.

It is well established that honey contains substantial antioxidant compounds that could protect cell components from the harmful action of free radicals. One can speculate that these compounds may strengthen the organism defenses and consequently prevent oxidative stress in humans. Therefore, over time, impaired cells can accumulate and lead to age-related diseases. A comparative study was carried out to assess the antioxidant activity of three varieties of honey from different botanical and geographical (Manuka honey from New Zealand, Acacia Honey from Germany and Wild carrot honey from Algeria). Manuka honey had the highest phenolic content with 899.09 ± 11.75 mg gallic acid/kg. A strong correlation between the antioxidant activities of honeys and their total phenol contents has been noticed.

Antibacterial and antioxidant potency of floral honeys from different botanical and geographical origins.

In order to assess their physicochemical and antioxidant properties as well as their antimicrobial potency, four varieties of honey from different botanical and geographical origins were used. The agar incorporation method was used to determine the antimicrobial potency of honeys. The total phenol content was determined by a modified Folin-Ciocalteu method and the free radical scavenging activity by the Fe(3+)reducing power (FRAP) assay. Manuka honey was the most effective against Staphylococcus aureus Oxa R and S. aureus Oxa S with a Minimum Inhibitory Concentration (MIC) of 6% and 7%, respectively, whereas wild carrot honey was the most effective against Pseudomonas aeruginosa, with a MIC of 12%. Lavender honey was the least effective against all tested strains, even though was found to have the lowest pH and water content. Manuka honey had the highest content of polyphenols, with 899.09 ± 11.75 mg gallic acid/kg, whereas lavender honey had the lowest, with 111.42 ± 3.54 mg gallic acid/kg. A very significant correlation (r value was 0.9079 at P < 0.05) was observed between the total polyphenolic content and the Fe(2+) content formed in the presence of the honey antioxidants. The differences between honey samples in terms of antibacterial and antioxidant activity could be attributed to the natural variations in floral sources of nectar and the different locations.

Phytochemicals to prevent inflammation and allergy.

Recently, much interest has been generated for a wide range of phyto-constituents with reports demonstrating their role in the modulation of inflammatory responses, including phenolics, alkaloids, and terpenoids. Natural products have long been, over the years, contributed to the development of modern therapeutic drugs. At present, steroids, antihistaminic drugs, suppressants or inhibitors of the release of mediators and the like have been used as anti-allergic agents. However, some of them lack immediate effectiveness or have central side effects. Drug discovery from plants involves a multidisciplinary approach combining botanical, ethno-botanical, phytochemical and biological techniques. Several natural product drugs of plant origin are in clinical use and some are undergoing Phase II and Phase III clinical trials. A major effort was directed toward discovery of novel anti-inflammatory and anti-allergic agents, which resulted in the invention of several patented formulations. These formulations concern a variety of pharmaceutical preparations which can be used as solid or liquid dosage forms or encapsulated as a soft or hard gelatin capsule. The present article is a short review of recent patents on the role of phytochemicals in preventing inflammation and allergy.