Virgin olive oil administration improves the effect of aspirin on retinal vascular pattern in experimental diabetes mellitus

Synergistic Effect of 3',4'-Dihidroxifenilglicol and Hydroxytyrosol on Oxidative and Nitrosative Stress and Some Cardiovascular Biomarkers in an Experimental Model of Type 1 Diabetes Mellitus

The objective of this study was to assess a possible synergistic effect of two extra-virgin olive oil polyphenols, 3,4,-dyhydroxyphenylglycol (DHPG) and hydroxytyrosol (HT), in an experimental model of type 1 diabetes. Seven groups of animals were studied: (1) Nondiabetic rats (NDR), (2) 2-month-old diabetic rats (DR), (3) DR treated with 5 mg/kg/day p.o. HT, (4) DR treated with 0.5 mg/kg/day p.o. DHPG, (5) DR treated with 1 mg/kg/day p.o. DHPG, (6) DR treated with HT + DHPG (0.5), (7) DR treated with HT + DHPG (1). Oxidative stress variables (lipid peroxidation, glutathione, total antioxidant activity, 8-isoprostanes, 8-hydroxy-2-deoxyguanosine, and oxidized LDL), nitrosative stress (3-nitrotyrosine), and some cardiovascular biomarkers (platelet aggregation, thromboxane B₂, prostacyclin, myeloperoxidase, and vascular cell adhesion protein 1 (VCAM-1)) were analyzed. The diabetic animals showed an imbalance in all of the analyzed variables. HT exerted an antioxidant and downregulatory effect on prothrombotic biomarkers while reducing the fall of prostacyclin. DHPG presented a similar, but quantitatively lower, profile. HT plus DHPG showed a synergistic effect in the reduction of oxidative and nitrosative stress, platelet aggregation, production of prostacyclin, myeloperoxidase, and VCAM-1. This synergism could be important for the development of functional oils enriched in these two polyphenols in the proportion used in this study.

Hydroxytyrosol Promotes Proliferation of Human Schwann Cells: An In Vitro Study

Recent advances in phytomedicine have explored some potential candidates for nerve regeneration, including hydroxytyrosol (HT). This study was undertaken to explore the potential effects of HT on human Schwann cells' proliferation. Methods: The primary human Schwann cell (hSC) was characterized, and the proliferation rate of hSC supplemented with various concentrations of HT was determined via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell cycle analysis and protein expression of glial fibrillary acidic protein (GFAP) and p75 nerve growth factor receptor (p75 NGFR) were evaluated via the immunofluorescence technique. Results: In vitro culture of hSCs revealed spindle-like, bipolar morphology with the expression of specific markers of hSC. Hydroxytyrosol at 10 and 20 ng/mL significantly increased the proliferation of hSCs by 30.12 ± 5.9% and 47.8 ± 6.7% compared to control (p < 0.05). Cell cycle analysis showed that HT-treated hSCs have a higher proliferation index (16.2 ± 0.2%) than the control (12.4 ± 0.4%) (p < 0.01). In addition, HT significantly increased the protein expression of GFAP and p75NGFR (p < 0.05). Conclusion: HT stimulates the proliferation of hSCs in vitro, indicated by a significant increase in the hSC proliferation index and protein expression of hSCs' proliferation markers, namely p75 NGFR and GFAP.

Neuroprotective Effect of Hydroxytyrosol in Experimental Diabetic Retinopathy: Relationship with Cardiovascular Biomarkers

The aim of the study was to test the neuroprotective effect of hydroxytyrosol (HT) on experimental diabetic retinopathy. Animals were divided in four groups: (1) control nondiabetic rats, (2) streptozotocin-diabetic rats (DR), (3) DR treated with 1 mg/kg/day p.o. HT, and (4) DR treated with 5 mg/kg/day p.o. HT. Treatment with HT was started 7 days before inducing diabetes and was maintained for 2 months. In the DR group, total area occupied by extracellular matrix was increased, area occupied by retinal cells was decreased; both returned to near-control values in DR rats treated with HT. The number of retinal ganglion cells in DR was significantly lower (44%) than in the control group, and this decrease was smaller after HT treatment (34% and 9.1%). Linear regression analysis showed that prostacyclin, platelet aggregation, peroxynitrites, and the dose of 5 mg/kg/day HT significantly influenced retinal ganglion cell count. In conclusion, HT exerted a neuroprotective effect on diabetic retinopathy, and this effect correlated significantly with changes in some cardiovascular biomarkers.

Synergistic analgesic, anti-pyretic and anti-inflammatory effects of extra virgin olive oil and ibuprofen in different experimental models of albino mice

AIM

Olive oil was used in the past as a remedy for many diseases due to its unlimited benefits in health. This study was carried out to assess the analgesic, anti-pyretic and anti-inflammatory activities of extra virgin olive oil (EVOO) at a dose of 8 mL/kg body weight and to compare it with ibuprofen (IBU) as an individual drug therapy and in combination with two different doses of IBU (therapeutic dose 100 mg/kg and low dose 40 mg/kg), on different animal models in albino mice.

METHOD

A total of 132 adult healthy male Swiss albino mice were used in this study. The analgesic effect was assessed using acetic acid-induced writhing test. The antipyretic effect was evaluated by brewer's yeast-induced pyrexia, while the anti-inflammatory activity was assessed by two different models; the carrageenan-induced paw edema and the carrageenan-induced peritonitis in which the levels of total leukocyte count (TLC), neutrophil count, prostaglandin E2 (PGE2) and interferon gamma (INF-γ) were measured in the peritoneal exudates.

RESULTS

The results revealed significant protection in all the treated groups; however, the combination of EVOO with IBU at its therapeutic dose showed superiority over the two compounds when used separately.

CONCLUSION

Using EVOO with the therapeutic dose of IBU showed synergistic effect in controlling the cardinal signs of acute inflammation rather than using non-steroidal anti-inflammatory drugs alone.

Effects of hydroxytyrosol on cardiovascular biomarkers in experimental diabetes mellitus

The aim of this study was to assess the influence of hydroxytyrosol (HT) on cardiovascular biomarkers and morphometric parameters of the arterial wall in streptozotocin-diabetic rats. Seven groups of rats (N=10 per group) were studied for 2 months: nondiabetic rats (NDR), diabetic rats treated with saline (DR) and DR treated with HT (0.5, 1, 2.5, 5 and 10 mg kg^-1 day^-1 p.o.). DR had higher platelet aggregation values, higher thromboxane B₂, plasma lipid peroxidation, 3-nitrotyrosine, oxidized LDL (oxLDL), myeloperoxidase, vascular cell adhesion molecule 1 (VCAM-1) and interleukin-1β (IL-1β) concentrations, and lower aortic 6-keto-prostaglandin F_1α and nitric oxide production than NDR. Aortic wall area and smooth muscle cell count were also higher in DR than in NDR. HT significantly reduced both oxidative and nitrosative stress, oxLDL concentration, VCAM-1 and inflammatory mediators, platelet aggregation and thromboxane B₂ production. Morphometric values in the aortic wall were reduced to values near those in NDR. In conclusion, HT influenced the major biochemical processes leading to diabetic vasculopathy, and reduced cell proliferation in the vascular wall in this experimental model.

Analgesic, anti-inflammatory and anticancer activities of extra virgin olive oil

Background. In folk medicine, extra virgin olive oil (EVOO) is used as a remedy for a variety of diseases. This study investigates the in vivo antinociceptive, anti-inflammatory, and anti-cancer effects of EVOO on mice and rats. Materials and Methods. In this experimental study, using the acetic acid-induced writhing and formalin tests in mice, the analgesic effect of EVOO was evaluated. Acetylsalicylic acid and morphine were used as standard drugs, respectively. The anti-inflammatory activity was investigated by means of the carrageenan-induced paw edema model in rats using acetylsalicylic acid and dexamethasone as standard drugs. Last, the xenograft model in athymic mice was used to evaluate the anticancer effect in vivo. Results. EVOO significantly decreased acetic acid-induced abdominal writhes and reduces acute and inflammatory pain in the two phases of the formalin test. It has also a better effect than Dexamethasone in the anti-inflammatory test. Finally, the intraperitoneal administration of EVOO affects the growth of HCT 116 tumours xenografted in athymic mice. Conclusion. EVOO has a significant analgesic, anti-inflammatory, and anticancer properties. However, further detailed studies are required to determine the active component responsible for these effects and mechanism pathway.