No abstract

The effects of guava leaves extracted using solvents of water, ethanol, methanol, and different concentrations of hydroethanolic solvents on phenolic compounds and flavonoids, and antioxidant properties have been investigated. The antioxidant capability was assessed based on 2,2-diphenyl-1-picrylhydrazyl radical and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging abilities, reducing power, and nitric oxide-and nitrate-scavenging activities. The results demonstrated that the antioxidant ability of guava leaf extracts has a strong relationship with phenolic compound content rather than flavonoid content. Phenolic compound content of water extracted guava leaves was higher compared to pure ethanol and methanol extracts. However, phenolic compound content extracted using hydroethanolic solvent was higher than water, whereas 50% hydroethanolic was observed to be the most effective solvent showing high antioxidant ability.

Mechanical stretch stimuli alter the morphology and function of cultured endothelial cells; however, little is known about the effects of daily muscle stretching on adaptations of endothelial function and muscle blood flow. The present study aimed to determine the effects of daily muscle stretching on endothelium-dependent vasodilatation and muscle blood flow in aged rats. The lower hindlimb muscles of aged Fischer rats were passively stretched by placing an ankle dorsiflexion splint for 30 min day , 5 days week , for 4 weeks. Blood flow to the stretched limb and the non-stretched contralateral limb was determined at rest and during treadmill exercise. Endothelium-dependent/independent vasodilatation was evaluated in soleus muscle arterioles. Levels of hypoxia-induced factor-1α, vascular endothelial growth factor A and neuronal nitric oxide synthase were determined in soleus muscle fibres. Levels of endothelial nitric oxide synthase and superoxide dismutase were determined in soleus muscle arterioles, and microvascular volume and capillarity were evaluated by microcomputed tomography and lectin staining, respectively. During exercise, blood flow to plantar flexor muscles was significantly higher in the stretched limb. Endothelium-dependent vasodilatation was enhanced in arterioles from the soleus muscle from the stretched limb. Microvascular volume, number of capillaries per muscle fibre, and levels of hypoxia-induced factor-1α, vascular endothelial growth factor and endothelial nitric oxide synthase were significantly higher in the stretched limb. These results indicate that daily passive stretching of muscle enhances endothelium-dependent vasodilatation and induces angiogenesis. These microvascular adaptations may contribute to increased muscle blood flow during exercise in muscles that have undergone daily passive stretch.

Aerobic or resistance training was unable to prevent tumor-induced body weight loss. However, aerobic training may have preserved function, reduced the inflammatory response of the spleen, and marginally rescued muscle mass possibly through activation of mTOR. Aerobic training may therefore have therapeutic value for patients with cancer cachexia. In contrast, resistance training induced the expression of genes associated with muscle damage and repair. This gene response may be supportive of excessive stress generated by high resistance loading in a tumor-bearing state.

Oxidative stress and inflammation are central to the development of a number of chronic diseases including cardiovascular disease and previous research suggests that blueberry consumption may attenuate these processes. The present study investigated the effects of blueberries on blood biomarkers of oxidative stress, inflammation, and antioxidant defense in postmenopausal women with pre- and stage 1-hypertension. In a randomized, parallel-arm, double-blind, placebo-controlled clinical trial, 40 pre- and stage 1-hypertensive postmenopausal women aged 45 to 65 years were randomly assigned to receive 22 g freeze-dried highbush blueberry powder per day (Blueberry) or 22 g placebo powder per day (Control) for 8 weeks. A blood biomarker of oxidative DNA damage, 8-hydroxy-2'-deoxyguanosine (8-OHdG), as well as blood biomarkers of oxidative stress, inflammation, and antioxidant defense were assessed at baseline, 4 and 8 weeks. 8-OHdG levels were significantly (P = 0.008) lower in Blueberry compared to Control at 4 weeks with a significant time-by-treatment interaction (P = 0.04). Levels were not different between groups at 8 weeks. Other biomarkers measured were not affected by blueberry consumption. Daily consumption of blueberries for 4 weeks, but not 8 weeks, attenuated a biomarker of oxidative DNA damage in pre- and stage 1-hypertensive postmenopausal women. Future clinical studies should directly evaluate the effects of blueberry consumption on oxidative stress, inflammation, and antioxidant defense at the cellular level and in the vasculature in this population.