Although there is evidence of the benefits of propolis on human health, the vast majority of studies have been conducted using animal models. The present study includes the chemical characterization and clinical evaluation of the effects of the oral administration of propolis solution on the oxidative status and modulation of lipids in a human population in Talca, Chile. Chemical characterization of propolis, total phenol, flavonoids, and total antioxidant capacity were determined by ORAC. Identification of phenols and flavonoids in propolis was assessed by HPLC-DAD. A double-blind, placebo-controlled clinical trial was conducted. Subjects provided informed consent form and the Bioethics Committee of the Universidad de Talca approved protocol. Eligible subjects (n = 67) were randomized in two groups: propolis (n = 35) and placebo (n = 32). All subjects were evaluated at 0 (baseline), 45, and 90 days. In the propolis group, we observed that increases in HDL-c went from 53.9 ± 11.9 to 65.8 ± 16.7 mg/dL (p < 0.001) from baseline to 90 days. Compared to placebo subjects, consumption of propolis induced a net increase in GSH levels (p < 0.0001) and a decrease (p < 0.001) in TBARS levels for the propolis group. Our findings indicate potential benefits of propolis use in human health. The use of propolis appears to have positive effects on oxidative status and improvement of HDL-c, both of which contribute to a reduced risk of cardiovascular disease.

Oxidative stress (OxS constitutes a disturbance caused by an imbalance between the generation of free radicals and antioxidant system, which causes damage to biomolecules. This, in turn, may lead the body to the occurrence of many chronic degenerative diseases. Therefore, it is very important to know the functioning of those endogenous (and exogenous antioxidants systems to prevent such diseases. Due to evolutionary conditions in living beings, among other functions have been developed and selected defense systems against the deleterious action of free radicals. Such systems are intrinsic in cells (at level intracellular and extracellular and act together with the dietary exogenous antioxidants. "ll these antioxidant systems have very important role in preserving the oxide/reduction equilibrium in the cell. To understand the role of the transcription factor Nrf in regulating the processes of antioxidant defense, it must also know the role of many of the endogenous antioxidants that occur because of its activation. Therefore, this chapter makes a literature review of the most important general aspects of endogenous antioxidant systems, which will provide another point of view from which to approach the study and treatment of many chronic degenerative diseases, such as diabetes, hypertension, and Parkinson. Keywords: oxidative stress, endogenous antioxidants, free radicals, catalase, glutathione . IntroductionThe aerobic organisms use mitochondria as the main generator of energy for the realization of its vital functions. To do this, these organelles produce "TP through reactions of oxidation and reduction and atach to the tricarboxylic acid cycle with the electron transport chain. This happen due to to the oxidation of the food and of the N"DH and F"DH , produced in diferent metabolic pathways, such as glycolysis, -oxidation, and the same Krebs cycle. However, these reactions invariably result in the generation of reactive oxygen species (ROS compounds that are unstable by having inal layer of electrons unpaired and that, in trying to stabilize itself sequester electrons from other biomolecules, making them also destabilizes and, therefore, is no longer able to perform their duties properly, thus altering the homeostasis and, ultimately, causing cell death. Due to the current oxidant characteristics of the atmosphere on our planet, organisms are afected by imbalances in the oxidation-reduction reactions, not only on many of their metabolic reactions but also on external factors, such as microbial infections, xenobiotics, toxins from the diet, radiation, environmental pollution, and so on. "ll this in conjunction can contribute to the generation or aggravation of many diseases, such as cancer, diabetes, Parkinson and so on [ ]. Other authors theorize that this imbalance in redox reactions has worked as an evolving pressure in order to develop efective mechanisms to eliminate the oxygen toxicity; this allowed the evolution of higher forms of living organisms, which are much more specialized and protected a...

The main objective of this study was to determine if glutathione (GSH) supplementation attenuated hyperoxic lung injury. Preterm (29 days) rabbits were delivered and exposed for 24 h to 1) room air, 2) room air and GSH, 3) 95% oxygen and GSH. GSH supplements (1 mM) were delivered in the nutritional support of 10% dextrose and saline through a peritoneal catheter. Animals assigned to oxygen had decreased lung volumes at 35 cmH2O, decreased lung compliance, increased edema, decreased cell viability, and decreased lung tissue and lavage-reduced/oxidized GSH levels, compared with control animals. Despite exposure to hyperoxia, animals supplemented with GSH were not different from room air controls with respect to lung mechanics, edema, cell viability, or tissue and lavage GSH. These studies suggest that GSH supplementation maintains normal lavage and lung tissue GSH levels in preterm animals exposed to hyperoxia and attenuates the changes in lung mechanics associated with oxygen-induced lung injury.

Irradiated eggs of Anastrepha ludens were evaluated as hosts of two fruit-fly parasitoids for mass rearing. Three different ages of A. ludens eggs (24-, 48-and 72-h-old) were analyzed for hatchability after being subjected to radiation doses of 2. 5, 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5 and 30 Gy. No significant reduction in hatchability occurred with the 72-h-old eggs at any of the radiation dose levels and no adult emergence occurred at radiation doses greater than 25 Gy. Seventy two-h-old eggs irradiated above 25 Gy were found to be the best age and dose for fruit fly egg hosts to be used in mass rearing the egg parasitoid Fopius arisanus. It was demonstrated that larvae hatching from the irradiated A. ludens eggs can also be used as hosts for Diachasmimorpha longicaudata. Parasitoid emergence of both species was not statistically different from the control group (parasitoids emerged from non-irradiated host). The fecundity of parasitoids emerged from irradiated hosts also was similar to that obtained with parasitoids reared with non-irradiated hosts. There were some statistical differences between the curves for longevity. However, these were not clearly correlated with radiation dose. The results of this study will aid in the design of improved methods for mass rearing and release of fruit-fly parasitoids.

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