Antioxidant activity of extract from Polygonum aviculare L

Free radicals induce numerous diseases by lipid peroxidation, protein peroxidation, and DNA damage. It has been reported that numerous plant extracts have antioxidant activities to scavenge free radicals. Whether Polygonum aviculare L. (Polygonaceae) has antioxidant activity is unknown. In this study, dried Polygonum aviculare L. was extracted by ethanol, and the extract was lyophilized. The antioxidant activities of extract powder were examined by free radical scavenging assays, superoxide radical scavenging assays, lipid peroxidation assays and hydroxyl radical-induced DNA strand scission assays. The results show that the IC50 value of Polygonum aviculare L. extract is 50 µg/ml in free radical scavenging assays, 0.8 µg/ml in superoxide radical scavenging assays, and 15 µg/ml in lipid peroxidation assays, respectively. Furthermore, Polygonum aviculare L. extract has DNA protective effect in hydroxyl radical-induced DNA strand scission assays. The total phenolics and flavonoid content of extract is 677.4 ± 62.7 µg/g and 112.7 ± 13 µg/g. The results indicate that Polygonum aviculare L. extract clearly has antioxidant effects.

Carrier screening and prenatal detection of chronic granulomatous disease in Iran

To develop an application that is simple and reliable using the nitroblue tetrazolium [NBT] method that clearly differentiates chronic granulomatous disease [CGD] patients with heterozygous carriers in groups suspected with CGD. This study was carried out in Shiraz University of Medical Sciences from October 2002 and March 2004. The study included 260 samples consisting of 123 children [2-24 months] and 106 neonates [<2 months], either suspected with bacterial infection or are immunodeficient, and 31 cord blood samples. Fifty healthy adult individuals were also diagnosed as normal control. Neutrophil reduction of NBT can be stimulated in vitro by protein kinase agonists such as phorbol myristate acetate [PMA], resulting to superoxide anion release. The PMA is an exceptionally powerful stimulant and when we used it in conjunction with adherence of glass slides, it causes transformation of nearly 100% of all normal neutrophils, and reduces NBT to formazan deposits. Of 260 blood samples, 12 unrelated CGD patients and 16 carriers of X-linked or autosomal recessive CGD patients were diagnosed. The carriers had a range of 15-75% stimulated neutrophils. We have established a PMA-stimulated NBT test for the detection of CGD patients, which clearly differentiate the CGD patients from heterozygote carriers. The results in the cord fetal blood samples indicate that this test may be used for antenatal diagnosis of affected boys, carrier females and autosomal recessive variants of CGD. The technique is simple, fast, inexpensive, and requires only a few microliters of blood

Mechanism, measurement, and prevention of oxidative stress in male reproductive physiology.

Numerous factors influence male fertility. Among these factors is oxidative stress (OS), which has elicited an enormous interest in researchers in recent period. Reactive oxygen species (ROS) are continuously produced by various metabolic and physiologic processes. OS occurs when the delicate balance between the production of ROS and the inherent antioxidant capacity of the organism is distorted. Spermatozoa are particularly sensitive to ROS as their plasma membrane contains polyunsaturated fatty acids (PUFA), which oxidizes easily. They also lack cytoplasm to generate a robust preventive and repair mechanism against ROS. The transition metal ions that are found in the body have a catalytic effect in the generation of ROS. Lifestyle behaviours such as smoking and alcohol use and environmental pollution further enhance the generation of ROS and thus, cause destructive effects on various cellular organelles like mitochondria, sperm DNA etc. This article analyzes the detrimental effects of OS on male fertility, measurement of OS and effective ways to decrease or eliminate them completely. We have also provided information on oxidative stress in other systems of the body, which may be applied to future research in the field of reproductive biology.

The effects of oxygen radicals on the activity of nitric oxide synthase and guanylate cyclase

Reactive oxygen species such as superoxides, hydrogen peroxide (H2O2) and hydroxyl radicals have been suggested to be involved in the catalytic action of nitric oxide synthase (NOS) to produce NO from L-arginine. An examination was conducted on the effects of oxygen radical scavengers and oxygen radical-generating systems on the activity of neuronal NOS and guanylate cyclase (GC) in rat brains and NOS from the activated murine macrophage cell line J774. Catalase and superoxide dismutase (SOD) showed no significant effects on NOS or GC activity. Nitroblue tetrazolium (NBT, known as a superoxide radical scavenger) and peroxidase (POD) inhibited NOS, but their inhibitory actions were removed by increasing the concentration of arginine or NADPH respectively, in the reaction mixture. NOS and NO-dependent GC were inactivated by ascorbate/FeSO4 (a metal-catalyzed oxidation system), 2'2'-azobis-amidinopropane (a peroxy radical producer), and xanthine/xanthine oxidase (a superoxide generating system). The effects of oxygen radicals or antioxidants on the two isoforms of NOS were almost similar. However, H2O2 activated GC in a dose-dependent manner from 100 microM to 1 mM without significant effects on NOS. H2O2-induced GC activation was blocked by catalase. These results suggested that oxygen radicals inhibited NOS and GC, but H2O2 could activate GC directly.