Critical Review on the Analytical Mechanistic Steps in the Evaluation of Antioxidant Activity.

Electrophysiological systems are prone to release free radicals for functioning of biological system with proper balancing of antioxidant-prooxidant ratio for establishing a healthy living system. The biostress condition releases different reactive oxygen species, such as hydroxyl, alkoxyl, superoxide, hydrogen peroxide, hydroperoxyl, ozone, singlet oxygen, hypochlorus acid, thiyl radical, etc. This review tries to discuss the general aspects of the antioxidant assay methodologies that are currently used for the detection of antioxidant property. The entire review has been divided into three different sections. The first deals with the release of free radical by mitochondrial dysfuctioning and its curbing action by local antioxidants. The second and third sections discuss the general procedure adopted and reaction mechanism involved in the assay procedure along with the limitations and advantages.

Simple spectrophotometric and titrimetric methods for the determination of sulfur dioxide.

The proposed work describes a simple spectrophotmetric as well as a titrimetric method to determine sulfur dioxide. The spectrophotometric method is based on a redox reaction between sulfur dioxide and iodine monochloride obtained from iodine with chloramine-T in acetic acid. The reagent iodine monochloride oxidizes sulfur dioxide to sulfate, thereby reducing itself to iodine. Thus liberated iodine will also oxidize sulfur dioxide and reduce itself to iodide. The obtained iodide is expected to combine with iodine to form a brown-colored homoatomictriiodide anion (460 nm), which forms an ion-pair with the sulfonamide cation, providing exceptional color stability to the system under an acidic condition, and is quantitatively relatd to sulfur dioxide. The system obeys Beer's law in the range 5 - 100 microg of sulfur dioxide in a final volume of 10 ml. The molar absorptivity is 5.03 x 10(3) l mol(-1)cm(-1), with a relative standard deviation of 3.2% for 50 microg of sulfur dioxide (n = 10). In the titrimetric method, the reagent iodine monochloride was reduced with potassium iodide (10%) to iodine, which oxidized sulfur dioxide to sulfate, and excess iodine was determined with a thiosulfate solution. The volume difference of thiosulfate with the reagent and with the sulfur dioxide determined the sulfur dioxide. Reproducible and accurate results were obtained in the range of 0.1 - 1.5 mg of sulfur dioxide with a relative standard deviation of 1.2% for 0.8 mg of sulfur dioxide (n = 10).

Antioxidant and antimicrobial properties of phenolic rich fraction of Seabuckthorn (Hippophae rhamnoides L.) leaves in vitro.

Phenolic rich fraction (PRF) from Seabuckthorn leaves was prepared by sequential fractionation. Total phenolic content of PRF estimated as gallic acid equivalent was found to be 319.33±7.02 mg/g of PRF. Its major constituents gallic acid, rutin, quercetin-3-galactoside, quercetin-3-glucoside, myricetin, quercetin, kaempferol and isorhamnetin, were found in the range of 1.551-196.89 mg/g of PRF as determined by RP-HPLC. Antioxidant activity of PRF evaluated using 2,2-diphenyl-2-picrylhydrazyl, superoxide and nitric oxide scavenging assays. Reducing power of PRF increased with increasing amount of PRF; the equation of reducing power (y) and amount of PRF (x) was y=8.004x (r(2)=0.99), indicating that reducing ability correlated well with amount of PRF. Antibacterial activity of PRF, tested against certain medically important bacterial species showed growth inhibiting effect against Escherichia coli, Salmonella typhi, Shigella dysenteriae, Streptococcus pneumoniae and Staphylococcus aureus. In conclusion, PRF has potent antioxidant and broad spectrum antibacterial properties.

Valeriana wallichii root extract improves sleep quality and modulates brain monoamine level in rats.

The present study was performed to investigate the effects of Valeriana wallichi (VW) aqueous root extract on sleep-wake profile and level of brain monoamines on Sprague-Dawley rats. Electrodes and transmitters were implanted to record EEG and EMG in freely moving condition and the changes were recorded telemetrically after oral administration of VW in the doses of 100, 200 and 300 mg/kg body weight. Sleep latency was decreased and duration of non-rapid eye movement (NREM) sleep was increased in a dose dependent manner. A significant decrease of sleep latency and duration of wakefulness were observed with VW at doses of 200 and 300 mg/kg. Duration of NREM sleep as well as duration of total sleep was increased significantly after treatment with VW at the doses of 200 and 300 mg/kg. VW also increased EEG slow wave activity during NREM sleep at the doses of 200 and 300 mg/kg. Level of norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC), serotonin (5-HT) and hydroxy indole acetic acid (HIAA) were measured in frontal cortex and brain stem after VW treatment at the dose of 200mg/kg. NE and 5HT level were decreased significantly in both frontal cortex and brain stem. DA and HIAA level significantly decreased only in cortex. DOPAC level was not changed in any brain region studied. In conclusion it can be said that VW water extract has a sleep quality improving effect which may be dependent upon levels of monoamines in cortex and brainstem.

Antioxidant and hepatoprotective activities of phenolic rich fraction of Seabuckthorn (Hippophae rhamnoides L.) leaves.

Present study was aimed to investigate antioxidant and hepatoprotective activities of phenolic rich fraction (PRF) of Seabuckthorn leaves on CCl(4) induced oxidative stress in Sprague Dawley rats. Total phenolic content was found to be 319.33 mg gallic acid equivalent (GAE)/g PRF and some of its phenolic constituents, such as gallic acid, myricetin, quercetin, kaempferol and isorhamnetin were found to be in the range of 1.935-196.89 mg/g of PRF as determined by reverse-phase high-performance liquid chromatography (RP-HPLC). Oral administration of PRF at dose of 25-75 mg/kg body weight significantly protected from CCl(4) induced elevation in aspartate aminotransferase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT) and bilirubin in serum, elevation in hepatic lipid peroxidation, hydroperoxides, protein carbonyls, depletion of hepatic reduced glutathione (GSH) and decrease in the activities of hepatic antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR) and glutathione-S-transferase (GST). The PRF also protected against histopathological changes produced by CCl(4) such as hepatocytic necrosis, fatty changes, vacuolation, etc. The data obtained in the present study suggests that PRF has potent antioxidant activity, prevent oxidative damage to major biomolecules and afford significant protection against CCl(4) induced oxidative damage in the liver.