The validity of the free radical theory of aging has been recently questioned. Our aim was to test whether there is oxidative stress in tissues critically involved in accelerated aging (senescence-accelerated mice, SAM) and whether this correlates with lower glucose consumption in vivo and behavioural tests. Positron emission tomography shows that brains of old SAM-prone animals consume less glucose than young ones. Behavioural characteristics, mitochondrial peroxide production, and damage in both the central nervous system and bone marrow stem cells also indicate that SAM-prone animals age faster than SAM-resistant ones. Our results support the role of the free radical theory of aging in critical tissues involved in aging and that this correlates with glucose consumption.

Stable radical 1, 1-dipheny-2-picrylhydrazyl (DPPH) is widely used at in vitro models to investigate antioxidant and radical scavenging abilities of natural extracts. This work presents comparative study on DPPH radical scavenging capacity before and after UV irradiation of aqueous extract of Glycyrrhiza Glabra, a plant species belonging to the Indian flora. DPPH scavenging activities of different extract concentrations (at different incubation time intervals) were analyzed and compared by in vitro spectrophotometry and electron paramagnetic resonance (EPR) spectroscopy. 9.93% and 16.79%, DPPH scavenging activities before and after UV irradiation respectively were found by spectrophotometry. By the EPR spectroscopy study statistical significant increase in DPPH radical scavenging for the Glycyrrhiza Glabra extracts was established after UV irradiation (78.39± 0.001%) comparing to the non irradiated samples (14.02± 0.02).

Phenoxyl radical (C 6 H 5 O) was prepared photochemically in low-temperature argon matrices. The infrared absorption spectra were obtained for C 6 H 5 O and for the isotopically labeled species C 6 D 5 O and 1-13 C 12 C 5 H 5 O. All but one IR-active fundamental vibrations were detected, most of them not previously observed. Combination of results from IR linear dichroism measurements on photooriented samples, determination of absolute IR intensities with the help of internal standards, analysis of isotopic shifts, and quantum chemical predictions (B3LYP/cc-pVTZ) led to a detailed assignment of phenoxyl radical vibrations. Significant frequency shifts are observed with respect to previously reported data based on resonance Raman studies in polar solutions. For some vibrations, these shifts reflect environment-induced structural changes, such as increase of the quinoid character of the phenoxyl radical in polar media. In particular, the frequency of the CO stretching vibration, readily observable in both IR and Raman experiments, is extremely sensitive to the environment and can thus be used to probe its polarity.

Leaves of several bamboo species have been used to treat a variety of diseases for thousands of years. The medicinal effects of bamboo leaves are mostly attributed to their bioactive polyphenol constituents. However, different classes of polyphenol have different degree of solubility in various solvents, a single solvent will not fully extract all phenolic compounds, thus may exhibit varying antioxidant potency. The present study was designed to examine extractive values of leaves of Bambusa nutans and Bambusa vulgaris using chloroform, acetone and methanol successively and to evaluate the total polyphenols contents and free radical scavenging capabilities of each extract. The total phenolic content of the various extracts was determined spectrophotometrically using a modified Folin-Ciocalteu method and antioxidant efficacy by following DPPH radical scavenging protocol. The extracts were also subjected to preliminary screening for presence or absences of various phytochemical constituents. The results showed that B. nutans produced better yield of polyphenol [methanol (15.3542 ± 0.1576 mg/ml GAE/100mg extract) > acetone (11.7992 ± 0.5502 mg/ml GAE/100mg extract) > chloroform (10.1618 ± 0.3284 mg/ml GAE/100mg extract)] than corresponding solvent extracts of B. vulgaris [methanol (12.7976 ± 0.4878 mg/ml GAE/100mg extract) > acetone (10.1328 ± 0.2135 mg/ml GAE/100mg extract) > chloroform (8.8549 ± 0.1747 mg/ml GAE/100mg extract)]. The DPPH radical scavenging assay showed that methanol extracts leaves of both the Bamboo species exhibited highest TPC and radical scavenging activity whereas leaves of B. nutans found to be superior to B. vulgaris in term of TPC and radical scavenging potency. Preliminary phytochemical screening of leaf extracts of the two bamboo species indicated the presence of major classes of phytochemicals. The study evidently showed that leaves of B. nutans and B. vulgaris are rich sources of phenolic compounds and natural antixodants and they could be used as natural antioxidant. The study further indicated methanol as the appropriate extractant for better yield of polyphenols and leaf extract of Bambusa nutans is superior to that of B. vulgaris in term of TPC and antioxidant efficacy.