NISCAIR Online Periodicals Repository Collection: IJBB Vol.47(2) [April 2010]

Propoxur-induced acetylcholine esterase inhibition and impairment of cognitive function: Attenuation by Withania somnifera

Mon, 29 Mar 2010 22:58:59 GMT

Title: Propoxur-induced acetylcholine esterase inhibition and impairment of cognitive function: Attenuation by Withania somnifera

Authors: Yadav, C S; Kumar, V; Suke, S G; Ahmed, R S; Mediratta, P K; Banerjee, B D

Abstract: Propoxur (2-isopropoxyphenyl N-methylcarbamate) is widely used as an acaricide in agriculture and public health programs. Studies have shown that sub-chronic exposure to propoxur can cause oxidative stress and immuno-suppression in rats. Carbamates are also known to exhibit inhibitory effect on cholinesterase activity, which is directly related to their cholinergic effects. In the present study, the effect of Withania somnifera (Ashwagandha), a widely used herbal drug possessing anti-stress and immuno-modulatory properties was studied on propoxur-induced acetylcholine esterase inhibition and impairment of cognitive function in rats. Male Wistar rats were divided into four groups. Group I was treated with olive oil and served as control. Group II was administered orally with propoxur (10 mg/kg b.wt.) in olive oil, group III received a combination of propoxur (10 mg/kg b.wt.) and W. somnifera (100 mg/kg b.wt.) suspension and group IV W. somnifera (100 mg/kg b.wt.) only. All animals were treated for 30 days. Cognitive behaviour was assessed by transfer latency using elevated plus maze. Blood and brain acetylcholine esterase (AChE) activity was also assessed. Oral administration of propoxur (10 mg/kg b.wt.) resulted in a significant reduction of brain and blood AChE activity. A significant prolongation of the acquisition as well as retention transfer latency was observed in propoxur-treated rats. Oral treatment of W. somnifera exerts protective effect and attenuates AChE inhibition and cognitive impairment caused by sub-chronic exposure to propoxur.

Page(s): 117-120

Assessment of free radical-mediated damage in head and neck squamous cell carcinoma patients and after treatment with radiotherapy

Mon, 29 Mar 2010 22:58:59 GMT

Title: Assessment of free radical-mediated damage in head and neck squamous cell carcinoma patients and after treatment with radiotherapy

Authors: Gupta, Aashita; Bhatt, M L B; Misra, M K

Abstract: Reactive oxygen species (ROS) produced as a part of cellular metabolism can interact with biological macromolecules such as DNA, proteins and lipids and interfere with their normal functions, leading to the loss of cellular viability. ROS have been implicated in many pathophysiological conditions including cancer. In the present study, the damage caused by ROS and the effect of radiation in head and neck squamous cell carcinoma (HNSCC) patients were assessed in the erythrocytes by analyzing the superoxide dismutase (SOD) and catalase (CAT) activities, and levels of total thiols (T-SH) and malondialdehyde (MDA, a marker for lipid peroxidation). Blood samples were collected before the start of treatment and after the completion of radiotherapy. Both SOD and CAT activities were decreased in untreated patients, but elevated in patients after treatment. The T-SH levels were also depleted in untreated HNSCC patients, but elevated non-significantly after radiation therapy (p>0.05). The levels of MDA showed a significant increase in both untreated patients and after radiation therapy when compared with normal subjects (p<0.05). Thus, the present study indicated that the free radical-mediated damage was aggravated in untreated HNSCC patients, but the levels of antioxidants returned to baseline or nearly so after the treatment with radiation therapy.

Page(s): 96-99

Hsp90 mediates activation of the heme regulated eIF-2 kinase during oxidative stress

Mon, 29 Mar 2010 22:58:59 GMT

Title: Hsp90 mediates activation of the heme regulated eIF-2 kinase during oxidative stress

Authors: Kulkarni, A P; Mittal, S P; Devasagayam, T P A; Pal, J K

Abstract: The heme-regulated inhibitor (HRI), a member of the eIF-2 kinase family is crucial for regulating protein synthesis during stress. In addition to heme, stress proteins Hsp90 and Hsp70 are known to regulate HRI. The present study aims to determine the physical association of these Hsps in the regulation of HRI activation during oxidative stress using human K562 cells as a model. Extracts from the stress-induced cells were used for determining HRI kinase activity by measuring eIF-2 phosphorylation, and Hsp-HRI interaction by immunoprecipitation and immunoblot analyses. The results indicate a significant increase in both Hsp70 and Hsp90 expression during AAPH (2, 2’-azobis (2-amidinopropane) dihydrochloride)-induced oxidative stress. Further, their interaction with HRI, which correlates well with its increased HRI kinase activity leads to inhibition of protein synthesis. Thus, we demonstrate that Hsps play an important role in the regulation of initiation of protein synthesis during oxidative stress.

Page(s): 67-74

Antioxidant activity of acetone extract/fractions of Terminalia bellerica Roxb. fruit

Mon, 29 Mar 2010 22:58:59 GMT

Title: Antioxidant activity of acetone extract/fractions of Terminalia bellerica Roxb. fruit

Authors: Guleria, Sanjay; Tiku, A K; Rana, Subhash

Abstract: Terminalia bellerica Roxb. (Family: Combretaceae) has been valued in Indian system of medicine for treatment of wide range of diseases and reported to have antioxidant properties. In the present study, the free radical scavenging activity and antioxidant potential of acetone extract/fractions of its fruit was investigated using in vitro assays, including scavenging ability against 2,2′-diphenyl-2-picrylhydrazyl (DPPH), β-carotene bleaching inhibition, reducing power and chelating ability on Fe²⁺ ions. The fruit powder was extracted at room temperature with different solvents in the order of increasing and decreasing polarity to obtain crude acetone extract which was further partitioned with ethyl acetate and water (1:1). It was found that ethyl acetate fraction was more effective than crude acetone extract in all antioxidant assays, except chelating power which was highest in water fraction. Maximum antioxidant activities (expressed as EC₅₀values) observed were 14.56 μg/ml, 27.81 μg/ml and 67.8 μg/ml in DPPH, β-carotene bleaching and reducing power assays, respectively. The antioxidant potential was compared with known antioxidant (butylated hydroxyl toluene) and correlated with total phenolic and flavonoid content in crude extract and fractions. Fractions rich in polyphenolic content were more effective than the crude extract.

Page(s): 110-116