Mushtaq Ahmed

Oxidative stress versus antioxidant defenses in patients with acute myocardial infarction

Acute myocardial infarction (AMI) is a highly dynamic event, which is associated with increasing production of reactive oxygen species (ROS). The imbalance between ROS production and antioxidant defenses leads to the condition known as oxidative stress. The most widely recognized effect of increasing oxidative stress is the oxidation and damage of macromolecules, membranes, proteins, and DNA. Therefore, in this study we sought to evaluate oxidative stress and antioxidant defenses in patients with AMI. Lipid peroxidation, protein carbonyl levels, and enzymatic and nonenzymatic antioxidants were assessed in samples obtained from 40 AMI patients and 40 control patients. AMI was characterized by clinical, electrocardiographic, and laboratory criteria. The control group was divided into two groups of 20 patients: a control group with healthy patients and a risk group. Our results demonstrated an increase in substances reactive to thiobarbituric acid (TBARS) and carbonyl protein levels in the AMI and risk groups. In addition, a positive correlation was found between TBARS, carbonyl protein levels, and troponin I in AMI patients. Surprisingly, for the enzymatic antioxidant defenses, catalase and superoxide dismutase, we observed an increase in these parameters in the AMI and risk groups when compared with healthy patients. However, a decrease in nonenzymatic antioxidants such as vitamin C and vitamin E was observed in AMI patients when compared with the healthy group and the risk group. The increase in oxidative stress was probably a result of the elevation in ROS production due to the ischemic/reperfusion event that occurs in AMI, in addition to the decrease of nonenzymatic antioxidant defenses.

Activity of ectonucleotidases and adenosine deaminase in rats exposed to cigarette smoke

Cigarette smoke is a complex mixture of various toxic substances that are capable of initiating oxidative damage and promoting blood platelet alterations. In this study, we investigated the activities of the ectoenzymes NTPDase (ectonucleoside triphosphate diphosphohydrolase, CD39) and 5′-nucleotidase (CD73) in platelets as well as adenosine deaminase (ADA) in the plasma of rats exposed to aged and diluted sidestream smoke during 4 weeks. The rats were divided into two groups: I (control) and II (exposed to smoke). After the exposure period, blood was collected and the platelets and plasma were separated for enzymatic assay. The results demonstrated that NTPDase (with ATP as substrate) and 5′-nucleotidase (AMP as substrate) activities were significantly higher in group II (pu2009<u20090.05) as compared to group I, while no significant difference was observed for NTPDase with ADP as substrate. The ADA activity was significantly reduced in group II (pu2009<u20090.05) as compared with group I. Platelet aggregation was significantly increased in group II (pu2009<u20090.05) as compared with group I. We suggest that these alterations in the activity of enzymes from the purinergic system are associated with an increase in platelet aggregation. However, our study has demonstrated that the organism tries to compensate for this enhanced aggregation by increasing hydrolysis of AMP and reducing hydrolysis of adenosine, a potent inhibitor of aggregation and an important modulator of vascular tone.

Effects of acidosis and Fe (II) on lipid peroxidation in phospholipid extract: Comparative effect of diphenyl diselenide and ebselen

The influence of acidosis on lipid peroxidation in phospholipids extract from egg yolk was studied. In addition, we have also tested the effect of pH on the anti-oxidant properties of diphenyl diselenide and ebselen. Acidosis increased rate of lipid peroxidation both in the absence and presence of Fe (II). Diphenyl diselenide significantly protected TBARS production at all studied pH values while ebselen offered only a small statistically non-significant protection. However, changing the pH of the reaction medium did not alter the anti-oxidant activity of the tested compounds. This study provides in vitro evidence for acidosis-induced oxidative stress in phospholipids extract and anti-oxidant action of diphenyl diselenide.

Nutritional investigation and biological activities of Parthenium hysterophorus

Parthenium hysterophorusxa0is used as a vegetable and in the treatment of various human ailments traditionally in Pakistan. The current study was arranged to investigate the nutritional importance, microbial inhibition and its potency against free radicals. The results revealed that extract possesses macro elements Ca, K, Na, Mg, Fe, Zn, as well as micro elements including Ni, Li, Pb, Co, Mn, Cu, Cr, and Cd. Scavenging of free radicals revealed that methanolic extract ofxa0P. hysterophorusxa0(PM) possesses lowest IC50 (2.5 ± 0.05 μg/ml) comparatively to ascorbic acid (3.7 ± 0.03) and n-hexane extract ofxa0P. hysterophorusxa0(PH) (5.1 ± 0.07 μg/ml). The extracts also showed maximum antibacterial potential in various concentrations of n-hexane and methanolic extract ofxa0P. hysterophorus. The results revealed thatxa0P. hysterophorusxa0contain a remarkable fungal inhibition due to the presence of bioactive constituents. Based on this screening various fractions ofxa0P. hysterophorusxa0are recommended for future bioassay guided isolation of bioactive constituents. n n xa0 n n Key words:xa0Parthenium hysterophorus, nutritional analysis, antimicrobial activity, 1,1-diphenyl 1-2-picryl-hydrazyl (DPPH).

Phytotoxic and antibacterial assays of crude methanolic extract of Mentha longifolia (Linn.)

Mentha longifoliaxa0(Horse Mint; syn.xa0M. sylvestrisxa0L.) is a well known species in the genusMenthaxa0(mint) widely applied in medicine as a constituent of various drugs, and is often used in aromatherapy. The current study was designed to investigate the antibacterial and phytotoxic capacity of methanolic extract ofxa0M. longifolia.xa0Five hundred gram of shade dried whole plant in powdered form was subjected to extract in methanol, which yielded approximately 80 g of plant extract. The extract was evaluated forxa0in vitroxa0bioassay including antibacterial activity againstStaphylococcus aureus, Micrococcus luteus, Escherichia colixa0andxa0Pseudomonas aeruginosa,through agar well diffusion technique. The herbicidal potency of the extract was also evaluated by phytotoxic assay in two modes. The extract showed maximum antibacterial potential in various concentrations, and also showed a significant inhibition in growth of shoot and root in both modes of phytotoxic assay, that is, plate and field study might be due to the presence of bioactive constituents in extract. n n xa0 n n Key words:xa0Mentha longifolia, antibacterial, methanolic extract, phytotoxic assay.

Phytochemical, antioxidant and cytotoxic activities of Periploca aphyla and Mentha longifolia, selected medicinal plants of District Bannu, Pakistan

Mentha longifoliaxa0andxa0Periphloca aphylaxa0are a well known species widely applied in medicine as a constituent of various drugs, and are very liked in aromatherapy. The current study was desighned to investigate the phytochemical screening, cytotoxic and antioxidant capacity of methanolic extract ofxa0Mentha longifoliaxa0andxa0Periphloca aphyla.xa0The methanolic extract ofMentha longifoliaxa0via qualitative analysis revealed the presence of terpenoids, saponins and flavonoids while anthraquinones, coumarins, cardiac glycosides, tannins, and phlobtannins remained absent. The extract also showed maximum free radical scavenging and cytotoxic potential in various concentrations inxa0Mentha longifoliaxa0andxa0Periphloca aphyla. The results revealed that methanolic extract of these plants contain a remarkable antioxidant and cytotoxic activity due the presence of bioactive constituents. n n xa0 n n Key words:xa0Antioxidant, cytotoxic,xa0Mentha longifolia,xa0phytochemical screening.

Comparative study of the inhibitory effect of antidepressants on cholinesterase activity in Bungarus sindanus (krait) venom, human serum and rat striatum

Cholinesterases are divided into two classes based on differences in their substrate specificity and tissue distribution: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). These enzymes may be inhibited by several compounds, such as antidepressants. The antidepressants paroxetine, imipramine, clomipramine and sertraline inhibited both venom AChE as well as human serum BChE in a concentration-dependent manner but had no effect on AChE in the rat brain striatum. The IC50 of venom calculated for imipramine was 0.3 mM, paroxetine 0.38 mM, clomipramine 0.34 mM and sertraline 0.35 mM. Analysis of kinetic data indicated that the inhibition caused by sertraline and paroxetine was mixed, i.e. Km values increased and Vmax decreased in a concentration dependent manner. Imipramine and clomipramine exhibited competitive inhibition, i.e. Km values increased and Vmax remained constant. The present results suggest that these therapeutic agents used for depression can also be considered as inhibitors of snake venom and human serum cholinesterase.

Protective effects of Trifolium alexandrinum L. against lung injury induced by environmental toxin CCl4 in experimental rats

Background In Pakistan numerous medicinal floras has used in the treatment of various human ailments. Among them Trifolium alexandrinum L. is traditionally used in the curing of disease. Presently we designed to ascertain the protective role of Trifolium alexandrinum methanolic extracts (TAME) against carbon tetrachloride (CCl4)-induced lung injury and oxidative stress in rats. Methods Exposure to CCl4 induces oxidative stress and causes tissue damage by the induction of CCl4 free radicals. Twenty-four male albino rats were divided equally into four groups. Rats in group I had free access to drinking water and laboratory food. Group II was treated with 1 ml/kg body weight (b.w.) CCl4 (30% in olive oil). Groups III and IV rats were fed (p.o.) 200 mg/kg b.w. TAME and 50 mg/kg b.w. silymarin after 24 h of CCl4 treatment for 2 weeks. Results Administration of CCl4 caused a significant (p<0.01) decrease in the activities of antioxidant enzymes (catalase, peroxidase, glutathione peroxidase, glutathione-S-transferase), and glutathione contents were decreased; however, thiobarbituric acid-reactive substances were increased (p<0.01). The alterations caused by CCl4 were significantly (p<0.01) reversed toward control levels by supplementation of TAME and silymarin. Conclusion These results suggest that in rats TAME and silymarin could protect the lungs against CCl4-induced oxidative damage.

Toxicological effect of N, N, N', N'-tetramethylethylene on rat brain acetylcholinesterase.

N, N, N′, N′-tetramethylethylenediamine (TEMED) is extensively used for initiating polymerization of acrylamide and bisacrylamide gel for electrophoresis and for inorganic complex structure formation. The present study evaluates the toxicological effect of TEMED on structures of rat brain acetylcholinesterase (AChE) activity. In vitro study showed that the Ki values for striatum, cortex, cerebellum and hypothalamus were found to be 1.24, 1.4, 1.45 and 1.47 mM. Kinetics studies indicated that TEMED caused mixed type of inhibition that is a combination of competitive and noncompetitive inhibition in striatum, cortex, hypothalamus and cerebellum. The result showed that km increased and V max decreased with increase in TEMED concentration. The IC50 values calculated for striatum, cortex, cerebellum and hypothalamus were found to be as 0.92, 0.92, 1.44 and 1.42 mM. The present study indicates that TEMED is a toxicant for brain via inhibition of AChE. Therefore, proper precaution should be made during its handling.