Mohammad Shahriar

Evaluation of in vitro antioxidant activity of bark extracts of Terminalia arjuna

To uncover the antioxidant and free radical scavenging activity, five different extracts of Terminalia arjuna bark were examined. In the present study, the free radical scavenging potential of five extracts of the bark of Terminalia arjuna was assessed by measuring its capability for scavenging 2, 2-diphenyl-1picrylhydrazyl (DPPH) radical, hydrogen peroxide radical, nitric oxide radicals (NO), as well as its ability in reducing power capacity assessment, cupric reducing antioxidant capacity, using appropriate assay systems compared to natural and synthetic antioxidants. Total antioxidant capacity, phenolic and flavonoid contents were determined spectrophotometrically. In DPPH free radical scavenging activity, the highest IC 50 value was showed by methanol extract with a value of 6.34 µg/ml followed by ethanol and petroleum ether having value of 7.76 and 25.63, respectively, as opposed to that of the scavenging effects of ascorbic acid and butylated hydroxytoluene (BHT) of 5.698 and 8.816, respectively. Methanol extract showed highest activity having IC 50 value of 14.436 and 25.184 µg/ml in hydrogen peroxide and nitric oxide scavenging assay, respectively. All the five fractions showed good reducing power and cupric reducing capacity with increasing concentration again taking methanol extract to the top position. The methanol extract yielded 817.488 ± 8.108 mg/g gallic acid equivalent phenolic content and 199.122 ± 8.282 mg/g Quercetin equivalent flavonoid content that was highest among five extracts. Methanol extract of T. arjuna was found to possess the highest total antioxidant capacity (415.925 ± 2.291) followed by ethanol (377.675 ± 1.889) mg/g Ascorbic Acid Equivalent, respectively. A linear correlation appeared between the total antioxidant capacity and the total phenolic contents of the extracts with good correlation coefficient (R 2 = 0.891). n-Hexane and chloroform extract showed least

Phytochemical screenings, thrombolytic activity and antimicrobial properties of the bark extracts of Averrhoa bilimbi

Article history: Received on: 05/02/2013 Revised on: 21/02/2013 Accepted on: 01/03/2013 Available online: 30/03/2013 In this present study, the bark extracts of Averrhoa bilimbi were subjected to the thrombolytic activities were assessed by using human erythrocyte and the results were compared with standard streptokinase (SK). On the other hand, bark extracts of A. bilimbi revealed moderate antibacterial activity against some microorganisms used in the screening. Preliminary phytochemical investigation suggested the presence of flavonoids, saponins and alkaloids.

The Effect of Chronic Alprazolam Intake on Memory, Attention, and Psychomotor Performance in Healthy Human Male Volunteers

Alprazolam is used as an anxiolytic drug for generalized anxiety disorder and it has been reported to produce sedation and anterograde amnesia. In the current study, we randomly divided 26 healthy male volunteers into two groups: one group taking alprazolam 0.5 mg and the other taking placebo daily for two weeks. We utilized the Cambridge Neuropsychological Test Automated Battery (CANTAB) software to assess the chronic effect of alprazolam. We selected Paired Associates Learning (PAL) and Delayed Matching to Sample (DMS) tests for memory, Rapid Visual Information Processing (RVP) for attention, and Choice Reaction Time (CRT) for psychomotor performance twice: before starting the treatment and after the completion of the treatment. We found statistically significant impairment of visual memory in one parameter of PAL and three parameters of DMS in alprazolam group. The PAL mean trial to success and total correct matching in 0-second delay, 4-second delay, and all delay situation of DMS were impaired in alprazolam group. RVP total hits after two weeks of alprazolam treatment were improved in alprazolam group. But such differences were not observed in placebo group. In our study, we found that chronic administration of alprazolam affects memory but attentive and psychomotor performance remained unaffected.

Allium sativum L. Improves Visual Memory and Attention in Healthy Human Volunteers.

Studies have shown that Allium sativum L. (AS) protects amyloid-beta peptide-induced apoptosis, prevents oxidative insults to neurons and synapses, and thus prevent Alzheimers disease progression in experimental animals. However, there is no experimental evidence in human regarding its putative role in memory and cognition. We have studied the effect of AS consumption by healthy human volunteers on visual memory, verbal memory, attention, and executive function in comparison to control subjects taking placebo. The study was conducted over five weeks and twenty volunteers of both genders were recruited and divided randomly into two groups: A (AS) and B (placebo). Both groups participated in the 6 computerized neuropsychological tests of the Cambridge Neuropsychological Test Automated Battery (CANTAB) twice: at the beginning and after five weeks of the study. We found statistically significant difference (p < 0.05) in several parameters of visual memory and attention due to AS ingestion. We also found statistically nonsignificant (p > 0.05) beneficial effects on verbal memory and executive function within a short period of time among the volunteers. Study for a longer period of time with patients suffering from neurodegenerative diseases might yield more relevant results regarding the potential therapeutic role of AS.

Exploration of Analgesic Activity of the Ethanolic Extract of Erythrina variegate Bark

The aim of this study was to evaluate analgesic activity of the ethanolic extract of the bark of Erythrina variegata . The analgesic potential of the extract was evaluated using acetic acid-induced writhing test for peripheral analgesic activity and tail immersion, hot plate, formalin and glutamate test at 50, 100, and 200 mg/kg body weight doses. In analgesic activity tests, the extract at the doses of 50, 100, and 200 mg/kg b.w. produced a remarkable increase in pain threshold in a dose dependent manner. In acetic acid induced writhing test, the inhibitory effect was to be parallel to the reference drug diclofenac sodium. The extract showed 18.89% writhing inhibitory effect at the dose 200 mg/kg b.w., whereas diclofenac sodium showed 79.42% inhibition of writhing at a dose of 10 mg/kg b.w. The results of tail immersion and hot plate test also showed potential analgesic activity of the extract which is also comparable to the standard drug morphine (5 mg/kg b.w.). In formalin test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 47.80% inhibitory effect in late phase, whereas the reference drug morphine showed 63.64% inhibitory effect on licking of the hind paw. In glutamate test, the bark extract at doses 200 mg/kg b.w. were found to exhibit the highest 68.07% inhibitory effect in late phase, whereas the reference drug diclofenac sodium showed 61.53% inhibitory effect on licking of the hind paw. In conclusion, it can be said that the plant part have potential analgesic activity and may be used to relief pain.

Study of Antinociceptive, Antipyretic and Neuropharmacological Activities of Leaf Extracts of Citrus assamensis

The present study was executed to explore in vivo antinociceptive, antipyretic and neuropharmacological activities of different leaf extracts of Citrus assamensis in Swiss albino mice. C. assamensis leaf extract displayed marked dose dependent antinociceptive potential in the five pain models. All leaf extracts except chloroform (200 mg/kg body weight) extract, produced significant (**p<0.01, ***p<0.001) antinociception against thermal induced pain stimuli in mice at various time points of post treatment in hot plate study compared to the control group. In acetic acid induced writhing assay, methanol (100 mg/kg body weight) and chloroform (200 mg/kg body weight) extracts showed significant (*p<0.01) result. In tail immersion test, basal reaction time was found significant (*p<0.01) in case of ethanol (100 mg/kg body weight) and chloroform (200 mg/kg body weight) extracts compared against control. Both the doses of all the extracts exhibited significant (***p<0.001) activity in formalin induced paw licking as well as percent inhibition of glutamate induced writhing study. Both the doses of methanol and ethanol extracts showed significant (*p<0.05) results in decreasing in rectal temperature after 1 hr. Higher doses of all the extracts showed significant (*p<0.05) decrease in duration of immobility in foreed swimming test (FST). The higher dose of ethanol extract (200 mg/kg body weight) significantly (*p<0.05) decreased the rate of movement with time in open field test. The test samples displayed marked antinociceptive potential in all the test procedures and also displayed marked antipyretic and neuropharmacological activities at different test doses.

Comparative In Vitro Equivalence Evaluation of Some Loratadine Generic Tablets Marketed in Bangladesh

Loratadine is a potent, rapidly effective and long-acting non-sedative, histamine H1 receptor antagonist, with anti-allergic properties. The purpose of this research work was to evaluate the pharmaceutical equivalent of six different brands of loratadine 10 mg tablets using various pharmacopoeial and nonpharmacopoeial tests with special landmark on in vitro dissolution study and with different price ranges purchased from retail pharmacies of Bangladesh. All brands complied with the official specification for friability, uniformity of weight and disintegration time but four brands did not comply with the official specification for hardness. Assay of loratadine tablets revealed that all samples contained 86.65-95.02% of labeled potency. Drug release was satisfactory for all brands, since more than 96.76% of the loratadine was dissolved in the medium within an hour of the test. The dissolution profiles were compared with the use of model independent approaches of difference factor and similarity factor, showing that all brands are similar with brand L3 and can be used interchangeably.

Evaluation of In vitro Antioxidant and In vivo Pharmacological Activity of Leaf Extracts of Hoya parasitica (Wall.)

In present study, leaf extract of Hoya parasitica Wall. was evaluated for in vitro antioxidant and membrane stabilizing activity along with in vivo gastro intestinal motility and acute toxicity. Five different assays were performed to evaluate antioxidant activity. In DPPH free radical scavenging activity, methanol, ethanol and chloroform extract exhibited IC50 value similar to standard ascorbic acid. The presence of flavonoid and phenolic contents was also similar in all the plant extracts. However, chloroform extract showed remarkable reducing power capacity (69.10% at 200µg/mL). In case of membrane stabilization, the chloroform extract showed maximum inhibition (32.62 %) of haemolysis, whereas the ethanol extract showed a significant (p

GENOMIC DNA EXTRACTION METHODS: A COMPARATIVE CASE STUDY WITH GRAM-NEGATIVE ORGANISMS

The cell wall structure of gram-negative bacteria is more complex than that of gram-positive bacteria because of the presence of two layers external to the cytoplasmic membrane. Purpose of this study is to compare the four different methods for genomic DNA extraction from three gram negative strains-Escherichia coli, Klebsiella species, and Salmonella typhi. The genomic DNA was extracted from gram-negative bacteria cultures using enzymatic lysis with Proteinase-K, chemical lysis with cetyl trimethyl ammonium bromide (CTAB), physical lysis with Triton X-100 and Beads beating methods. The yield and quality of DNA were compared by spectrophotometry and agarose gel electrophoresis. The genomic DNA purity ratio was found within 1.1-1.9 for all four methods. This study revealed that the chemical lysis with CTAB was the most efficient method for extracting genomic DNA from gram negative strains. In terms of chemical lysis with CTAB for Salmonella typhi and Klebsiella species the highest purity ratio were 1.9 and 1.8 respectively. However Escherichia coli also showed the highest purity ratio (1.7) for CTAB extraction. Enzymatic lysis with Proteinase-K was also very effective and purity ratio for Salmonella typhi and Klebsiella species were 1.8 and 1.7 respectively.