Hana Hammad

α2A Adrenergic Receptor Activation Inhibits Epileptiform Activity in the Rat Hippocampal CA3 Region

Norepinephrine has potent antiepileptic properties, the pharmacology of which is unclear. Under conditions in which GABAergic inhibition is blocked, norepinephrine reduces hippocampal cornu ammonis 3 (CA3) epileptiform activity through α2 adrenergic receptor (AR) activation on pyramidal cells. In this study, we investigated which α2AR subtype(s) mediates this effect. First, α2AR genomic expression patterns of 25 rat CA3 pyramidal cells were determined using real-time single-cell reverse transcription-polymerase chain reaction, demonstrating that 12 cells expressed α2AAR transcript; 3 of the 12 cells additionally expressed mRNA for α2CAR subtype and no cells possessing α2BAR mRNA. Hippocampal CA3 epileptiform activity was then examined using field potential recordings in brain slices. The selective αAR agonist 6-fluoronorepinephrine caused a reduction of CA3 epileptiform activity, as measured by decreased frequency of spontaneous epileptiform bursts. In the presence of βAR blockade, concentration-response curves for AR agonists suggest that an α2AR mediates this response, as the rank order of potency was 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK-14304) ≥ epinephrine >6-fluoronorepinephrine > norepinephrine ⋙ phenylephrine. Finally, equilibrium dissociation constants (Kb) of selective αAR antagonists were functionally determined to confirm the specific α2AR subtype inhibiting CA3 epileptiform activity. Apparent Kb values calculated for atipamezole (1.7 nM), MK-912 (4.8 nM), BRL-44408 (15 nM), yohimbine (63 nM), ARC-239 (540 nM), prazosin (4900 nM), and terazosin (5000 nM) correlated best with affinities previously determined for the α2AAR subtype (r = 0.99, slope = 1.0). These results suggest that, under conditions of impaired GABAergic inhibition, activation of α2AARs is primarily responsible for the antiepileptic actions of norepinephrine in the rat hippocampal CA3 region.

Volatile Oil Composition and Antiplatelet Activity of Jordanian Achillea biebersteinii Collected at Different Growth Stages

Abstract Achillea biebersteinii Afan. (Asteraceae) is used as a traditional medicine for healing wounds and in the treatment of abdominal pain and stomach ache. Fresh and air dried flowering parts of A. biebersteinii at different growth stages were subjected to hydro-distillation and the different essential oils obtained were analyzed by GC-MS technique. Monoterpenoids dominated the different flowering stages of both, fresh and air dried flowering parts. The fresh pre-flowering stage was dominated by monoterpene hydrocarbons (56.62 %) with α-terpinene as the major component (51.67 %). Oxygenated monoterpenes were detected as the principal constituents during both, the fresh flowering and fresh post-flowering stages (55.61 %, 56.45 %, respectively). The major representatives of this class included ascaridol (38.84 %) and iso-ascaridol (25.39 %). Oxygenated monoterpenes dominated all flowering stages of the air-dried blooms and ascaridol was the main volatile compound in these oils (28.20 %, 27.03 % and 44.39 %, respectively). The oil of the dried mature flowering blooms of A. biebersteinii exhibited dose-dependent inhibition of the platelet aggregation caused by ADP and collagen.

Biological activities of the hydro-alcoholic and aqueous extracts of Achillea falcata L. (Asteraceae) grown in Jordan.

Aim: This study aimed to screen the aqueous and hydro-alcoholic extracts of Achillea falcata L. (Asteraceae) grown in Jordan for their antioxidant, antibacterial, antiplatelet and anti-proliferative efficacy. Study Design: HPLC-MS evaluation of the aqueous and hydro-alcoholic extracts and in vitro investigations. Place and Duration of Study: Faculties of Pharmacy and Science, The University of Jordan and Centre of Misanalysis, National Institute for Biological Sciences, between August 2012 and June 2013. Methodology: Total phenols and flavonoids were determined colorimetrically. The radical Original Research Article European Journal of Medicinal Plants, 4(3): 259-270, 2014 260 scavenging activities were evaluated using 2,2′ -azino-bis-3-ethylbenzthiazoline-6sulphonic acid (ABTS) radical scavenging activity assay. Antimicrobial activities were determined by the disc-diffusion method, and the minimum inhibition concentration and the minimum bactericidal concentration tests. In vitro antiplatelet activity was tested on human whole blood using an electrical impedance method. Anti-proliferative activity was investigated using the MTT assay. High performance liquid chromatography-mass spectrometry (HPLC-MS) evaluation was performed. Results: Hydro-alcoholic extract had a bactericidal activity against Streptococcus pneumoniae, Bacillus cereus and Klebsiella pneumoniae rather than inhibitory effect. No significant activity was observed against gram negative bacteria and Candida albicans. In vitro antiplatelet activity was tested on human whole blood using an electrical impedance method. At concentrations (50, 100, and 200 μg/ml), hydro-alcoholic extract did not show effect on platelet aggregation. Extracts did not possess cytotoxic activity against the MCF7 cells at concentrations up to 200 μg/ml. HPLC-MS analysis resulted in the identification of 8 phenolic compounds in the hydro-alcoholic extract and 6 compounds in the aqueous extract; quercetin 3-β-D-glucoside was the main component for both extracts. Conclusion: The present investigation supported the traditional use A. falcata in the Jordanian folk medicine as a depurative agent and as an antimicrobial active representative of the genus Achillea.

Ligand-based computational modelling of platelet-derived growth factor beta receptor leading to new angiogenesis inhibitory leads

Platelet derived growth factor beta receptor (PDGFR- β) plays an important role in angiogenesis. PDGFR-β expression is correlated with increased vascularity and maturation of blood vessels in cancer. Pharmacophore modeling and quantitative structure-activity relationship (QSAR) analysis were combined to explore the structural requirements for ligand-PDGFR-β recognition using 107 known PDGFR-β inhibitors. Genetic function algorithm (GFA) coupled to k nearest neighbor (kNN) and multiple linear regression (MLR) analysis were employed to generate predictive QSAR models based on optimal combinations of pharmacophores and physicochemical descriptors. The successful pharmacophores were complemented with exclusion spheres to optimize their receiver operating characteristic curve (ROC) profiles. The QSAR models and their associated pharmacophore hypotheses were validated by identification and experimental evaluation of new angiogenesis inhibitory leads retrieved from the National Cancer Institute (NCI) structural database. Two hits illustrated low micromolar IC50 values in two distinct anti-angiogenesis bioassays.

Phytochemical Analysis and Evaluation of Anti-angiogenic and Antiproliferative Activities of the Leaves of Elaeagnus angustifolia L. Grown in Jordan

Elaeagnus angustifolia L. has a long history of use in ethnopharmacology. Only few studies examined the potential activities of the leaves. Furthermore, the leaves’ chemical composition was not fully investigated. In this study, the chemical composition of E. angustifolia leaves extract was analysed and major compounds were isolated and identified. Extract obtained by maceration was further extracted with solvents differing in their polarity then submitted to open column chromatography, followed by isolation of major compounds. They were analysed using UV-Vis and/or NMR. One terpene (β-sitosterol) and four flavonoids (chrysin-7-glucoside, rutin, luteolin and kaempferol) were isolated and identified. For the biological activities, leaves were extracted using ethanol, ethyl acetate, chloroform and water. Anti-angiogenic activity was studied by rat aortic ring assay. Anti-proliferative activity was studied against MCF-7 and T-47D breast cancer cell lines. Ethyl acetate extract was found cytotoxic against T-47D breast cancer cell line (IC50=23.05 μg/mL). Potent anti-angiogenic activity of ethanol-(IC50=3.039 μg/mL), ethyl acetate- (IC50=6.289 μg/mL) and water-extract (IC50=7.153 μg/mL) was reported for the first time.

Dihydrotestosterone regulates expression of CD44 via miR-328-3p in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is an aggressive subtype that lacks effective targeted therapeutics strategy and has poor prognosis. Targeting androgen receptor (AR) in TNBC is thought to be a promising approach. We hypothesized that AR, functioning as a transcription factor, controls cell behavior via regulating the expression of microRNA molecules (miRNAs). The expression of 84 breast cancer-specific miRNAs in MDA-MB-231 cells, a highly invasive TNBC model system, was investigated using PCR arrays following treatment of cells with 5α-dihydrotestosterone (DHT). The expression of 33 miRNAs was changed by more than 2 folds including miR-328-3p, which was up-regulated by 13 folds. Transfection of cells with either miR-328-3p mimic or anti-sense molecules decreased cell motility. DHT-mediated effect on the expression and function of CD44, a target of miR-328-3p, was investigated. CD44 expression and cell adhesion to hyaluronic acid (HA) were down-regulated when cells were treated with DHT or transfection with a miR-328-3p mimic. On the other hand, the AR antagonist, bicalutamide, or transfection of cells with miR-328-3p anti-sense molecules had the opposite effect. Cells transfected with miR-328-3p anti-sense molecules reduced the negative effect of DHT on CD44 expression and cell adhesion to HA. In addition, DHT further reduced the expression of CD44 and cell adhesion to HA in cells transfected with miR-328-3p mimic. These results strongly suggest that miRNAs can mediate AR regulation of breast cancer cells and that AR controls the expression of CD44 via miRNA-dependent and independent mechanisms.

Topical Anti-Inflammatory Potential of Six Salvia Species Grown in Jordan

Inflammation is a host defense mechanism to get rid of injurious stimuli and to induce tissue healing process. In Jordan, Salvia species are traditionally used to treat inflammation and other ailments. The aim of this study was to evaluate the potential of six Salvia species grown in Jordan to inhibit cutaneous inflammation. Topical anti-inflammatory activities of hexane (Hex), ethyl acetate (EtOAc) and methanol (MeOH) extracts from Salvia species aerial parts (S. ceratophylla, S. dominica, S. multicaulis, S. palaestina, S. spinosa and S. syriaca) were evaluated for the inhibition of croton oil-induced mouse ear oedema. Almost all extracts reduced oedema at the tested dose (300 µg/cm2). Hex and EtOAc extracts exhibited the best anti-inflammatory effect in a dose-dependent pattern. Dose inducing 50% oedema inhibition (ID50) in vivo was found to be in the range of 87 - 300 µg/cm2 and 47-146 µg/cm2 for Hex and EtOAc extracts, respectively. In comparison with indomethacin (ID50 96 µg/cm2), S. palaestina and S. multicaulis EtOAc extracts were two folds more potent (ID50 47 and 50 µg/cm2, respectively).Whereas, the ID50 of S. syriaca Hex extract (87µg/cm2) was comparable to that of indomethacin. In conclusion, the results illustrated that S. multicaulis, S. palaestina and S. syriaca can be regarded as promising natural sources of anti-inflammatory drugs.