A MAJOR APPROACH- 2-CHLOROPYRIDINE-5-TRIFLUOROMETHYL DERIVATIVE AS ANTIAMNESIC AGENTS
3.3.1 PASS PREDICTION-RESULTS-
The PASS predictions can be interpreted and used in a flexible manner—(i) only activities with Pa > Pi are considered as possible for a particular compound. (ii) If Pa > 0.7—the chance to find the activity experimentally is high. But, in many cases the compound may occur to be a close analogue of known pharmaceutical agents. (iii) If 0.5 < Pa < 0.7—the chance to find the activity experimentally is less, but the compound is probably not so similar to known pharmaceutical agents.(iv) If Pa < 0.5—the chance to find the activity experimentally is even less, but the chance to find a structurally new compound, that is, NCEs increases33.
COMPOUND CODE & No.
Table 4:The probabilities of being active for nootropic activity (Pa) of the synthesized compounds (25-28) on the basis of PASS prediction.
PASS prediction results showed that for all the synthesized compounds (25-28) the probability of being active was observed in the range of 0.600 > Pa > 0.478 for nootropic activity (table 4). This showed that for compounds (27,28) with values 0.7 < Pa > 0.5 the chance of finding the activity experimentally is less but the chance of finding a structurally new compound was greater. Compound (25, 26) is having Pa value less than 0.5, so the chance of finding the activity experimentally is even lesser but the chance of finding a structurally new compound is maximum.
3.4 PHARMACOLOGICAL EVALUATION
3.4.1 ANTIAMNESIC ACTIVITY34
ELEVATED PLUS MAZE
The test measures the transfer latency (TL) i.e. the time in which the mouse moves from open arm to the enclosed arm.TL was recorded on the first day. If the animal did not enter into one of the covered arms within 90 s, it was gently pushed into one of the two covered arms and the TL was assigned as 90 s. The mouse was allowed to explore the maze for 10 s and then returned to its home cage. Immediately after the training, the animals were administered the test compounds intraperitonially (i.p.). On the second day i.e. 24 h after the first exposure, TL was again noted. The decrease in TL was taken as index of antiamnesic activity.The results are expressed as % retention (Mean ±S.E.M) calculated as:
TL on 1st day - TL on 2nd day Χ 100
TL on 1st day
3.5 BIOCHEMICAL EVALUATION
The biochemical study to be carried out in two phases, the estimation of acetylcholinesterase activity and IC50 and second is the estimation of protein Content.
3.5.1 ASSAY OF ACETYLCHOLINESTERASE
The activity of acetylcholinesterase to be determined in the brain homogenate according to the Ellman et al (1961) method35.
The substrate used in the assay system is acetylthiocholine iodide, the ester of thiocholine and acetic acid. The substrate, acetylthiocholine is hydrolyzed into thiocholine and acetate by the enzyme AChE. Thiocholine forms mercaptan, which reacts with the oxidizing agent 5, 5’-dithio-bis-2-nitrobenzoic acid (DTNB) to form 5-thio-2-nitrobenzoate, which has a maximum absorption at 412 nm. Thus the activity of AChE can be measured by following an increase in absorbance at 412 nm.
· 0.1 M Sodium phosphate buffer (pH 8.0)
· 10 mM DTNB (Ellman’s reagent)
· 14.9 mM Acetylthiocholine iodide
AChE activity to be calculated using molar extinction coefficient of 5-thio-2-nitrobenzoic acid (14.15 ´103 M-1cm-1). The results to be expressed as nmols of acetylthiocholine iodide hydrolyzed/min/mg protein.
Change in absorbance per minute Volume of assay
------------------------ ? ------------------------
14150 mg of protein by protein estimation
3.5.2 ESTIMATION OF PROTEIN CONTENT
The protein content to be estimated according to the method of Lowry36et al, 1951.
This method is based on the colour reactions of amino acids tryptophan and tyrosine with the Folin’s phenol reagent. These amino acids react with phosphomolybdic acid and phosphotungstic acid (present in Folin’s reagent) to give blue colour, which is estimated colourimetrically. This colour is the result of reduction of phosphomolybdic acid and phosphotungstic acid and biuret reaction of proteins with Cu2+ ions in alkaline medium.
· Reagent A: 1 % (w/v) Copper sulphate solution.
· Reagent B: 2 % (w/v) Sodium potassium tartarate.
· Reagent C: 2 % (w/v) Sodium carbonate in 0.1 N Sodium hydroxide.
· Lowry’s reagent: It was prepared just before use by mixing reagents A, B and C in the ratio of 1:1:98.
· Folin-Ciocalteau reagent: It was prepared fresh by diluting the commercial 2N Folin’s reagent with double distilled water (1:1, v/v).
· Standard bovine serum albumin (BSA) solution (1 mg/ml).
The protein concentration was calculated from the standard curve made by taking different concentrations of the BSA standard.
Volume of homogenate X sample OD X
------------------------------ ------- = mg/ml protein
0.372 (Standard) 1000
1. Anonymous, “alzinfo.org” accessed on 21/09/10.
2. Abdelouahid Samadi, Jose Marco-Contelles, Elena Soriano, Monica Alvarez-Perez, Mourad Chioua, Neuroprotective properties for the treatment of Alzheimer and neuronal vascular diseases. Bioorganic & Medicinal Chemistry, 2010, 5861-5872.
3. Alan M. Palmer, Pharmacotherapy for Alzheimer’s disease: progress and prospects, trends in Pharmacological Sciences Vol.23 No.9, September 2002.
4. Anonymous “pubs.acs.org.” accessed on 29/09/10.
5. Mark A. Smith and George , Causes and Consequences of Oxidative Stress in Alzheimer’s Disease, Free Radical Biology & Medicine, Vol. 32, No. 11, 2002,1061–1070.
6. Anonymous,“whoindia.org/en/section3/ section128/ section 235_426.html” accessed on 11.10.2010.
7. Anonymous, “alz.org” accessed on 21/10/10.
8. Tripathi, K. D. Essentials of Medical pharmacology. 6th ed.; Jaypee Brothers, New Delhi, 2008.
9. Kaj Blennow, Mony Leon, Henrik Zetterberg, Alzheimer’s disease thelancet.com Vol 368, 2006 387-406.
10. Hardy, J Higgins, G. A. Amyloid deposition as the central event in the etiology of Alzheimer’s disease. Trends Pharmacol. Sci. 1992, 12, 383–388
11. Abdelouahid Samadi, Jose Marco-Contelles, Elena Soriano, Monica Alvarez-Perez, Mourad Chioua, Neuroprotective properties for the treatment of Alzheimer and neuronal vascular diseases. Bioorganic & Medicinal Chemistry, 2010, 5861-5872.
12. Todd E. Golde and Steven G. Younkin, Presenilins as therapeutic targets for the treatment of Alzheimer’s disease, trends in Molecular Medicine Vol.7 June 2001.
13. Aldo Andreani, Alberto Leoni, Alessandra Locatelli, Rita Morigi, Mirella Rambaldi, 4-Aminopyridine derivatives with antiamnesic activity, Eur. J. Med. Chem. 35 2000 77−82.
14. Alan M. Palmer, Pharmacotherapy for Alzheimer’s disease: progress and prospects, trends in Pharmacological Sciences Vol.23 No.9, September 2002.
15. Michael S. Malamas, Keith Barnes , Yu Hui , Matthew Johnson , Frank Lovering , Jeff Condon , William Fobare , William Solvibile , Novel pyrrolyl 2-aminopyridines as potent and selective human b-secretase (BACE1) inhibitors, Bioorganic & Medicinal Chemistry Letters, 20, 2010, 2068–2073.
16. Kaj Blennow, Mony Leon, Henrik Zetterberg, Alzheimer’s disease www.thelancet.com Vol 368, 2006 387-406.
17. Nicole Hottecke , Miriam Liebeck , Karlheinz Baumann , Robert Schubenel , Edith Winkler ,Harald Steiner , Inhibition of c-secretase by the CK1 inhibitor IC261 does not depend on CK1d, Bioorganic & Medicinal Chemistry Letters, 20, 2010, 2958–2963.
18. John P. Caldwell , Chad E. Bennett, Troy M. McCracken, Robert D. Mazzola, Thomas Bara, Alexei Buevich, Iminoheterocycles as c-secretase modulators, Bioorganic & Medicinal Chemistry Letters, 20, 2010, 5380–5384.
19. Alexey Rivkin , Sean P. Ahearn , Stephanie M. Chichetti , Yoona R. Kim , Chaomin Li , Andrew Rosenau , Piperazinyl pyrimidine derivatives as potent c-secretase modulators, Bioorganic & Medicinal Chemistry Letters, 20, 2010,1269–1271.
20. Heiko Zettl1, Sascha Weggen, Petra Schneider and Gisbert Schneider, Exploring the chemical space of γ-secretase modulators, Trends in Pharmacological Sciences, Vol.31, No.9., 2010
21. Johan Lundkvist and Jan Na slund, γ-Secretase: a complex target for Alzheimer’s disease Current Opinion in Pharmacology, 2007, 7,112–118.
22. Cyril Ronco, Geoffroy Sorin, Florian Nachon , Richard Foucault , Ludovic Jean, Anthony Romieu , Synthesis and structure–activity relationship of Huprine derivatives as human acetylcholinesterase inhibitors, Bioorganic & Medicinal Chemistry, 17, 2009 ,4523–4536.
23. C.T. Sadashiva, J.N. Narendra Sharath Chandra, C.V. Kavitha, A. Thimmegowda, M.N. Subhash, Synthesis and pharmacological evaluation of novel N-alkyl/aryl substituted thiazolidinone arecoline analogues as muscarinic receptor 1 agonist in Alzheimer’s dementia models, European Journal of Medicinal Chemistry, 44, 2009, 4848–4854.
24. Y. C. Sunil Kumar, Manish Malviya, J. N. Narendra Sharath Chandra,C. T. Sadashiva, M. N. Subhashb, Effect of novel N-aryl sulfonamide substituted 3-morpholino arecoline derivatives as muscarinic receptor 1 agonists in Alzheimer’s dementia models, Bioorganic & Medicinal Chemistry, 16 ,2008,5157–5163.
25. Graham R. Lawton, Hantamalala Ralay Ranaivo, Laura K. Chico, Haitao Ji, Fengtian Xue, Pavel Martásek, Silverman, Analogues of 2-aminopyridine-based selective inhibitors of neuronal nitric oxide synthase with increased bioavailability, Bioorganic & Medicinal Chemistry, 17, 2009, 2371–2380.
26. Zhen-Wei Cai, Donna Wei, Gretchen M. Schroeder, Lyndon A. M. Cornelius, Kyoung Kim, Xiao-Tao Chen, Discovery of orally active pyrrolopyridine- and aminopyridine-based Met kinase inhibitors, Bioorganic & Medicinal Chemistry Letters, 18, 2008, 3224–3229.
27. Bo Zhang, Aifang Nie, Wei Bai, Ziqiang Meng , Effects of aluminum chloride on sodium current, transient outward potassium current and delayed rectifier potassium current in acutely isolated rat hippocampal CA1 neurons, Food and Chemical Toxicology, 42, 2004, 1453–1462.
28. Luigi Scipione, Daniela De Vita, Alessandra Musella, Lisa Flammini, Simona Bertonib, 4-Aminopyridine derivatives with anticholinesterase and antiamnesic activity, Bioorganic & Medicinal Chemistry Letters, 18, 2008, 309–312.
29. Daniel T. Smith, Riyi Shi, Richard B. Borgens, Jennifer M. McBride, Kevin Jackson, Development of novel 4-aminopyridine derivatives as potential treatments for neurological injury and disease, European Journal of Medicinal Chemistry, 40 ,2005 ,908–917.
30. Pajouhesh, H.; Lenz, G. R. Medicinal chemical properties of successful central nervoussystem drugs, J. American Society Exp. Neuro. Ther. 2005, 2, 541-553.
31. Geronikaki, A. A.; Dearden, J. C.; Filimonov D.; Galaeva, I.; Garibova, T. L. Design of new cognition enhancers: from computer prediction to synthesis and biological evaluation. J. Med. Chem. 2004, 47, 2870-2876.
32. Marwaha, A.; Goel, R. K.; Mahajan, M. P. PASS-predicted design, synthesis and biological evaluation of cyclic nitrones as nootropics. Bio. Med. Chem. Letters 2007, 17, 5251-5255.
33. Anzali S.; Barnickel G.; Cezanne B.; Krug M.; Filimonov D.; Poroikov V. Discriminating between drugs and nondrugs by Prediction of Activity Spectra for Substances (PASS). J. Med. Chem. 2001, 44, 2432-2437.
34. Manetti, D.; Martini, E.; Ghelardini, C.; Dei, S.; Galeotti, N.;Guandalini, L.; Romanelli, M. N.; Scapecchi, S.; Teodori, E.; Bartolini, A.; Gualtieri, F. 4-Aminopiperidine derivatives as a new class of potent cognition enhancing drugs. Bioorg. Med. Chem. Lett. 2003, 13, 2303-2306.
35. Andreani, A.; Leoni, A.; Locatelli, A.; Morigi, R.; Rambaldi, M.; Pietra, C.; Villetti, G. 4-Aminopyridine derivatives with antiamnesic activity. Eur. J. Med. Chem. 2000, 35, 77−82.
36. Gerhardt, P.; Murray, R.G.E.; Wood, W.A.; Krieg, N.R. (1994) “Methods for General and Molecular Bacteriology”, ASM, Washington DC, ISBN 1-55581-048-9, p 518.
37. Frolund, B.; Palmgren, R.; Keiding, K.; Nielsen, P.H. (1996). “Extraction of extracellular polymers from activated sludge using a cation exchange resin”, Water Res 30(8), pp. 1749-1758.
38. Lowry, O.H.; Rosenbrough, N.J.; Farr, A.L.; Randall, R.J. (1951) “Protein measurement with the Folin Phenol Reagent”, J Biol Chem 193, pp. 265-275.
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