Antibacterial activity of Abies webbiana.
The methanol extract of the dried leaves of Abies webbiana was evaluated for antimicrobial activity. The methanol extract showed a broad spectrum of antibacterial activity.
Abies↗
Biomedical subjects
Shovanlal Gayen
Publications and source records attributed to Shovanlal Gayen.
Exploring QSAR on 3-aminopyrazoles as antitumor agents for their inhibitory activity of CDK2/cyclin A.
Chemical inhibitors of cyclin-dependent kinases have great therapeutic potential against various proliferative and neurodegenerative disorders. The pharmacophoric requirement of 3-aminopyrazole, inhibitors of CDK2/cyclin A as antitumor agents was explored. QSAR study was performed using ETSA index, RTSA index, indicator parameters and atomic charges to consider quantitatively the effect of the structural variation on the antitumor activity of 3-aminopyrazole. Result showed that atom number 5 is important for the activity. It plays some electronic roles in the interaction of these compounds with enzymes as well as assumed to be involved through the dispersive/van der Waals interactions with enzyme. Presence of meta substitutions on the phenyl ring indicate the detrimental effects towards the activity. The presence of substituted biphenyl/2-thenyl phenyl at R1 are favorable towards the activity. QSAR study also indicates that with increasing the electronegativity of oxygen at position 8, the activity increases.
Antineoplastic Agents↗
QSAR modeling on dopamine D2 receptor binding affinity of 6-methoxy benzamides.
QSAR modeling was performed on 58 (S) N-[(1-ethyl-2-pyrrolidinyl) methyl]-6-methoxy benzamides as dopamine (DA) D2 receptor antagonists to identify the structural requirements for DA D2 receptor binding affinity. The study pointed out that the presence of hydrophobic substituents at R3 position and electron-donating groups at R5 position increased the biological activity. Substitutions at phenyl ring favored the binding affinity of these benzamides. Ethyl group and iodine at R3 position were advantageous to the activity whereas nitro group at phenyl ring hindered the antagonistic activity.
Benzamides↗
Quantitative structure-activity relationship study using refractotopological state atom index on some neonicotinoid insecticides.
Importance of atom-level topological descriptors like electrotopological state atom (E-state) index in QSAR study is increasing. These descriptors help to relate structure and activity at atomic/fragmental level. In view of the earlier success of E-state index on some azidopyridinyl neonicotinoid insecticides, a relatively new atom-level topological descriptor; refractotopological state atom (R-state) index was used in this work. This was used to identify the important atoms/fragments related to dispersive/van der Waals interactions of neonicotinoids with the nicotinic acetylcholine receptor (nAChR). This study showed the structural requirements for the mammal alpha(4)beta(2) and Drosophila nAChR agonistic activity. It also revealed that substituted imine, nitromethylene at X-position were selective to the insecticidal activity. Azido substitution at pyridine ring of neonicotinoids disfavored the binding with the receptors. This study confirmed the validity of the R-state index as a new tool for quantitative structure-activity relationships. It has the ability to find out the required structural features as well as to predict the activity of the neonicotinoids.
Anabasine↗
Quantitative structure-activity relationship study on some benzodiazepine derivatives as anti-Alzheimer agents.
A QSAR study was performed in an attempt to explore the pharmacophore of some benzodiazepine derivatives as anti-Alzheimer agents for the inhibition of gamma-secretase. The study, which used the electrotopological state atom (ETSA) index, which encodes electronic and topological information, reveals the importance of two phenyl rings-one substituted and another unsubstituted, for the inhibition of the enzyme. Fluorine substitution on the substituted phenyl ring has an important contribution to the activity. R-configurations of the aliphatic chain substituents provide the exact conformation of the molecules to enter into the binding pockets of the receptor(s). [figure: see text]. General structure of benzodiazepine containing gamma-secretase inhibitors.
Alzheimer Disease↗
QSAR study on some anti-HIV HEPT analogues using physicochemical and topological parameters.
A Quantitative Structure-Activity Relationship (QSAR) study has been carried out using topological indices, physicochemical and indicator parameters on a series of HEPT analogues for their HIV reverse transcriptase inhibitory activity. Correlation analysis and multiple linear regression (MLR) method were used to find out the best QSAR model. The results clearly explained that decreased hydrophobicity of substituents at R(1) and R(2) positions are favorable for the activity and presence of di-substitution at phenyl ring as well as i-Pr at R(1) position have detrimental effect but presence of OH group at R(2) position increases the activity. The atoms numbered as 1, 2, 3, 4, 5, 6 and 11 may constitute pharmacophore moiety of the HEPT analogues for their anti-HIV activity. Leave one out (LOO-) cross validation method was used to judge the predictive power of final equations. From the study one can propose that atom or fragmental level descriptors are more useful to interpret drug-receptor interactions in these analogues. The potentiality of ETSA index to recognize these atoms (Pharmacophoric atoms) was established.
Anti-HIV Agents↗
5-N-Substituted-2-(substituted benzenesulphonyl) glutamines as antitumor agents. Part II: synthesis, biological activity and QSAR study.
Cancer is a major killer disease throughout human history. Thus, cancer becomes a major point of interest in life science. It was proved that cancer is a nitrogen trap and tumor cells are avid glutamine consumers. The non-essential amino acid glutamine, which is a glutamic acid derivative, supplies its amide nitrogen to tumor cells in the biosynthesis of purine and pyrimidine bases of nucleic acids as well as takes part in protein synthesis. Based on these and in continuation of our composite programme of development of new potential anticancer agents through rational drug design, 17 new 5-N-Substituted-2-(substituted benzenesulphonyl) glutamines were selected for synthesis. These compounds as well as 36 earlier synthesized glutamine analogues were screened for antitumor activity using percentage inhibition of tumor cell count as the activity parameter. QSAR study was performed with 53 compounds in order to design leads with increased effectiveness for antitumor activity using both physicochemical and topological parameters. QSAR study showed that steric effect on the aromatic ring is conducive to the activity. n-butyl substitution on aliphatic side chain and atom no 12 is important for antitumor activity of glutamine analogues.
Animals↗
QSAR study on some pyridoacridine ascididemin analogues as anti-tumor agents.
Pyridoacridine ascididemin analogues have been reported as anticancer agents for their interesting antitumor activity against human cancer cells. A quantitative structure-activity relationship (QSAR) analysis of ascididemin analogues was attempted using the physicochemical parameters and the electrotopological state atom (ETSA) indices. This study indicates that the electron withdrawing substituents with higher MR (molar refractivity) value at R(1) position favor the anti-tumor activity and the presence of NHR (R is hydrogen or alkyl group) at the R(3) position has contribution to the anti-tumor activity. ETSA indices have been incorporated as independent variable in the QSAR model with physicochemical parameters. It clearly suggests the importance of atoms 2, 3, 4, 5, 6 and 7 to the anti-tumor activity.
Acridines↗
Quantitative structure-activity relationship study on some azidopyridinyl neonicotinoid insecticides for their selective affinity towards the drosophila nicotinic receptor over mammalian alpha4beta2 receptor using electrotopological state atom index.
Neonicotinoids are the most important class of synthetic insecticides increasingly used in agriculture and veterinary medicine. Fundamental differences between the nicotinic acetylcholine receptors (nAChRs) of insects and mammals confer remarkable selectivity of the neonicotinoids at insect nAChR over mammalian nAChR. To identify pharmacophoric requirements of azidopyridinyl neonicotinoids for their efficacy and selectivity towards the insect nAChR over the mammalian one, quantitative structure-activity relationship (QSAR) study was performed using electrotopological state atom (ETSA) indices. This study clearly showed that nitroimines, nitromethylenes, and cyanoimines are more selective to Drosophila nAChR and safe for human being, whereas N-substituted imines have affinity to mammalian receptor. Pharmacophore mapping for both the activities was done.
Anabasine↗