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
Tarun Jha
Publications and source records attributed to Tarun Jha.
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↗
Synergistic effect of methanol extract of Abies webbiana leaves on sleeping time induced by standard sedatives in mice and anti-inflammatory activity of extracts in rats.
During the determination of LD50 values of extracts of Abies webbiana, it was observed that the methanol extract (MEAW) produces sedation of animals. This led to investigation of the effect of MEAW on sleeping time in mice. When various doses of the methanol extract (100, 150, and 200 mg/kg body weight) were administered alone, no hypnotic activity was observed. However, these exhibited significant synergistic effects (P < 0.001) at those dose levels in mice when administered prior to the administration of standard sedatives (pentobarbitone sodium: 50 mg/kg and diazepam: 6 mg/kg, respectively). In addition anti-inflammatory effects of methanol, chloroform, and petroleum ether extracts of Abies webbiana leaves in rats were performed to assess scientific validity of the medicinal claim of Indian folk medicine. The effects of leaf extracts (methanol, chloroform, and petroleum ether) against inflammation were studied by carrageenan-induced paw edema model in rats. The methanol extract (400 mg/kg p.o.) of leaves of Abies webbiana showed the best significant anti-inflammatory activity as compared to that of diclofenac sodium (150 mg/kg p.o.). The LD50 values of methanol, chloroform, and petroleum ether extracts were found to be 986, 1387, and > 3200 mg/kg, respectively. Thus, the therapeutic index of methanol extract may be favorable to open a new vista on combination therapy of hypnotics and may also against inflammation.
Abies↗
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↗
QSAR study on the affinity of some arylpiperazines towards the 5-HT1A/alpha1-adrenergic receptor using the E-state index.
QSAR models represent the relationship of biological activity with either physicochemical parameters or structural indices. QSAR study was performed on some arylpiperazines as 5-HT(1A)/alpha(1)-adrenergic receptor antagonists using E-state indices to identify the pharmacophoric requirements. It was found that some of the atoms played important roles to both activities and some played important role in selectivity of compound to the 5-HT(1A) antagonistic activity. The presence of COONHPr group at the ortho-position of the phenyl ring might be disadvantageous and Br at meta-position might be conducive to the activity. COOPr at the ortho-position might be disfavored the adrenergic alpha(1)-antagonistic activity, thus increase the selectivity.
Adrenergic alpha-1 Receptor Antagonists↗
QSAR study on some p-arylthio cinnamides as antagonists of biochemical ICAM-1/LFA-1 interaction and ICAM-1/JY-8 cell adhesion in relation to anti-inflammatory activity.
In an attempt to find out the chemical and structural features of some p-arylthio cinnamides 1 as antagonists of biochemical ICAM-1/LFA-1 interaction as well as ICAM-1/JY-8 cell adhesion in relation to anti-inflammatory activity, QSAR study was performed. Steric effect on the arylthio ring and lipophilic substitutions at 2,3-positions, especially 2,3-disubstitution with Cl or CF(3) or both on cinnamides 1 were conducive to the activity, whereas simultaneous presence of methoxy group at arylthio ring and NCOCH(3) group at heterocyclic ring of cinnamides 1 were detrimental to activity in antagonism of biochemical ICAM-1/LFA-1 interaction. When inhibition of ICAM-1/JY-8 cell adhesion was considered, lipophilic substitution on ring B and simultaneous presence of CF(3) groups at 2 and 3 positions of the ring B were advantageous to antagonism. This QSAR study showed that B ring has played the most important role for both types of activities.
Anti-Inflammatory Agents, Non-Steroidal↗
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↗
QSAR study on adenosine kinase inhibition of pyrrolo[2,3-d]pyrimidine nucleoside analogues using the hansch approach.
QSAR studies on series of pyrrolo[2,3-d]pyrimidine nucleoside analogues were performed for their adenosine kinase (AK) inhibitory activity using the Hansch approach. Significant correlations were obtained with hydrophobic parameter at position 'X'. Electronic and steric parameters on pyrimidine and pyrrole rings found to play an important role in the ligand-receptor interactions with the active sites of the enzyme. Presence of bulkier groups at 'X' and 'Y' positions seems to protect the title compounds from biodegradation, as is evident from their positive sterimol steric parameter B1 at these positions.
Adenosine Kinase↗
Syntheses, biological evaluation and QSAR study on antitumor activity of 1,5-N,N'-disubstituted-2-(substituted benzenesulphonyl) glutamamides.
We have reported [unpublished data] the synthesis and QSAR of 5-substituted-2-(substituted benzenesulphonyl) glutamines which have shown the importance of steric factor on the aliphatic chain. N-Phthalyl isoglutamine, having the substitution at position 1 of the glutamic acid moiety, is the metabolite of recently approved thalidomide for different types of tumors by US FDA. Based on these, 36 new 1,5-N,N'-disubstituted-2-(substituted benzenesulphonyl) glutamamides were synthesized, as tools for further elucidation of the structural requirements for antitumor activity. All the synthesized compounds were tested for antitumor activity against Ehrlich Ascites Carcinoma (EAC) in Swiss albino mice using tumor weight as inhibitory parameter. Quantitative structure-activity relationship (QSAR) studies of these analogues revealed that the electron donating groups on the phenyl ring are found to be mandatory for the activity which was also proved by the negative coefficient of indicator parameter I(3,) for NO(2) group on the phenyl ring. Molecular volume (MV) and steric factor at R(5) position also plays a role in ligand-receptor interactions.
Animals↗
Synthesis, screening and quantitative structure-activity relationship (QSAR) studies of some glutamine analogues for possible anticancer activity.
We described the syntheses, biological activities and QSAR studies of 36 new 5-n-substituted-2-(substituted benzenesulphonyl) glutamines 6-41 with different substitutions. These compounds were designed as structural analogues of most reactive amino acid, 'glutamine' (GLN), especially in the tumor cells. They present the new basic lateral chains at R(5) position as well as different substitutions at 2', 3', 4', and 5' positions on the benzene ring. The synthesized compounds have been tested for antitumor activity against Ehrlich ascites carcinoma (EAC) in Swiss albino mice using percentage inhibition of tumor weight as inhibitory parameter. In order to elucidate the structural requirements for antitumor activity, quantitative structure-activity relationship (QSAR) studies have been performed using extra thermodynamic model of Hansch. QSAR equations showed that the electronic parameter (sigma) on the aromatic ring system, steric parameter (Es) and to some extent Sterimol length of the substituent (L) on the aliphatic side chain correlate significantly with the antitumor activity. Resonance factor occupies the major electronic contribution on the aromatic ring system to the activity.
Antineoplastic Agents↗