SYNTHESIS AND ANTIMICROBIAL SCREENING OF 2,6-DIAMINOPYRIDINE SCHIFF BASES OF ISATIN DERIVATIVES

Objective: Synthesis and in vitro antimicrobial screening of 2,6-diaminopyridine Schiff bases of isatin derivatives. Methods: Isatin and it’s 5-substituted derivatives (S1-5) were prepared by Sandmeyer method and N2-Benzylidenepyridine-2,6-Diamine (M) was obtained by the reacting 2,6-diaminopyridine with benzaldehyde. Schiff bases (MS1-5) were prepared by reacting isatin derivatives (S1-5) with N2-Benzylidenepyridine-2,6-Diamine (M). Resultant compound structures were confirmed by some analytical techniques’ data. All synthesized compound were screened for in vitro antimicrobial activity by broth dilution methods against Staphylococcus aureus (MTCC-3160), Bacillus subtilus (MTCC-441), Escherichia coli (MTCC-452), Klebsiella pneumoniae (MTCC-432), Candida albicans (MTCC-183), Aspergillus flavus (MTCC-277) using ciprofloxacin and fluconazole as standard drugs. Results: All compounds exhibited better antibacterial activity compared to standard. Among all compounds, MS2 and MS4 were found most effective against all strains of bacteria. Only MS3 and MS5 showed antifungal activity against both fungal strains. Conclusion: All newly synthesized Schiff bases of isatin showed significant antibacterial activity against the tested strain of bacteria, only a few compounds were found effective as antifungal

SYNTHESIS, CHARACTERIZATION AND ASSESMENT THE ANTIBACTERIAL EFFICACCY OF SCHIFF BASED COMPOUNDS GENRATED FROM ISATIN

Indole-2,3-dione (isatin) and its derivative have been recated with 2 and 4 substituted 1,3,4-thiadiazole derivative form Schiff bases of these compounds were synthesized in the presence of alcohol. Their chemical structure have been confirmed by mean of their IR and 1HNMR. Antimicrobial screening of synthesized compounds was done by well diffusion method against 4 pathogenic becteria and 2 pathogenic fungi. Amongst the tested compounds 5-fluoro-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one, 5-methyl-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one,and 5-nitro-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one exhibit significant antibacterial activity and 5-chloro-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one, 5-fluoro-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one and 5-methyl-3-[(5-sulfanyl-1,3,4-thiadiazol-2-yl)imino]-1,3-dihydro-2H-indol-2-one  showed favourable antifungal activity

QSAR Studies of Flavonoids Derivatives for Antioxidant and Antimicrobial Activity

The biological activity and the molecular structures are the two main aspects for the QSAR study of a specific compound, which leads to generate a new chemical moiety. The Quantitative Structure Activity Relationship (QSAR) paradigm is based on the assumption that there is an underlying relationship between the molecular structure and biological activity. Physico-chemical properties were calculated employing the modeling software Win CAChe 6.1. The calculated descriptors were conformational minimum energies (CME) , HOMO energy, LUMO energy, heat of formation (HF), ionization potential (IP), molar refractivity(MR), Shape Index (basic kappa, order 1) (SI1), log P, electron affinity (EA), solvent accessible surface area (SAS). In random selection, 18 compounds were in training set and 10 in test set. Subsequently with the stepwise multiple linear regression analysis was carried out to achieve the best models. The equation generated was validated. The selected QSAR model showed correlation coefficient R2 0.7609, and cross-validated squared correlation coefficient Q2   of 0.5041 for antioxidant activity  ANOVA of predicted value for  Variance were found as 0.063638, 201.73 and 0.112396 for group -1.51851, 86.27 and -8.151 respectively. Source of Variation for between and within group i.e. SS value 40522.91 df value 2, MS value 20261.45 F value 301.0527 and p-value 1.01E-17. The HOMO-LUMO range were 73.149 to 84.775, Molar refractivity range was observed -7.409 to -8.84, Predicted value range was -2.52559 to -2.98191 for compound V1 to V5 and R1, R2. The result of study indicated that C5 [1-(2- hydroxyphenyl)-5-phenylpenta-2,4-dien-1-one]; is only inactive against Streptococcus mutans. All 3-hydroxyflavone derivatives exhibited their MIC to be in range of 250-125 µg/ml., 2,3-dihydroflavan-3-ol derivatives exhibited their MIC to be in  range of  1000- 500 µg/ml. The chalcone derivatives exhibited their MIC to be at 250µg/ml. Keywords: QSAR, Streptococcus mutans, Win CAChe 6.1 and antioxidant activit

Designing and Synthesis of Flavonoids Derivatives and Screening of their Antioxidant Activity

The flavonoids present in red wine were responsible this low cardiovascular mortality rate. Epidemiologic studies further suggest that dietary flavonoids are useful to control and protect the CHD. The flavonoids are yellow color substance (pigments) and the name given on the basis of Latin term Flavus which means yellow color. Flavonoids are derivatives of benzo-pyrone. Banzopyrone is a group of heterocyclic aromatic oxygen containing compounds. Finely powdered zinc chloride (8.25) was dissolved in glacial acetic acid (18ml)  by heating on sand bath then dry resorcinol (appx.5.5 gm) was added with  continuous  stirring to the mixture at  1400C. Antioxidant Screening by hydrogen peroxide scavenging assays. Hydrogen peroxide solution (40 mini moles) was prepared with standard phosphate buffer of pH 7.4. Different concentration of the compound stock solution and 4ml distilled water was added to 0.6 ml of hydrogen peroxide solution. UV absorbance was determined at the wavelength of 230 nm after 10 min with a blank solution containing phosphate buffer without H2O2. Take 4 ml different concentration of sample solution and 1ml sodium nitroprusside solution, added and incubated for 2.5 hrs at 370C. After incubation baseline was taken with methanol and 1ml sodium nitroprusside solution as blank solution. Griess reagent and methanol was added immediately before recording of readings. The readings were recorded at 546nm wavelenth. In the series of synthesized and evaluated compounds of Flavanoid electron withdrawing group at position four shows good activity. 2,3-dihydroflavan-3-ol derivatives showed lower activity than that of 3- hydroxyflavone derivatives. The 4-oxo (keto double bond at position 4 of the C ring), especially in association with the J2-J3 double bond, increases scavenger activity by delocalizing electrons, 3-hydroxy group on the C ring generates an extremely active scavenger; the combination of J2-J3 double bond,3-hydroxy group and 4-oxo group appears to be the best combination for potent antioxidant activity. Keywords: Flavonoids, Antioxidant activity, Hydrogen peroxide scavenging, free radical

Designing and Synthesis of Flavonoids Derivatives and Screening of their Antimicrobial Activity

Antimicrobial drugs either kill microbes (microbicidal) or prevent the growth of microbes (microbistatic). The streptococcus mutans is a bacteria that found in the human mouth cavity. This bacterial strain produces plaque and acids that break down tooth enamel and cause dental caries. Gram positive cocci, facultatively anaerobic bacteria that forms rod-like chains. the chemical reaction of 2- hydroxyacetophenones with aromatic acylchloride occurs to form 1,3-diketones. This rearrangement reaction proceeds via enolate formation followed by acyl transfer. Then it cyclises into flavone.13 As the same of above scheme can be worked out as 2- Methoxybenzoyl Chloride is prepared by reaction of 2- methoxybenzoic acid  with  Thionyl chloride and DMF. 2-Methoxybenzoyl Chloride then added to mixture of 2- hydroxyacetophenone and pyridine, 2-[(2-Methoxybenzoyl)oxy]acetophenone thus obtained is treated with pyridine and KOH which gives1-(2-Hydroxyphenyl)-3-(2- methoxyphenyl)-propan1,3-dione. The result of study indicated that C5 [1-(2- hydroxyphenyl)-5-phenylpenta-2,4-dien-1-one]; is only inactive against Streptococcus mutans. All 3-hydroxyflavone derivatives exhibited their MIC to be in range of 250-125 µg/ml., 2,3-dihydroflavan-3-ol derivatives exhibited their MIC to be in  range of  1000- 500 µg/ml. The chalcone derivatives exhibited their MIC to be at 250 µg/ml. Keywords: Streptococcus mutans, flavonoids derivatives, MIC, 2,3-dihydroflavan-3-ol

Synthesis and Evaluation of Aldehyde Derivatives of Sulfonyl Chloride Quinoxaline

In pyrazine mesomeric interaction between the protonated & neutral nitrogen atoms probably destabilizes the cation.N, N’-diprotonation is very easier for pyrazine Synthesis of 2, 3-diphenylquinoxaline by phenylene-diamine in 16 ml of rectified spirit was added & combine solution was warm in water bath for 30 min. added water until slight colorless persist & allow to cool recrystallize the product in ethanol.   Synthesis of 2, 3-diphenylquinoxaline 7-sulfonylchloride (R) using chlorosulfonic acid under ice-cold condition, then Synthesis of  2-hydroxyphenyl-2,3-diphenylquinoxaline-7-sulphonate(R1) throughresorcinol with 3ml pyridine & sulphonyl chloride derivative, Synthesis of 2-formylphenyl-2,3-diphenylquinoxaline-7-sulphonate(R7)obtained by reaction of salicylaldehyde with pyridine & sulphonyl chloride derivative then Synthesis of 3-formylphenyl-2,3-diphenylquinoxaline-7-sulphonate(R9) obtained by heating on water bath mixture of3-hydroxybenzaldehyde with pyridine & sulphonyl chloride, Synthesized quinoxaline derivatives were subjected to antimicrobial susceptibility testing by well diffusion method against gram positive (S.aureus, 2079) and gram negative bacteria (E. coli, 2685). The results of quinoxaline derivatives in terms of zone of inhibition recorded. MIC of quinoxaline derivative was determined by tube micro dilution technique against S. aureus and E. coli. The turbidity was measured by UV at about 420 nm. Hydrogen peroxide scavenging activity and 1, 1 diphenyl 2, picryl hydrazyl Method (DPPH) calculated and Most of the derivatives have shown comparable antioxidant activity in relation to standard Ascorbic acid and DPPH.  Keywords: QSAR, Sulfonyl Chloride Quinoxaline, Ant-microbial, Antioxidan

Synthesis and Anti-Oxidant Activity of Phenol and Aldehyde Derivatives of Sulfonyl Chloride Quinoxaline

N, N’-diprotonation is very easier for pyrazine Synthesis of 2, 3-diphenylquinoxaline by phenylene-diamine in 16 ml of rectified spirit was added & combine solution was warm in water bath for 30 min. added water until slight colorless persist & allow to cool recrystallize the product in ethanol.   Synthesis of 2, 3-diphenylquinoxaline 7-sulfonylchloride (R) using chlorosulfonic acid under ice-cold condition, thenSynthesis of  2-hydroxyphenyl-2,3-diphenylquinoxaline-7-sulphonate (R1) throughresorcinol with 3ml pyridine &sulphonyl chloride derivative, Synthesis of 2-formylphenyl-2,3-diphenylquinoxaline-7-sulphonate (R7)obtained by reaction of salicylaldehyde with pyridine &sulphonyl chloride derivative then Synthesis of 3-formylphenyl-2,3-diphenylquinoxaline-7-sulphonate (R9) obtained by heating on water bath mixture of 3-hydroxybenzaldehyde with pyridine &sulphonyl chloride, Synthesized quinoxaline derivatives were subjected to antioxidant activity.Hydrogen peroxide solution (40 mM) was prepared with standard phosphate buffer (pH 7.4). Different concentration of the compound stock solution and 4ml distilled water was added to 0.6 ml of hydrogen peroxide solution. Absorbance was determined at 230 nm after 10 min against a blank solution containing phosphate buffer without hydrogen peroxide. DPPH radical scavenging activity was measured using the method of Cotelleet al. with some modifications. 3 ml of reaction mixture containing 0.2 ml of DPPH (100 μM in methanol) 2.8 ml of test solution, at various concentrations (5, 10, 20, 40, 80, 160 320 μg/ml) of the extract fractions was incubated at 37°C for 30 min absorbance of the resulting solution was measured at 517 nm using Beckman model DU-40 spectrophotometer. Most of the derivatives have shown comparable antioxidant activity in relation to standard Ascorbic acid and DPPH Keywords: DPPH,Quinoxaline, Antioxidant activity,Sulfonyl chloride quinoxaline

Synthesis and Evaluation of Phenol Derivatives of Sulfonyl Chloride Quinoxaline

The objective of the present study was to synthesize some new 7-sulfonate of 2, 3- Diphenyl quinoxaline which are more potential as antibacterial than parent quinoxalines. The present study was synthesis of derivatives of sulfonyl chloride quinoxaline and physicochemical and spectral characterization, in vitro antimicrobial screening against gram positive and gram negative bacteria.The concentration of derivatives used as 200 and 400 microgram initially. When 200 µg concentrations was used R6 shows sensitivity towards S. aureus and R6 shows sensitivity towards gram negative E. coli organism. When 400 µg used then R3, R5, and R6 shows sensitivity in case of gram positive organism. And in case of gram negative organism R5, R6 shows sensitivity.Azithromycin is used as Reference drug and a comparative study was done. As compare to reference drug all derivatives shows less sensitivity than S- Standard and R- quinoxaline derivatives. Keywords: Diphenyl quinoxaline, QSAR, Quinoxaline, Phenol derivative

Assessment of the In-vitro antioxidant activity of the alcoholic extract/fractions of Bombax malabaricum DC.

Various parts of Bombax malabaricum are used in traditional Indian medicine for the treatment of inflammatory diseases, diarrhea, fever, acute swelling and diuretic. Current research on Bombax malabaricum DC is aimed at finding of natural plants derived from antioxidants that provide sustenance through additional components or synergistic training as the plant's cellular reinforcements are necessary to prevent the movement of interfaced free radical problems. The antioxidant activity in Bombax malabaricum DC can be detected by alcoholic extract fraction using unique laboratory models. These include free radical activity of 1,1-Diphenyl-2-picryl-hydrazil (DPPH) assay, ABTS assay, total antioxidant capacity, and o-phenanthroline assay/Iron chelating assay. The plant contains a large number of phenolic and flavonoid compounds. The plant shows great antioxidant activity. The thought was taught to investigate the use of the Bombax malabaricum Keywords: Bombax malabaricum, Antioxidant, DPPH, ABTS, O-phenanthroline

Nootropic Activity of Rhodiola rosea Root

Nootropic are mediator that enhance the cognitive skills of brain function, Alzheimer’s disease, primarily affects the elderly population and is estimated to account for 50–60% of dementia cases in persons over 65 years of age. The present study aimed to evaluate the Nootropic activity of Rhodiola rosea. Methanoilc extract of R. rosea was used to estimate elevated plus maze (EPM) model in mice, the effect of extract on learning and memory in number of entries open and closed arms using the EPM in mice at a dose of 300 and 500 mg/kg. R. rosea extract in EPM showed transfer latency entries, which is indicative of cognition improvement. The results suggested that the treatment of methanolic extract of R. rosea enhances memory in EPM experimental models