A study on the antioxidant activities of some new benzazole derivatives

Biology-oriented Drug Synthesis (BIODS), Structural Characterization and Bioactivities of Novel Albendazole Derivatives

Background:

Albendazole is a drug, belongs to the family of benzimidazole, and used as an anthelmintic agent in both human and veterinary medicine. It is marketed as Albenza which is used for the treatment of a variety of parasitic worm infestations such as roundworms, tapeworms, and flukes. In recent past, we have reported various classes of compounds as anti-glycating agents, in continuation of Biology-oriented Drug Synthesis (BIODS), seventeen albendazole derivatives 2-18 were synthesized evaluated for yeast glucose uptake activity.

Methods:

In the present study, Albendazole (2 g, 7.5 mmol), potassium hydroxide (3 g) were dissolved in ethanol (50 mL) into a 250 mL round-bottomed flask and refluxed for 48 h. TLC (ethyl acetate: hexane, 6:4) was monitored in order to check the reaction progress. After completion, the reaction mixture was dried under air and washed with an excess of distilled water. Precipitates were dried and crystallized from ethanol. The product was characterized by EI-MS and 1H-NMR.

Results:

Our present study showed that all compounds showed a varying degree of yeast glucose uptake activity ranging between IC50 = 51.41-258.40 µM, compared with standard metronidazole (IC50 = 41.86 ± 0.09 µM). This study has identified a series of potential leads for anti-glycating agents.

Conclusion:

Biology-oriented drug synthesis and in vitro yeast glucose uptake activity of albendazole derivatives gave rise to a number of lead molecule such as 3 (IC50 = 59.37 ± 0.26 µM), 5 (IC50 = 59.70 ± 0.32 µM), 6 (IC50 = 60.78 ± 0.54 µM), 8 (IC50 = 54.61 ± 0.20 µM), 16 (IC50 = 56.57 ± 0.04 µM) and 14 (IC50 = 51.41 ± 1.25 µM).

Synthesis of Pyridinyl-benzo[d]imidazole/Pyridinyl-benzo[d]thiazole Derivatives and their Yeast Glucose Uptake Activity In Vitro

Background:

Diabetes is the primary cause of fatality and disability all over the world, in recent past, we have reported various classes of compounds as anti-glycating agents and we have also reported benzimidazole and benzothiazole derivatives as a potential class of anti-glycating agents. This encouraged us to evaluate the pyridinyl benzimidazole/pyridinyl benzothiazole derivatives 1-27 for yeast glucose uptake activity.

Methods:

In the present study, an equimolar mixture of pyridine carboxaldehyde derivatives (1 mmol) and sodium metabisulphite (1 mmol) in DMF (10 mL) was stirred for 10 to 15 min, followed by addition of o-phenylene diamine/2-aminothiophenol (1 mmol) into it and refluxed for 3 h. The progress of the reaction was monitored by TLC. After completion, the reaction mixture was poured into crushed ice. Precipitates were formed which were collected by filtration to produce compounds 1-27 in good yields. Recrystallization from methanol yielded pure crystals.

Results:

Our present study showed that all compounds showed a varying degree of yeast glucose uptake activity in the range IC50 = 36.43-272.20 µM, compared to standard metronidazole (IC50 = 41.86 ± 0.09 µM). Compounds 5 (IC50 = 38.14 ± 0.17 µM), 6 (IC50 = 40.23 ± 0.20 µM), and 7 (IC50 = 36.43 ± 0.02 µM) showed an excellent yeast glucose uptake activity better than the standard.

Conclusion:

Pyridinyl benzimidazole/pyridinyl benzothiazole derivatives 1-27 were synthesized, structurally characterized, and evaluated for in vitro yeast glucose uptake activity. Compounds 5 (IC50 = 38.14 ± 0.17 µM), 6 (IC50 = 40.23 ± 0.20 µM), and 7 (IC50 = 36.43 ± 0.02 µM) demonstrated potent yeast glucose uptake activity as compared to standard metronidazole (IC50 = 41.86 ± 0.09 µM). This study identified a number of potential lead molecules which can be helpful in lowering the blood glucose level in hyperglycemia.

Synthesis and Antioxidant Properties of New Oxazole-5(4H)-one Derivatives

Objectives

To synthesize and characterize 4-(substituted benzylidene)-2-(substituted phenyl)oxazol-5(4H)-one derivatives (E1-E10), and evaluate them for antioxidant activity.

Materials and Methods

Required oxazole-5(4H)-one derivatives were synthesized in two steps to obtain novel hippuric acid derivatives (7-13); glycine and acylated appropriate benzoic acid derivatives were used and then, final compounds were obtained with condensation of 7-13 with appropriate benzaldehydes (E1-E10). These products were purified by column chromatography using ethyl acetate/n-hexane as eluent. All the compounds were unequivocally characterized using the combination of ¹H and ¹³C-nuclear magnetic resonance, mass spectrometry (ESI-MS), and elemental analysis. The inhibition of lipid peroxidation and its effects on hepatic cytochrome P450-dependent ethoxyresorufin-O-deethylase (EROD) enzyme were determined in rats in vitro.

Results

The most active analogue on the microsomal EROD activity was E3 which inhibited the microsomal EROD activity (89%) and was similarly better than that of the specific inhibitor caffeine (85%) at 10-3 M concentration.

Conclusion

The findings of this study indicate that the synthesized compounds, such as E3, display significant antioxidant activity.

Biological evaluation and docking studies of some benzoxazole derivatives as inhibitors of acetylcholinesterase and butyrylcholinesterase

A series of 2,5-disubstituted-benzoxazole derivatives (1–13) were evaluated as possible inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The results demonstrated that the compounds exhibited a broad spectrum of AChE and BChE inhibitory activity ranging between 6.80% and 90.21% except one compound which showed no activity against AChE at the specified molar concentration. Another derivative displayed a similar activity to that of reference drug (galanthamine) for inhibition of AChE and BChE. In addition, molecular docking of the compounds into active site of AChE was performed using recombinant human AChE (PDB ID: 4ey6) in order to understand ligand–protein interactions.

A novel small molecule, Rosline, inhibits growth and induces caspase-dependent apoptosis in human lung cancer cells A549 through a reactive oxygen species-dependent mechanism

Chemical screening using synthetic small molecule libraries has provided a huge amount of novel active molecules. It generates lead compound for drug development and brings focus on molecules for mechanistic investigations on many otherwise intangible biological processes. In this study, using non-small cell lung cancer cell A549 to screen against a structurally novel and diverse synthetic small molecule library of 2,400 compounds, we identified a molecule named rosline that has strong anti-proliferation activity on A549 cells with a 50% cell growth inhibitory concentration (IC50 ) of 2.87 ± 0.39 µM. We showed that rosline treatment increased the number of Annexin V-positive staining cell, as well as G2/M arrest in their cell cycle progression. Further, we have demonstrated that rosline induces a decrease of mitochondrial membrane potential (Δφm ) and an increase of caspases 3/7 and 9 activities in A549 cells, although having no effect on the activity of caspase 8. Moreover, we found that rosline could induce the production of reactive oxygen species (ROS) and inhibit the phosphorylation of signaling molecule Akt in A549 cells. Alternatively, an antioxidant N-acetyl-L-cysteine (NAC) significantly attenuated rosline's effects on the mitochondrial membrane potential, caspases 3/7 and 9 activities, cell viabilities and the phosphorylation of Akt. Our results demonstrated that ROS played an important role in the apoptosis of A549 cells induced by rosline.

Synthesis and different biological activities of novel benzoxazoles

A series of 2-[4-(4-substitutedbenzamido/phenylacetamido/butanamido)phenyl]-5-ethylsulphonyl-benzoxazole derivatives were synthesized and biologically evaluated as possible antimicrobial agents and inhibitors of tyrosinase, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE). The results demonstrated that the synthesized compounds exhibited a broad spectrum of activity with minimum inhibitory concentration (MIC) values of 128-16 μg/ml against some Gram-positive, Gram-negative bacteria as well as Candida albicans and C. krusei. The compound 10 displayed higher activity in this series against methicilline resistant Staphylococcus aureus (MRSA) with a MIC value of 16 μg/ml than the compared control drugs ampicillin and ceftriaxone. Compound 14 showed moderate tyrosinase inhibition, however, none of the compounds showed effect as inhibitor of AChE and BChE.

Chemical composition and in vitro antioxidant activity of hydro-ethanolic extracts from Bauhinia forficata subsp. pruinosa and B. variegata

Bauhinia species are known to have hypoglycemiant and antioxidant activities. Here, hydro-ethanolic leaf extracts from Bauhinia forficata subsp. pruinosa and Bauhinia variegata, collected in a Pampa biome region of Brazil, were investigated to characterize their chromatographic profile, flavonoid content and in vitro antioxidant activity (TBARS and DPH assays). The extracts were obtained from dried and fresh leaves. The total flavonoid content was assessed by spectrophotometric determination, and the results ranged between 572.08 and 1,102.99 μg mL-1. Moreover, flavonoids were more predominant in B. variegata than in B. forficata subsp. pruinosa. HPLC analysis detected a complex profile of phenolic compounds, being the flavonoid kaempferitrin founded B. forficata subsp. pruinosa; in addition, other kaempferol and quercetin derivatives were present. In vitro antioxidant assays demonstrated a different behavior depending on the species, leaf treatment and extract concentration. In general, B. variegata extracts obtained from fresh material presented higher antioxidant potential, which can be attributed to the predominance of flavonoids in their chemical composition.

6-Nitrobenzimidazole derivatives: potential phosphodiesterase inhibitors: synthesis and structure-activity relationship

6-Nitrobenzimidazole derivatives (1-30) synthesized and their phosphodiesterase inhibitory activities determined. Out of thirty tested compounds, ten showed a varying degrees of phosphodiesterase inhibition with IC(50) values between 1.5±0.043 and 294.0±16.7 μM. Compounds 30 (IC(50)=1.5±0.043 μM), 1 (IC(50)=2.4±0.049 μM), 11 (IC(50)=5.7±0.113 μM), 13 (IC(50)=6.4±0.148 μM), 14 (IC(50)=10.5±0.51 μM), 9 (IC(50)=11.49±0.08 μM), 3 (IC(50)=63.1±1.48 μM), 10 (IC(50)=120.0±4.47 μM), and 6 (IC(50)=153.2±5.6 μM) showed excellent phosphodiesterase inhibitory activity, much superior to the standard EDTA (IC(50)=274±0.007 μM), and thus are potential molecules for the development of a new class of phosphodiesterase inhibitors. A structure-activity relationship is evaluated. All compounds are characterized by spectroscopic parameters.