Flavonoids as dual inhibitors of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX): molecular docking and in vitro studies

Background

Inflammation is known to involve in many pathological processes of different diseases, but the current therapy causes adverse effects. Thus, there is a great interest for the discovery of flavonoids as a valuable alternative to classical analgesic and anti-inflammatory agent with dual-inhibitory action, especially on both COX-2 and 5-LOX which can minimize or overcome this problem.

Results

In the present work, drug-likeness properties of the synthesized flavonoids via Lipinski’s Rule of Five were predicted using QikProp prior to evaluation of their COX and LOX inhibitory activities using enzyme assays. Subsequently, molecular docking was performed using GLIDE to analyse their binding behaviour. The results showed that all compounds obeyed the Lipinski’s Rule of Five. NPC6 and NPC7 had displayed better selectivity towards COX-2 as compared to Indomethacin with less than 50% inhibition against COX-1. In addition, these compounds also inhibited activity of 5-LOX. Their selectivity to COX-2 was due to the binding to hydrophobic region and extends to lobby region near the entrance of COX binding site forming hydrogen bond with Ser530. Interestingly, these compounds showed a similar binding mode as Zileuton in the active site of 5-LOX and formed hydrogen bond interaction with Ala424.

Conclusion

NPC6 and NPC7 had potential as dual inhibitor of COX-2 and 5-LOX. The scaffolds of these chemical entities are useful to be as lead compounds for the dual inhibition of COX-2 and 5-LOX.

Efficient Synthesis of Novel 1-Substituted β- Carboline Derivatives via Pictet-Spengler Cyclization of 5-Hydroxy-L-Tryptophan

A facile synthesis of novel 1-substituted β-carboline derivatives by using three efficient reaction steps was described. The synthetic route began with the construction of β-carboline frameworks involving the coupling of 5-hydroxy-L-tryptophan with different substituted phenylglyoxal via Pictet-Spengler condensation. Subsequent reduction of carbonyl functionality on carbon-7’ by using Wolff-Kishner reaction followed by N-alkylation afforded a practical access to a series of 1-substituted β-carboline derivatives in moderate yields. These novel derivatives were successfully synthesized without the use of expensive metal catalyst, prolonged reaction hours or critical reaction conditions. The molecular structures of all synthesized derivatives were confirmed by infrared (IR), gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) spectroscopy.

Review on Synthesis of (S)-5-Benzylpyrrolidine-2,4-dione Derivatives with Substitution at C-3 Position by Employing Functional Groups Interconversion-

Abstract:

5-benzylpyrrolidine-2,4-dione 9 are versatile scaffolds with a unique structural feature responsible for the diversity of its biological importance. Over the past years, many researchers have reported the synthesis of various bio-active (S)-5-benzylpyrrolidine-2,4-dione derivatives due to its simplicity yet exhibiting promising bioactivities. This review focuses on the synthesis of core structure 9 and its derivatives based on the substitution at carbon-3 position of (S)-5-benzylpyrrolidine-2,4-dione 9. This review also reported the effective method for the synthesis of core structure 9 with 98% yield. Biological evaluations of various prepared derivatives by various researchers were described.

Discovery of polymethoxyflavones as potential cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and phosphodiesterase 4B (PDE4B) inhibitors

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely prescribed to treat inflammatory-related diseases, pain and fever. However, the prolong use of traditional NSAIDs leads to undesirable side effects such as gastric, ulceration, and renal toxicity due to lack of selectivity toward respective targets for COX-2, 5-LOX, and PDE4B. Thus, targeting multiple sites can reduce these adverse effects of the drugs and increase its potency. A series of methoxyflavones (F1-F5) were synthesized and investigated for their anti-inflammatory properties through molecular docking and inhibition assays. Among these flavones, only F2 exhibited selectivity toward COX-2 (Selectivity Index, SI: 3.90, COX-2 inhibition: 98.96 ± 1.47%) in comparison with celecoxib (SI: 7.54, COX-2 inhibition: 98.20 ± 2.55%). For PDEs, F3 possessed better selectivity to PDE4B (SI: 4.67) than rolipram (SI: 0.78). F5 had the best 5-LOX inhibitory activity among the flavones (33.65 ± 4.74%) but less than zileuton (90.81 ± 0.19%). Docking analysis indicated that the position of methoxy group and the substitution of halogen play role in determining the bioactivities of flavones. Interestingly, F1-F5 displayed favorable pharmacokinetic profiles and acceptable range of toxicity (IC₅₀>70 µM) in cell lines with the exception for F1 (IC₅₀: 16.02 ± 1.165 µM). This study generated valuable insight in designing new anti-inflammatory drug based on flavone scaffold. The newly synthesized flavones can be further developed as future therapeutic agents against inflammation.

Crystal structure of ethyl 3-(4-methoxyphenyl)-5-methylcarbamoyl-1H-pyrazole-4-carboxylate, C15H17N3O4

C15H17N3O4, triclinic, P1̄ (no. 2), a = 10.5986(5) Å, b = 11.5298(5) Å, c = 13.5386(6) Å, α = 102.694(1)°, β = 102.999(1)°, γ = 108.918(1)°, V = 1446.03(11) Å3, Z = 4, Rgt(F) = 0.0525, wRref(F2) = 0.1526, T = 100(1) K.

Antinociceptive activity of a synthetic oxopyrrolidine-based compound, ASH21374, and determination of its possible mechanisms

This study was carried out to determine the antinociceptive activity of a novel synthetic oxopyrrolidine-based compound, (2R,3R,4S)-ethyl 4-hydroxy-1,2-dimethyl-5-oxopyrrolidine-3-carboxylate (ASH21374), and to elucidate the involvement of the opioid, vanilloid, glutamate, and nitric oxide - cyclic guanosine monophosphate (NO/cGMP) systems in modulating the observed antinociception. ASH21374, in the doses of 2, 10, and 100 mg/kg body mass, was administered orally to mice 60 mins prior to exposure to various antinociceptive assays. From the results obtained, ASH21374 exhibited significant (P < 0.05) antinociceptive activity in the abdominal constriction, hot-plate, and formalin tests that was comparable with 100 mg/kg acetylsalicylic acid or 5 mg/kg morphine, respectively. ASH21374 also attenuated capsaicin- and glutamate-induced paw licking. Pre-treatment with 5 mg/kg naloxone significantly (P < 0.05) inhibited the activity in all assays, while pretreatment with 10 mg/kg β-funaltraxamine, 1 mg/kg naltrindole, or 1 mg/kg nor-binaltorphimine significantly (P < 0.05) reversed the activity in the abdominal constriction test. l-Arginine, N(G)-nitro-l-arginine methyl esters (l-NAME), methylene blue, and their combinations, failed to inhibit the ASH21374 antinociceptive activity. In conclusion, ASH21374 demonstrated antinociceptive activities on the peripheral and central nervous systems, mediated through the activation of opioid receptors, inhibition of the glutamatergic system, and attenuation of vanilloid-mediated nociceptive transmission. Further studies have been planned to determine the pharmacological potential of ASH21374.

Ethyl 4-hydroxy-1-methyl-5-oxo-2-phenylpyrrolidine-3-carboxylate 1.25-hydrate

The asymmetric unit of the title compound, C₁₄H₁₇NO₄·1.25H₂O, consists of four substituted pyrrolidone mol­ecules (two pairs of enanti­omers) and five water mol­ecules. The five-membered rings each have an envelope conformation, with the C atom bonded to the ester group as the flap. The mean planes of the five-membered rings of the four pyrrolidone mol­ecules make dihedral angles of 60.87 (5), 64.45 (5), 62.03 (5) and 65.79 (5)° with respect to the phenyl rings. In the crystal, the pyrrolidone and water mol­ecules are connected through O—H⋯O hydrogen bonds, forming a layer parallel to the ab plane. The two-dimensional network is further stabilized by inter­molecular C—H⋯O hydrogen bonds.

Evaluation of the bioactivity of novel spiroisoxazoline typecompounds against normal and cancer cell lines

The aim of this study was to investigate the in vitro cellular activity of novel spiroisoxazoline type compounds against normal and cancer cell lines from lung tissue (Hs888Lu), neuron-phenotypic cells (SH-SY5Y), neuroblastoma (SH-SY5Y), human histiocytic lymphoma (U937), lung cancer (A549), and leukaemia (HL-60). Our bioassay program revealed that the spiroisoxazoline type compounds show cytotoxicity only in lymphoma cell lines, which is in contrast with the pyrrolidine precursor of these spiroisoxazoline compounds, where significant cytotoxicity is seen in all normal and cancer cell lines. These data suggest a tumour-specific mechanism of action. In addition these data also show that spiroisoxazoline compounds are non-toxic in the human neuronphenotypic neuroblastoma SH-SY5Y cell line, and furthermore that they might protect cells from neurodegenerative disease.

Methyl 2-{[(4-hydroxyphenyl)(methoxycarbonyl)methyl]aminocarbonyl}ethanoate hemihydrate

In the structure of the title compound, C₁₃H₁₅NO₆·0.5H₂O, the water O atom lies on a twofold rotation axis. The methoxy­carbonyl­methyl and amino groups are essentially coplanar and the methoxy­carbonyl­methyl group makes a dihedral angle of 79.73 (10)° with the mean plane of the hydroxy­phenyl ring. The amino and methoxy­carbonyl­methyl groups are involved in an intra­molecular N—H⋯O hydrogen bond which generates an S(5) ring motif. In the crystal structure, mol­ecules are linked via N—H⋯O and O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions into a two-dimensional network parallel to the (01) plane. The crystal structure is further stabilized by C—H⋯π inter­actions.

tert-Butyl 5-(4-methoxy-phen-yl)-1-methyl-2-oxopyrrolidin-3-yl carbonate

In the title compound, C₁₇H₂₃NO₅, the pyrrolidinone ring is in an envelope conformation. The tert-butyl carbonate and 4-methoxy­phenyl groups are arranged on the same side of the pyrrolidinone ring. The meth­oxy group is coplanar with the attached benzene ring. The mol­ecules are linked into chains along the b axis via C—H⋯O hydrogen bonds.

4-Hydr-oxy-5-(4-methoxy-phen-yl)pyrrolidin-2-one

In the title compound, C₁₁H₁₃NO₃, the pyrrolidin-2-one ring is in an envelope conformation with the hydroxyl and 4-methoxy­phenyl substituents mutually cis. The methoxy group is slighty twisted away from the mean plane of the attached benzene ring. The mol­ecules are arranged into screw chains along the c axis. These chains are inter­connected via inter­molecular O—H⋯O and N—H⋯O hydrogen bonds into sheets parallel to the ac plane. The crystal structure is further stabilized by weak inter­molecular C—H⋯O and C—H⋯π inter­actions.