Malina Jasamai

Synthesis and Biological Evaluation of Chalcone Derivatives (Mini Review)

Chalcones are the principal precursors for the biosynthesis of flavonoids and isoflavonoids. A three carbon α, β-unsaturated carbonyl system constitutes chalcones. Chalcones are the condensation products of aromatic aldehyde with acetophenones in attendance of catalyst. They go through an assortment of chemical reactions and are found advantageous in synthesis of pyrazoline, isoxazole and a variety of heterocyclic compounds. In synthesizing a range of therapeutic compounds, chalcones impart key role. They have showed worth mentioning therapeutic efficacy for the treatment of various diseases. Chalcone based derivatives have gained heed since they own simple structures, and diverse pharmacological actions. A lot of methods and schemes have been reported for the synthesis of these compounds. Amongst all, Aldol condensation and Claisen-Schmidt condensation still grasp high up position. Other distinguished techniques include Suzuki reaction, Witting reaction, Friedel-Crafts acylation with cinnamoyl chloride, Photo-Fries rearrangement of phenyl cinnamates etc. These inventive techniques utilize various catalysts and reagents including SOCl(2) natural phosphate, lithium nitrate, amino grafted zeolites, zinc oxide, water, Na(2)CO(3), PEG400, silicasulfuric acid, ZrCl(4) and ionic liquid etc. The development of better techniques for the synthesis of α, β- unsaturated carbonyl compounds is still in high demand. In brief, we have explained the methods and catalysts used in the synthesis of chalcones along with their biological activities in a review form to provide information for the development of new-fangled processes targeting better yield, less reaction time and least side effects with utmost pharmacological properties.

Anti-inflammatory trends of 1, 3-diphenyl-2-propen-1-one derivatives.

Chalcones (1, 3-Diphenyl-2-propen-1-one) are constituted by a three carbon α, β-unsaturated carbonyl system. The biosynthesis of flavonoids and isoflavonoids is initiated by chalcones. Notable pharmacological activities of chalcones and its derivatives include anti-inflammatory, antifungal, antibacterial, antimalarial, antituberculosis, antitumor, antimicrobial and antiviral effects respectively. Owing to simplicity of the chemical structures and a huge variety of pharmacological actions exhibited, the entities derived from chalcones are subjected to extensive consideration. This review article is an effort to sum up the anti-inflammatory activities of chalcone derived chemical entities. Effect of chalcones on lipid peroxidation, heme oxygenase 1(HO-1), cyclooxygenase (COX), interleukin 5 (IL-5), nitric oxide (NO) and expression of cell adhesion molecules (CAM) is summarized stepwise.

Effects of Novel Diarylpentanoid Analogues of Curcumin on Secretory Phospholipase A2, Cyclooxygenases, Lipo-oxygenase, and Microsomal Prostaglandin E Synthase-1

Arachidonic acid and its metabolites have generated a heightened interest due to their significant role in inflammation. Inhibiting the enzymes involved in arachidonic acid metabolism has been considered as the synergistic anti‐inflammatory effect. A series of novel curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on activity of secretory phospholipase A2, cyclooxygenases, soybean lipo‐oxygenase as well as microsomal prostaglandin E synthase‐1. Among the curcumin analogues, compounds 3, 6, 9, 12, and 17 exhibited strong inhibition of secretory phospholipase A2 activity, with IC50 values ranging from 5.89 to 11.02 μm. Seven curcumin analogues 1, 3, 6, 7, 9, 11, and 12 showed inhibition of cyclooxygenases‐2 with IC50 values in the range of 46.11 to 94.86 μm, which were lower than that of curcumin. Compounds 3, 6, 7, 12, and 17 showed strong inhibition of lipo‐oxygenase enzyme activity. Preliminary screening of diarylpentanoid curcumin analogues for microsomal prostaglandin E synthase‐1 activity revealed that four diarylpentanoid curcumin analogues 5, 6, 7, and 13 demonstrated higher inhibition of microsomal prostaglandin E synthase‐1 activity with IC50 ranging from 2.41 to 4.48 μm, which was less than that of curcumin. The present results suggest that some of these diarylpentanoid analogues were able to inhibit the activity of these enzymes. This raises the possibility that diarylpentanoid analogues of curcumin might serve as useful starting point for the design of improved anti‐inflammatory agents.

Current Prospects of Synthetic Curcumin Analogs and Chalcone Derivatives Against Mycobacterium Tuberculosis

Tuberculosis, caused by Mycobacterium tuberculosis, is amongst the foremost infectious diseases. Treatment of tuberculosis is a complex process due to various factors including a patients inability to persevere with a combined treatment regimen, the difficulty in eradicating the infection in immune-suppressed patients, and multidrug resistance (MDR). Extensive research circumscribing molecules to counteract this disease has led to the identification of many inhibitory small molecules. Among these are chalcone derivatives along with curcumin analogs. In this review article, we summarize the reported literature regarding anti tubercular activity of chalcone derivatives and synthetic curcumin analogs. Our goal is to provide an analysis of research to date in order to facilitate the synthesis of superior antitubercular chalcone derivatives and curcumin analogs.

Effects of diarylpentanoid analogues of curcumin on chemiluminescence and chemotactic activities of phagocytes.

Objectives  A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.

Inhibitory effects of acetylmelodorinol, chrysin and polycarpol from mitrella kentii on prostaglandin E2 and thromboxane B2 production and platelet activating factor receptor binding

Acetylmelodorinol, chrysin and polycarpol, together with benzoic acid, benzoquinone and stigmasterol were isolated from the leaves of Mitrella kentii (Bl.) Miq. The compounds were evaluated for their ability to inhibit prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) production in human whole blood using a radioimmunoassay technique. Their inhibitory effect on platelet activating factor (PAF) receptor binding to rabbit platelet was determined using 3H-PAF as a ligand. Among the compounds tested, chrysin showed a strong dose-dependent inhibitory activity on PGE2 production (IC50 value of 25.5 µM), which might be due to direct inhibition of cyclooxygenase-2 (COX-2) enzymatic activity. Polycarpol, acetylmelodorinol and stigmasterol exhibited significant and concentration-dependent inhibitory effects on TXB2 production with IC50 values of 15.6, 19.1 and 19.4 µM, respectively, suggesting that they strongly inhibited COX-1 activity. Polycarpol and acetylmelodorinol showed strong dose-dependent inhibitory effects on PAF receptor binding with IC50 values of 24.3 and 24.5 µM, respectively.

Synthesis and Effects of Pyrazolines and Isoxazoles on the Phagocytic Chemotaxis and Release of Reactive Oxygen Species by Zymosan Stimulated Human Neutrophils

A series of novel isoxazole and pyrazoline derivatives has been synthesized and evaluated for their effects on the chemiluminescence and chemotactic activity of human phagocytes. Their effects on the chemotactic migration of isolated polymorphonuclear leukocytes (PMNs) and on the release of reactive oxygen species (ROS) during respiratory burst of human whole blood and PMNs were carried out using the Boyden chamber technique and luminol-based chemiluminescence assay, respectively. Of the compounds tested, compounds 8, 9, 11 and 12 exhibited higher inhibitory activity on the release of ROS (with IC50 values ranging from 5.6 to 8.4 μM) than acetylsalicylic acid (IC50 = 9.5 μ M). These compounds also showed strong inhibitory activity on the migration of PMNs with compound 8 exhibiting an IC50 value lower than that of ibuprofen. The results suggest that some of these isoxazole and pyrazoline derivatives have ability to modulate the innate immune response of phagocytes at different steps, indicating their potential as a source of new immunomodulatory agents.

Immunomodulatory effects of diarylpentanoid analogues of curcumin

Diarylpentanoid analogues of curcumin are known for their various pharmacological activities which include the inhibition of inflammatory mediators and are good candidates as immunomodulators that could be useful in the treatment of inflammation. In the work described here, seventeen diarylpentanoid curcumin analogues were assessed for their inhibitory effects on the reactive oxygen species (ROS) production, chemotaxis and phagocytosis of human neutrophils. ROS production was evaluated using luminol and lucigenin-based chemiluminesence assay, while inhibition of isolated polymorphonuclear neutrophils chemotaxis and phagocytosis abilities were investigated using the Boyden chamber technique and the Phagotest kit, respectively. Two of the analogues, compounds 1e and 2e, which contain the 2-methyl-4(N-ethyl-N-ethylacetonitrile)aniline functional group, were active in all the assays performed. Moreover, analogues containing heteroatoms (1a, 1e, 2c, 2d, 2e, 3a and 3c) were active in suppressing the neutrophil phagocytic activity. The information obtained gave new insight into curcumin analogues with the potential to be developed as new immunomodulators.

Effects of synthetic chalcone derivatives on oxidised palmitoyl arachidonoyl phosphorylcholine-induced proinflammatory chemokines production

Oxidised 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OxPAPC) induces the production of proinflammatory chemokines has been widely studied for its role in vascular inflammation. There is increasing evidence on the role of chalcones as potential anti-inflammatory agents but less is known about its effects on OxPAPC-induced chemokines production and the involvement of unfolded protein response (UPR) signalling, particularly through XBP1 pathway. The present study sought to investigate the inhibitory potential of synthetic chalcone derivatives on the release of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), induced by OxPAPC through XBP1 signalling pathway on differentiated U-937 macrophages. The effects of synthetic chalcone derivatives on the chemokines productions were investigated using enzyme-linked immunosorbent assays, while the inhibitions of XBP1 signalling were detected using western immunoblot. Results show that all the three tested synthetic chalcone derivatives inhibited OxPAPC-induced chemokines production in a concentration-dependent manner. Compound 1.5 exhibited the strongest inhibition of IL-8 and MCP-1 at 61.4 ± 4.23% and 63.8 ± 2.16%, respectively. Compound 1.5 also achieved the lowest IC50 values for both IL-8 (18.33 ± 1.59 μM) and MCP-1 (13.05 ± 1.37 μM) inhibitions. For XBP1 protein expression, both compound 1.4 and 1.5 exhibited significant concentration-dependent suppression of the protein expressions. The results suggest that synthetic chalcone derivatives may serve as potential alternatives for future development of anti-inflammatory agents, particularly in vascular inflammation.

Synthesis of novel 6-azapyrimidine acyclic nucleoside analogues and antiviral evaluation.

Acyclic nucleosides have been of considerable interest since the approval of aciclovir by the FDA to be used as an antiviral agent in the 1990s. The acyclic moieties and the bases used in the experiment were either available commercially or synthesized using literature methods. Vorbrüggen coupling method was utilized involving reaction of persilylated heterocyclic bases with the appropriate acyclic moiety in the presence of a Lewis acid catalyst. A series of novel 6-azapyrimidine acyclic oxosugar nucleosides was successfully synthesized with a promising yield (more than 50%). An efficient method of protection and deprotection was also investigated.