Phospholipase A2 (Pla2) is an enzyme that induces inflammation, making Pla2 activity an effective approach to reduce inflammation. Therefore, investigating natural compounds for this Pla2 inhibitory activity has important therapeutic potential. The objective of this study was to investigate the potential in bromelain-phytochemical complex inhibitors via a combination of in silico and in vitro methods. Bromelain-amenthoflavone displays antagonistic effects on Pla2. Bromelian-asiaticoside and bromelain-diosgenin displayed synergistic effects at high concentrations of the combined compounds, with inhibition percentages of more than 70% and 90%, respectively, and antagonistic effects at low concentrations. The synergistic effect of the bromelain-asiaticoside and bromelain-diosgenin combinations represents a new application in treating inflammation. These findings not only provide significant quantitative data, but also provide an insight on valuable implications for the combined use of bromelain with asiaticoside and diosgenin in treating inflammation, and may help researchers develop more natural bioactive compounds in daily foods as anti-inflammatory agent.
Some novel hydrazone derivatives 6a-o were synthesized from the key intermediate 4-Chloro-N-(2-hydrazinocarbonyl-phenyl)-benzamide 5 and characterized using IR, ¹H-NMR, 13C-NMR, mass spectroscopy and elemental analysis. The inhibitory potential against two secretory phospholipase A₂ (sPLA₂), three protease enzymes and eleven bacterial strains were evaluated. The results revealed that all compounds showed preferential inhibition towards hGIIA isoform of sPLA₂ rather than DrG-IB with compounds 6l and 6e being the most active. The tested compounds exhibited excellent antiprotease activity against proteinase K and protease from Bacillus sp. with compound 6l being the most active against both enzymes. Furthermore, the maximum zones of inhibition against bacterial growth were exhibited by compounds; 6a, 6m, and 6o against P. aeruginosa; 6a, 6b, 6d, 6f, 6l, 6m, 6n, and 6o against Serratia; 6k against S. mutans; and compounds 6a, 6d, 6e, 6m, and 6n against E. feacalis. The docking simulations of hydrazones 6a-o with GIIA sPLA₂, proteinase K and hydrazones 6a-e with glutamine-fructose-6-phosphate transaminase were performed to obtain information regarding the mechanism of action.
Arachidonic acid and its metabolites have generated high level of interest among researchers due to their vital role in inflammation. The inhibition of enzymes involved in arachidonic acid metabolism has been considered as synergistic anti-inflammatory effect. A series of novel α,β-unsaturated carbonyl based compounds were synthesized and evaluated for their inhibitory activity on secretory phospholipase A₂ (sPLA₂), cyclooxygenases (COX), soybean lipoxygenase (LOX) in addition to proinflammatory cytokines comprising IL-6 and TNF-α. Six α,β-unsaturated carbonyl based compounds (2, 3, 4, 12, 13 and 14) exhibited strong inhibition of sPLA₂ activity, with IC₅₀ values in the range of 2.19-8.76 μM. Nine compounds 1-4 and 10-14 displayed inhibition of COX-1 with IC₅₀ values ranging from 0.37 to 1.77 μM (lower than that of reference compound), whereas compounds 2, 10, 13 and 14 strongly inhibited the COX-2. The compounds 10-14 exhibited strong inhibitory activity against LOX enzyme. All compounds were evaluated for the inhibitory activities against LPS-induced TNF-α and IL-6 release in the macrophages. On the basis of screening results, five active compounds 3, 4, 12, 13 and 14 were found strong inhibitors of TNF-α and IL-6 release in a dose-dependent manner. Molecular docking experiments were performed to clarify the molecular aspects of the observed COX and LOX inhibitory activities of the investigated compounds. Present findings increases the possibility that these α,β-unsaturated carbonyl based compounds might serve as beneficial starting point for the design and development of improved anti-inflammatory agents.
Arachidonic acid metabolism leads to the generation of key lipid mediators which play a fundamental role during inflammation. The inhibition of enzymes involved in arachidonic acid metabolism has been considered as a synergistic anti-inflammatory effect with enhanced spectrum of activity. A series of 1,3-diphenyl-2-propen-1-one derivatives were investigated for anti-inflammatory related activities involving inhibition of secretory phospholipase A2, cyclooxygenases, soybean lipoxygenase, and lipopolysaccharides-induced secretion of interleukin-6 and tumor necrosis factor-alpha in mouse RAW264.7 macrophages. The results from the above mentioned assays exhibited that the synthesized compounds were effective inhibitors of pro-inflammatory enzymes and cytokines. The results also revealed that the chalcone derivatives with 4-methlyamino ethanol substitution seem to be significant for inhibition of enzymes and cytokines. Molecular docking experiments were carried out to elucidate the molecular aspects of the observed inhibitory activities of the investigated compounds. Present findings increase the possibility that these chalcone derivatives might serve as a beneficial starting point for the design and development of improved anti-inflammatory agents.
To enhance the cytotoxicity of benzimidazole and/or benzoxazole core, the benzimidazole/benzoxazole azo-pyrimidine were synthesized through diazo-coupling of 3-aminophenybenzimidazole (6a) or 3-aminophenylbenzoxazole (6b) with diethyl malonate. The new azo-molanates 6a&b mixed with urea in sodium ethoxide to afford the benzimidazolo/benzoxazolopyrimidine 7a&b. The structure elucidation of new synthesized targets was proved using spectroscopic techniques NMR, IR and elemental analysis. The cytoxicity screening had been carried out against five cancer cell lines: prostate cancer (PC-3), lung cancer (A-549), breast cancer (MCF-7), pancreas cancer (PaCa-2) and colon cancer (HT-29). Furthermore, the antioxidant activity, phospholipase A2-V and cyclooxygenases inhibitory activities of the target compounds 7a&b were evaluated and the new compounds showed potent activity (cytotoxicity IC50 range from 4.3 to 9.2 µm, antioxidant activity from 40% to 80%, COXs or LOX inhibitory activity from 1.92 µM to 8.21 µM). The docking of 7a&b was made to confirm the mechanism of action.
Snake bite has been regarded as an important health problem in Myanmar since early 1960's. In the recent years, there has been growing interest in alternative therapies and therapeutic use of natural products, especially those derive from plants. In Myanmar and Indian traditional medicine, various plants have used as a remedy for treating snake bite. The present study was carried out to evaluate the effects of alcohol extract of Tamarind (Tamarindus indica Linn.) seed on some biologic properties of Russell's viper (Daboia russelli siamensis) venom (RVV). The Phospholipase A2 (PLA2) enzyme, coagulase enzyme and caseinolytic enzyme activities of Russell's viper venom (RVV) were reduced when mixed and incubated with the extract. When the RVV and the different amount of extracts were preincubated and injected intramuscularly into mice, all of them survived, but all the mice in the control group died. On the other hand, when RVV were injected first followed by the extract into mice, all of them died. If the extract was injected near the site where Russell's viper venom was injected, all the mice survived for more than 24 hours and the survival time prolonged but they all died within 96 hours. In conclusion, according to the results obtained, the extract neutralizes some biologic properties of the Russell's viper venom and prolonged the survival time if the extract was injected near the site where the Russell's viper venom was injected.