ARTICLE | doi:10.20944/preprints201902.0124.v4
Subject: Life Sciences, Biophysics Keywords: enzymes Cyclooxygenase, ligand, metabolites, antiinflammatory, Molecular Docking
Online: 29 May 2019 (11:39:02 CEST)
Cyclooxygenases (COX), or prostaglandin endoperoxide synthases (PTGS), are key enzimes in the synthesis of prostaglandins, which are chemical species critical in mediating inflammatory processes. There are two highly homologous COX isoforms: COX-1 and COX-2. COX-1 is involved in the production of prostaglandins, chemical compuounds that take part in physiological processes such as: protection of the gastric epithelium, maintenance of renal flow, platelet aggregation, neutrophil migration and, also, are expressed in the vascular endothelium. Meanwhile, COX-2 is induced by proinflammatory stimuli. It is very frequent the use of nonsteroidal antiinflammatory drugs (NSAIDs) to counteract the symptoms of inflammatory processes. These drugs, in addition to its benefits, can cause side effects on people’s health, such as cardiovascular and respiratory problems, among others. In the past years, it has been recognized the potential of plants secondary metabolites as pharmacological agents, prompting the need for investigations that shed light into its mechanism of action. In this work we have applied computational techniques, based on quantum chemistry and mechanical statistics, to study the protein-ligand interaction involving COX’s and secondary metabolites from natural sources. Our aim is to determine the structure activity interplay in processes involving the participation of secondary plant metabolites such as luteolin, galangin, kaempferol, apigenin, morine and quercetin on the inactivation of COX’s. From molecular docking analysis, we have extracted the energetics of the COX-(1,2)/metabolite coupling. By defining energy based factors, we have determined a procedure that predicts the chemical species with highest stability and selectivity towards inactivation of COX-2 over COX-1. The results are discussed with regard to conformational features of the selected ligands and its intermolecular strong/weak interactions inside the active-sites of the COX’s hosts.
ARTICLE | doi:10.20944/preprints202011.0706.v1
Subject: Life Sciences, Biochemistry Keywords: Chlorogenic acid; coffee; cyclooxygenase; espresso; instant coffee; platelet aggregation
Online: 30 November 2020 (08:07:40 CET)
Coffee is rich in caffeine (CF), chlorogenic acid (CGA) and phenolics. Differing types of coffee beverages and brewing procedures may result in differences in total phenolic contents (TPC) and biological activities. Inflammation and increases of platelet activation and aggregation can lead to thrombosis. We focused on determining the chemical composition, antioxidant activity and inhibitory effects on agonist-induced platelet aggregation and cyclooxygenase (COX) of coffee beverages in relation to their preparation method. We prepared instant coffee and brewed coffee beverages using drip, espresso and boiling techniques. Coffee extracts were assayed for their CF and CGA contents using HPLC, TPC using colourimetry, platelet aggregation with an aggregometer and COX activity using ELISA. The findings have shown all coffee extracts, except the decaffeinated types, contained nearly equal amounts of CF, CGA and TPC. Inhibitory effects of coffee extracts on platelet aggregation differed depending on the activation pathways induced by different agonists. All espresso, drip and boiled coffee extracts caused dose dependent inhibition of platelet aggregation induced by ADP, collagen, epinephrine, and arachidonic acid (ARA). The most marked inhibition was seen at low doses of collagen or ARA. Espresso and drip extracts inhibited collagen-induced platelet aggregation more than purified caffeine or CGA. Espresso, boiled and drip coffee extracts were also a more potent inhibitors of COX-1 and COX-2 than purified caffeine or CGA. We conclude that inhibition of platelet aggregation and COX-1 and COX-2 may contribute to anti-platelet and anti-inflammatory effects of espresso and drip coffee extracts.
ARTICLE | doi:10.20944/preprints202005.0308.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: Oral health care products; cyclooxygenase; lipoxygenase; periodontal disease; Candida albicans; Candida glabrata; medicinal herbs
Online: 19 May 2020 (03:45:56 CEST)
Background: Given the increasing request for natural pharmacological molecules, this study assessed the antimicrobial capacity of Pistacia lentiscus L. essential oil (PLL-EO) obtained from the leaves of wild plants growing in North Sardinia (Italy), toward a wide range of periodontal bacteria and Candida including laboratory and clinical isolates sp., together with its anti-inflammatory activity and safety; Methods: PLL-EO was screened by gas chromatography / mass spectrometry. The minimal inhibitory concentration (MIC) was determined. The anti-inflammatory activity was measured by cyclooxygenase (COX 1/2) and lipoxygenase (LOX) inhibition while the antioxidant capacity was determined electro-chemically and by the MTT assay. The WST-1 assay was used to ascertain cytotoxicity toward four line of oral cells; Results: According to the concentrations of terpens, PLL-EO is a pharmacologically active phytocomplex. MICs against periodontal bacteria ranged between 3.13 and 12.5 µg/ml, while against Candida sp. were between 6.25 and 12.5 µg/ml. Oxidation by COX 1/2 and LOX was inhibited by 80% and 20% µg/mL of the oil respectively. Antioxidant activity seemed negligible, and no cytotoxicity arose; Conclusions: PLL-EO exhibits a broad-spectrum activity against periodontal bacteria and Candida, with an interesting dual inhibitory capacity toward COX2 and LOX inflammatory enzymes and without side effects against oral cells.
ARTICLE | doi:10.20944/preprints201811.0229.v1
Subject: Life Sciences, Molecular Biology Keywords: quercetogetin (QUE); anti-inflammatory; inducible nitric oxide synthase (iNOS); cyclooxygenase-2 (COX-2); MAPK; NF-κB
Online: 9 November 2018 (03:31:28 CET)
Citrus peel has been used in Asian traditional medicine for the treatment of cough, asthma, and bronchial disorders. However, the anti-inflammatory effect of quercetogetin (QUE), a polymethoxylated flavone isolated from the peel of citrus unshui is poorly understood. We investigated the anti-inflammatory effect and the molecular mechanisms of QUE in lipopolysaccharide (LPS)-induced RAW264.7 cells. QUE inhibited the production of NO and prostaglandin E2 by suppressing the LPS-induced expression of inducible nitric oxide synthase and cyclooxygenase-2 at both the mRNA and protein levels. QUE suppressed the production of proinflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α. QUE also inhibited the translocation of the nuclear factor kappa B subunit, p65, into the nucleus by interrupting the phosphorylation of IκB-α in LPS-induced RAW 264.7 cells. Based on the finding that QUE significantly decreased p-ERK protein expression in LPS-induced RAW264.7 cells, we confirmed that suppression of the inflammatory process by QUE was mediated through the MAPK pathway. This is the first report on the strong anti-inflammatory effects of QUE, which is a compound that can potentially be used as a therapeutic agent for inflammatory diseases.
Subject: Medicine & Pharmacology, Allergology Keywords: cyclooxygenase-2; head and neck cancers; head and neck squamous cell carcinoma; prostaglandins; inflammation; carcinogenesis; potentially premalignant lesions.
Online: 3 November 2020 (15:14:13 CET)
The cyclooxygenase-2 (COX-2) is a potent enzyme that converts arachidonic acid to prostaglandins (PG), including PGE2, a key mediator of inflammation and angiogenesis. Importantly, COX-2 is activated in response to inflammatory stimuli, where it is also believed to promote the development and progression of head and neck cancers (HNC). COX-2 can mediate its protumorigenic effect through various mechanisms such as inducing cell proliferation, inhibition of apoptosis, and suppressing the host’s immune response. Furthermore, COX-2 can induce the production of vascular endothelial growth factors, hence promoting angiogenesis. Indeed, the ability of COX-2 inhibitors to selectively restrict the proliferation of tumor cells and mediating apoptosis provides promising therapeutic targets for cancer patients. Thus, in this comprehensive review, we summarized the reported differential expression patterns of COX-2 in different stages of head and neck carcinogenesis—from potentially premalignant lesions to invasive carcinomas. Furthermore, we examined the available meta-analysis evidence for COX-2 role in the carcinogenesis of HNC. Finally, further understanding of the biological processes of COX-2 and its role in orchestrating cell proliferation, apoptosis and angiogenesis may give therapeutically beneficial insight to develop the management plan of HNC patients and improve their clinical outcomes.
Subject: Life Sciences, Biochemistry Keywords: Oleuropein; colon cancer; activated macrophages; chronic inflammation; inducible nitric oxide synthetase (iNOS); cyclooxygenase-2 (COX-2); nitric oxide (NO)
Online: 2 August 2021 (12:04:58 CEST)
Abstract: Oleuropein, the major compound of olive leaves, has been reported to exert numerous pharmacological properties, including anti-inflammatory, antidiabetic and anticancer. The purpose of this study is to evaluate, for the first time, the effect of oleuropein-rich leaf extracts (ORLE) in already-developed colon tumours colon tumours arising in an Apc (adenomatous polyposis coli) mutated PIRC rats (F344/NTac-Apcam1137). Here, we were able to investigate in parallel the anti-cancer effect of ORLE, both in vivo and in vitro, and its anti-inflammatory effect on macrophages, which represents a critical and abundant population in most solid tumours microenvironment. We found that in vivo ORLE treatment promoted apoptosis and attenuated iNOS activity both in colon tumours as in peritoneal macrophages of PIRC rats. We confirmed in vitro using primary RAW264.7 cells: ORLE reduced iNOS activity in parallel with COX-2 and pro-inflammatory cytokines, such as IL-1, IL-6 and TGF-. These findings suggest that ORLE possess a strong anti-inflammatory activity, which could be crucial for dampening the pro-tumourigenic activity elicited by a chronic inflammatory state generated by either tumour cells or tumour-associated macrophages.