Elastase, a serine proteinase released by activated human neutrophils, can degrade a wide variety of biomacromolecules including elastin, and is considered a marker of inflammatory diseases. As the logical strategy to protect tissue is to inhibit excessive elastase activity, experimental and clinical researches have concentrated on trying to find efficient elastase inhibitors. As thymol, one of the major components of thyme oil with a phenolic structure, has been credited with a series of pharmacological properties, that include antimicrobial and antioxidant effects, the aim of this study was to explore whether it can also interfere with the release of elastase by human neutrophils stimulated with the synthetic chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP). After the neutrophils were incubated with increasing amounts of thymol (2.5, 5, 10, 20 µg/ml), elastase release was initiated by fMLP and measured using MeO-Suc-Ala-Ala-Pro-Val-MCA. The results showed that thymol inhibited fMLP-induced elastase release in a concentration-dependent manner, with the effects of 10 and 20 µg/ml being statistically significant. The behavior of cytosolic calcium mobilization revealed by fura-2 closely resembled that of elastase, thus suggesting that they may be related. The hydrophobic nature of thymol means that it can approach ion channel proteins through the lipid phase of the membrane, alter the local environment of calcium channels and thus inhibit capacitative calcium entry. In brief, thymol inactivates calcium channels machinery, thus triggering a corresponding reduction in elastase. The antibacterial and antimycotic activity of thymol is already well known, but our findings that it inhibits elastase extend our knowledge of the anti-inflammatory activity of this interesting molecule that is already credited with antioxidant activity. These two latter characteristics make thymol a molecule that can have helpful effects in controlling the inflammatory processes present in many infections.
The aim of this study was to compare the amount and activity of phytonutrients in raw, grilled, and boiled eggplant fruit using chemical measures and a biological assay of oxidative bursts in human neutrophils. The thermally treated samples showed various changes in their chemical composition (dry matter, soluble solids, acidity, and the amount of alcohol insoluble substances) due to the cooking processes and were much richer in the main phenolic compounds such as chlorogenic and caffeic acids, which are known to be antioxidants. Consequently, their free radical scavenging activity was significantly higher, especially that of superoxide anion. The biological assay of oxidative bursts from human neutrophils in the presence of N-formyl-methionyl-leucyl-phenylalanine confirmed the greater activity of extracts of the cooked eggplants with respect to raw eggplants. Successive extract dilutions showed a significant activity up to 1.25 microg/mL after cooking, while raw fruits resulted in an activity up to 10.00 microg/mL. These results showed that the thermal treatment commonly used before consumption can increase the content and biological activity of antioxidant compounds of eggplants.
Acute and chronic lung diseases both lead to an extensive recruitment of neutrophils in the lungs. These cells play a major defensive role but, when activated, they are also an important source of reactive oxygen species, which generate a cytotoxic oxidant stress that triggers a self-sustaining phlogogenic loop. Erdosteine (CAS 84611-23-4) is a mucoactive drug whose metabolization leads to active metabolites with an SH group, and molecules bearing an SH group are also considered to have antioxidant activity. Luminol amplified chemiluminescence was used to investigate the oxidative bursts of human neutrophils and it was found that concentrations of 2.5, 5, 10 and 20 micrograms/ml of metabolite I of erdosteine significantly inhibit oxidative bursts in a concentration-related manner that overlaps the inhibition induced by the control drug N-acetylcysteine. Chemiluminescence was also studied in cell-free systems to see whether the drug also has direct scavenger activity, which was observed from 2.5 to 20 micrograms/ml of metabolite I using the xanthine/xanthine oxidase assay and at concentrations of 0.039 to > or = 2.5 micrograms/ml using the highly-sensitive hypochlorous acid/H2O2 assay. The findings indicate that the metabolite I of erdosteine has antioxidant activity which, together with the drug's mucomodifying activity, may lead to a useful antiphlogistic effect.
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