Evaluation of novel 4-(4-fluorobenzyl)piperazin-1-yl]-based compounds as competitive tyrosinase inhibitors endowed with anti-melanogenic effects

There is a considerable attention for the development of inhibitors of tyrosinase (TYR) as therapeutic strategy for the treatment of hyperpigmentation disorders in humans. Continuing in our efforts to identify TYR inhibitors, we describe the design, synthesis and pharmacophore exploration of new small molecules structurally characterized by the presence of the 4-fluorobenzylpiperazine moiety as key pharmacophoric feature for the inhibition of TYR from  Agaricus bisporus (AbTYR). Our investigations resulted in the discovery of the competitive inhibitor [4-(4-fluorobenzyl)piperazin-1-yl]-(3-chloro-2-nitro-phenyl)methanone 26 (IC 50  = 0.18 μM) that proved to be ∼100-fold more active than reference compound kojic acid (IC 50  = 17.76 μM). Notably, compound 26 exerted anti-melanogenic effect on B16F10 cells in absence of cytotoxicity. Docking analysis suggested its binding mode into AbTYR and into modelled human TYR

Design, Synthesis, and in Vitro Evaluation of 4-(4-Hydroxyphenyl)piperazine-Based Compounds Targeting Tyrosinase

Melanin biosynthesis is enzymatically regulated by tyrosinase (TYR, EC 1.14.18.1), which is efficiently inhibited by natural and synthetic phenols, demonstrating potential therapeutic application for the treatment of several human diseases. Herein we report the inhibitory effects of a series of (4-(4-hydroxyphenyl)piperazin-1-yl)arylmethanone derivatives, that were designed, synthesised and assayed against TYR from Agaricus bisporus (AbTYR). The best inhibitory activity was predominantly found for compounds bearing selected hydrophobic ortho-substituents on the aroyl moiety (IC50 values in the range of 1.5–4.6 μM). They proved to be more potent than the reference compound kojic acid (IC50=17.8 μM) and displayed competitive mechanism of inhibition of diphenolase activity of AbTYR. Docking simulation predicted their binding mode into the catalytic cavities of AbTYR and the modelled human TYR. In addition, these compounds displayed antioxidant activity combined with no cytotoxicity in MTT tests. Notably, the best inhibitor affected tyrosinase activity in α-MSH-stimulated B16F10 cells, thus demonstrating anti-melanogenic activity

COVID-19 in rheumatic diseases in Italy: first results from the Italian registry of the Italian Society for Rheumatology (CONTROL-19)

OBJECTIVES: Italy was one of the first countries significantly affected by the coronavirus disease 2019 (COVID-19) epidemic. The Italian Society for Rheumatology promptly launched a retrospective and anonymised data collection to monitor COVID-19 in patients with rheumatic and musculoskeletal diseases (RMDs), the CONTROL-19 surveillance database, which is part of the COVID-19 Global Rheumatology Alliance. METHODS: CONTROL-19 includes patients with RMDs and proven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) updated until May 3rd 2020. In this analysis, only molecular diagnoses were included. The data collection covered demographic data, medical history (general and RMD-related), treatments and COVID-19 related features, treatments, and outcome. In this paper, we report the first descriptive data from the CONTROL-19 registry. RESULTS: The population of the first 232 patients (36% males) consisted mainly of elderly patients (mean age 62.2 years), who used corticosteroids (51.7%), and suffered from multi-morbidity (median comorbidities 2). Rheumatoid arthritis was the most frequent disease (34.1%), followed by spondyloarthritis (26.3%), connective tissue disease (21.1%) and vasculitis (11.2%). Most cases had an active disease (69.4%). Clinical presentation of COVID-19 was typical, with systemic symptoms (fever and asthenia) and respiratory symptoms. The overall outcome was severe, with high frequencies of hospitalisation (69.8%), respiratory support oxygen (55.7%), non-invasive ventilation (20.9%) or mechanical ventilation (7.5%), and 19% of deaths. Male patients typically manifested a worse prognosis. Immunomodulatory treatments were not significantly associated with an increased risk of intensive care unit admission/mechanical ventilation/death. CONCLUSIONS: Although the report mainly includes the most severe cases, its temporal and spatial trend supports the validity of the national surveillance system. More complete data are being acquired in order to both test the hypothesis that RMD patients may have a different outcome from that of the general population and determine the safety of immunomodulatory treatments

Coumarins from Cachrys sicula L.

One new coumarin, 8-hydroxymethylpsoralen (1), was isolated from the dried leaves of Cachrys sicula L. along with the known coumarins sprengelianin (2) and (RS)-oxypeucedanin (3). The structure of the new compound was elucidated on the basis of NMR and ESI-MS spectral analysis

New Insights on Phytochemical Features and Biological Properties of <i>Alnus glutinosa</i> Stem Bark

Alnus glutinosa (namely black alder or European alder) is a tree of the Betulaceae family widely spread through Europe, Southeastern Asia, the Caucasus mountains, and Western Siberia. Its bark is traditionally used for medicinal purposes as an astringent, cathartic, febrifuge, emetic, hemostatic, and tonic, suggesting that it may contain bioactive compounds useful to counteract inflammation. The aim of this study was to investigate the phytochemical profile of A. glutinosa stem bark extract (AGE) by LC-DAD-ESI-MS/MS analysis and to validate some biological activities such as antioxidant, anti-inflammatory and anti-angiogenic properties by in vitro and in vivo models (chick chorioallantoic membranes and zebrafish embryos), that can justify its use against inflammatory-based diseases. The AGE showed a high total phenols content expressed as gallic acid equivalents (0.71 g GAE/g of AGE). Diarylheptanoids have been identified as the predominant compounds (0.65 g/g of AGE) with oregonin, which alone constitutes 74.67% of the AGE. The AGE showed a strong and concentration-dependent antioxidant (IC50 0.15–12.21 µg/mL) and anti-inflammatory (IC50 5.47–12.97 µg/mL) activity. Furthermore, it showed promising anti-angiogenic activity, inhibiting both the vessel growth (IC50 23.39 µg/egg) and the release of an endogenous phosphatase alkaline enzyme (IC50 44.24 µg/embryo). In conclusion, AGE is a promising source of antioxidant, anti-inflammatory and angio-modulator compounds

Characterization and In Vivo Antiangiogenic Activity Evaluation of Morin-Based Cyclodextrin Inclusion Complexes

Morin (MRN) is a natural compound with antiangiogenic, antioxidant, anti-inflammatory, and anticancer activity. However, it shows a very low water solubility (28 μg/mL) that reduces its oral absorption, making bioavailability low and unpredictable. To improve MRN solubility and positively affect its biological activity, particularly its antiangiogenic activity, in this work, we prepared the inclusion complexes of MNR with sulfobutylether-β-cyclodextrin (SBE-β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD). The inclusion complexes obtained by the freeze-drying method were extensively characterized in solution (phase-solubility studies, UV–Vis titration, and NMR spectroscopy) and in the solid state (TGA, DSC, and WAXD analysis). The complexation significantly increased the water solubility by about 100 times for MRN/HP-β-CD and 115 times for MRN/SBE-β-CD. Furthermore, quantitative dissolution of the complexes was observed within 60 min, whilst 1% of the free drug dissolved in the same experimental time. 1H NMR and UV–Vis titration studies demonstrated both CDs well include the benzoyl moiety of the drug. Additionally, SBE-β-CD could interact with the cinnamoyl moiety of MRN too. The complexes are stable in solution, showing a high value of association constant, that is, 3380 M−1 for MRN/HP-β-CD and 2870 M−1 for MRN/SBE-β-CD. In vivo biological studies on chick embryo chorioallantoic membrane (CAM) and zebrafish embryo models demonstrated the high biocompatibility of the inclusion complexes and the effective increase in antiangiogenic activity of complexed MRN with respect to the free drug

Evaluation of Anthocyanin Profile, Antioxidant, Cytoprotective, and Anti-Angiogenic Properties of Callistemon citrinus Flowers

Lemon bottlebrush (Callistemon citrinus (Curtis) Skeels) is one of the most common ornamental plants, diffused worldwide, and characterized by the presence of flowers with an intense red/purple coloration. There is increasing interest in the use and application of anthocyanins for their unique structural/chemical features in both food and pharmaceutical applications. RP-HPLC-DAD-ESI-MS/MS analysis of an enriched fraction of acidified methanolic extract of C. citrinus flowers allow the possibility of identifying, for the first time, the presence of four anthocyanins: cyanidin-3,5-O-diglucoside (cyanin), peonidin-3,5-O-diglucoside (peonin), cyanidin-3-O-glucoside, and cyanidin-coumaroylglucoside-pyruvic acid. Moreover, the evaluation of antioxidant and biological potential showed a remarkable activity of this fraction, able to actively scavenge DPPH, AAPH, and ABTS radicals, and to counteract the &beta;-carotene-bleaching. In addition, it protects human mononuclear cells from oxidative injuries and prevents angiogenesis (acting in the range of few &mu;g/ml); furthermore, it does not show significant iron-chelating ability (up to 200 &micro;g/mL). The easy way of cultivation, robustness, and adaptability to different environments make the flowers of this plant a useful source of anthocyanins, with remarkable health promoting properties

Pedoclimatic Conditions Influence the Morphological, Phytochemical and Biological Features of <i>Mentha pulegium</i> L.

In this study, Mentha pulegium leaves and flowers harvested in three different Sicilian areas were investigated from a micromorphological, phytochemical and biological point of view. Light and scanning electron microscopy showed the presence of spherocrystalline masses of diosmin both in the leaf epidermal cells and in thin flower petals. Two different chemotypes were identified (I, kaempferide/rosmarinic acid; II, jaceidin isomer A). Phytochemical screening identified plant from collection site II as the richest in total phenolics (16.74 g GAE/100 g DE) and that from collection site I as the richest in flavonoids (46.56 g RE/100 g DE). Seventy-seven metabolites were identified both in flower and leaf extracts. Plant from site II showed the best antioxidant (0.90–83.72 µg/mL) and anti-inflammatory (27.44–196.31 µg/mL) activity expressed as half-maximal inhibitory concentration (IC50) evaluated by DPPH, TEAC, FRAP, ORAC, BSA denaturation and protease inhibition assays. These data were also corroborated by in vitro cell-based assays on lymphocytes and erythrocytes. Moreover, plant of site II showed the best antiangiogenic properties (IC50 33.43–33.60 µg/mL) in vivo on a chick chorioallantoic membrane. In conclusion, pedoclimatic conditions influence the chemotype and the biological activity of M. pulegium, with chemotype I showing the most promising biological properties

Leveraging the 3-Chloro-4-fluorophenyl Motif to Identify Inhibitors of Tyrosinase from <i>Agaricus bisporus</i>

Tyrosinase (EC 1.14.18.1) is implicated in melanin production in various organisms. There is a growing body of evidence suggesting that the overproduction of melanin might be related to several skin pigmentation disorders as well as neurodegenerative processes in Parkinson’s disease. Based on this consideration, the development of tyrosinase inhibitors represents a new challenge to identify new agents in pharmaceutical and cosmetic applications. With the goal of identifying tyrosinase inhibitors from a synthetic source, we employed a cheap and facile preliminary assay using tyrosinase from Agaricus bisporus (AbTYR). We have previously demonstrated that the 4-fluorobenzyl moiety might be effective in interactions with the catalytic site of AbTYR; moreover, the additional chlorine atom exerted beneficial effects in enhancing inhibitory activity. Therefore, we planned the synthesis of new small compounds in which we incorporated the 3-chloro-4-fluorophenyl fragment into distinct chemotypes that revealed the ability to establish profitable contact with the AbTYR catalytic site. Our results confirmed that the presence of this fragment is an important structural feature to improve the AbTYR inhibition in these new chemotypes as well. Furthermore, docking analysis supported the best activity of the selected studied compounds, possessing higher potency when compared with reference compounds