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The release of pro-inflammatory mediators, such as prostaglandines (PGs) and leukotrienes (LTs), arising from the arachidonic acid (AA) cascade, play a crucial role in initiating, maintaining, and regulating inflammatory processes. New dual inhibitors of 5-lipoxygenase (5-LO) and microsomal prostaglandin E 2 synthase-1 (mPGES-1), that block, at the same time, the formation of PGE 2 and LTs, are currently emerged as a highly interesting drug candidates for better pharmacotherapie of inflammation-related disorders. Following our previous studies, we here performed a detailed structure-based design of benzo[g]indol-3-carboxylate derivatives, disclosing several new key factors that affect both enzyme activity. Ethyl 2-(3,4-dichlorobenzyl)-5-hydroxy-1H-benzo[g]indole-3-carboxylate (4b, RAF-01) and ethyl 2-(3,4-dichlorophenyl)-5-hydroxy-1H-benzo[g]indole-3-carboxylate (7h, RAF-02) emerged as the most active compounds of the series. Additionally, together with selected structure based analogues, both derivatives displayed significant in vivo anti-inflammatory properties. In conclusion, modeling and experimental studies lead to the discovery of new candidate compounds prone to further developments as multi-target inhibitors of the inflammatory pathway., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

We recently identified indole derivatives (IIIe and IIIf) with anti-chikungunya virus (CHIKV) activities at lower micro molar concentrations and a selective index of inhibition higher than the lead compound Arbidol. Here we highlight new structural information for the optimization of the previously identified lead compounds that contain the indole chemical core. Based on the structural data, a series of indole derivatives was synthesized and tested for their antiviral activity against chikungunya virus in Vero cell culture by a CPE reduction assay. Systematic optimization of the lead compounds resulted in tert-butyl-5-hydroxy-1-methyl-2-(2-trifluoromethysulfynyl)methyl)-indole-3-carboxylate derivative IIc with a 10-fold improved anti-CHIKV inhibitory activity (EC 50 =6.5±1μM) as compared to Arbidol demonstrating a potent, selective and specific inhibition of CHIKV replication with only a moderate cell protective effect against other related alphaviruses. The reported computational insights, together with the accessible synthetic procedure, pave the road towards the design of novel synthetic derivatives with enhanced anti-viral activities., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Following the results we previously reported on a series of ethyl 2-phenylthiomethyl 5-hydroxyindole-3-carboxylate derivatives as 5-lipoxygenase (5-LOX) inhibitors, in order to obtain a more selective compound with respect to the previous generation of derivatives, we decided to modify the structure of the core ligand. The first level of structural modification involved the annelation of benzene to the indole, yielding corresponding benzo[g]indole derivatives, systematic optimization of methyl or chlorine groups in meta-, ortho- and ortho/para-position of 2-phenylthiomethyl moiety were applied. The reported results show that extension of the aromatic core led to a great enhancement of activity, especially in cell-free assay, and the accurate structure-based design provided compounds 6f, 6g and 6l that block 5-LOX activity in cell-free assays with IC50 ranging from 0.17 to 0.22 μM, and suppress 5-LOX product synthesis in polymorphonuclear leukocytes with IC50 ranging from 0.19 to 0.37 μM. Moreover we have identified 6f and 6l as dual 5-lipoxygenase (5-LO) and microsomal prostaglandin E2 synthase-1 (mPGES-1) inhibitors and compound 6l significantly reduces inflammatory reactions in the carrageenan-induced mouse paw oedema. The reported in vivo analysis, together with the accessible synthetic procedure, stimulate for the generation of further potent antinflammatory benzoindoles-based agents., (Copyright © 2015. Published by Elsevier Masson SAS.)

Chikungunya virus (CHIKV), a mosquito-borne arthrogenic Alphavirus, causes an acute febrile illness in humans, that is, accompanied by severe joint pains. In many cases, the infection leads to persistent arthralgia, which may last for weeks to several years. The re-emergence of this infection in the early 2000s was exemplified by numerous outbreaks in the eastern hemisphere. Since then, the virus is rapidly spreading. Currently, no drugs have been approved or are in development for the treatment of CHIKV, which makes this viral infection particularly interesting for academic medicinal chemistry efforts. Several molecules have already been identified that inhibit CHIKV replication in phenotypic virus-cell-based assays. One of these is arbidol, a molecule that already has been licensed for the treatment of influenza A and B virus infections. For structural optimization, a dedicated libraries of 43 indole-based derivatives were evaluated leading to more potent analogues (IIIe and IIIf) with anti-chikungunya virus (CHIKV) activities higher than those of the other derivatives, including the lead compound, and with a selective index of inhibition 13.2 and 14.6, respectively, higher than that of ARB (4.6)., (Copyright © 2014. Published by Elsevier Ltd.)

Arbidol (ARB) is an antiviral drug that has broad-spectrum activity against a number of viral infections. To date, there are no specific data regarding its effects against a herpesvirus. Here, the in vitro antiviral effect of ARB and structurally related derivatives were evaluated in HaCat cells on different steps of herpes simplex virus type 1 replication: adsorption, entry and post-entry. The simplified pyrrolidine analogue, 9a2, showed the best antiviral activity in vitro by reducing the plaque numbers by about 50% instead of 42% obtained with ARB at the same concentration. Furthermore, we have reported that all tested compounds evaluated for their immunomodulatory activity showed the ability to reduce the viral proteins VP16 and ICP27 and to modify the virus-induced cytokine expression, allowing the host cell a more efficient antiviral response., (© 2014 The Authors.)

5-Lipoxygenase (5-LO), an enzyme that catalyzes the initial steps in the biosynthesis of pro-inflammatory leukotrienes, is an attractive drug target for the pharmacotherapy of inflammatory and allergic diseases. Here, we present the design, synthesis and biological evaluation of novel series of ethyl 5-hydroxyindole-3-carboxylate derivatives that efficiently inhibit human 5-LO. SAR analysis revealed that the potency of compounds is closely related to the positioning of the substituents at the phenylthiomethyl ring. The introduction of methyl or chlorine groups in ortho- and ortho/para-position of thiophenol represent the most favorable modifications. Among all tested compounds, ethyl 5-hydroxy-2-(mesitylthiomethyl)-1-methyl-1H-indole-3-carboxylate (19) is the most potent derivative which blocks 5-LO activity in cell-free assays with IC50 = 0.7 μM, and suppressed 5-LO product synthesis in polymorphonuclear leukocytes with IC50 = 0.23 μM., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

The fusion of virus and endosome membranes is an essential early stage in influenza virus infection. The low pH-induced conformational change which promotes the fusogenic activity of the haemagglutinin (HA) is thus an attractive target as an antiviral strategy. The anti-influenza drug Arbidol is representative of a class of antivirals which inhibits HA-mediated membrane fusion by increasing the acid stability of the HA. In this study two series of indole derivatives structurally related to Arbidol were designed and synthesized to further probe the foundation of its antiviral activity and develop the basis for a structure-activity relationship (SAR). Ethyl 5-(hydroxymethyl)-1-methyl-2-(phenysulphanylmethyl)-1H-indole-3-carboxylate (15) was identified as one of the most potent inhibitors and more potent than Arbidol against certain subtypes of influenza A viruses. In particular, 15 exhibited a much greater affinity and preference for binding group 2 than group 1 HAs, and exerted a greater stabilising effect, in contrast to Arbidol. The results provide the basis for more detailed SAR studies of Arbidol binding to HA; however, the greater affinity for binding HA was not reflected in a comparable increase in antiviral activity of 15, apparently reflecting the complex nature of the antiviral activity of Arbidol and its derivatives., (Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.)