Synergistic Effects of Caffeine in Combination with Conventional Drugs: Perspectives of a Drug That Never Ages

Plants have been known since ancient times for their healing properties, being used as preparations against human diseases of different etiologies. More recently, natural products have been studied and characterized, isolating the phytochemicals responsible for their bioactivity. Most certainly, there are currently numerous active compounds extracted from plants and used as drugs, dietary supplements, or sources of bioactive molecules that are useful in modern drug discovery. Furthermore, phytotherapeutics can modulate the clinical effects of co-administered conventional drugs. In the last few decades, the interest has increased even more in studying the positive synergistic effects between plant-derived bioactives and conventional drugs. Indeed, synergism is a process where multiple compounds act together to exert a merged effect that is greater than that of each of them summed together. The synergistic effects between phytotherapeutics and conventional drugs have been described in different therapeutic areas, and many drugs are based on synergistic interactions with plant derivatives. Among them, caffeine has shown positive synergistic effects with different conventional drugs. Indeed, in addition to their multiple pharmacological activities, a growing body of evidence highlights the synergistic effects of caffeine with different conventional drugs in various therapeutic fields. This review aims to provide an overview of the synergistic therapeutic effects of caffeine and conventional drugs, summarizing the progress reported to date

New Thiazolidine-4-One Derivatives as SARS-CoV-2 Main Protease Inhibitors

It has been more than four years since the first report of SARS-CoV-2, and humankind has experienced a pandemic with an unprecedented impact. Moreover, the new variants have made the situation even worse. Among viral enzymes, the SARS-CoV-2 main protease (Mpro) has been deemed a promising drug target vs. COVID-19. Indeed, Mpro is a pivotal enzyme for viral replication, and it is highly conserved within coronaviruses. It showed a high extent of conservation of the protease residues essential to the enzymatic activity, emphasizing its potential as a drug target to develop wide-spectrum antiviral agents effective not only vs. SARS-CoV-2 variants but also against other coronaviruses. Even though the FDA-approved drug nirmatrelvir, a Mpro inhibitor, has boosted the antiviral therapy for the treatment of COVID-19, the drug shows several drawbacks that hinder its clinical application. Herein, we report the synthesis of new thiazolidine-4-one derivatives endowed with inhibitory potencies in the micromolar range against SARS-CoV-2 Mpro. In silico studies shed light on the key structural requirements responsible for binding to highly conserved enzymatic residues, showing that the thiazolidinone core acts as a mimetic of the Gln amino acid of the natural substrate and the central role of the nitro-substituted aromatic portion in establishing π-π stacking interactions with the catalytic His-41 residue

Discovery of quinolinonyl derivatives as anti-HIV-1 inhibitors endowed with an innovative mechanism of action.

HIV integrase (IN) is a pivotal antiretroviral drug target. In this regard, IN strand transfer inhibitors (INSTIs), binding to the IN active site, have proven to be highly effective, becoming a potent first-line therapy to treat infected patients. However, despite their effectiveness as therapeutic options and the high barriers with the second-generation FDA-approved INSTIs, drug therapy selects for drug resistance and mutations responsible for multiple INSTIs resistance, underscoring the need for the development of more effective antiretroviral compounds. The development of small molecule protein-protein interaction inhibitors is a new attractive strategy for discovering anti-HIV agents. In this field of research, allosteric IN inhibitors (ALLINIs), are a promising new class of antiretroviral agents. These inhibitors act differently in respect to INSTIs, in fact, they alter the functional IN multimerization. Recently, it was unraveled that aberrant IN multimerization underlies the inhibition of IN-vRNA interactions by ALLINIs. In doing so, ALLINIs indirectly disrupt the IN-vRNA binding, leading to the formation of defective viral particles with greatly reduced infective potential with mis-localization of the vRNA outside the viral capsid. While the indirect disruption of IN-vRNA binding (caused by the impairment of functional IN multimerization) has been described with the treatment of virus-producing cells with ALLINIs, the direct disruption of this binding (without affecting IN multimerization properties) by small molecules has not been reported so far. We describe a series of compounds identified as inhibitors of the IN-vRNA binding via a direct mechanism. In particular, we deepened the mechanism of action of some compounds previously described by us as INSTIs. Indeed, we speculated that these quinolinonyl derivatives, being endowed with two DKA chains, could also act as protein-nucleic acid interaction inhibitors. To verify our hypothesis, we decided to test a set of derivatives and their analogues endowed with a variable “base-like” functional group. We assessed the capability of our derivatives of inhibiting at low micromolar concentrations both IN 3’-processing and strand transfer reactions in a LEDGF/p75 independent assay. In addition, we performed in vitro binding assays, and we found that our quinolinonyl derivatives are able to disrupt the IN-vRNA interaction, that is vital for a correct generation of a functional infective virion. The data coming from the biological assays will be shown and discussed

Identification of novel aminopyrimidine derivatives as protein kinase inhibitors blocking cell growth.

Aminopyrimidine scaffold is typical of some of the most promising anticancer drug recently discovered thanks to their ability to inhibit different types of protein kinases. Kinase deregulation has emerged as a relevant mechanism by which cancer cells evade normal physiological constraints and kinases inhibitors have become one of the most intensively pursued classes of recent antitumoral drugs. Owing to the significance of pyrimidine derivatives as anticancer agents through kinase inhibition and our longstanding expertise in the development of pyrimidine derivatives, we designed and synthesized various classes of anilino and bis-anilinopyrimidines. Most of them were found active in in vitro HTRF inhibition assays in low nanomolar range against one or more kinases, like EGFR, c-KIT, VEGFR, PDGFR, Akt and AURKA, wild type or mutated and double-mutated isoforms. Some compounds were also crystallized in the active site of some kinases, showing a preference for DFG-in or DFG-out conformation. Subsequently, the antitumor activity of selected compounds was evaluated on three different human cancer types chosen on the basis of their unsatisfactory therapeutic strategies and poor prognosis: glioblastoma multiforme, triple-negative breast cancer, colon adenocarcinoma, tongue squamous carcinoma and hypopharyngeal squamous carcinoma. Various pyrimidines demonstrated to also hinder cell proliferation and cell cycle and to induce apoptosis in all the tested cell lines, without exerting cytotoxic effects at the same concentrations. The data coming from the biological assays will be shown and discussed

New diketo acid derivatives as dual SARS-CoV-2 nsp13 inhibitors active against viral replication.

The diffusion of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic with unprecedent socioeconomical impact, enlightening the need of new antiviral agents able to block viral replication. The development of vaccines is essential in the containment of the diffusion of the virus, and an incredible joint effort led to a global vaccination campaign in about 1 year after the virus outbreak. However, vaccines may be less or no effective against emerging variants of SARS-CoV-2 and, also, it is still unknown how long this vaccine-induced immunity will last. Therefore, the development of antiviral drugs against SARS-CoV-2 is of pivotal importance. The SARS-CoV-2 non-structural protein 13 (nsp13) has been identified as a target for antiviral drugs thanks to its critical role in viral replication and to its high sequence conservation within the coronavirus family. Nsp13 targets the natural nucleotides and deoxynucleotides as substrates when performing its adenosine triphosphatase (ATPase) activity, utilizing the energy of nucleotide triphosphate hydrolysis to catalyze the unwinding of double-stranded DNA or RNA in a 5′ to 3′ direction. Although the roles of nsp13 in the viral lifecycle, there is a paucity of information about small molecules compounds reported in literature endowed with nsp13-inhibitory activity. Aryl diketo acids (DKAs) have been previously described as inhibitors of nsp13 of SARS-CoV-1. Basing on these literature data and thanks to our longstanding expertise in the design and synthesis of DKA derivatives, we carried out a semi-random screening on our in-house library of DKA compounds, identifying a promising hit compound as micromolar nsp13 inhibitor. We synthesized a set of indolyl DKA derivatives as structurally correlated with the identified hit, obtaining new dual SARS-CoV-2 nsp13 ATPase and helicase inhibitors, also capable of inhibiting viral replication. Mode-of-action studies revealed ATP-non-competitive kinetics of inhibition, not affected by substrate-displacement effect, suggesting an allosteric binding. The data coming from the biological assays will be shown and discussed

Miconazole-like compounds as brain permeable anti-Naegleria Fowleri agents targeting CYP51.

The free-living ameboflagellate Naegleria fowleri is an opportunistic pathogen causing a fulminating brain infection namely primary amoebic meningoencephalitis (PAM) that can result in death within days, with a worldwide distribution and over 97% fatality rate. Even though PAM is considered rare, with 381 global PAM cases reported by the Center for Disease Control and Prevention, this is likely an underestimate of the true worldwide occurrence of PAM. Currently, there is no standard regimen to treat N. fowleri infections in humans and only seven patients have been successfully treated so far using Amphotericin B (AmpB), either alone or in combination with other drugs. However, clinical use of AmpB is limited due to its toxicity, including acute infusion-related reactions and dose-related nephrotoxicity. For these reasons the development of effective and safe drugs for the PAM treatment represents a real unmet medical need. Over the past few years, we validated several steroidogenic enzymes as drug targets. In particular, disruption of sterol 14-demethylase (CYP51) function by sterol biosynthesis inhibitors, induced massive autophagocytosis leading to N. fowleri cell death after 24 h of drug exposure. Notably, in vitro growth inhibition of N. fowleri by CYP51 inhibitors, including antifungal conazole drugs, has been reported in literature and some of them, even though endowed with poor blood-brain barrier (BBB) permeability, have been used in combination therapies with AmpB for the treatment of PAM patients. In this work, we provide evidence that miconazole-like compounds could be considered as drug candidates for the treatment of PAM. We used a combination of the cheminformatics, target-based and phenotypic drug discovery methods to identify a lead scaffold conducive to BBB permeability capable of targeting N. fowleri CYP51 (NfCYP51). 124 compounds pre-selected in silico were tested against N. fowleri trophozoites, allowing to identify nine hits with EC 50 ≤ 10 μM. The top hit was identified via cross- validation in co-crystallization with the NfCYP51 target that singled out a miconazole-like scaffold having the best drug-target fit. Based on the co-crystal structure, a set of analogs was synthesized and biochemically evaluated, confirming the superiority of the S- over R-configuration and the advantage of ether over ester linkage. The two best acting compounds exhibited improved EC 50 and K D compared to hit, both readily distributed into the brain. Brain-to-plasma distribution coefficient of the best acting compound was 1.02±0.12, holding a promise for further optimization into a drug candidate. Synthetic pathways, in vitro activities, X-ray crystallography data and pharmacokinetic study will be shown and discussed