Antiretroviral Activity Research Articles

PREDICTION OF BIOLOGICAL ACTIVITY BY MEANS OF SYNTHESIS AND QSAR MODEL OF PHENYLHYDRAZONE BASED ON METHYL 4-FORMYLBENZOATE

In the submitted article, on the basis of methyl 4-formylbenzoate, the corresponding phenylhydrazones were synthesized and their structure was confirmed by NMR. A computer simulation was carried out to assess the possible toxicological risks, antiviral, antibacterial, antifungal activities and antiretroviral activities of the compounds, taking into account the high biological activity of phenylhydrazones, in particular the benzoate group. Five online computer programs were used for this: Gusar (Acute Rat Toxicity), PASS Online (AntiVir-Pred), PASS Online (AntiBac-Pred), PASS Online (AntiFun-Pred), PASS Online (AntiHiv-Pred). The predictions of toxicity and antiviral, antibacterial, antifungal activations and antiretroviral activity using the mentioned programs are based on computer learning based on the structural similarity of molecules, widespread character traits and predetermined real (in vitro and in vivo) models, resulting in predicted biological activity of existing and virtual compounds. The results obtained are satisfactory and may provide information about the existence of the biological activity of the compounds mentioned.

Emergent resistance-associated mutations at first- or second-line HIV-1 virologic failure with second-generation InSTIs in two- and three-drug regimens: the Virostar-1 study.

Second-generation integrase strand transfer inhibitors (InSTIs) have a high barrier to resistance and potent antiretroviral activity. They are recommended as first- or second-line (FL and SL) options in two- and three-drug regimens (2DR and 3DR) in international treatment guidelines. However, there are limited real-world data on emerging resistance at the time of virological failure (VF) with these regimens. The Virostar-1 study objective is to analyse the emergence of resistance-associated mutations (RAMs) over 3 years with DTG-based 2DRs and DTG- or bictegravir (BIC)-based 3DRs in people living with HIV (PLWH) experiencing a VF (FL or SL). Retrospective analysis of genotypic resistance detected at the time of a FL or SL VF with BIC/FTC/TAF, DTG/ABC/3TC, DTG/3TC and DTG/RPV between 2019 and 2022 was conducted from a French multicentre database. VF was defined as two consecutive HIV-1 plasma viral loads > 50 c/mL. Sanger assays were performed at VF within standard clinical care. Resistance mutations were reported using the ANRS algorithm. Selection biases prevent group comparisons. During the period, N = 5986 PLWH were followed either in FL or SL. The VF rate was overall low: BIC/FTC/TAF, 6.8%; DTG/ABC/3TC, 7.5%; DTG/3TC, 5.1%; and DTG/RPV, 2.1%. Some emergent InSTI or NRTI RAMs were detected with BIC/FTC/TAF 4%, DTG/ABC/3TC 8.5%, DTG/3TC 18% and 39% emergent NNRTI RAMs with DTG/RPV. However, a complete absence of dual resistance against NRTIs and InSTIs was observed. We detected rare emergent InSTI RAMs and few emergent NRTI RAMs in PLWH failing DTG- or BIC-based regimens in FL or SL. The observed rates of emergent RAMs at VF were 4% with BIC/FTC/TAF, 8.5% with DTG/ABC/3TC, 18% with DTG/3TC and 39% with DTG/RPV.

On the health effects of curcumin and its derivatives.

Turmeric (Curcuma longa) is an herbaceous plant that contains a phytochemical which is bright yellow and is known as curcumin. Turmeric, a member of Zingiberaceae family, has extensive application worldwide due to its beneficial medicinal attributes and is extensively used as a medicinal plant. Most people use turmeric as a spice, and it is a chief source of polyphenol curcumin. Curcuma longa has therapeutic properties, and since the initial extraction of curcumin from this plant, it has gained prodigious consideration from scientists in the medical field. The biological properties of curcumin, also known as 1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, or diferuloylmethane, include anti-inflammatory, anti-oxidant, anti-cancer, anti-asthmatic, anti-arthritic, neuroprotective, anti-diabetic, anti-obesity, wound-healing, hepatoprotective, skin curative, reproductive role, etc. This work has reviewed many clinical trials and their findings about these activities. The focus of this review manuscript is concentrated on the presently existing clinical and animal studies, which exposed the possible anti-retroviral activities of curcumin and its by-products.

Development of an extended action fostemsavir lipid nanoparticle

An extended action fostemsavir (FTR) lipid nanoparticle (LNP) formulation prevents human immunodeficiency virus type one (HIV-1) infection. This FTR formulation establishes a drug depot in monocyte-derived macrophages that extend the drug’s plasma residence time. The LNP’s physicochemical properties improve FTR’s antiretroviral activities, which are linked to the drug’s ability to withstand fluid flow forces and levels of drug cellular internalization. Each is, in measure, dependent on PEGylated lipid composition and flow rate ratios affecting the size, polydispersity, shape, zeta potential, stability, biodistribution, and antiretroviral efficacy. The FTR LNP physicochemical properties enable the drug-particle’s extended actions.

Antiviral therapy in cats progressively infected with feline leukaemia virus: lessons from a series of 18 consecutive cases from Australia.

It is doubtful that any of the treatments proposed for feline leukaemia virus (FeLV) infection are effective, despite the entity being described 60 years ago. Eighteen pet cats with progressive FeLV infections were recruited in Australia. One or more antiviral drugs were trialled in 16 cats, while two FeLV-infected cats were not handleable and served as untreated controls. Six cats were administered RetroMAD1™ only (0.5 mg/kg orally twice daily), a commercially available recombinant chimeric protein with proposed antiretroviral activity. Three cats were administered the integrase inhibitor raltegravir only (10-15 mg/kg orally twice daily), a drug used as a component of highly effective antiretroviral therapy for human immunodeficiency virus (HIV-1) infection. Three cats were administered RetroMAD1™ and raltegravir concurrently, and four cats were administered raltegravir and the reverse transcriptase inhibitor zidovudine (AZT, 5 mg/kg orally twice daily) concurrently. FeLV RNA and p27 antigen loads were measured at two timepoints (T1-2 months and T3-5 months) during therapy and compared to baseline (pretreatment) levels, to assess the response to therapy using linear modelling. The median survival time (MST) of the cats from commencement of FeLV treatment to death was also determined and compared between treatments. The MST for the 16 FeLV-positive cats which received antiviral therapy was 634 days, while the MST from FeLV diagnosis to death for the two untreated control cats was 780 days. In cats treated with RetroMAD1™, FeLV viral load decreased from T0 to T1-2 months (median viral load reduced from 1339 × 106 to 705 × 106 copies/mL plasma; P = 0.012), but MST was reduced compared to cats not given RetroMAD1™ (426 days vs 1006 days; P = 0.049). Cats treated with raltegravir and AZT had no significant changes in FeLV viral load over time, but p27 antigen load was decreased from T0 to T3-5 months in cats treated with raltegravir (median p27 antigen level reduced from 50.2% to 42.7%; P = 0.005). All other results were not significantly affected by the treatment provided. Importantly, statistically significant and substantial associations were found between age at FeLV diagnosis and survival time (P = 0.046, R2 = 18.6) and between FeLV viral load at T0 and survival time (P = 0.004, R2 = 44.4). Younger cats, and cats with higher levels of pretreatment FeLV RNA, had reduced survival times. Cats treated with RetroMAD1™ were typically younger (median age 2.0 vs 8.0 years), likely explaining the observed reduction in MST. A significant association was found between FeLV viral load and p27 antigen load at T0 (P = 0.015, R2 = 32.9). Results from this small case series do not provide convincing support for the use of RetroMAD1™, raltegravir or AZT, alone or in combination, for the treatment of cats progressively infected with FeLV. The changes observed were biologically insignificant. Age and FeLV viral load at diagnosis are useful prognostic markers, and p27 antigen concentration can be used to predict viral load. Larger field trials should be performed examining antiretroviral therapy in FeLV-positive cats with progressive infections, preferably using three or more drugs from at least two classes, as is standard with human antiretroviral therapy. Future studies would be easier in countries with a higher prevalence of FeLV infections than Australia.

Antiretroviral activity from elderberry (<i>Sambucus nigra</i> L.) flowers against HIV-2 infection via reverse transcriptase inhibition: a viroinformatics study

HIV-2 infection is a unique concern with fewer cases than HIV-1, but it poses a high mortality rate due to its resistance to all HIV-1 antiretroviral treatments. This study focuses on one type of antiretroviral, reverse transcriptase (RT) inhibitors, as they play an important role in HIV-2 replication. The screening of potential HIV-2 antiretroviral candidates was carried out using compounds from elderberry (Sambucus nigra L.) flower extract. There is a lack of research on the antiviral potential of elderberry flower extracts, particularly in HIV-2; therefore, this study is important to explain the molecular mechanism underlying the potential of elderberry (Sambucus nigra L.) flower extracts to inhibit RT activity in HIV-2 through bioinformatics simulations. This study uses the in silico method, involving sample preparation in the database, drug-like molecular prediction through the server, molecular docking simulation, chemical bond interaction analysis, and three-dimensional structure visualization. Isorhamnetin has the most negative binding affinity of -9.9 kcal/mol compared to other compounds. It interacts with the HIV-2 RT domain at residues Trp4(B), Pro25(B), Asn137(B), Pro133(B), Gln23(B), Pro140(B), Leu21(B), Ile90(A), Thr131(B), Asn57(B), Arg22(B), and Glu89(A) with hydrophobic bond interactions. Hydrogen bond interactions are formed at the positions of Ser134(B), Gly141(B), and Thr88(A). Isorhamnetin from elderberry (Sambucus nigra L.) flower extract could be a potential HIV-2 antiretroviral candidate because it has the most negative binding affinity and the formation of hydrophobic hydrogen bond interactions on the RT domain.

Broad synergistic antiviral efficacy between a novel elite controller-derived dipeptide and antiretrovirals against drug-resistant HIV-1.

The naturally occurring dipeptide Tryptophylglycine (WG) is enhanced in human immunodeficiency virus (HIV-1) infected Elite Controllers (EC). We have shown that this dipeptide has an anti-HIV-1 effect and evaluated now its synergistic antiretroviral activity, in combination with current antiretrovirals against multi-drug resistant HIV-1 isolates. Drug selectivity assay with WG-am and ARVs agains HIV-1 resistant isolates were carried out. Subsequently, two methods, Chou-Talalay's Combination Index (CI) and ZIP synergy score (SS), were used to quantify the synergism. WG-am had a moderate/strong synergism with the four tested antiretrovirals: raltegravir, tenofovir, efavirenz, darunavir. WG-am:TDF had strong synergism at ED50, ED75, ED90 (CI: <0.2) in isolates resistant to protease inhibitors or integrase strand inhibitors (INSTI), and a slightly less synergism in isolates resistant to non-nucleoside or nucleotide reverse transcriptase inhibitors. WG-am combined with each of the four drugs inhibited all drug-resistant isolates with over 95% reduction at maximum concentration tested. The highest selectivity indexes (CC50/ED50) were in INSTI-resistant isolates. Our data suggest that WG, identified as occurring and enhanced in Elite Controllers has a potential to become a future treatment option in patients with HIV-1 strains resistant to any of the four major categories of anti-HIV-1 compounds.

CCR5 Decorated Rilpivirine Lipid Nanoparticles Build Myeloid Drug Depots Which Sustains Antiretroviral Activities.

Antiretroviral therapy (ART) improves the quality of life for those living with the human immunodeficiency virus type one (HIV-1). However, poor compliance reduces ART effectiveness and leads to immune compromise, viral mutations, and disease co-morbidities. A novel drug formulation is made whereby a lipid nanoparticle (LNP) carrying rilpivirine (RPV) is decorated with the C-C chemokine receptor type 5 (CCR5). This facilitates myeloid drug depot deposition. Particle delivery to viral reservoirs is tracked by positron emission tomography. The CCR5-mediated RPV LNP cell uptake and retention reduce HIV-1 replication in human monocyte-derived macrophages and infected humanized mice. Focused ultrasound allows the decorated LNP to penetrate the blood-brain barrier and reach brain myeloid cells. These findings offer a role for CCR5-targeted therapeutics in antiretroviral delivery to optimize HIV suppression.

Discovery of low-molecular-weight phenylalanine derivatives as novel HIV capsid modulators with improved antiretroviral activity and metabolic stability.

The HIV capsid (CA) protein is a promising target for anti-AIDS treatment due to its critical involvement in viral replication. Herein, we utilized the well-documented CA inhibitor PF74 as our lead compound and designed a series of low-molecular-weight phenylalanine derivatives. Among them, compound 7t exhibited remarkable antiviral activity with a high selection index (EC50 = 0.040 µM, SI = 2815), surpassing that of PF74 (EC50 = 0.50 µM, SI = 258). Furthermore, when evaluated against the HIV-2 strain, 7t (EC50 = 0.13 µM) demonstrated approximately 14-fold higher potency than that of PF74 (EC50 = 1.76 µM). Insights obtained from surface plasmon resonance (SPR) revealed that 7t exhibited stronger target affinity to the CA hexamer and monomer in comparison to PF74. The potential interactions between 7t and the HIV-1 CA were further elucidated using molecular docking and molecular dynamics simulations, providing a plausible explanation for the enhanced target affinity with 7t over PF74. Moreover, the metabolic stability assay demonstrated that 7t (T1/2 = 77.0 min) significantly outperforms PF74 (T1/2 = 0.7 min) in human liver microsome, exhibiting an improvement factor of 110-fold. In conclusion, 7t emerges as a promising drug candidate warranting further investigation.

A Variety of Mouse PYHIN Proteins Restrict Murine and Human Retroviruses.

PYHIN proteins are only found in mammals and play key roles in the defense against bacterial and viral pathogens. The corresponding gene locus shows variable deletion and expansion ranging from 0 genes in bats, over 1 in cows, and 4 in humans to a maximum of 13 in mice. While initially thought to act as cytosolic immune sensors that recognize foreign DNA, increasing evidence suggests that PYHIN proteins also inhibit viral pathogens by more direct mechanisms. Here, we examined the ability of all 13 murine PYHIN proteins to inhibit HIV-1 and murine leukemia virus (MLV). We show that overexpression of p203, p204, p205, p208, p209, p210, p211, and p212 strongly inhibits production of infectious HIV-1; p202, p207, and p213 had no significant effects, while p206 and p214 showed intermediate phenotypes. The inhibitory effects on infectious HIV-1 production correlated significantly with the suppression of reporter gene expression by a proviral Moloney MLV-eGFP construct and HIV-1 and Friend MLV LTR luciferase reporter constructs. Altogether, our data show that the antiretroviral activity of PYHIN proteins is conserved between men and mice and further support the key role of nuclear PYHIN proteins in innate antiviral immunity.

Navigating the Antiretroviral Therapy Switch Conundrum: Unveiling the Dilemma of Drug Resistance and Disease Progression in HIV/AIDS.

There is a need to establish consensus for harmonization in antiretroviral (ARV) therapy (ART) switch treatment strategy and address the dilemma that exists in terms of subpar immune response to therapy or an immunologic deterioration while on therapy. The purpose of thisreview is to identifythe factors that contribute to ARV treatment failure, such as insufficient dosage, drug interactions, poor adherence, drug resistance, and poor medication absorption. It is crucial to adopt a more efficient strategy to address this challenging dilemma. After ARV treatment failure, the aim of therapy is virologic suppression, which targets plasma viral load below the limits of detection as assessed by very sensitive tests with lower limits of quantification of 20 to 75 RNA copies/ml. The therapeutic objectives when complete virologic suppression is not possible, should be to maintain or restore immunologic function, stop the progression of the clinical illness, and minimize the emergence of new drug resistance that could further restrict the options for ARV drugs. Treatment history and drug-resistance testing, including the findings of previous and ongoing resistance tests, should be considered while selecting ARV regimens. Hence, the treatment approach post-ARV failure can be personalized based on clinical, immunologic, virologic, or as a mix of the three domains on a case-to-case basis. The evaluation of projected ARV activity should be based on treatment history and previous resistance test findings.

IFNα Subtypes in HIV Infection and Immunity.

Type I interferons (IFN), immediately triggered following most viral infections, play a pivotal role in direct antiviral immunity and act as a bridge between innate and adaptive immune responses. However, numerous viruses have evolved evasion strategies against IFN responses, prompting the exploration of therapeutic alternatives for viral infections. Within the type I IFN family, 12 IFNα subtypes exist, all binding to the same receptor but displaying significant variations in their biological activities. Currently, clinical treatments for chronic virus infections predominantly rely on a single IFNα subtype (IFNα2a/b). However, the efficacy of this therapeutic treatment is relatively limited, particularly in the context of Human Immunodeficiency Virus (HIV) infection. Recent investigations have delved into alternative IFNα subtypes, identifying certain subtypes as highly potent, and their antiviral and immunomodulatory properties have been extensively characterized. This review consolidates recent findings on the roles of individual IFNα subtypes during HIV and Simian Immunodeficiency Virus (SIV) infections. It encompasses their induction in the context of HIV/SIV infection, their antiretroviral activity, and the diverse regulation of the immune response against HIV by distinct IFNα subtypes. These insights may pave the way for innovative strategies in HIV cure or functional cure studies.

Antiretroviral action of Rosemary oil-based atazanavir formulation and the role of self-nanoemulsifying drug delivery system in the management of HIV-1 infection.

Atazanavir or ATV is an FDA-approved, HIV-1 protease inhibitor that belongs to the azapeptide group. Over time, it has been observed that ATV can cause multiple adverse side effects in the form of liver diseases including elevations in serum aminotransferase, indirect hyper-bilirubinemia, and idiosyncratic acute liver injury aggravating the underlying chronic viral hepatitis. Hence, there is an incessant need to explore the safe and efficacious method of delivering ATV in a controlled manner that may reduce the proportion of its idiosyncratic reactions in patients who are on antiretroviral therapy for years. In this study, we assessed ATV formulation along with Rosemary oil to enhance the anti-HIV-1 activity and its controlled delivery through self-nanoemulsifying drug delivery system or SNEDDS to enhance its oral bioavailability. While the designing, development, and characterization of ATV-SNEDDS were addressed through various evaluation parameters and pharmacokinetic-based studies, in vitro cell-based experiments assured the safety and efficacy of the designed ATV formulation. The study discovered the potential of ATV-SNEDDS to inhibit HIV-1 infection at a lower concentration as compared to its pure counterpart. Simultaneously, we could also demonstrate the ATV and Rosemary oil providing leads for designing and developing such formulations for the management of HIV-1 infections with the alleviation in the risk of adverse reactions.

In vivo evaluation of the antiretroviral activity of Melia azedarach against small ruminant lentiviruses in goat colostrum and milk.

This study aimed to evaluate in vivo the use of the extract from the leaves of Melia azedarach in the ethyl acetate fraction at a concentration of 150µg/mL as an antiretroviral treatment against small ruminant lentiviruses (SRLV) in goat colostrum, and milk with a 90-min action. Two groups of six kids were treated with the extract. One group received three supplies of colostrum from does naturally positive for SRLV, treated with the ethyl acetate fraction of M. azedarach (EAF-MA) for three days, while the other group consumed milk from does also carrying the virus with the respective extract twice a day for five days. After undergoing treatment, all animals began to receive thermized milk until weaning (60days) and were monitored for six months using nested polymerase chain reaction (nPCR) and western blot (WB) tests. The study revealed cumulative percentages of positive animals in WB or nPCR in the milk group of 66.66% on the seventh day, 83.33% in the following week, and 100% at 120days, while the colostrum group showed values of 66.66% at 14days, 83.33% at 90days, and 100% at 120days. Variation and intermittency were observed in viral detection, but all animals tested positive in WB or nPCR at some point. A potential delay in infection was observed, which was more significant in the colostrum group. The need for the combination of serological and molecular tests for a more efficient detection of the disease is also emphasized.

Exploring the HIV-1 Rev Recognition Element (RRE)-Rev Inhibitory Capacity and Antiretroviral Action of Benfluron Analogs.

Human immunodeficiency virus-type 1 (HIV-1) remains one of the leading contributors to the global burden of disease, and novel antiretroviral agents with alternative mechanisms are needed to cure this infection. Here, we describe an exploratory attempt to optimize the antiretroviral properties of benfluron, a cytostatic agent previously reported to exhibit strong anti-HIV activity likely based on inhibitory actions on virus transcription and Rev-mediated viral RNA export. After obtaining six analogs designed to modify the benzo[c]fluorenone system of the parent molecule, we examined their antiretroviral and toxicity properties together with their capacity to recognize the Rev Recognition Element (RRE) of the virus RNA and inhibit the RRE-Rev interaction. The results indicated that both the benzo[c] and cyclopentanone components of benfluron are required for strong RRE-Rev target engagement and antiretroviral activity and revealed the relative impact of these moieties on RRE affinity, RRE-Rev inhibition, antiviral action and cellular toxicity. These data provide insights into the biological properties of the benzo[c]fluorenone scaffold and contribute to facilitating the design of new anti-HIV agents based on the inhibition of Rev function.

Novel HIV-1 RNA biogenesis inhibitors identified by virtual pharmacophore-based screening

The complex between the Rev protein of HIV-1 and the Rev Recognition Element (RRE) within the virus RNA promotes nuclear export of unspliced or incompletely spliced viral transcripts and is required for virus transmission. Here, we have screened a virtual collection of compounds using a pharmacophore based on the chemical similarity of previously characterized inhibitors to identify new chemical scaffolds blocking the RRE-Rev interaction. The best molecules discovered with this strategy inhibited the complex by binding to the RRE and exhibited substantial antiretroviral activity (between 0.582 and 11.3 μM EC50 values) likely associated to inhibitory actions on viral transcription and Rev function. These results have allowed us to identify structural features required for RRE-Rev inhibition as well as to add new compounds to the pool of possible candidates for developing antiretroviral agents based on blockage of HIV-1 RNA biogenesis.

Withania somnifera extracts induced attenuation of HIV-1: a mechanistic approach to restrict viral infection

BackgroundSeveral anti-retroviral drugs are available against Human immunodeficiency virus type-1, but have multiple adverse side effects. Hence, there is an incessant compulsion for effectual anti-retroviral agents with minimal or no intricacy. Traditionally, natural products have been the most successful source for the development of new medications. Withania somnifera, also known as Ashwagandha, is the utmost treasured medicinal plant used in Ayurveda, which holds the potential to give adaptogenic, immunomodulatory, and antiviral effects. However, its effect on HIV-1 replication at the cellular level has never been explored. Herein, we focused on the anti-HIV-1 activity and the probable mechanism of action of hydroalcoholic and aqueous extracts of Withania somnifera roots and its phytomolecules.MethodsThe cytotoxicity of the extracts was determined through MTT assay, while the in vitro anti-HIV-1 activity was assessed in TZM-bl cells against the HIV-1 strains of X4 and R5 subtypes. Results were confirmed in peripheral blood mononuclear cells, using the HIV-1 p24 antigen assay. Additionally, the mechanism of action was determined through the Time of Addition assay, which was further validated through the series of enzymatic assays, i.e. HIV-1 Integrase, Reverse transcriptase, and Protease assays. To explore the role of the identified active metabolites of Withania somnifera in antiretroviral activity, molecular docking analyses were performed against these key HIV-1 replication enzymes.ResultsThe hydroalcoholic and aqueous extracts of Withania somnifera roots were found to be safer at the sub-cytotoxic concentrations and exhibited their ability to inhibit replication of two primary isolates of HIV-1 through cell-associated and cell-free assays, in dose-dependent kinetics. Several active phytomolecules found in Withania somnifera successfully established hydrogens bonds in the active binding pocket site residues responsible for the catalytic activity of HIV replication and therefore, signifying their role in the attenuation of HIV-1 infection as implied through the in silico molecular docking studies.ConclusionsOur research identified both the hydroalcoholic and aqueous extracts of Withania somnifera roots as potent inhibitors of HIV-1 infection. The in silico analyses also indicated the key components of Withania somnifera with the highest binding affinity against the HIV-1 Integrase by 12-Deoxywithastramonolide and 27-Hydroxywithanone, HIV-1 Protease by Ashwagandhanolide and Withacoagin, and HIV-1 Reverse transcriptase by Ashwagandhanolide and Withanolide B, thereby showing possible mechanisms of HIV-1 extenuation. Overall, this study classified the role of Withania somnifera extracts and their active compounds as potential agents against HIV-1 infection.

Derivatives of 3′‐Azidothymidine with 6‐Cyanopyridone as Base or as Phosphoramidate Ester and their Antiretroviral Activity

AbstractStrongly pairing ethynylpyridone C‐nucleosides are attractive surrogates for thymidine in oligonucleotides. Exploratory work on the antiviral activity of 3′‐azidothymidine (AZT) derivatives with ethynylpyridone as base had identified strong lipophilicity as a limiting factor. Two strategies are being pursued to overcome this issue. In order to make the base more polar, the ethynyl group has been replaced with a cyano group, leading to a cyanopyridone C‐nucleoside, whose eleven‐step synthesis is reported here, together with the synthesis of a 3′‐azido‐2′,3′‐dideoxynucleoside derivative. The base pairing with adenine in a DNA duplex was studied by UV melting analysis of a self‐complementary hexamer containing the 6‐cyano‐2′‐deoxynucleoside instead of thymidine. A melting point increase of 2 °C compared to the unmodified control was found. The other strategy employs a phosphoramidate prodrug design with less lipophilic amino acid esters. Here, anti‐HIV test of the alaninyl and prolinyl methyl esters of AZT gave promising results in cell culture experiments, increasing the selectivity index up to 5.8‐fold for the IIIB strain and up to 5‐fold for the ROD strain of the virus, as compared to the parent nucleoside. These findings help to design the next generation of pyridone C‐nucleosides with potential applications as antivirals.

The Use of Zidovudine Pharmacophore in Multi-Target-Directed Ligands for AIDS Therapy

The concept of polypharmacology embraces multiple drugs combined in a therapeutic regimen (drug combination or cocktail), fixed dose combinations (FDCs), and a single drug that binds to different targets (multi-target drug). A polypharmacology approach is widely applied in the treatment of acquired immunodeficiency syndrome (AIDS), providing life-saving therapies for millions of people living with HIV. Despite the success in viral load suppression and patient survival of combined antiretroviral therapy (cART), the development of new drugs has become imperative, owing to the emergence of resistant strains and poor adherence to cART. 3'-azido-2',3'-dideoxythymidine, also known as azidothymidine or zidovudine (AZT), is a widely applied starting scaffold in the search for new compounds, due to its good antiretroviral activity. Through the medicinal chemistry tool of molecular hybridization, AZT has been included in the structure of several compounds allowing for the development of multi-target-directed ligands (MTDLs) as antiretrovirals. This review aims to systematically explore and critically discuss AZT-based compounds as potential MTDLs for the treatment of AIDS. The review findings allowed us to conclude that: (i) AZT hybrids are still worth exploring, as they may provide highly active compounds targeting different steps of the HIV-1 replication cycle; (ii) AZT is a good starting point for the preparation of co-drugs with enhanced cell permeability.

Anticancer and antiretroviral activities of methanolic extract from Theobroma cacao L pod husk: focusing on the ethyl acetate partition

Background: Many researchers have paid attention to Theobroma cocoa pod husk for its bioactive phytoconstituents which have several medicinal benefits. Herein, we aim to evaluate the methanolic extract from T. cocoa pod husk and its partitions for their anticancer and antiretroviral activities. Methods: The T. cocoa pod husk was macerated using methanol, and then sequentially partitioned with n-hexane and ethyl acetate. MCF-7 and HeLa cells were used to assess the anticancer activities, while the simian retrovirus-2 (SRV-2)-infected A549 cells were used for antiretroviral study. The ethyl acetate partition (TCEA) was then fractionated and screened for in-vitro antioxidant and cytotoxicity. The most active fraction was sub-fractionated and analyzed using gas chromatography-mass spectroscopy (GC-MS). Results: The results suggested that TCEA had moderate and weak activities against MCF-7 (IC50=53.91 μg/mL) and HeLa cells (IC50=120.71 μg/mL), respectively. TCEA 125 μg/mL had higher anti-SRV-2 activity in comparison with lamivudine 25 μg/mL after 1—7 days of incubation. The GC-MS analysis of the polyphenol-predominated sub-fraction from the most active fraction revealed the presence of lupeol, syringaresinol, catechol, and squalene. Conclusions: TCEA derived from the methanolic extract of T. cacao pod husk had moderate activity against MCF-7 cells and weak activity against HeLa cells. Antiretroviral study suggests that TCEA 125 μg/mL had higher inhibitory activity against SRV-2 replication as compared to lamivudine 25 μg/mL.