Recent Updates on the Anticancer Activity of Quinoxaline Hybrids (Jan. 2017-Jan. 2022).

Cancer being one of the leading causes of death among non-communicable diseases, has already posed a heavy burden on the world health system. Chemotherapy is one of the most effective approaches for cancer treatment, but multidrug resistance, lack of efficacy, and toxic side effects hamper efficacious cancer chemotherapy, creating an urgent need to develop novel, more effective and less toxic anticancer therapeutics. Quinoxalines, as fascinating structures, constitute an important class of heterocycles in drug discovery. Quinoxaline hybrids could exert anticancer activity through diverse mechanisms and possess profound in vitro and in vivo efficacy against various cancers, including multidrug-resistant forms. Thus, quinoxaline hybrids represent useful templates for the control and eradication of cancer. The purpose of the present review article is to provide an emphasis on the recent developments (Jan. 2017-Jan. 2022) in quinoxaline hybrids with insights into their in vitro and in vivo anticancer potential as well as structure-activity relationships (SARs) to facilitate further rational design of more effective candidates.

Cinnamic acid hybrids as anticancer agents: A mini-review.

Cancer, as a long-lasting and dramatic disease, affects almost one-third of human beings globally. Chemotherapeutics play an important role in cancer treatment, but multidrug resistance and severe adverse effects have already become the main causes of failure in tumor chemotherapy. Therefore, it is an urgent need to develop novel chemotherapeutics. Cinnamic acid contains a ubiquitous α,ß-unsaturated acid moiety presenting potential therapeutic effects in the treatment of cancer as these derivatives could act on cancer cells by diverse mechanisms of action. Accordingly, cinnamic acid derivatives are critical scaffolds in discovering novel anticancer agents. This review provides a comprehensive overview of cinnamic acid hybrids as anticancer agents. The structure-activity relationship, as well as the mechanisms of action, are also discussed, covering articles published from 2012 to 2021.

Benzimidazole hybrids as anticancer drugs: An updated review on anticancer properties, structure-activity relationship, and mechanisms of action (2019-2021).

Cancer, characterized by a deregulation of the cell cycle which mainly results in a progressive loss of cellular differentiation and uncontrolled cellular growth, remains a prominent cause of death across the world. Almost all currently available anticancer agents used in clinical practice have developed multidrug resistance, creating an urgent need to develop novel chemotherapeutics. Benzimidazole derivatives could exert anticancer properties through diverse mechanisms, inclusive of the disruption of microtubule polymerization, the induction of apoptosis, cell cycle (G2/M) arrest, antiangiogenesis, and blockage of glucose transport. Moreover, several benzimidazole-based agents have already been approved for the treatment of cancers. Hence, benzimidazole derivatives are useful scaffolds for the development of novel anticancer agents. In particular, benzimidazole hybrids could exert dual or multiple antiproliferative activities and had the potential to overcome drug resistance, demonstrating the potential of benzimidazole hybrids as potential prototypes for clinical deployment in the control and eradication of cancers. The purpose of the present review article is to provide a comprehensive landscape of benzimidazole hybrids as potential anticancer agents, and the structure-activity relationship as well as mechanisms of action are also discussed to facilitate the further rational design of more effective candidates, covering articles published from 2019 to 2021.

1,2,3-Triazole hybrids with anti-HIV-1 activity.

The human immunodeficiency virus type 1 (HIV-1) is the major etiological agent responsible for the acquired immunodeficiency syndrome (AIDS), which is a serious infectious disease and remains one of the most prevalent problems at present. Currently, combined antiretroviral therapy is the primary modality for the treatment and management of HIV/AIDS, but the long-term use can result in major drawbacks such as the development of multidrug-resistant viruses and multiple side effects. 1,2,3-Triazole is the common framework in the development of new drugs, and its derivatives have the potential to inhibit various HIV-1 enzymes such as reverse transcriptase, integrase, and protease, consequently possessing a potential anti-HIV-1 activity. This review covers the recent advances regarding the 1,2,3-triazole hybrids with potential anti-HIV-1 activity; it focuses on the chemical structures, structure-activity relationship, and mechanisms of action, covering articles published from 2010 to 2020.

Hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant Plasmodium falciparum.

Malaria is a tropical disease, leading to around half a million deaths annually. Antimalarials such as quinolines are crucial to fight against malaria, but malaria control is extremely challenged by the limited pipeline of effective pharmaceuticals against drug-resistant strains of Plasmodium falciparum which are resistant toward almost all currently accessible antimalarials. To tackle the growing resistance, new antimalarial drugs are needed urgently. Hybrid molecules which contain two or more pharmacophores have the potential to overcome the drug resistance, and hybridization of quinoline privileged antimalarial building block with other antimalarial pharmacophores may provide novel molecules with enhanced in vitro and in vivo activity against drug-resistant (including multidrug-resistant) P falciparum. In recent years, numerous of quinoline hybrids were developed, and their activities against a panel of drug-resistant P falciparum strains were screened. Some of quinoline hybrids were found to possess promising in vitro and in vivo potency. This review emphasized quinoline hybrid molecules with potential in vitro antiplasmodial and in vivo antimalarial activity against drug-resistant P falciparum, covering articles published between 2010 and 2019.

Recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents.

Tetrazole, a bioisostere of the carboxylic acid group, can replace the carboxyl group in drugs to increase the lipophilicity, bioavailability and reduce side effects. Tetrazole derivatives possess a broad-spectrum of biological properties including anti-tubercular and anti-malarial activities, and some tetrazole-based compounds have already been used in clinics for the treatment of various diseases. Therefore, tetrazole is an important pharmacophore in the development of new drugs. This review covers the recent advances of tetrazole derivatives as potential anti-tubercular and anti-malarial agents, and the structure-activity relationship is also discussed for the further rational design of tetrazole derivatives.

Recent advances of imidazole-containing derivatives as anti-tubercular agents.

Tuberculosis still remains one of the most common, communicable, and leading deadliest diseases known to mankind throughout the world. Drug-resistance in Mycobacterium tuberculosis which threatens to worsen the global tuberculosis epidemic has caused great concern in recent years. To overcome the resistance, the development of new drugs with novel mechanisms of actions is of great importance. Imidazole-containing derivatives endow with various biological properties, and some of them demonstrated excellent anti-tubercular activity. As the most emblematic example, 4-nitroimidazole delamanid has already received approval for treatment of multidrug-resistant tuberculosis infected patients. Thus, imidazole-containing derivatives have caused great interests in discovery of new anti-tubercular agents. Numerous of imidazole-containing derivatives were synthesized and screened for their in vitro and in vivo anti-mycobacterial activities against both drug-sensitive and drug-resistant Mycobacterium tuberculosis pathogens. This review aims to outline the recent advances of imidazole-containing derivatives as anti-tubercular agents, and summarize the structure-activity relationship of these derivatives. The enriched structure-activity relationship may pave the way for the further rational development of imidazole-containing derivatives as anti-tubercular agents.

Bis-coumarin Derivatives and Their Biological Activities.

Bis-coumarins have caused great interests in the recent years. These compounds exhibit diverse biological activities which are ascribed to their ability to exert noncovalent interactions with the various active sites in organisms. Some of them such as dicoumarolum and dicoumarol were approved for therapeutic purposes in clinical practice. Encouraged by the above facts, numerous biscoumarin derivatives have been synthesized and screened for their biological activities, and many of them showed promising potency. This review is focused on the biological potential of bis-coumarin derivatives with particular mention of those exhibiting antibacterial, anticoagulant, antiinflammatory, antiviral, anti-parasite and antitumor activities, and their structure-activity relationships are also discussed.

Fluoroquinolone derivatives and their anti-tubercular activities.

Tuberculosis (TB) remains one of the most widespread and leading deadliest diseases, around one-third of the world's population harbor a latent infection by Mycobacterium tuberculosis (MTB), and 5-10% eventually develop an active TB. The emergency of MTB new virulent forms as well as the co-infection between MTB and HIV alarming the serious problem in TB control and demanding the need for new drugs more potent than earlier with safe ADME profile. Fluoroquinolones are emerged as a large family of synthetic broad spectrum antibiotics, and some of them were recommended as the second-line agents for the treatment of TB mainly in cases involving resistance or intolerance to first-line anti-TB therapy by WHO. Numerous of FQs derivatives have been synthesized for seeking for new anti-TB agents, and some of them exhibited promising potency. This review aims to summarize the recent advances made towards the discovery of FQs derivatives as anti-TB agents and the structure-activity relationship of these derivatives.

Antiplasmodial and antimalarial activities of quinolone derivatives: An overview.

Malaria remains one of the most deadly infectious diseases globally. Considering the growing spread of resistance, development of new and effective antimalarials remains an urgent priority. Quinolones, which are emerged as one of the most important class of antibiotics in the treatment of various bacterial infections, showed potential in vitro antiplasmodial and in vivo antimalarial activities, making them promising candidates for the chemoprophylaxis and treatment of malaria. This review presents the current progresses and applications of quinolone-based derivatives as potential antimalarials to pave the way for the development of new antimalarials.

4-Quinolone derivatives and their activities against Gram positive pathogens.

Gram-positive bacteria are responsible for a broad range of infectious diseases, and the emergency and wide spread of drug-resistant Gram-positive pathogens including MRSA and MRSE has caused great concern throughout the world. 4-Quinolones which are exemplified by fluoroquinolones are mainstays of chemotherapy against various bacterial infections including Gram-positive pathogen infections, and their value and role in the treatment of bacterial infections continues to expand. However, the resistance of Gram-positive organisms to 4-quinolones develops rapidly and spreads widely, making them more and more ineffective. To overcome the resistance and reduce the toxicity, numerous of 4-quinolone derivatives were synthesized and screened for their in vitro and in vivo activities against Gram-positive pathogens, and some of them exhibited excellent potency. This review aims to outlines the recent advances made towards the discovery of 4-quinolone-based derivatives as anti-Gram-positive pathogens agents and the critical aspects of design as well as the structure-activity relationship of these derivatives. The enriched SAR paves the way to the further rational development of 4-quinolones with a unique mechanism of action different from that of the currently used drugs to overcome the resistance, well-tolerated and low toxic profiles.

Recent Development of Coumarin Derivatives as Potential Antiplasmodial and Antimalarial Agents.

Malaria still remains one of the leading deadliest diseases throughout the world, leading to around 1 million deaths annually. The emergence and spread of growing resistance to the firstline antimalarials are an alarming the serious problem in malaria control, demanding the need for new drugs more potent than earlier with improved Absorption, Distribution, Metabolism, and Excretion (ADME) profiles. Coumarins, which exhibited various biological properties, also displayed potential in vitro antiplasmodial and in vivo antimalarial activities. Moreover, many of coumarin derivatives have already been used in clinical practice for the treatment of several diseases. Therefore, coumarin derivatives play a pivotal role in medicinal chemistry, also making them promising candidates for the treatment of malaria. This review aims to summarize the recent advances made towards the development of coumarin-containing derivatives as antiplasmodial and antimalarial agents and their structure-activity relationship is also discussed.

Recent Developments of Coumarin Hybrids as Anti-fungal Agents.

Fungi place a huge burden on global healthcare systems attributed to the fact that fungal infections are responsible for the high morbidity and mortality rates in patients who received stem cell transplantation, antineoplastic chemotherapy, organ transplants or suffered Human Immunodeficiency Virus (HIV) infection. Unfortunately, almost none of the representative anti-fungal agents currently used in clinical therapy are ideal in terms of efficacy, anti-fungal spectrum or safety. Moreover, the rapid development of resistance to existing anti-fungal drugs has further aggravated the mortality and spread of fungi, creating an urgent need for novel anti-fungal agents. The broad spectrum of biological activities and successful usage in clinic made coumarins a promising anti-fungal candidate. Furthermore, hybridization of other pharmacophores with coumarin motif may enhance the anti-fungal efficacy, broaden the anti-fungal spectrum and improve the safety profiles. Thus, numerous coumarin hybrids have been assessed for their anti-fungal activities, and some of them showed promising potency and may have a novel mechanism of action. This review aims to outline the recent development of coumarin hybrids as potential anti-fungal agents and summarize their Structure-Activity Relationship (SAR) to provide an insight for rational designs of more active agents.

4-Quinolone hybrids and their antibacterial activities.

The emergence and wide-spread of drug-resistant bacteria including multi-drug resistant and pan-drug resistant pathogens which are associated with considerable mortality, represent a significant global health threat. 4-Quinolones which are exemplified by fluoroquinolones are the second largest chemotherapy agents used in clinical practice for the treatment of various bacterial infections. However, the resistance of bacteria to 4-quinolones develops rapidly and spreads widely throughout the world due to the long-term, inappropriate use and even abuse. To overcome the resistance and improve the potency, several strategies have been developed. Amongst them, molecular hybridization, which is based on the incorporation of two or more pharmacophores into a single molecule with a flexible linker, is one of the most practical approaches. This review aims to summarize the recent advances made towards the discovery of 4-quinolone hybrids as potential antibacterial agents as well as their structure-activity relationship (SAR). The enriched SAR may pave the way for the further rational development of 4-quinolone hybrids with excellent potency against both drug-susceptible and drug-resistant bacteria.