Medicinal Chemistry - Volume 19, Issue 8, 2023

Severe emergencies occurred across the globe, beginning with the outbreak of SARSCoV in 2002, followed by MERS-CoV in 2012. In December 2019, an acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in Wuhan, China as the agent responsible for the recent COVID-19 pandemic outbreak. The virus rapidly spread throughout the world due to its high transmissibility, leading to enormous health problems and complexities. The COVID-19 pandemic has affected public health, the weak persons were severely affected by this virus. To stop the disease from spreading further, effective remedies are the need of the hour. Although SARS-CoV-2 vaccination campaigns are being carried out all over the globe, several new SARS-CoV-2 variants have emerged, and each has caused a wave of infections, highlighting an urgent need for therapeutics targeting SARS-CoV-2. Heterocyclic compounds have been explored extensively for a very long time for their biological activities, namely, anti-inflammatory, antimalarial, antitubercular, anticancer, antiviral, antimicrobial, antidiabetic, and many more bio-activities. Through this review, the author has tried to report the heterocyclic compounds synthesized all over the world over the last 2 years to fight against the SARS CoV-2 coronaviruses. The heterocyclic motifs mentioned in the review can serve as important resources for the development of COVID-19 treatment methods.

The 1,3,4-thiadiazole nucleus has attracted the attention of medicinal chemists during the last decades due to its multiple pharmacological activities, such as antiviral, anticancer, antibacterial, and anticonvulsant activity. This scaffold's structural alteration could aid in developing novel therapeutically effective drugs. Incorporating this adaptable pharmacophore into a well-established medicinally active molecule results in hybrid molecules with diverse pharmacological effects. These encouraging reports suggested that this privileged skeleton should be thoroughly researched for medicinal purposes. Hence, an attempt has been made in this compilation to review the structure-activity relationships of numerous thiadiazole derivatives reported in the literature with varied pharmacological properties. This review provides an up-to-date explanation of the various synthesized 1,3,4- thiadiazole analogs and their pharmacological importance.

Background: Xanthones, natural or synthetic, due to their wide range of biological activities, have become an interesting subject of investigation for many researchers. Xanthonic scaffold has proven to have a vital role in anticancer drug development since many of its derivatives have shown anticancer activities on various cell lines. In addition, targeting epigenetic markers in cancer has yielded promising results. There have also been reports on the impact of xanthone and related polyphenolic compounds on epigenetics markers in cancer prevention and therapy. Objective: The objective of this review is to comprehensively highlight the main natural and nonnatural sources of xanthones having potential anti-cancer effects along with their key structural elements, structure-activity relationships (SARs), mechanisms of action, and epigenetic profile of xanthone- based anti-cancer compounds. The challenges and future directions of xanthone-based therapies are also discussed briefly. Method: The methods involved in the preparation of the present review included the collection of all recent information up to November 2021 from various scientific databases, indexed periodicals, and search engines such as Medline Scopus, Google Scholar, PubMed, PubMed Central, Web of Science, and Science Direct. Results: Exploration of the diversity of the xanthone scaffold led to the identification of several derivatives having prominent anti-cancer activity. Their unique structural diversity and synthetic modifications showed the ongoing endeavour of enriching the chemical diversity of the xanthone molecular framework to discover pharmacologically interesting compounds. However, studies regarding their modes of action, pharmacokinetic properties, clinical data, epigenetics, and safety are limited. Conclusion: Elucidation of the exact biological mechanisms and the associated targets of xanthones will yield better opportunities for these compounds to be developed as potential anticancer drugs. Further clinical studies with conclusive results are required to implement xanthones as treatment modalities in cancer.

Quinoline has recently become an important heterocyclic molecule due to its numerous industrial and synthetic organic chemistry applications. Quinoline derivatives have been used in clinical trials for a variety of medical conditions that causes cancer. The present literature study is composed of recent progress (mainly from 2010 to the present) in the production of novel quinoline derivatives as potential anti-cancer agents, as well as their structure-activity relationship, which will provide insight into the development of more active quinoline hybrids in the future. The present review comprises the synthetic protocols of biologically active Quinoline analogs with their structure-activity relationship studies as anti-cancer agents, which provide depth view of work done on quinoline derivatives to the medicinal chemist for future research.

Background: The structure modification of steroids is commonly used to change the biological activity of steroids in medicinal chemistry. In recent years, it has been found that some derivatives derived from the structural modification of cholesterol display good inhibitory activity against tumor cell proliferation in vitro. Methods: Using cholesterol as the starting material, different types of B-norcholesterol-6-amide derivatives were synthesized by the reaction of 6-carboxyl-B-norcholesterol with different alkyl amines or 6-amino-B-norcholesterol with different acyl chlorides. The inhibitory activity of compounds on the proliferation of tumor cell lines was investigated by the MTT method. Results: The results showed that the B-norcholesterol-6-amide compounds displayed distinct cytotoxicity against Sk-Ov-3 cells but caused no obvious damage against HEK-293T cells. Additionally, the steroidal amide derivatives formed from 6-amino-B-norcholesterol showed stronger cytotoxicity than those produced from 6-carboxyl-B-norcholesterol. Specially, compounds with chloroalkyl structure displayed significant inhibitory activity against all tumor cells tested. Among them, compounds 19-21 showed cytotoxicity like 2-methoxyestradiol as a positive control, and the IC50 value of compound 20 on HeLa cells was 3.9 μM. Conclusion: After introducing chloroalkyl acyl groups into 6-position of 6-amino-B-norcholesterol, the cytotoxicity of resulting B-norcholesterol-6-amide compounds can be greatly enhanced.