Synthesis, spectral characterization and antitumor activity of phenothiazine derivatives

Anticancer Potential of the S-Heterocyclic Ring Containing Drugs and its Bioactivation to Reactive Metabolites

Sulfur-containing heterocyclic derivatives have been disclosed for binding with a wide range of cancer-specific protein targets. Various interesting derivatives of sulfur-containing heterocyclics such as benzothiazole, thiazole, thiophene, thiazolidinedione, benzothiophene, and phenothiazine, etc have been shown to inhibit diverse signaling pathways implicated in cancer. Significant progress has also been made in molecular targeted therapy against specific enzymes such as kinase receptors due to potential binding interactions inside the ATP pocket. Sulfur-containing heterocyclic ring metal complexes i. e., benzothiazole, thiazole, thiophene, benzothiophene and phenothiazines are among the most promising active anticancer compounds. However, sulfur heteroaromatic rings, particularly thiophene, are of high structural alert due to their metabolism to reactive metabolites. The mere presence of a structural alert itself does not determine compound toxicity therefore, this review focuses on some specific findings that shed light on factors influencing the toxicity. In the current review, synthetic strategies of introducing the sulfur core ring in the synthesized derivatives are discussed with their structure-activity relationships to enhance our understanding of toxicity mechanisms and develop safer therapeutic options. The sulfur-containing marketed anticancer drugs included in this review direct the synthesis of novel compounds and will help in the development of potent, safer sulfur-based anticancer drugs in near future.

Phenothiazines as anti-cancer agents: SAR overview and synthetic strategies

Cancer is a leading cause of death worldwide and there are still limited options for cure. Chemotherapy is the most significant treatment for cancer which increased survival rates, despite this, it is associated with numerous side effects, as well as cancer relapsing due to drug resistance insurgence; consequently, it is still a challenging task to develop new potent and less toxic anti-cancer agents for patients' care. Phenothiazine moiety, which leads a class of well-known antipsychotic drugs, possesses a wide range of biological activities and has been also introduced in cancer chemotherapy. This review aims in disclosing the use of phenothiazines during the last five years for the development of different anti-cancer drug candidates. The design and the synthetic strategies adopted, the SAR investigations and the role of reviewed phenothiazine derivatives as anti-cancer agents and multi-drug resistance (MDR) reversals are here fully described and discussed.

Expedition of sulfur-containing heterocyclic derivatives as cytotoxic agents in medicinal chemistry: A decade update

This review article proposes a comprehensive report of the design strategies engaged in the development of various sulfur-bearing cytotoxic agents. The outcomes of various studies depict that the sulfur heterocyclic framework is a fundamental structure in diverse synthetic analogs representing a myriad scope of therapeutic activities. A number of five-, six- and seven-membered sulfur-containing heterocyclic scaffolds, such as thiazoles, thiadiazoles, thiazolidinediones, thiophenes, thiopyrans, benzothiazoles, benzothiophenes, thienopyrimidines, simple and modified phenothiazines, and thiazepines have been discussed. The subsequent studies of the derivatives unveiled their cytotoxic effects through multiple mechanisms (viz. inhibition of tyrosine kinases, topoisomerase I and II, tubulin, COX, DNA synthesis, and PI3K/Akt and Raf/MEK/ERK signaling pathways), and several others. Thus, our concise illustration explains the design strategy and anticancer potential of these five- and six-membered sulfur-containing heterocyclic molecules along with a brief outline on seven-membered sulfur heterocycles. The thorough assessment of antiproliferative activities with the reference drug allows a proficient assessment of the structure-activity relationships (SARs) of the diversely synthesized molecules of the series.

Synthesis of Novel Chalcone-Based Phenothiazine Derivatives as Antioxidant and Anticancer Agents

Based on reported results for the potential medicinal impact of phenothiazine core, as well as the chalcone skeleton that is widely present in many natural products, together with their reported bioactivities, the present work was aimed at combining both moieties in one molecular skeleton and to synthesize and characterize a novel series of chalone-based phenothiazine derivatives. For this purpose, 2-acetylphenothiazine was N-alkylated, followed by the Claisen-Schmidt reaction to produce the chalcones with good yield. Antioxidant activity, as evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, was assessed to determine if their antioxidant potential was comparable with ascorbic acid, and attributable to the phenothiazine core. Screening anticancer activities of the synthesized chalone-based phenothiazine derivatives against human breast cancer cell line MCF-7 cells, and human hepatocellular carcinoma HepG-2 cells, compared with standard drugs cisplatin and doxorubicin, was evaluated. The results revealed that compounds 4a, 4b, 4d, 4h, 4j, 4k, 4m, 4o, and 4p were good against human hepatocellular carcinoma HepG-2 cells, and among these compounds 4b and 4k were the most effective compounds, with IC₅₀ values of 7.14 μg/mL and 7.6 1 μg/mL, respectively. On the other hand, compounds 4a, 4b, 4k, and 4m were good against human breast cancer cell line MCF-7 cells and, among these compounds, 4k and 4b were the most effective compounds, with IC₅₀ values of 12 μg/mL and 13. 8 μg/mL, respectively. The overall results suggest that these compounds could, potentially, be further modified for the formation of more potent antioxidant and anticancer agents.