Ramit Singla

Coumarins as anticancer agents: A review on synthetic strategies, mechanism of action and SAR studies

Coumarins are fused benzene and pyrone ring systems which prompt biological investigation to assess their potential therapeutic significance. It possesses immeasurable anticancer potential with minimum side effects depending on the substitutions on the basic nucleus. Coumarins have a tremendous ability to regulate diverse range of cellular pathways that can be explored for selective anticancer activity. This is the first standalone review that emphasis on the assorted retrosynthetic approaches, important targets for molecularly targeted cancer therapy and structure activity relationship studies that highlight the chemical groups responsible for evoking the anticancer potential of coumarin derivatives reported from 2011 to 2014.

Recent developments of C-4 substituted coumarin derivatives as anticancer agents

Cancer is a prominent cause of death in global. Currently, the numbers of drugs that are in clinical practice are having a high prevalence of side effect and multidrug resistance. Researchers have made an attempt to expand a suitable anticancer drug that has no MDR and side effect. Coumarin scaffold became an attractive subject due to their broad spectrum of pharmacological activities. Coumarin derivatives extensively explored for anticancer activities as it possesses minimum side effect along with multi-drug reversal activity. Coumarin derivatives can act by various mechanisms on different tumor cell lines depending on substitution pattern of the core structure of coumarin. Substitution on coumarin nucleus leads to the search for more potent compounds. In this review, we have made an effort to give a synthetic strategy for the preparation of C-4 substituted coumarin derivatives as anticancer agents based on their mechanism of action and also discuss the SAR of the most active compound.

Indole Derivatives as Anticancer Agents for Breast Cancer Therapy: A Review.

Breast cancer (BC) is the second most common cause of cancer-related deaths in women throughout the world. Multiple drugs have been approved by US-FDA for breast related malignancies. Frequent emergence of resistances creates the severe need of newer moieties that are free from such problems. Drugs targeting breast cancer have been observed to be based on the multiple mechanisms of action, and various indole based anticancer agents have also been explored. Moreover, indoles have promising anti-cancer potential; there has been the emphasis on the synthesis of indole derivatives to overcome problems faced by existing therapeutic agents. Taking into consideration the above-mentioned facts we have analyzed in detail the possible role of indole based anticancer agents typically for breast related malignancies. This is the first exhaustive review that jointly covers various synthetic anticancer indole derivatives and related signaling pathways by which these derivatives have shown promising anti-breast cancer potential.

Design, synthesis and biological evaluation of novel indole-benzimidazole hybrids targeting estrogen receptor alpha (ER-α)

In the course of efforts to develop novel selective estrogen receptor modulators (SERMs), indole-benzimidazole hybrids were designed and synthesised by fusing the indole nucleus with benzimidazole. All the compounds were first inspected for anti-proliferative activity using ER-α responsive T47D breast cancer cell lines and ER-α binding assay. From this study, two representative bromo substituted compounds 5f and 8f were found to be most active and thus were escalated for gene expression studies for targeting ER-α. Cell imaging experiment clearly suggest that compounds were able to cross cell membrane and accumulate thus causing cytotoxicity. RT-PCR and Western blotting experiments further supported that both compounds altered the expression of mRNA and receptor protein of ER-α, thereby preventing the further transactivation and signalling pathway in T47D cells lines. Structural investigation from induced fit simulation study suggest that compound 5f and 8f bind in antagonistic conformation similar to bazedoxifene by extensive hydrogen bonding and Van der Waals forces. All these results strongly indicate that compound 5f and 8f represents a novel potent ER-α antagonist properties and will proved promising in the discovery of SERM for the management of breast cancer.

Design, synthesis and biological evaluation of novel indole-xanthendione hybrids as selective estrogen receptor modulators

Ground breaking clinical therapeutic advances in the treatment of breast cancer (BC) is the introduction of selective estrogen receptor modulators (SERMs). We have expeditiously designed and synthesized indole-xanthendione hybrids by coalescing the indole nucleus with xanthendione. All the compounds were first screened for anti-proliferative activity, cytotoxicity and ER-α binding affinity by utilizing ER-α dominant T47D BC cell lines, PBMCs and ER-α competitor assay kit. From this study, two representative compounds 6e and 6f showing most promising activity were advanced for gene expression studies for targeting ER-α. Cell imaging experiment undoubtedly indicate that both the compounds were able to cross cellular bio membrane and accumulate thus instigating cytotoxicity. RT-PCR and Western blotting experiments further strengthened that both compounds altered the expression of mRNA and receptor protein of ER-α, thereby forestalling downstream transactivation and signalling pathway in T47D cells line. Structural investigation from induced fit simulation study suggest that indole moiety of the compounds 6e and 6f helps in the anchoring of the xanthendione moiety in the hydrophobic region of the cavity thus enabling the compound to bind in antagonistic conformation similar to bazedoxifene by extensive hydrogen bonding and Van der Waals forces. All these finding collectively imply that compound 6e and 6f represents a novel potent ER-α antagonist and in the development of SERMs for the management of BC.

Coumarin Derivatives as Anticancer Agents for Lung Cancer Therapy: A Review

BACKGROUND The prevalence of lung cancer is 14% among the newly diagnosed cancer cases worldwide. Currently, the number of drugs that are in clinical practice is having a high prevalence of side effect and multidrug resistance. Researchers have made an attempt to expand a suitable anticancer drug that has no MDR and side effect. OBJECTIVE Extensive exploration of Coumarin derivatives as a potent inhibitor of variety of proteins including EGFR, tyrosine kinase, ERK1/2, PI3K, HSP 90, Bax, STAT proteins, NF-κB and telomerase which have been associated with lung cancer. METHOD The recent literature was surveyed utilizing the online resources and databases including scifinder, pubchem, EMBL, scopus and google scholar. RESULTS Upon analyzing the structure-activity relationship, it was found that N-aryl carboxamide, phenyl substitution at the C-3 position and 1,2,3- triazolyl, trihydroxystilbene, amino substitution at the C-4 position of the coumarin nucleus were the most effective in targeting lung cancer. CONCLUSION This review is a collaborative and extensive compilation of synthetic strategies, mechanism of action, and the structure-activity relationship thereof for the management of lung carcinoma.

Identification of novel indole based heterocycles as selective estrogen receptor modulator

In the present study, we have designed and synthesized indole derivatives by coalescing the indole nucleus with chromene carbonitrile and dihydropyridine nucleus. Two compounds 5c and 6d were selected from series I and II after sequential combinatorial library generation, docking, absorption, distribution, metabolism and excretion (ADME) filtering, anti-proliferative activity, cytotoxicity, and ER-α competitor assay kit by utilizing estrogen receptor-α (ER-α) dominant T47D BC cells line and PBMCs (Peripheral Blood Mononuclear Cells). Cell imaging experiment suggested that both the compounds successfully cross cellular biomembrane and accumulate in nuclear, cytoplasmic and plasma membrane region. Semiquantitative RT-PCR and Western blotting experiments further supported that both compounds reduced the expression of mRNA and receptor protein of ER-α, thereby preventing downstream transactivation and signaling pathway in T47D cells line. Current findings imply that 5c and 6d represent novel ER-α antagonists and may be used in the development of chemotherapy for the management of BC.

Stevia rebaudiana targeting α-amylase: An in-vitro and in-silico mechanistic study

Abstract Diabetes mellitus (DM) is the fastest growing metabolic disorder in the world. Recently, more attention is paid to the study of natural products due to side effects of synthetic drugs. Stevia rebaudiana (Bertoni) is considered an encouraging starting point for the antidiabetic lead development. In the present study, the in vitro α-amylase inhibitory activity of the extracts of S. rebaudiana is investigated. In order to understand the molecular mechanism and future pharmacophore development, in silico study of secondary metabolites isolated from S. rebaudiana was carried out. Results indicated that water extract shows highest α-amylase inhibitory activity as compared to other extracts. Moreover, compound 20 (rebaudioside A) which has been previously reported and isolated from water extract showed the impressive binding profile with α-amylase. Therefore, our study suggests that S. rebaudiana could be used in the development of therapeutic drugs for the treatment of diabetes.