Secondary Metabolites from Marine Sources with Potential Use as Leads for Anticancer Applications

The development of novel anticancer agents is essential to finding new ways to treat this disease, one of the deadliest diseases. Some marine organisms have proved to be important producers of chemically active compounds with valuable bioactive properties, including anticancer. Thus, the ocean has proved to be a huge source of bioactive compounds, making the discovery and study of these compounds a growing area. In the last few years, several compounds of marine origin, which include algae, corals, and sea urchins, have been isolated, studied, and demonstrated to possess anticancer properties. These compounds, mainly from securamines and sterols families, have been tested for cytotoxic/antiproliferative activity in different cell lines. Bioactive compounds isolated from marine organisms in the past 5 years that have shown anticancer activity, emphasizing the ones that showed the highest cytotoxic activity, such as securamines H and I, cholest-3β,5α,6β-triol, (E)-24-methylcholest-22-ene-3β,5α,6β-triol, 24-methylenecholesta-3β,5α,6β-triol, and 24-methylcholesta-3β,5α,6β-triol, will be discussed in this review. These studies reveal the possibility of new compounds of marine origin being used as new therapeutic agents or as a source of inspiration to develop new therapeutic agents.     

Amino Acid Esters Substituted Phosphorylated Emtricitabine and Didanosine Derivatives as Antiviral and Anticancer Agents

Owing to the promising antiviral activity of amino acid ester-substituted phosphorylated nucleosides in the present study, a series of phosphorylated derivatives of emtricitabine and didanosine substituted with bioactive amino acid esters at P-atom were synthesized. Initially, molecular docking studies were screened to predict their molecular interactions with hemagglutinin-neuraminidase protein of Newcastle disease virus and E2 protein of human papillomavirus. The title compounds were screened for their antiviral ability against Newcastle disease virus (NDV) by their in ovo study in embryonated chicken eggs. Compounds 5g and 9c exposed well mode of interactions with HN protein and also exhibited potential growth of NDV inhibition. The remaining compounds exhibited better growth of NDV inhibition than their parent molecules, i.e., emtricitabine (FTC) and didanosine (ddI). In addition, the in vitro anticancer activity of all the title compounds were screenedagainst HeLa cell lines at 10 and 100 μg/mL concentrations. The compounds 5g and 9c showed an effective anticancer activity than that of the remaining title compounds with IC₅₀ values of 40 and 60 μg/mL, respectively. The present in silico and in ovo antiviral and in vitro anticancer results of the title compounds are suggesting that the amino acid ester-substituted phosphorylated FTC and ddI derivatives, especially 5g and 9c, can be used as NDV inhibitors and anticancer agents for the control and management of viral diseases with cancerous condition.

Global reactivity indexes and nonparametric statistics in the study of the proapoptotic activity of coumarins

Coumarins are widely distributed as secondary metabolites and are popular structural motifs among known anticancer agents; their planarity and electronic environment are very important building blocks for bioactive compounds. Due to the broad scope of their biological activity, anticancer properties of these molecules remain an important goal for medicinal chemistry. In this work, the knowledge and understanding of the correlation between electronic environment and global reactivity of a series of hydroxycoumarins lead to develop a statistical model to study the proapoptotic activity of this type of compounds. Thus, the analysis of the charge distribution within the molecule and experimental data of proapoptotic activity of known coumarins are analyzed through a regression model. This model offers the possibility of predicting whether a structural related coumarin will show the desired activity or not, which increases the ability to a target-directed approach in the development of anticancer therapeutic agents.     

Bioactive Metabolites from Marine Algae as Potent Pharmacophores against Oxidative Stress-Associated Human Diseases: A Comprehensive Review

In addition to cancer and diabetes, inflammatory and ROS-related diseases represent one of the major health problems worldwide. Currently, several synthetic drugs are used to reduce oxidative stress; nevertheless, these approaches often have side effects. Therefore, to overcome these issues, the search for alternative therapies has gained importance in recent times. Natural bioactive compounds have represented, and they still do, an important source of drugs with high therapeutic efficacy. In the “synthetic” era, terrestrial and aquatic photosynthetic organisms have been shown to be an essential source of natural compounds, some of which might play a leading role in pharmaceutical drug development. Marine organisms constitute nearly half of the worldwide biodiversity. In the marine environment, algae, seaweeds, and seagrasses are the first reported sources of marine natural products for discovering novel pharmacophores. The algal bioactive compounds are a potential source of novel antioxidant and anticancer (through modulation of the cell cycle, metastasis, and apoptosis) compounds. Secondary metabolites in marine Algae, such as phenolic acids, flavonoids, and tannins, could have great therapeutic implications against several diseases. In this context, this review focuses on the diversity of functional compounds extracted from algae and their potential beneficial effects in fighting cancer, diabetes, and inflammatory diseases.     

Novel Marine Secondary Metabolites Worthy of Development as Anticancer Agents: A Review

Secondary metabolites from marine sources have a wide range of biological activity. Marine natural products are promising candidates for lead pharmacological compounds to treat diseases that plague humans, including cancer. Cancer is a life-threatening disorder that has been difficult to overcome. It is a long-term illness that affects both young and old people. In recent years, significant attempts have been made to identify new anticancer drugs, as the existing drugs have been useless due to resistance of the malignant cells. Natural products derived from marine sources have been tested for their anticancer activity using a variety of cancer cell lines derived from humans and other sources, some of which have already been approved for clinical use, while some others are still being tested. These compounds can assault cancer cells via a variety of mechanisms, but certain cancer cells are resistant to them. As a result, the goal of this review was to look into the anticancer potential of marine natural products or their derivatives that were isolated from January 2019 to March 2020, in cancer cell lines, with a focus on the class and type of isolated compounds, source and location of isolation, cancer cell line type, and potency (IC₅₀ values) of the isolated compounds that could be a guide for drug development.     

Novel Quinazoline Derivatives Bearing a Sulfapyridine Moiety as Anticancer and Radiosensitizing Agents

Quinazoline derivatives posses many types of biological activities and have recently been reported to show substantial antitumor activity in vitro and/or in vivo. There is a variety of mechanisms for their anticancer activity. The present work reports the possible utility of methyl anthranilate in the synthesis of some new quinazoline derivatives, bearing a substituted sulfonamide moiety. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against human liver cancer cell line, using doxorubicin as a reference drug. In addition, the most active compounds 14 and 15 were selected and evaluated for their ability to enhance the cell killing effect of γ‐radiation.     

1-Benzamido-1,4-dihydropyridine derivatives as anticancer agents: in vitro and in vivo assays

1,4-Dihydropyridine is a privileged scaffold present in many bioactive molecules, from coenzymes to commercially available drugs. Among other interesting properties, it has been found good anticancer activity in some of these 1,4-DHPs, therefore many research groups are trying to develop new compounds based on this structural core.For this purpose, in this work, a family of 23 new 1,4-dihydropyridines has been synthesized using hydrazide and malononitrile derivatives as precursors. This straightforward catalytic process has given rise to the desired products with moderate to excellent yields. All the compounds have been tested against four different cancer cell lines [HeLa (human cervical carcinoma), Jurkat (leukemia), A549 (human lung cancer) and MIA PaCa-2 (pancreatic cancer)] to establish a preliminary structure–activity relationship. From this study, and among the best candidates, we chose 4-chlorophenyl and 4-(trifluoromethyl)phenyl derivatives in the malononitrile ring to synthesize a second generation of molecules with enhanced cytotoxicity, modifying the substituent in the N-heterocyclic position (acylhydrazine moieties). With this second generation of compounds, we successfully decreased the IC₅₀ until 7 µM.An in-depth analysis of their biological properties suggests that these promising compounds trigger a non-conventional cell death mechanism known as paraptosis. Moreover, the tested photophysical properties of these products show in some cases an interesting long wavelength emission and excitation, potentially leading to new biosensors or theragnostic agents.Finally, in vivo assays concerning the acute toxicity in mice of two of the most active compounds (with an alkyl chain of seven carbon atoms in the acylhydrazine moiety) demonstrated that even dosed at thousands fold the corresponding IC₅₀ values (2500 and 3300 times more concentrated than the IC₅₀ values for the two compounds studied), there was no sign of harmful effects on the tested subjects, results that support their use in further studies to discover new anticancer drugs.     

Highlights on Steroidal Arylidene Derivatives as a Source of Pharmacologically Active Compounds: A Review

Steroids constitute a unique class of chemical compounds, playing an important role in physiopathological processes, and have high pharmacological interest. Additionally, steroids have been associated with a relatively low toxicity and high bioavailability. Nowadays, multiple steroidal derivatives are clinically available for the treatment of numerous diseases. Moreover, different structural modifications on their skeleton have been explored, aiming to develop compounds with new and improved pharmacological properties. Thus, steroidal arylidene derivatives emerged as a relevant example of these modifications. This family of compounds has been mainly described as 17β-hydroxysteroid dehydrogenase type 1 and aromatase inhibitors, as well as neuroprotective and anticancer agents. Besides, due to their straightforward preparation and intrinsic chemical reactivity, steroidal arylidene derivatives are important synthetic intermediates for the preparation of other compounds, particularly bearing heterocyclic systems. In fact, starting from arylidenesteroids, it was possible to develop bioactive steroidal pyrazolines, pyrazoles, pyrimidines, pyridines, spiro-pyrrolidines, amongst others. Most of these products have also been studied as anti-inflammatory and anticancer agents, as well as 5α-reductase and aromatase inhibitors. This work aims to provide a comprehensive overview of steroidal arylidene derivatives described in the literature, highlighting their bioactivities and importance as synthetic intermediates for other pharmacologically active compounds.     

An efficient synthesis of new thiazolidin-4-one fused s-triazines as potential antimicrobial and anticancer agents

As a part of our endeavor toward the synthesis of new heterocyclic bioactive agents, two series of thiazolidin-4-one fused s-triazines were synthesized by applying an efficient palladium catalyzed C–C Suzuki coupling using catalyst system Pd(OAC)₂, Xphos and K₃PO₄ as a base in toluene solvent. Moreover, the synthesized analogs were further screened for their in vitro antimicrobial as well as anticancer efficacy against prostate cancer PC3 cells. Some compounds displayed remarkable antimicrobial activity and noticeable anticancer activity. It was observed that, both benzonitrile and nicotinonitrile are essential to increase the different pharmacological activities. The newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and MS analysis.     

Allium schoenoprasum L.: a review of phytochemistry,pharmacology and future directions

Allium schoenoprasum L. (family Amaryllidaceae), commonly known as chives has great culinary value besides being used as ethnomedicine. This review emphasises on phytochemistry and pharmacological activities of A. schoenoprasum, and discusses the future opportunities for systematic investigations. Scientific evaluation of chives validates its traditional claims and demonstrates diverse pharmacological potential including an anti-inflammatory, anticancer, antioxidant, anthelmintic and antihypertensive. Though phytochemical studies revealed the presence of sulphur and phenolic compounds, flavonoids, saponin and steroidal glycosides yet methodical research to identify bioactive compounds is required. This review confirms the medicinal importance of A. schoenoprasum and could stimulate future research on its unexplored aspects, especially identification of bioactive compounds and related mechanisms and safety, which might develop it as a drug.     

Synthesis of Pyrazole Derivatives Possessing Anticancer Activity: Current Status

Pyrazole is a versatile lead compound to design potent bioactive molecules for drug discovery and development, particularly in cancer therapy. The aim of this review is to present the most recent deeds in the field of synthetic route made for functionalized pyrazole derivatives active against cell proliferation disease. The review article covers the synthesis of 1H-pyrazole, synthesis of N-substituted pyrazoles, synthesis of pyrazolopyrazoles, and synthesis of pyrazoles fused with a naturally occurring moiety. Some of these reported compounds have passed the preclinical or initial-phase clinical trials for their anticancer activity.     

Design,Synthesis, and In Vitro Evaluation of Novel Indolyl DiHydropyrazole Derivatives as Potential Anticancer Agents

Indoles derived from both natural sources or artificial synthetic methods have been known to interact with aryl hydrocarbon receptors (AhR), and exhibit anticancer activity. In light of these attractive properties, a series of hybrid molecules with structural features of indoles, i.e., those bearing a pyrazoline nucleus, were evaluated for their enhanced anticancer activity. The designed molecules were subjected to molecular docking in order to screen for potential AhR interacting compounds, and the identified indolyl dihydropyrazole derivatives were synthesized. The synthesized compounds were characterized, and their cytotoxicity was evaluated against four human cancer cell lines using the MTT assay. Based on the Glide g-score, H-bonding interactions and bonding energy of 20 candidate molecules were selected for further analysis from the 64 initially designed molecules. These candidate molecules have shown promising anti-proliferative activity against the cell lines tested. Among these candidate molecules, the compounds with hydroxy phenyl substitution on the pyrazoline ring have shown potent activity across all the tested cell lines. The designed scaffold was proven effective for screening potential candidate molecules with anticancer properties, and may be further optimized structurally for yielding the ideal anti-tumorigenic compound for the treatment of various cancers.     

Synthesis of various fused heterocyclic rings from thiazolopyridine and their pharmacological and antimicrobial evaluations

Various fused-heterocyclic-derivatives containing thiazolopyridine moieties has been synthesized by allowing 5-aminothiazolo[3,2-a]pyridine derivative 1 to undergo annulations reactions with different reagents under different-reaction conditions. The biological assessment of compounds 2 , 11 , 14 , 15 , and 19 showed remarkable antimicrobial activities. In addition, selected derivatives of the products were screened for their anticancer activities against two tumor cell lines using MTT assay and the results showed that some of these compounds have potent cytotoxic effect, as concluded from their IC₅₀ values. Meanwhile, compounds 3a , 7 have exhibited very strong potency as anticancer candidates. Thiazolopyridine structures have been confirmed as a useful lead compounds for the development of new anticancer agents. Molecular docking showed that,-some of the synthesized compounds more suitable inhibitor against-ALR2 with farther alteration in future.     

Imidazoles as Potential Anticancer Agents: An Update on Recent Studies

Nitrogen-containing heterocyclic rings are common structural components of marketed drugs. Among these heterocycles, imidazole/fused imidazole rings are present in a wide range of bioactive compounds. The unique properties of such structures, including high polarity and the ability to participate in hydrogen bonding and coordination chemistry, allow them to interact with a wide range of biomolecules, and imidazole-/fused imidazole-containing compounds are reported to have a broad spectrum of biological activities. This review summarizes recent reports of imidazole/fused imidazole derivatives as anticancer agents appearing in the peer-reviewed literature from 2018 through 2020. Such molecules have been shown to modulate various targets, including microtubules, tyrosine and serine-threonine kinases, histone deacetylases, p53-Murine Double Minute 2 (MDM2) protein, poly (ADP-ribose) polymerase (PARP), G-quadraplexes, and other targets. Imidazole-containing compounds that display anticancer activity by unknown/undefined mechanisms are also described, as well as key features of structure-activity relationships. This review is intended to provide an overview of recent advances in imidazole-based anticancer drug discovery and development, as well as inspire the design and synthesis of new anticancer molecules.     

Cyclodextrin‐modified capillary electrophoresis for achiral and chiral separation of ergostane and lanostane compounds extracted from the fruiting body of Antrodia camphorata

A CD‐modified capillary electrophoretic method has been developed for achiral and chiral analysis of seven bioactive compounds isolated from the fruiting body of Antrodia camphorata. Such important target analytes exhibit similar chemical structures and are known for their diverse properties including antioxidant and anticancer effects. The analytes were separated in 25 min using a pH 9.3, 20 mM sodium borate buffer containing 20 mM methyl‐β‐CD and 30 mM sulfobutylether‐β‐CD. With the exception of the optical isomer pairs (antcin B or zhankuic acid A, zhankuic acid C, and antcin A), the remaining bioactive compounds including the chiral pair antcin C were baseline‐separated. Analysis time was noticeably longer to baseline separate all of the above chiral pairs (～38 min) by adding 5% DMF to the running buffer. The migration order was reversed compared with the HPLC elution. More hydrophobic compounds complexed favorably with methyl‐β‐CD and emerged earlier in the electropherogram than their more hydrophilic counterparts which were strongly associated with sulfobutylether‐β‐CD. The simple capillary electrophoretic method developed was applicable for rapid separation and characterization of several important bioactive compounds isolated from the fruiting body of A. camphorata.     

Natural Peptides Inducing Cancer Cell Death: Mechanisms and Properties of Specific Candidates for Cancer Therapeutics

Nowadays, cancer has become the second highest leading cause of death, and it is expected to continue to affect the population in forthcoming years. Additionally, treatment options will become less accessible to the public as cases continue to grow and disease mechanisms expand. Hence, specific candidates with confirmed anticancer effects are required to develop new drugs. Among the novel therapeutic options, proteins are considered a relevant source, given that they have bioactive peptides encrypted within their sequences. These bioactive peptides, which are molecules consisting of 2–50 amino acids, have specific activities when administered, producing anticancer effects. Current databases report the effects of peptides. However, uncertainty is found when their molecular mechanisms are investigated. Furthermore, analyses addressing their interaction networks or their directly implicated mechanisms are needed to elucidate their effects on cancer cells entirely. Therefore, relevant peptides considered as candidates for cancer therapeutics with specific sequences and known anticancer mechanisms were accurately reviewed. Likewise, those features which turn certain peptides into candidates and the mechanisms by which peptides mediate tumor cell death were highlighted. This information will make robust the knowledge of these candidate peptides with recognized mechanisms and enhance their non-toxic capacity in relation to healthy cells and further avoid cell resistance.     

Anticancer potential of Annona genus: A detailed review

Genus Annona is widely distributed in tropical and subtropical regions around the world. From root to shoot, plant parts of different species of Annona were used traditionally in many countries for treatment of different types of diseases and as a general health supplement. It is naturally enriched with a large number of bioactive molecules which attributed to the several biological activities including antioxidant, anti-inflammatory, antimicrobial and anticancer effects. These bioactive constituents isolated from the leaf, bark, fruit and stem of this plant genus have found terpenoids, steroids, flavonoids, cardiac glycosides, tannins, phenols and alkaloids. Studies have reported that annonaceous acetogenins and alkaloids from this genus were very effective against different types of tumour cell lines. This review highlights anticancer effects of Annona species in cancer therapy, the efficacy of its bioactive components on diverse cancer types and their mechanism of action and also summarizes the use of these phytochemicals for the purpose of developing a promising anticancer drug candidate in future.     

A Multitargeted Approach: Organorhodium Anticancer Agent Based on Vorinostat as a Potent Histone Deacetylase Inhibitor

The combination of more than one bioactive moiety in a multitargeted anticancer agent may result in synergistic activity of its components. Using this concept, bioorganometallic compounds were designed to feature a metal center, a 2‐pyridinecarbothioamide (PCA), and a hydroxamic acid, which is found in the anticancer drug vorinostat (SAHA). The organometallics showed inhibitory activity in the nanomolar range against histone deacetylases (HDACs) as the key target for SAHA. In particular, the Rh complex was a potent inhibitor of HDAC6 over HDAC1 and HDAC8. Whereas this complex was highly cytotoxic in human cancer cells, it showed low toxicity in hemolysis studies and zebrafish, demonstrating the role of the metal center. For this complex a slightly reduced expression of vascular endothelial growth factor receptor 2 (VEGFR2) was established, which was upregulated by SAHA. This finding indicates that the new organometallics display different modes of action than their bioactive components.     

Lewis acid-mediated cross-coupling reaction of 7-azaindoles and aldehydes: Cytotoxic evaluation of C3-linked bis-7-azaindoles

The synthesis of 3,3′-bis-7-indolylmethane derivatives is important for their further development as pharmaceutical compounds and other synthetic purposes. Herein, we describe the zinc- or acid-mediated cross-coupling reaction of 7-azaindoles with aldehydes, such as paraformaldehyde, alkyl aldehydes, aryl aldehydes, enal, and α-ketoaldehyde, providing the corresponding C3-linked bis-7-azaindole derivatives, which are a crucial class towards the development of novel bioactive compounds. High levels of site selectivity and functional group tolerance were observed. Synthesized 3,3′-bis-7-azaindole derivatives were evaluated against human breast adenocarcinoma cells (MCF-7) and human ovarian carcinoma cells (SKOV-3), respectively. Notably, compounds 3s and 4e displayed promising anticancer properties competitive with anticancer doxorubicin as a positive control.     

2-Phenylindole derivatives as anticancer agents: synthesis and screening against murine melanoma,human lung and breast cancer cell lines

Indole derivatives have attractive anticancer properties and may be a future hope for better anticancer drug(s) of low toxicity and high potency. In this paper, syntheses of 2-phenylindole derivatives have been described via Fischer indole synthesis through a one-pot solvent-free method. The synthesized compounds were screened for anticancer potential in vitro against murine melanoma (B16F10), human lung cancer (A549), and human breast cancer (MDA-MB-231) cell lines. The results highlighted that 2-phenylindole derivatives are also promising anticancer agents in case of melanoma and lung cancer along with the breast cancer. Molecular docking analyses with possible targets for melanoma (NEDD4-1) and lung cancer (EGFR) were also performed to understand specific interactions of 2-phenylindole derivatives with the amino acid residues of the receptors.