Structure-anti-leukemic activity relationship study of ortho-dihydroxycoumarins in U-937 cells: key role of the δ-lactone ring in determining differentiation-inducing potency and selective pro-apoptotic action

Dihydrocaffeic Acid-Is It the Less Known but Equally Valuable Phenolic Acid?

Dihydrocaffeic acid (DHCA) is a phenolic acid bearing a catechol ring and three-carbon side chain. Despite its being found in minor amounts in numerous plants and fungi of different origins, it has attracted the interest of various research groups in many fields of science, from food to biomedical applications. The review article presented herein aims to show a wider audience the health benefits and therapeutic, industrial, and nutritional potential of dihydrocaffeic acid, by sheddinglight on its occurrence, biosynthesis, bioavailability, and metabolism. The scientific literature describes at least 70 different derivatives of dihydrocaffeic acid, both those occurring naturally and those obtained via chemical and enzymatic methods. Among the most frequently used enzymes that were applied for the modification of the parent DHCA structure, there are lipases that allow for obtaining esters and phenolidips, tyrosinases used for the formation of the catechol ring, and laccases to functionalize this phenolic acid. In many studies, both in vitro and in vivo, the protective effect of DHCA and its derivatives on cells subjected to oxidative stress and inflammation were acknowledged.

The five Ferulago species inhibited cell proliferation and induced apoptosis of A549, MCF-7, PC3 and SW480 cancer cells in vitro

In this study, it was aimed to evaluate the cytotoxic and apoptotic activities of ethanolic extracts prepared from the roots of 5 Ferulago species [F. humilis Boiss., F. macrosciadia Boiss. & Balansa, F. sandrasica Peşmen & Quézel, F. silaifolia (Boiss.) Boiss., F. trojana Akalın & Pimenov] on various human cancer cell lines. The cytotoxicity analyses against human lung (A549), breast (MCF-7), prostate (PC3) and colon (SW480) cancer cell lines were determined by MTT test; while the apoptotic effect was evaluated by Annexin V binding assay. All studied extracts showed concentration-dependent cytotoxic activity with an IC50 value ranging from 0.416 to 5.336 mg/mL. The studied Ferulago species significantly induced apoptosis of cancer cells, while F. macrosciadia had the highest apoptotic activity on MCF-7 cells with 21.79 ± 1.63% apoptotic cell population (p < 0.0001). In addition, felamedin and prantschimgin content of the extracts, which are common coumarins in Ferulago species, were evaluated by HPLC. According to HPLC analysis, the highest amount of felamedin content was found in F. trojana, while the highest content of prantschimgin was found in F. sandrasica among the studied Ferulago species. This preliminary research has revealed that the studied Ferulago species have promising effects on various cancer cell lines. Further studies are planned to determine the compounds responsible for the effect and underlying mechanism.

Phytochemical Profiling, Isolation, and Pharmacological Applications of Bioactive Compounds from Insects of the Family Blattidae Together with Related Drug Development

In traditional Chinese medicine (TCM), insects from the family Blattidae have a long history of application, and their related active compounds have excellent pharmacological properties, making them a prominent concern with significant potential for medicinal and healthcare purposes. However, the medicinal potential of the family Blattidae has not been fully exploited, and many problems must be resolved urgently. Therefore, a comprehensive review of its chemical composition, pharmacological activities, current research status, and existing problems is necessary. In order to make the review clearer and more systematic, all the contents were independently elaborated and summarized in a certain sequence. Each part started with introducing the current situation or a framework and then was illustrated with concrete examples. Several pertinent conclusions and outlooks were provided after discussing relevant key issues that emerged in each section. This review focuses on analyzing the current studies and utilization of medicinal insects in the family Blattidae, which is expected to provide meaningful and valuable relevant information for researchers, thereby promoting further exploration and development of lead compounds or bioactive fractions for new drugs from the insects.

Design and Synthesis of Coumarin Derivatives as Cytotoxic Agents through PI3K/AKT Signaling Pathway Inhibition in HL60 and HepG2 Cancer Cells

In this study, a series of coumarin derivatives, either alone or as hybrids with cinnamic acid, were synthesized and evaluated for their cytotoxicity against a panel of cancer cells using the MTT assay. Then, the most active compounds were inspected for their mechanism of cytotoxicity by cell-cycle analysis, RT-PCR, DNA fragmentation, and Western blotting techniques. Cytotoxic results showed that compound (4) had a significant cytotoxic effect against HL60 cells (IC₅₀ = 8.09 µM), while compound (8b) had a noticeable activity against HepG2 cells (IC₅₀ = 13.14 µM). Compounds (4) and (8b) mediated their cytotoxicity via PI3K/AKT pathway inhibition. These results were assured by molecular docking studies. These results support further exploratory research focusing on the therapeutic activity of coumarin derivatives as cytotoxic agents.

Biologically Active Compounds of Plants: Structure-Related Antioxidant, Microbiological and Cytotoxic Activity of Selected Carboxylic Acids

Natural carboxylic acids are plant-derived compounds that are known to possess biological activity. The aim of this review was to compare the effect of structural differences of the selected carboxylic acids (benzoic acid (BA), cinnamic acid (CinA), p-coumaric acid (p-CA), caffeic acid (CFA), rosmarinic acid (RA), and chicoric acid (ChA)) on the antioxidant, antimicrobial, and cytotoxic activity. The studied compounds were arranged in a logic sequence of increasing number of hydroxyl groups and conjugated bonds in order to investigate the correlations between the structure and bioactivity. A review of the literature revealed that RA exhibited the highest antioxidant activity and this property decreased in the following order: RA > CFA ~ ChA > p-CA > CinA > BA. In the case of antimicrobial properties, structure-activity relationships were not easy to observe as they depended on the microbial strain and the experimental conditions. The highest antimicrobial activity was found for CFA and CinA, while the lowest for RA. Taking into account anti-cancer properties of studied NCA, it seems that the presence of hydroxyl groups had an influence on intermolecular interactions and the cytotoxic potential of the molecules, whereas the carboxyl group participated in the chelation of endogenous transition metal ions.

Synthesis of new triazole linked carbohybrids with ROS-mediated toxicity in breast cancer

Carbohybrids are an important class of molecules which exhibit diverse biological activities. New coumarins and quinolones linked carbohybrids are synthesised which are showing selective anticancer activity.

Pharmacological and Nutritional Effects of Natural Coumarins and Their Structure-Activity Relationships

Coumarins are fused benzene and pyrone ring systems with a wide spectrum of bioactivities, including antitumor, anti-inflammation, antiviral, and antibacterial effects. In this paper, the current development of coumarin-based drugs is introduced, and their structure-activity relationship is discussed by reviewing the relevant literature published in the past 20 years. Coumarin molecules can be customized by the target site to prevent systemic side effects by virtue of structural modification. The ortho-phenolic hydroxyl on the benzene ring has remarkable antioxidant and antitumor activities. Coumarins with aryl groups at the C-4 position have good activities in anti-HIV, antitumor, anti-inflammation, and analgesia. C-3 phenylcoumarins have strong anti-HIV and antioxidant effects. Tetracycline pyranocoumarins can significantly inhibit HIV; osthol structural analogues have antimicrobial activity. Praeruptorin C and its derivatives play an important role in lowering blood pressure and dilating coronary arteries, and khellactone derivatives have significant inhibitory effects on AIDS, cancer, and cardiovascular diseases. It is concluded that the specific site on the core structure of coumarin exhibits one or more activities due to the electronic or steric effects of the substituents. This review is intended to be conducive to rational design and development of more active and less toxic agents with a coumarin scaffold.

Design and synthesis of new coumarin hybrids and insight into their mode of antiproliferative action

Molecular hybridization approach was used to synthesize three series of coumarin based hybrids by conglomerate a substituted chalcones, acrylohydrazides, and pyridines moieties with 8-methoxy coumarin. The hybrids showed significant cytotoxic activity against liver cancer Hep G2 and Leukemia K562 cell lines with IC₅₀ values 0.49-3.96μM, comparable to the positive controls and exhibited weak activity against the normal cell line WI-38, thus indicating selectivity toward the tumor cells. Coumarin-chalcone hybrids 2a-c have demonstrated the most promising activity against both cancer cell lines with IC₅₀ values of 0.65-2.02μM. Interestingly, the acrylohydrazide hybrid 4c showed the highest cytotoxic activity against the leukemia cell line (K562) with IC₅₀ value of 0.49μM. All the investigated coumarin hybrids were able to increase the caspase-3 and caspase-9 proteins level expression relative to that of the untreated cells suggesting that coumarin hybrids-induced apoptosis was, in part, due to activation of caspases 3 and 9. Apoptosis was further confirmed with down-regulation of Bcl-2 and up-regulation of Bax protein expression level. Furthermore, cell cycle analysis of 2a and 4c showed apoptotic signals activation, as a consequence of arrest in G2/M phase. Results of our study can shed light on coumarin-based hybrids as promising anticancer leads.

Theoretical study of optical activity of 1:1 hydrogen bond complexes of water with S-warfarin

The molecular interaction between S-warfarin (SW) and a single water molecule was investigated using the B3LYP method at 6-311++G(d,p) basis set. The vibrational spectra of the optimized complexes have been investigated for stabilization checking. Quantum theories of atoms in molecules, natural bond orbitals, molecular electrostatic potentials and energy decomposition analysis methods have been applied to analyze the intermolecular interactions. The intermolecular charge transfer in the most stable complex is in the opposite direction from those in the other complexes. The optical spectra and the hyperpolarizabilities of SW-water hydrogen bond complexes have been computed.

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.

Structure-activity relationship studies of 4-methylcoumarin derivatives as anticancer agents

CONTEXT

Cancer is a leading cause of death worldwide and novel chemotherapeutic agents with better efficacy and safety profiles are much needed. Coumarins are natural polyphenolic compounds with important pharmacological activities, which are present in many dietary plants and herbal remedies.

OBJECTIVES

The objective of this study is to investigate natural and synthetic coumarin derivatives with considerable anticancer capacity against three human cancer cell lines.

MATERIALS AND METHODS

We synthesized 27 coumarin derivatives (mostly having 4-methyl moiety) and examined their cytotoxic effect on three human cancer cell lines, K562 (chronic myelogenous leukemia), LS180 (colon adenocarcinoma), and MCF-7 (breast adenocarcinoma) by MTT reduction assay. Screened compounds included 7-hydroxy-4-methylcoumarins (7-HMCs), 7-acetoxy-4-methylcoumarins (7-AMCs), and different dihydroxy-4-methylcoumarin (DHMC) and diacetoxy-4-methylcoumarin (DAMC) derivatives. Some compounds with methoxy, amine, and bromine substitutions were also examined.

RESULTS

7,8-DHMCs bearing alkyl groups at C3 position were the most effective subgroup, and of which, the most potent is compound 11, with an n-decyl chain at C3, which had IC50 values of 42.4, 25.2, and 25.1 µM against K562, LS180, and MCF-7 cells, respectively. The second most active subgroup was 7,8-DAMCs containing ethoxycarbonylmethyl and ethoxycarbonylethyl moieties at C3 position. Compound 27 (6-bromo-4-bromomethyl-7-hydroxycoumarin), the only derivative containing bromine also showed reasonable cytotoxic activities (IC50 range: 32.7-45.8 µM).

DISCUSSION AND CONCLUSION

This structure-activity relationship (SAR) study of 4-methylcoumarins shows that further investigation of these derivatives may lead to the discovery of novel anticancer agents.

Synthesis, in vitro and in vivo antitumor activity of scopoletin-cinnamic acid hybrids

A series of hybrids of scopoletin and substituted cinnamic acid were designed, synthesized and evaluated in vitro and in vivo against five human tumor cell lines [MCF-7, MDA-MB-231, A549, HCT-116, and HeLa] with doxorubicin as the positive control. Compounds 17a, 17b, 17c and 17g exhibited potent cytotoxic activity. Especially, compound 17b displayed broad spectrum activity with IC50 values ranging from 0.249 μM to 0.684 μM. Moreover, in a preliminary pharmacological study, 17b not only remarkably induced cellular apoptosis, but also clearly induced A549 cells cycle arrest at S phase. In vivo study showed that 17b significantly suppressed tumor growth in a dose-dependent manner without causing the loss of the mean body weight of mice, which was superior to doxorubicin. These preliminary results indicate that 17b is an optimal anti-cancer leading compound and merit further structural modification.

Comparative Evaluation of Cytotoxic and Apoptogenic Effects of Several Coumarins on Human Cancer Cell Lines: Osthole Induces Apoptosis in p53-Deficient H1299 Cells

Natural products are excellent resources for finding lead structures for the development of chemotherapeutic agents. Coumarins are a class of natural compounds found in a variety of plants. In this study, we evaluated the cytotoxic potential of coumarins isolated from Prangos ferulacea (L.) Lindl. in PC3, SKNMC, and H1299 (p53 null) human carcinoma cell lines. Osthole proved to be an outstanding potent cytotoxic agent especially against PC3 cells. Isoimperatorin exhibited moderate inhibitory effect against SKNMC and PC3 cell lines. Oxypeucedanin and braylin did not display any cytotoxic activity. In the next set of experiments, the apoptotic potentials of osthole and isoimperatorin were investigated. Induction of apoptosis by isoimperatorin was accompanied by an increase in activation of caspase-3, -8, and -9 in SKNMC cells and caspase-3 and -9 in PC3 cells. Moreover, isoimperatorin induced apoptosis by upregulating Bax and Smac/DIABLO genes in PC3 and SKNMC cells. Osthole induced apoptosis by downregulating antiapoptotic Bcl-2 in only PC3 cells and upregulating the proapoptotic genes Bax and Smac/DIABLO in PC3, SKNMC, and H1299 cells. The effects of osthole on H1299 cells are important because the loss of p53 has been associated with poor clinical prognosis in cancer treatment.

Lanthanide and transition metal complexes of bioactive coumarins: molecular modeling and spectroscopic studies

The present paper summarizes theoretical and spectroscopic investigations on a series of active coumarins and their lanthanide and transition metal complexes with application in medicine and pharmacy. Molecular modeling as well as IR, Raman, NMR and electronic spectral simulations at different levels of theory were performed to obtain important molecular descriptors: total energy, formation energy, binding energy, stability, conformations, structural parameters, electron density distribution, molecular electrostatic potential, Fukui functions, atomic charges, and reactive indexes. The computations are performed both in gas phase and in solution with consideration of the solvent effect on the molecular structural and energetic parameters. The investigations have shown that the advanced computational methods are reliable for prediction of the metal-coumarin binding mode, electron density distribution, thermodynamic properties as well as the strength and nature of the metal-coumarin interaction (not experimentally accessible) and correctly interpret the experimental spectroscopic data. Known results from biological tests for cytotoxic, antimicrobial, anti-fungal, spasmolytic and anti-HIV activities on the studied metal complexes are reported and discussed.

Anticancer activity of new coumarin substituted hydrazide-hydrazone derivatives

Drug resistance is a major impediment for cancer treatment, to overcome it we designed and synthesized sixteen coumarins bearing hydrazide-hydrazone moiety and evaluated them against human drug-resistant pancreatic carcinoma (Panc-1) cells and drug-sensitive (hepatic carcinoma; Hep-G2 and leukemia; CCRF) cell lines in vitro. The 6-brominated coumarin hydrazide-hydrazone derivatives (BCHHD) 7c, 8c and 10c were more potent than doxorubicin (DOX) against resistant Panc-1 cells. BCHHD 7c showed significant cytotoxicity against all tested cells (IC50: 3.60-6.50 μM) on comparison with all other coumarin hydrazide-hydrazone derivatives (CHHD), whereas BCHHD's 8c and 10c showed significant antiproliferative activity only against resistant Panc-1 cells with IC50 of 2.02 μM and 2.15 μM, respectively. All the investigated BCHHD's were able to activate caspases 3/7 and they could induce apoptosis in resistant Panc-1 cells. Microarray analysis showed that BCHHD 7c induced the expression of apoptotic- and cell cycle arrest (G2/M)- genes in resistant Panc-1 cells. Moreover, BCHHD 7c induced the up-regulation of CDKN1A, DDIT4, GDF-15 and down-regulation of CDC2, CDC20, CDK2 genes. Based on our results, we conclude that 7c could be a potent anticancer drug to overcome drug resistance in cancer and it could be highly beneficial for patients in the clinic.

Enhancement of cisplatin cytotoxicity in combination with herniarin in vitro

Combinatorial chemotherapy is a valuable route, which can be conducted by different approaches. Use of cisplatin has been approved by the U.S. Food and Drug Administration for different kinds of cancers including bladder cancer. Herniarin is a member of simple coumarins, which are a group of common secondary metabolites in plants. In this study, the enhancing effects of herniarin on cisplatin cytotoxicity were investigated. Cytotoxicity of herniarin on transitional cell carcinoma (TCC) cells was first investigated in comparison with umbelliferone, the parent compound for a large number of coumarins including herniarin, by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. In order to test the effects of herniarin on cisplatin cytotoxicity, TCC cells were also treated with various combining concentrations of herniarin and cisplatin. In these experiments same amounts of dimethyl sulfoxide were used as controls. After 24, 48 and 72 h of treatments, the effects of herniarin on cisplatin cytotoxicity were evaluated by MTT assay. The level of chromatin condensation which represents the apoptotic morphology was also investigated by 4',6-diamidino-2-phenylindole (DAPI) staining. Results indicated that unlike umbelliferone, its methoxy analog, herniarin, had no significant cytotoxicity on TCC cells. On the other hand, the combination of 80 µg/mL herniarin with 5 µg/mL cisplatin, significantly enhanced the cytotoxicity of cisplatin. Furtheremore, DAPI staining revealed that combining concentrations of herniarin and cisplatin resulted in increased chromatin condensation in comparison with controls. This study is another confirmation for bioactivity of herniarin and shows that it might be a good candidate for further experiments investigating its mechanism of action.

Pharmacodynamic study of the 7,8-dihydroxy-4-methylcoumarin-induced selective cytotoxicity toward U-937 leukemic cells versus mature monocytes: cytoplasmic p21(Cip1/WAF1) as resistance factor

The development of tumor-selective drugs with low systemic toxicity has always been a major challenge in cancer treatment. Our group previously identified the 7,8-dihydroxy-4-methylcoumarin (DHMC) as a potential chemotherapeutic agent due to its potent, selective anti-proliferative and apoptosis-inducing effects on several cancer cell lines over peripheral blood mononuclear cells. However, there are still no published reports that can explain such selectivity of action. Herein, we addressed this question by using the U-937 promonocytic leukemia cell line, which can be forced to differentiate into a monocyte-like phenotype in vitro. U-937 cells differentiation is dependent on the nuclear expression of p21(Cip1/WAF1), a protein that is absent in immature U-937 cells but present in both the nucleus and the cytoplasm of normal DHMC-resistant monocytes. Considering that induction of differentiation rendered U-937 cells resistant to DHMC, we evaluated the possible causal role of cytoplasmic p21(Cip1/WAF1) in the onset of such resistance by employing U-937 cells stably transfected with a ZnCl2-inducible p21(Cip1/WAF1) variant lacking the nuclear localization signal (U-937/CB6-ΔNLS-p21 cells). Expression of cytoplasmic p21(Cip1/WAF1) did not induce differentiation of the cells but turned them resistant to DHMC through inhibition of JNK, a crucial mediator of DHMC-induced apoptosis in U-937 cells. Sub-acute toxicity evaluation of DHMC in Balb/c mice indicated that DHMC administered intraperitoneally at doses up to 100mg/kg induced no systemic damage. Collectively, our results explain for the first time the selective cytotoxicity of DHMC for tumor cells over normal monocytes, and encourage further in vivo studies on this compound as potential anti-leukemic agent.