Simple 2(5H)-furanone derivatives with selective cytotoxicity towards non-small cell lung cancer cell line A549 – Synthesis, structure-activity relationship and biological evaluation

The role of silicon in drug discovery: a review

This review aims to highlight the role of silicon in drug discovery. Silicon and carbon are often regarded as being similar with silicon located directly beneath carbon in the same group in the periodic table. That being noted, in many instances a clear dichotomy also exists between silicon and carbon, and these differences often lead to vastly different physiochemical and biological properties. As a result, the utility of silicon in drug discovery has attracted significant attention and has grown rapidly over the past decade. This review showcases some recent advances in synthetic organosilicon chemistry and examples of the ways in which silicon has been employed in the drug-discovery field.

Design, synthesis and biological evaluation of rhein-piperazine-furanone hybrids as potential anticancer agents

Novel rhein-piperazine-furanone hybrids, 5, were designed and synthesized efficiently from rhein. Cytotoxicity of all hybrids 5a-j against A549 human lung cancer cells was superior to the parent rhein and the reference cytarabine (CAR). Hybrid 5e (IC50 = 5.74 μM), the most potent compound, was 46- and 35-fold more toxic against A549 cells than rhein (IC50 = 265.59 μM) and CAR (IC50 = 202.57 μM), respectively. Moreover, hybrid 5e (IC50 = 69.28 μM) was less toxic to normal WI-38 human lung fibroblast cells with good selectivity (WI-38/A549, SI ≈ 12), being much higher than rhein (SI ≈ 1) and CAR (SI ≈ 2). Structure-activity relationship (SAR) analysis showed that cytotoxicity and selectivity against A549 lung cancer cells were greatly enhanced when methoxy-containing furanone was introduced to the hybrids (5e and 5h). Further, hybrid 5e showed better cytotoxicity against four types of human lung cancer cells (H460, A549, PC-9, and Calu-1; IC50 = 4.35-15.39 μM) than six other types of human cancer cells (SK-BR-3, SK-OV-3, 786-O, Huh-7, HCT116, and HeLa; IC50 = 13.77-60.45 μM), showing specificity. In particular, hybrid 5e showed the highest cytotoxicity (IC50 = 4.35 μM) and the highest selectivity (WI-38/H460, SI ≈ 16) against H460 human lung cancer cells. Flow cytometric analysis showed that hybrid 5e induced apoptosis in a concentration-dependent manner in H460 cells. The results show that the cytotoxicity and selectivity of rhein can be greatly enhanced by hybridization with furanone. Hybrid 5e is expected to be a leading candidate for anti-lung cancer drugs.

DBDMH-Promoted Methylthiolation in DMSO: A Metal-Free Protocol to Methyl Sulfur Compounds with Multifunctional Groups

Organic thioethers play an important role in the discovery of drugs and natural products. However, the green synthesis of organic sulfide compounds remains a challenging task. The convenient and efficient synthesis of 5-alkoxy-3-halo-4-methylthio-2(5H)-furanones from DMSO is performed via the mediation of 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), affording a facile route for the sulfur-functionalization of 3,4-dihalo-2(5H)-furanones under transition metal-free conditions. This new approach has demonstrated the functionalization of non-aromatic Csp2-X-type halides with unique structures containing C-X, C-O, C=O and C=C bonds. Compared with traditional synthesis methods using transition metal catalysts with ligands, this reaction has many advantages, such as the lower temperature, the shorter reaction time, the wide substrate range and good functional group tolerance. Notably, DMSO plays multiple roles, and is simultaneously used as an odorless methylthiolating reagent and safe solvent.

Antileishmanial evaluation of triazole-butenolide conjugates: design, synthesis, in vitro screening, SAR and in silico ADME predictions

In the quest to discover novel scaffolds with leishmanicidal effects, a series of 23 compounds containing the most promising 1,2,3-triazole and highly potent butenolide in one framework were synthesized. The synthesized conjugates were screened against Leishmania donovani parasite; five of them showed moderate antileishmanial activity against promastigotes (IC50 30.6 to 35.5 μM) and eight of them exhibited significant activity against amastigotes (IC50 ≤12 μM). Compound 10u was found to be the most active (IC50 8.4 ± 0.12 μM) with the highest safety index (20.47). The series was further evaluated against Plasmodium falciparum (3D7 strain) and seven compounds were found to be moderately active. Among them, again 10u emerged as the most active compound (IC50 3.65 μM). In antifilarial assays against adult female Brugia malayi, five compounds showed grade II inhibition (50-74%). Structure-activity relationship (SAR) analysis suggested a substituted phenyl ring, triazole and butenolide as essential structural features for bioactivity. Moreover, the results of in silico ADME parameter and pharmacokinetic studies indicated that the synthesized triazole-butenolide conjugates abide by the required criteria for the development of orally active drugs, and thus this scaffold can be used as a pharmacologically active framework that should be considered for the development of potential antileishmanial hits.

Volatile and Non-Volatile Content Determination and Biological Activity Evaluation of Fresh Humulus lupulus L. (cv. Chinook) Leaves and Inflorescences

In this work, the fresh leaves and inflorescences of Humulus lupulus L. cv. Chinook hops were investigated in order to describe their chemical composition and evaluate their biological activities. The analyses were carried out first on fresh untreated samples and then on pulverized ones using the SPME-GC-MS technique. In total, forty-two molecules belonging to different chemical classes were identified, and among these, twenty-three were terpene compounds. In order to carry out the activity assays, the powders were subjected to extraction with two different solvents (methanol and distilled water) by stirring and subsequent sonication at room temperature. To chemically characterize the extracts, the methanolic ones were analyzed by direct injection into the GC-MS apparatus, while the aqueous ones were analyzed by DI-SPME-GC-MS. In addition, with the aim to obtain information on the non-volatile content of the methanolic extracts, they were also subjected to derivatization, and the silylated derivatives were analyzed by GC-MS. The antioxidant activity was then evaluated by means of DPPH and ABTS assays after the determination of the total content of polyphenols and flavonoids. The greatest effects were observed on the methanolic extracts rather than on the aqueous ones. Furthermore, a preliminary study on the cytotoxic power of the methanolic extracts was also conducted on three different human cancer cell lines, such as non-small cell lung cancer (H1299), melanoma (A375) and breast cancer (MCF7). The obtained results showed that the two extracts induced a marginal effect on reducing breast tumor, melanoma and non-small cell lung cancer cell proliferation.

Synthesis of dihydrofuran-3-one and 9,10-phenanthrenequinone hybrid molecules and biological evaluation against colon cancer cells as selective Akt kinase inhibitors

A series of dihydrofuran-3-one and 9,10-phenanthrenequinone hybrid compounds were synthetized through a one-pot gold-catalyzed oxidative cyclization and Aldol-type addition cascade reaction of homopropargylic alcohols with 9,10-phenanthrenequinone. The cytotoxicity of newly synthesized compounds was evaluated in CCK8 assay against different human cancer cells, showing significantly antiproliferative activity against tested tumor cell lines with a lowest IC₅₀ value of 0.92 μM over HCT-116. Further investigation revealed that the treatment of HCT-116 cell line with the promising compound 4c induced cell death as a selective Akt inhibitor. In addition, controlled experiments and molecular docking study suggested that the significant antitumor activity might be attributed to the unique hybrid structure, which implied the promising potential of this dual heterocycle hybrid method in the discovery of novel bioactive molecules with structural diversity.

Furanonyl amino acid derivatives as hemostatic drugs: design, synthesis and hemostasis performance

Using 3,4-dihalo-2(5H)-furanones and easily available hemostatic drugs, such as tranexamic acid (TA), 4-aminomethylbenzoic acid (ABA), aminocaproic acid (AA) as starting materials, serial multi-functional molecules 2(5H)-furanonyl amino acids are designed by the combination of different pharmacophores, and successfully synthesized by a transition metal-free Michael addition-elimination reaction. The reaction is carried out under mild conditions with ethanol-dichloromethane as solvent and only stirring at room temperature for 24 h, and the yield can be up to 91%. All products are well characterized by infrared spectroscopy (IR), nuclear magnetic resonance (NMR), high-resolution mass spectra (HRMS). Ten typical target compounds among them are selected out for the experiments of hemostasis performance by the evaluation of in vitro clot formation model and liver hemorrhage model. The test results show that, their hemostasis effect is better than the original drugs. Especially the target compound G, a TA derivative from 5-borneoloxy-3,4-dibromo-2(5H)-furanone, has the best hemostasis effect among all the tested compounds. These obtained target molecules are expected to be used as multi-functional hemostatic drugs.

Anticancer and Apoptotic Activity in Cervical Adenocarcinoma HeLa Using Crude Extract of Ganoderma applanatum

Cancer is currently one of the foremost health challenges and a leading cause of death worldwide. Cervical cancer is caused by cofactors, including oral contraceptive use, smoking, multiparity, and HIV infection. One of the major and considerable etiologies is the persistent infection of the oncogenic human papilloma virus. G. applanatum is a valuable medicinal mushroom that has been widely used as a folk medicine for the treatment and prevention of various diseases. In this study, we obtained crude extract from G. applanatum mushroom with a subcritical water extraction method; cell viability assay was carried out and the crude extract showed an antiproliferative effect in HeLa cells with IC₅₀ of 1.55 ± 0.01 mg/mL; however, it did not show any sign of toxicity in HaCaT. Protein expression was detected by Western blot, stability of IκBα and downregulation of NFκB, IKKα, IKKβ, p-NFκB-65(Ser 536) and p-IKKα/β(Ser 176/180), suggesting loss of survival in a dose-dependent manner. RT-qPCR revealed RNA/mRNA expression; fold changes of gene expression in Apaf-1, caspase-3, cytochrome-c, caspase-9, Bax and Bak were increased, which implies apoptosis, and NFκB was decreased in a dose-dependent manner. DNA fragmentation was seen in the treatment groups as compared to the control group using gel electrophoresis. Identification and quantification of compounds were carried out by GC–MS and HPLC, respectively; 2(5H)furanone with IC₅₀ of 1.99 ± 0.01 μg/mL could be the responsible anticancer compound. In conclusion, these findings suggest the potential use of the crude extract of G. applanatum as a natural source with anticancer activity against cervical cancer.

Synthesis and Preliminary Anticancer Activity Assessment of N-Glycosides of 2-Amino-1,3,4-thiadiazoles

The addition of 2-amino-1,3,4-thiadiazole derivatives with parallel iodination of differently protected glycals has been achieved using a double molar excess of molecular iodine under mild conditions. The corresponding thiadiazole derivatives of N-glycosides were obtained in good yields and anomeric selectivity. The usage of iodine as a catalyst makes this method easy, inexpensive, and successfully useable in reactions with sugars. Thiadiazole derivatives were tested in a panel of three tumor cell lines, MCF-7, HCT116, and HeLa. These compounds initiated biological response in investigated tumor models in a different rate. The MCF-7 is resistant to the tested compounds, and the cytometry assay indicated low increase in cell numbers in the sub- G1 phase. The most sensitive are HCT-116 and HeLa cells. The thiadiazole derivatives have a pro-apoptotic effect on HCT-116 cells. In the case of the HeLa cells, an increase in the number of cells in the sub-G1- phase and the induction of apoptosis was observed.

Effect of Selected Silyl Groups on the Anticancer Activity of 3,4-Dibromo-5-Hydroxy-Furan-2(5H)-One Derivatives

The pharmacological effects of carbon to silicon bioisosteric replacements have been widely explored in drug design and medicinal chemistry. Here, we present a systematic investigation of the impact of different silyl groups on the anticancer activity of mucobromic acid (MBA) bearing furan-2(5H)-one core. We describe a comprehensive characterization of obtained compounds with respect to their anticancer potency and selectivity towards cancer cells. All four novel compounds exert stronger antiproliferative activity than MBA. Moreover, 3b induce apoptosis in colon cancer cell lines. A detailed investigation of the mechanism of action revealed that 3b activity stems from the down-regulation of survivin and the activation of caspase-3. Furthermore, compound 3b attenuates the clonogenic potential of HCT-116 cells. Interestingly, we also found that depending on the type of the silyl group, compound selectivity towards cancer cells could be precisely controlled. Collectively, we demonstrated the utility of silyl groups for adjusting both the potency and selectivity of silicon-containing compounds. These data reveal a link between the types of silyl group and compound potency, which could have bearings for the design of novel silicon-based anticancer drugs.

Synthesis of artemisinin-piperazine-furan ether hybrids and evaluation of in vitro cytotoxic activity

For the first time, eight novel artemisinin-piperazine-furane ether hybrids (5a-h) were efficiently synthesized and investigated for their in vitro cytotoxic activity against some human cancer and benign cells. The absolute configuration of hybrid 5c was determined by X-ray crystallographic analysis. Hybrids 5a-h exhibited more pronounced growth-inhibiting action on hepatocarcinoma cell lines than their parent dihydroartemisinin (DHA) and the reference cytosine arabinoside (ARA). The hybrid 5a showed the best cytotoxic activity against human hepatocarcinoma cells SMMC-7721 (IC₅₀ = 0.26 ± 0.03 μM) after 24 h. Furthermore, hybrid 5a also showed good cytotoxic activity against human breast cancer cells MCF-7 and low cytotoxicity against human breast benign cells MCF-10A in vitro. We found the cytotoxicity of hybrid 5a did not change when tumour cells absorb iron sulfate (FeSO₄); thus, we conclude the anti-tumour mechanism induced by iron ions (Fe²⁺) is unclear.

Synthesis of N-2(5H)-furanonyl sulfonyl hydrazone derivatives and their biological evaluation in vitro and in vivo activity against MCF-7 breast cancer cells

A series of (E)-N-2(5H)-furanonyl sulfonyl hydrazone derivatives have been rationally designed and efficiently synthesized by one-pot reaction with good yields for the first time. This green approach with wide substrate range and good selectivity can be achieved at room temperature in a short time in the presence of metal-free catalyst. The cytotoxic activities against three human cancer cell lines of all newly obtained compounds have been evaluated by MTT assay. Among them, compound 5 k exhibits high cytotoxic activity against MCF-7 human breast cancer cells with an IC₅₀ value of 14.35 μM. The cytotoxic mechanism may involve G2/M phase arrest pathway, which is probably caused by activating DNA damage. Comet test and immunofluorescence results show that compound 5 k can induce DNA damage in time- and dose-dependent manner. Importantly, 5 k also can effectively inhibit the proliferation of MCF-7 cells and angiogenesis in the zebrafish xenograft model. It is potential to further develop N-2(5H)-furanonyl sulfonyl hydrazone derivatives as potent drugs for breast cancer treatment with higher cytotoxic activity by modifying the structure of the compound.

Synthesis and Biological Evaluation of Analogues of Butyrolactone I as PTP1B Inhibitors

In recent years, a large number of pharmacologically active compounds containing a butenolide functional group have been isolated from secondary metabolites of marine microorganisms. Butyrolactone I was found to be produced by Aspergillus terreus isolated from several marine-derived samples. The hypoglycemic activity of butyrolactone I has aroused our great interest. In this study, we synthesized six racemic butenolide derivatives (namely BL-1–BL-6) by modifying the C-4 side chain of butyrolactone I. Among them, BL-3 and BL-5 improved the insulin resistance of HepG2 cells and did not affect the proliferation of RIN-m5f cell line, which indicated the efficacy and safety of BL-3 and BL-5. Furthermore, BL-3, BL-4, BL-5, and BL-6 displayed a significant protein tyrosine phosphatase 1B (PTP1B) inhibitory effect, while the enantiomers of BL-3 displayed different 50% percentage inhibition concentration (IC₅₀) values against PTP1B. The results of molecular docking simulation of the BLs and PTP1B explained the differences of biological consequences observed between the enantiomers of BL-3, which supported BLs as PTP1B inhibitors, and also indicated that the chirality of C-4 might influence the inhibitory effect of the BLs. Our findings provide a novel strategy for the development of butyrolactone derivatives as potential PTP1B inhibitors for the treatment of type 2 diabetes mellitus.

E-Liquid Containing a Mixture of Coconut, Vanilla, and Cookie Flavors Causes Cellular Senescence and Dysregulated Repair in Pulmonary Fibroblasts: Implications on Premature Aging

Electronic cigarette (e-cig) usage has risen dramatically worldwide over the past decade. While they are touted as a safe alternative to cigarettes, recent studies indicate that high levels of nicotine and flavoring chemicals present in e-cigs may still cause adverse health effects. We hypothesized that an e-liquid containing a mixture of tobacco, coconut, vanilla, and cookie flavors would induce senescence and disrupt wound healing processes in pulmonary fibroblasts. To test this hypothesis, we exposed pulmonary fibroblasts (HFL-1) to e-liquid at varying doses and assessed cytotoxicity, inflammation, senescence, and myofibroblast differentiation. We found that e-liquid exposure caused cytotoxicity, which was accompanied by an increase in IL-8 release in the conditioned media. E-liquid exposure resulted in elevated senescence-associated beta-galactosidase (SA-β-gal) activity. Transforming growth factor-β1 (TGF-β1) induced myofibroblast differentiation was inhibited by e-liquid exposure, resulting in decreased α-smooth muscle actin and fibronectin protein levels. Together, our data suggest that an e-liquid containing a mixture of flavors induces inflammation, senescence and dysregulated wound healing responses.