Cytotoxic activity and apoptosis-inducing potential of di-spiropyrrolidino and di-spiropyrrolizidino oxindole andrographolide derivatives

Inhibitory effects of medium-chain fatty acids on the proliferation of human breast cancer cells via suppression of Akt/mTOR pathway and modulating the Bcl-2 family protein

Medium-chain fatty acids (MCFAs) have 6-12 carbon atoms and are instantly absorbed into the bloodstream before traveling to the portal vein and the liver, where they are immediately used for energy and may have antitumor effects. Its role in breast cancer is poorly understood. To investigate the apoptosis-inducing effect of MCFAs in breast cancer cells, cell viability assay, colony formation assay, cell migration assay, cell invasion assay, nuclear morphology, cell cycle assay, intracellular reactive oxygen species (ROS), matrix metalloproteinase (MMP), apoptosis, RT-qPCR analysis, and Western blot analysis were performed. In the present study, MCFA treatments reduced proliferative capability, increased ROS level, increased the depletion of MMP, induced G0/G1 and S phase cell cycle arrest, and late apoptosis of breast cancer cells in an effective concentration. Besides, MCFA treatment contributed to the upregulation of proapoptotic protein (BAK) and caspase-3, and the downregulation of antiapoptotic protein (Bcl-2). Mechanistically, phosphorylation levels of EGFR, Akt, and mTOR were significantly reduced in breast cancer cells treated with MCFAs. However, no significant changes in apoptosis and signaling-related proteins were observed in lauric acid-treated ER-positive cancer cells. Our findings suggested that MCFAs suppressed breast cancer cell proliferation by modulating the PI3K/Akt/mTOR signaling pathway. MCFAs may be a promising therapeutic drug for treating breast cancer.

Design, synthesis, and anti-cancer evaluation of C-14 arylcarbamate derivatives of andrographolide

In this study, we explored a concise and mild synthetic route to produce novel C-14 arylcarbamate derivatives of andrographolide, a known anti-inflammatory and anticancer natural product. Upon assessing their anti-cancer efficacy against pancreatic ductal adenocarcinoma (PDAC) cells, some derivatives showed stronger cytotoxicity against PANC-1 cells than andrographolide. In addition, we demonstrated one derivative, compound 3m, effectively reduced the expression of oncogenic p53 mutant proteins (p53R273H and p53R248W), proliferation, and migration in PDAC lines, PANC-1 and MIA PaCa-2. Accordingly, the novel derivative holds promise as an anti-cancer agent against pancreatic cancer. In summary, our study broadens the derivative library of andrographolide and develops an arylcarbamate derivative of andrographolide with promising anticancer activity against PDAC.

Semisynthesis of Novel Dispiro-pyrrolizidino/thiopyrrolizidino-oxindolo/indanedione Natural Product Hybrids of Parthenin Followed by Their Cytotoxicity Evaluation

Natural products possess unique and broader intricacies in the chemical space and have been essential for drug discovery. The crucial factor for drug discovery success is not the size of the library but rather its structural diversity. Although reports on the number of new structurally diverse natural products (NPs) have declined recently, researchers follow the next logical step: synthesizing natural product hybrids and their analogues using the most potent tool, diversity-oriented synthesis (DOS). Here, we use weed Parthenium hysterophorus as a source of parthenin for synthesis of novel dispiro-pyrrolizidino/thiopyrrolizidino-oxindolo/indanedione natural product hybrids of parthenin via chemo-, regio-, and stereoselective azomethine ylide cycloaddition. All synthesized compounds were characterized through a detailed analysis of one-dimensional (1D) and two-dimensional (2D) NMR and HRMS data, and the stereochemistries of the compounds were confirmed by X-ray diffraction analysis. All compounds were evaluated for their cytotoxicity against four cell lines (HCT-116, A549, Mia-Paca-2, and MCF-7), and compound 6 inhibited the HCT-116 cells with an IC50 of 5.0 ± 0.08 μM.

Andrographolide protects against doxorubicin-and arsenic trioxide-induced toxicity in cardiomyocytes

BACKGROUND

Andrographolide (AG) is a lactone diterpene with valuable biological activities. This in vitro study evaluated whether AG can protect cardiomyocytes under toxicities triggered with anti-cancer chemotherapeutic agents, doxorubicin (DOX) and arsenic trioxide (ATO).

METHODS AND RESULTS

H9C2 cells were pretreated with AG (0.5-10 µM) for 24 h and then exposed to DOX (1 μM) or ATO (35 μM) for another 24 h period. For determination of cell viability or cytotoxicity, MTT and lactate dehydrogenase (LDH) assay were used. Total oxidant and antioxidant capacities were estimated by determining hydroperoxides and ferric reducing antioxidant power (FRAP) levels. Real time-polymerase chain reaction was also used for quantitative evaluation of TLR4 gene expression. AG inhibited cardiomyocytes proliferation at the concentrations of more than 20 μM. However, it considerably enhanced cell viability and decreased cytotoxicity of DOX and ATO at the concentration range of 2.5-10 μM in MTT and LDH assays. AG significantly declined hydroperoxides concentration in ATO-treated cardiomyocytes and raised FRAP value in DOX- and ATO-treated cells. Furthermore, AG notably lessened TLR4 expression in H9C2 cells after exposure to DOX- and ATO.

CONCLUSION

In conclusion, these data presented that AG was able to reverse DOX- and ATO-induced cardiotoxicity in vitro. The cardiomyocyte protective activities of AG may be due to the decrease in TLR4 expression and total oxidant capacity and increase in total antioxidant capacity.

Andrographolide inhibits non-small cell lung cancer cell proliferation through the activation of the mitochondrial apoptosis pathway and by reprogramming host glucose metabolism

Background

The main aim of this research was to explore the role and mechanism of Andrographolide (Andro) in controlling non-small cell lung cancer (NSCLC) cell proliferation.

Methods

Human NSCLC H1975 cells were treated with Andro (0–20 µM) for 4–72 h. B-cell leukemia/lymphoma 2 (Bcl-2)-antagonist/killer (Bak)-small interfering RNA (siRNA) (Bak-siRNA) and fructose-1,6-bisphosphatase (FBP1)-siRNA were transfected into H1975 cells to inhibit the endogenic Bak and FBP1 expression, respectively, and their expressions were detected by real-time quantitative reverse transcription–polymerase chain reaction (qRT-PCR) and western blotting (WB). Cellular proliferation ability was determined through various assessments, including 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, and cell counting kit-8 (CCK-8) assays. Cell apoptosis ability was measured using flow cytometry. Pro-apoptotic-related proteins (cleaved caspase 9, cleaved caspase 8, and cleaved caspase 3) and mitochondrial apoptosis pathway proteins [Bcl2-associated X (Bax), Bak, Bcl-2, and cytochrome C (cyto C)] were assessed by WB. Aerobic glycolysis-associated genes [pyruvate kinase M2 (PKM2), lactate dehydrogenase A (LDHA), and glucose transporter 1 (GLUT1)] and gluconeogenesis genes [phosphoenolpyruvate carboxykinase 1 (PEPCK1), fructose-1,6-bisphosphatase 1 (FBP1), and phosphofructokinase (PFK)] were measured by qRT-PCR. The mitochondrial membrane depolarization sensor, 5, 50, 6, 60-tetrachloro-1, 10, 3, 30 tetraethyl benzimidazolo carbocyanine iodide (JC-1) assay was used for the measurement of mitochondrial membrane potential (ΔΨm). Additionally, glycolytic metabolism, lactate production, and adenosine triphosphate (ATP) synthesis were also analyzed.

Results

Andro inhibited human NSCLC cellular proliferation and induced apoptosis in a dose-time or dose-dependent manner via activation of the mitochondrial apoptosis pathway. Andro inhibited glycolysis, promoted the gluconeogenesis pathway, and increased the levels of cleaved caspase 9, cleaved caspase 8, cleaved caspase 3, Bax, Bak, PEPCK1, FBP1, and PFK, and decreased the levels of Bcl-2, PKM2, LDHA, and GLUT1. Moreover, it also decreased the ΔΨm and facilitated the release of cyto C from mitochondria into the cytoplasm. Furthermore, Andro enhanced the mitochondrial translocation of Bak, glucose uptake, lactate release, and intracellular ATP synthesis. Suppression of endogenic Bak and FBP1 expression significantly reduced the effects of Andro in H1975 cells.

Conclusions

Andro represses NSCLC cell proliferation through the activation of the mitochondrial apoptosis pathway and by reprogramming glucose metabolism.

Phytochemicals from Ajwa dates pulp extract induce apoptosis in human triple-negative breast cancer by inhibiting AKT/mTOR pathway and modulating Bcl-2 family proteins

Ajwa dates (Phoenix dactylifera L.) have been described in traditional and alternative medicine to provide several health benefits, but their mechanism of apoptosis induction against human triple-negative breast cancer MDA-MB-231 cells remains to be investigated. In this study, we analyzed the phytoconstituents in ethanolic Ajwa Dates Pulp Extract (ADPE) by liquid chromatography-mass spectrometry (LC-MS) and investigated anticancer effects against MDA-MB-231 cells. LC-MS analysis revealed that ADPE contained phytocomponents belonging to classes such as carbohydrates, phenolics, flavonoids and terpenoids. MTT assay demonstrated statistically significant dose- and time-dependent inhibition of MDA-MB-231 cells with IC50 values of 17.45 and 16.67 mg/mL at 24 and 48 h, respectively. Hoechst 33342 dye and DNA fragmentation data showed apoptotic cell death while AO/PI and Annexin V-FITC data revealed cells in late apoptosis at higher doses of ADPE. More importantly, ADPE prompted reactive oxygen species (ROS) induced alterations in mitochondrial membrane potential (MMP) in ADPE treated MDA-MB-231 cells. Cell cycle analysis demonstrated that ADPE induced cell arrest in S and G2/M checkpoints. ADPE upregulated the p53, Bax and cleaved caspase-3, thereby leading to the downregulation of Bcl-2 and AKT/mTOR pathway. ADPE did not show any significant toxicity on normal human peripheral blood mononuclear cells which suggests its safe application to biological systems under study. Thus, ADPE has the potential to be used as an adjunct to the mainline of treatment against breast cancer.

Iodinated 1,2-diacylhydrazines, benzohydrazide-hydrazones and their analogues as dual antimicrobial and cytotoxic agents

Hydrazide-hydrazones have been described as a scaffold with antimicrobial and cytotoxic activities as well as iodinated compounds. A resistance rate of bacterial and fungal pathogens has increased considerably. That is why we synthesized and screened twenty-two iodinated hydrazide-hydrazones 1 and 2, ten 1,2-diacylhydrazines 3 and their three reduced analogues 4 for their antibacterial, antifungal, and cytotoxic properties. Hydrazide-hydrazones were prepared by condensation of 4-substituted benzohydrazides with 2-/4-hydroxy-3,5-diiodobenzaldehydes, diacylhydrazines from identical benzohydrazides and 3,5-diiodosalicylic acid via its chloride. These compounds were investigated in vitro against eight bacterial and eight fungal strains. The derivatives were found potent antibacterial agents against Gram-positive cocci including methicillin-resistant Staphylococcus aureus with the lowest values of minimum inhibitory concentrations (MIC) of 7.81 µM. Four compounds inhibited also human pathogenic fungi (MIC of ≥1.95 µM). The derivatives had different degrees of cytotoxicity for HepG2 and HK-2 cell lines (IC₅₀ values from 11.72 and 26.80 µM, respectively). Importantly, normal human cells exhibited lower sensitivity. The apoptotic effect was also investigated. In general, the presence of 3,5-diiodosalicylidene scaffold (compounds 1) is translated into enhanced both antimicrobial and cytotoxic properties whereas its 4-hydroxy isomers 2 share a low biological activity. N'-Benzoyl-2-hydroxy-3,5-diiodobenzohydrazides 3 have a non-homogeneous activity profile. Focusing on 4-substituted benzohydrazide part, the presence of an electron-withdrawing group (F, Cl, CF₃, NO₂) was found to be beneficial.

In silico and in vitro studies on the anti-cancer activity of andrographolide targeting survivin in human breast cancer stem cells

Breast cancer stem cells (BCSCs) express high levels of the anti-apoptotic protein, survivin. This study aimed to discover a natural active compound with anti-cancer properties that targeted survivin in human breast cancer stem cells. From the seven examined compounds, andrographolide was selected as a lead compound through in silico molecular docking with survivin, caspase-9, and caspase-3. We found that the affinity between andrographolide and survivin is higher than that with caspase-9 and caspase-3. Human CD24-/CD44+ BCSCs were treated with andrographolide in vitro for 24 hours. The cytotoxic effect of andrographolide on BCSCs was compared to that on human mesenchymal stem cells (MSCs). The expression of survivin, caspase-9, and caspase-3 mRNA was analyzed using qRT-PCR, while Thr34-phosphorylated survivin and total survivin levels were determined using ELISA and Immunoblotting assay. Annexin-V/PI flow cytometry assays were performed to evaluate the apoptotic activity of andrographolide. Our results demonstrate that the CC50 of andrographolide in BCSCs was 0.32mM, whereas there was no cytotoxic effect in MSCs. Moreover, andrographolide decreased survivin and Thr34-phosphorylated survivin, thus inhibiting survivin activation and increasing survivin mRNA in BCSCs. The apoptotic activity of andrographolide was revealed by the increase of caspase-3 mRNA and protein, as well as the increase in both the early and late phases of apoptosis. In conclusion, andrographolide can be considered an anti-cancer compound that targets BCSCs due to its molecular interactions with survivin, caspase-9, and caspase-3, which induce apoptosis. We suggest that the binding of andrographolide to survivin is a critical aspect of the effect of andrographolide.

Natural Products Containing Olefinic Bond: Important Substrates for Semi-synthetic Modification Towards Value Addition

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Semi-synthesis, the way of preparing novel bioactive molecules via modification of compounds isolated from natural sources is very much useful nowadays in the drug discovery process. The modification is based on the reaction of functional group(s) present in a natural compound. Among the examples of functional group transformation, double bond modification is also common in the literature. Several reactions like hydrogenation, cyclopropanation, epoxidation, addition reaction (halogenations, hydroxylation), Michael addition, Heck reaction, cycloaddition, dipolar cycloaddition, etc. are employed for this purpose. In this review, we have tried to gather the reactions performed with several double bond containing classes of natural products like diterpenes, xanthones, sesquiterpene exomethylene lactones, diaryl heptanoids, steroidal lactones, triterpenoids, limonoids, and alkamides. Where available, the effects of transformations on the biological activities of the molecules are also mentioned.

Triptycene-Based and Schiff-Base-Linked Porous Networks: Efficient Gas Uptake, High CO2/N2 Selectivity, and Excellent Antiproliferative Activity

A set of unique triptycene-based and organic Schiff-base-linked polymers (TBOSBLs) are conveniently synthesized in which triptycene motifs are connected with 1,3,5-triformylphloroglucinol units via Schiff-base linkages. TBOSBLs are amorphous, thermally stable with a reasonable surface area (SABET up to 649 m2/g), and have abundant nanopores (pore size < 100 nm). TBOSBLs are good sorbents for small gas molecules (such as CO2, H2, and N2) and they can selectively capture CO2 over N2. Additionally, TBOSBLs show superior antiproliferative activity against human colorectal cancer cells relative to previously reported covalent organic frameworks (COFs). The mechanism of cell death is also studied elaborately.

Andrographolide is an Alternative Treatment to Overcome Resistance in ER-Positive Breast Cancer via Cholesterol Biosynthesis Pathway

Oestrogen receptor (ER)-positive breast cancer is one of the common forms of breast cancer affecting women worldwide. ER-positive breast cancer patients are subjected to anti-oestrogen therapy such as selective oestrogen receptor modulator (SERM) and aromatase inhibitors (AIs). Recently, the emergence of resistance to anti-oestrogen treatment is under intensive focus. The different mechanisms postulated to explain the occurrence of resistance in ER-positive breast cancer treatment include the loss of ER function and the crosstalk between signalling pathways in cancer cells. Recent literature highlighted that the cholesterol biosynthesis pathway acts as a novel mechanism underlying resistance to oestrogen deprivation. The present study aimed to highlight the role of cholesterol biosynthesis in anti-oestrogen treatment resistance, putatively suggesting an alternative plant-based treatment using andrographolide from Andrographis paniculata. The hypolipidaemic effect of andrographolide can be utilised to prevent the resistance in the treatment of ER-positive breast cancer contributed by cholesterol biosynthesis.

Azomethine ylide cycloaddition: a versatile tool for preparing novel pyrrolizidino-spiro-oxindolo hybrids of the doubly conjugated alkamide piperine

A facile, multicomponent (MCR) atom-economic synthesis of novel spiro-oxindolo pyrrolizidine adducts of piperine has been achieved via an intermolecular 1,3-dipolar azomethine ylide cycloaddition reaction. Either of the two conjugated double bonds in piperine takes part in the reaction to produce two regioisomeric adducts in racemic form. Acenaphthoquinone, ninhydrin and different isatin derivatives were reacted with proline and piperine to afford a never before reported library of 22 compounds. The structures of the products were determined by 1D/2D NMR, mass spectral analysis and confirmed by X-ray crystallography of selected products. Chiral HPLC separation was performed to measure the specific rotation and CD spectra of the enantiomers for two racemic compounds.

Synthesis of Triazole-Substituted Quinazoline Hybrids for Anticancer Activity and a Lead Compound as the EGFR Blocker and ROS Inducer Agent

A series of triazole-substituted quinazoline hybrid compounds were designed and synthesized for anticancer activity targeting epidermal growth factor receptor (EGFR) tyrosine kinase. Most of the compounds showed moderate to good antiproliferative activity against four cancer cell lines (HepG2, HCT116, MCF-7, and PC-3). Compound 5b showed good antiproliferative activity (IC₅₀ = 20.71 μM) against MCF-7 cell lines. Molecular docking results showed that compound 5b formed hydrogen bond with Met 769 and Lys 721 and π-sulfur interaction with Met 742 of EGFR tyrosine kinase (PDB ID: 1M17). Compound 5b decreases the expression of EGFR and p-EGFR. It also induces apoptosis through reactive oxygen species generation, followed by the change in mitochondrial membrane potential.

Friedelane, isolated from Pouzolzia indica Gaud. exhibits toxic effect against melanoma

Melanoma is a predominant cause of skin cancer-related deaths. It was reported that, the methanolic extract of Pouzolzia Indica (P. indica) on chromatography gave five compounds (1-hentriacontanyl palmitate, myricyl alcohol, 6,7-dimethoxycoumarin, trichadonic acid and friedelane), which inhibited the acute promyelocytic leukemia cell lines, NB4, and HT93A. Friedelane was extracted as active compound from methanolic extract of P. indica. In this study, friedelane was tested on murine metastatic B16F10 and B16BL6 melanoma cell lines. To achieve the target, the cell viability using trypan blue exclusion, acridine orange/EtBr staining and cell cytotoxicity were tested using MTT assay. Caspase-3, caspase-9, Cyt-c, BAD and Bax protein were assayed to evidence the apoptosis induction. The compound friedelane shows potent cytotoxic effect against metastatic melanoma mouse cell lines in 10 µg/ml concentration.

Increased reactive oxygen species levels cause ER stress and cytotoxicity in andrographolide treated colon cancer cells

Chemotherapy continues to play an essential role in the management of many cancers including colon cancer, the third leading cause of death due to cancer in the United States. Many naturally occurring plant compounds have been demonstrated to possess anti-cancer cell activity and have the potential to supplement existing chemotherapy strategies. The plant metabolite andrographolide induces cell death in cancer cells and apoptosis is dependent upon the induction of endoplasmic reticulum stress (ER stress) leading to the unfolded protein response (UPR). The goal of the present study was to determine the mechanism by which andrographolide induces ER stress and to further evaluate its role in promoting cell death pathways. The T84 and COLO 205 cancer cell lines were used to demonstrate that andrographolide induces increased ROS levels, corresponding anti-oxidant response molecules, and reduced mitochondrial membrane potential. No increases in ROS levels were detected in control colon fibroblast cells. Andrographolide-induced cell death, UPR signaling, and CHOP, Bax, and caspase 3 apoptosis elements were all inhibited in the presence of the ROS scavenger NAC. Additionally, andrographolide-induced suppression of cyclins B1 and D1 were also reversed in the presence of NAC. Finally, Akt phosphorylation and phospho-mTOR levels that are normally suppressed by andrographolide were also expressed at normal levels in the absence of ROS. These data demonstrate that andrographolide induces ER stress leading to apoptosis through the induction of ROS and that elevated ROS also play an important role in down-regulating cell cycle progression and cell survival pathways as well.

Andrographolide, a diterpene lactone from Andrographis paniculata and its therapeutic promises in cancer

The diterpene lactone andrographolide, isolated from Andrographis paniculata, has been proven to possess several important protective biological activities, including antioxidant, anti-inflammatory, immunomodulatory, antiseptic, antimicrobial, cytotoxic, hypolipidemic, cardioprotective, hepatoprotective, and neuroprotective effects. In addition, it has been reported to play a therapeutic role in the treatment of major human diseases, such as Parkinson's disease, rheumatoid arthritis, and colitis. This systematic review aims to highlight andrographolide as a promising agent in cancer treatment. To this purpose, a number of databases were used to search for the cytotoxic/anticancer effects of andrographolide in pre-clinical and clinical studies. Among 1703 identified literature articles, 139 were included in this review; 109 were investigated as non-clinical, whereas 24, 3, and 3 were pre-clinical, clinical, and non-pre-clinical trials, respectively. Among the model systems, cultured cell lines appeared as the most frequently (79.14%) used, followed by in vivo models using rodents, among others. Furthermore, andrographolide was found to exert cytotoxic/anticancer effects on almost all types of cell lines with the underlying mechanisms involving oxidative stress, cell cycle arrest, anti-inflammatory and immune system mediated effects, apoptosis, necrosis, autophagy, inhibition of cell adhesion, proliferation, migration, invasion, anti-angiogenic activity, and other miscellaneous actions. After careful consideration of the relevant evidence, we suggest that andrographolide can be one of the potential agents in the treatment of cancer in the near future.

Porous Polymer Bearing Polyphenolic Organic Building Units as a Chemotherapeutic Agent for Cancer Treatment

Cancer is one of the most deadly diseases worldwide. Although several chemotherapeutic agents are available at present for its treatment, they have their own limitations. The main problems of these chemotherapeutic agents are cost involvement and severe life-threatening antagonistic effects. Here, we report a new biodegradable N-rich porous organic polymer methylenedianiline-triformyl phloroglucinol (MDTFP-1) synthesized via a Schiff base condensation reaction between two reactive monomers, that is, 4,4'-methylenedianiline and 2,4,6-triformyl phloroglucinol under inert atmosphere. Because this porous polymer contains polyphenolic building units and has a high Brunauer-Emmett-Teller surface area (283 m2 g-1), it has been explored in the anticancer activity using HCT 116, A549, and MIA PaCa-2 cell lines. We have carried out the flow cytometric assessment using Annexin-V-FITC/PI staining through the exposed level of phosphatidylserine in the outer membrane of cells with MDTFP-1-induced apoptosis. Our results suggested that apoptosis of cells have been enhanced in a time-dependent manner in the presence of this novel porous polymer.

Reactive oxygen species and colorectal cancer

Colorectal cancer (CRC) has become the fourth leading cause of cancer-related death in the worldwide. It is urgent to find more effective therapeutic strategies for it. Reactive oxygen species (ROS) play multiple roles in normal cellular physiology processes. Thus, a certain level of ROS is essential to keep normal cellular function. However, the accumulation of ROS shows dual roles for cells, which is mainly dependent on the concentration of ROS, the origin of the cancer cell and the activated signaling pathways during tumor progression. In general, moderate level of ROS leads to cell damage, DNA mutation and inflammation, which promotes the initiation and development of cancer. Excessive high level of ROS induces cancer cell death, showing an anti-cancer role. ROS are commonly higher in CRC cells than their normal counterpart cells. Therefore, it is possible that ROS induce cell death in cancer cells while not affecting the normal cells, demonstrating lower side effects. Besides, ROS also play a role in tumor microenvironment and drug resistance. These multiple roles of ROS make them a promising therapeutic target for cancer. To explore potential ROS-target therapies against CRC, it is worth to comprehensively understanding the role of ROS in CRC and therapy. In this review, we mainly discuss the strategies of ROS in CRC therapy, including direct CRC cell target and indirect tumor environment target. In addition, the influences of ROS in drug resistance will also been discussed.

Synthesis and cytotoxic characteristics displayed by a series of Ag(i)-, Au(i)- and Au(iii)-complexes supported by a common N-heterocyclic carbene

The design, synthesis and anticancer properties of a series of Ag(i), Au(i) and Au(iii)–NHC complexes supported by pyridyl[1,2-a]{2-acetylylphenylimidazol}-3-ylidene are described.

Synthesis of diversely substituted bis-pyrrolizidino/ thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via sequential azomethine ylide cycloaddition

Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction using isatins/acenaphthoquinone and proline/thioproline as the reagents. The products were separated via extensive chromatography and characterized by 1D/2D NMR and HRMS analysis.

Curcumin has been transformed to several diversely substituted bis-pyrrolizidino/thiopyrrolizidino oxindolo/acenaphthyleno curcuminoids via a sequential azomethine ylide cycloaddition reaction.

Covalent Organic Framework Material Bearing Phloroglucinol Building Units as a Potent Anticancer Agent

Covalent organic frameworks (COFs) having periodicity in pores of nanoscale dimensions can be suitably designed for the organic building units bearing reactive functional groups at their surfaces. Thus, they are an attractive option as an anticancer agent to overcome the limitations of chemotherapy. Herein, we first report a new porous biodegradable nitrogen containing COF material, EDTFP-1 (ethylenedianiline-triformyl phloroglucinol), synthesized using 4,4'-ethylenedianiline and 2,4,6-triformylphloroglucinol via Schiff base condensation reaction. EDTFP-1 exhibited 3D-hexagonal porous structure with average pores of ca. 1.5 nm dimension. Here, we have explored the anticancer potentiality of EDTFP-1. Result demonstrated an enhanced cytotoxicity was observed against four cancer cells HCT 116, HepG2, A549, and MIA-Paca2 with significant lower IC₅₀ on HCT116 cells. Additionally, EDTFP-1-induced cell death was associated with the characteristic apoptotic changes like cell membrane blebbing, nuclear DNA fragmentation, externalization of phosphatidylserine from the cell membrane followed by a loss of mitochondrial membrane potential as well as modulation of pro and antiapoptotic proteins. Further, the result depicted a direct correlation between the generations of ROS with mitochondrial-dependent apoptosis through the involvement of p53 phosphorylation upon EDTFP-1 induction, suggesting this COF material is a novel chemotherapeutic agent for cancer treatment.

Pinocembrin enriched fraction of Elytranthe parasitica (L.) Danser induces apoptosis in HCT 116 colorectal cancer cells

BACKGROUND

Colorectal cancer (CRC) is a highly predominant malignancy affecting millions worldwide. Plants belonging to Loranthaceae family have remarkable chemopreventive properties.

OBJECTIVE

The goal of the present study was to assess the antiproliferative and apoptosis-inducing effects of stem parts of Elytranthe parasitica (L.) Danser (EP) on colorectal cancer and identify the bioactive phytochemicals.

MATERIAL AND METHODS

EP methanol extract (EP.M) and its subsequent fractions were screened for antiproliferative activity in human colorectal carcinoma HCT 116 cell line. Phytocomposition of the bioactive fraction was analyzed by GC-MS. Further, apoptotic induction and cell cycle arrest was assessed in the most bioactive fractions.

RESULTS

EP.DEE (Diethyl Ether) fraction and a subsequent fraction derived by column chromatography, Fraction 3A (FR 3A) significantly inhibited the proliferation of HCT 116 cells (P < 0.05). FR 3A triggered apoptosis and notably modulated the cell cycle checkpoints. GC-MS analysis of FR 3A revealed the presence of 24 phytochemicals, the most prominent of which was pinocembrin (70.67%), a flavonoid.

CONCLUSION

Hence, it could be speculated that pinocembrin and its related derivatives may be the chief phytochemicals involved in apoptosis - mediated cytotoxicity of the enriched fraction. Our findings indicate the enriched fraction is a promising candidate which could be developed into a natural chemotherapeutic product for colorectal cancer therapy.

Anticancer effects of synthetic hexahydrobenzo [g]chromen-4-one derivatives on human breast cancer cell lines

BACKGROUND

Cancer results from a series of molecular changes that alter the normal function of cells. Breast cancer is the second leading cause of cancer death in women. To develop novel anticancer agents, new series of chromen derivatives were synthesized and evaluated for their cytotoxic activity against human breast cancer cell lines.

METHOD

The growth inhibitory activities of synthesized hexahydrobenzo chromen-4-one were screened against six human cancer cell lines using an in vitro cell culture system (MTT assay). Fluorochrome staining (acridine orange/ethidium bromide double staining) and DNA fragmentation by the diphenylamine method were used to investigate the effects of most potent compounds on the process of apoptosis in breast cancer cell lines. To determine the mechanism of apoptosis, ROS and NOX production in treated breast cancer cells with compounds was evaluated.

RESULTS

The cytotoxicity data of tested compounds demonstrate these compounds had varying degree of toxicity. Compound 7h was the most potent compound with IC₅₀ = 1.8 ± 0.6 µg/mL against T-47D cell line. Analyses of the compounds treated (MCF-7, MDA-MB-231, and T-47D) cells by acridine orange/ethidium bromide double staining and DNA fragmentation by the diphenylamine method showed that the synthetic compounds induce apoptosis in the cells. A significant increase in ROS production was observed in T-47D cells treated with IC₅₀ value of compound 7g. Incubation with IC₅₀ value of synthetic compounds increased the NOX production in cell lines, especially T-47D cells.

CONCLUSION

Our results show that most compounds have a significant anti-proliferative activity against six human cancer cell lines. The observations confirm that chromen derivatives have induced the cell death through apoptosis.

Purification and Characterization of Glutaminase Free Asparaginase from Enterobacter cloacae: In-Vitro Evaluation of Cytotoxic Potential against Human Myeloid Leukemia HL-60 Cells

Asparaginase is an important antileukemic agent extensively used worldwide but the intrinsic glutaminase activity of this enzymatic drug is responsible for serious life threatening side effects. Hence, glutaminase free asparaginase is much needed for upgradation of therapeutic index of asparaginase therapy. In the present study, glutaminase free asparaginase produced from Enterobacter cloacae was purified to apparent homogeneity. The purified enzyme was found to be homodimer of approximately 106 kDa with monomeric size of approximately 52 kDa and pI 4.5. Purified enzyme showed optimum activity between pH 7-8 and temperature 35-40°C, which is close to the internal environment of human body. Monovalent cations such as Na+ and K+ enhanced asparaginase activity whereas divalent and trivalent cations, Ca2+, Mg2+, Zn2+, Mn2+, and Fe3+ inhibited the enzyme activity. Kinetic parameters Km, Vmax and Kcat of purified enzyme were found to be 1.58×10-3 M, 2.22 IU μg-1 and 5.3 × 104 S-1, respectively. Purified enzyme showed prolonged in vitro serum (T1/2 = ~ 39 h) and trypsin (T1/2 = ~ 32 min) half life, which is therapeutically remarkable feature. The cytotoxic activity of enzyme was examined against a panel of human cancer cell lines, HL-60, MOLT-4, MDA-MB-231 and T47D, and highest cytotoxicity observed against HL-60 cells (IC50 ~ 3.1 IU ml-1), which was comparable to commercial asparaginase. Cell and nuclear morphological studies of HL-60 cells showed that on treatment with purified asparaginase symptoms of apoptosis were increased in dose dependent manner. Cell cycle progression analysis indicates that enzyme induces apoptosis by cell cycle arrest in G0/G1 phase. Mitochondrial membrane potential loss showed that enzyme also triggers the mitochondrial pathway of apoptosis. Furthermore, the enzyme was found to be nontoxic for human noncancerous cells FR-2 and nonhemolytic for human erythrocytes.

Synthesis of gold(iii) ← gold(i)–NHC through disproportionation: the role of gold(i)–NHC in the induction of apoptosis in HepG2 cells

The anticancer activities of novel Au(i) and Au(iii)–NHC complexes based on 2-[(6-methylpyridin-2-yl)]imidazo[1,5-a]pyridin-4-ylium hexafluorophosphate have been investigated.

Synthesis of Bis-pyrrolizidine-Fused Dispiro-oxindole Analogues of Curcumin via One-Pot Azomethine Ylide Cycloaddition: Experimental and Computational Approach toward Regio- and Diastereoselection

Curcumin has been transformed to racemic curcuminoids via an azomethine ylide cycloaddition reaction using isatin/acenaphthoquinone and proline as the reagents. The products were characterized by extensive 1D/2D NMR analysis and single-crystal X-ray crystallographic studies. The enantiomers of one racemic product were separated by HPLC on a Chiralcel OD-H column and were indeed confirmed by the CD spectra of the separated enantiomers.

Bio-assay Guided Isolation of Anti-cancer Compounds from Anthocephalus Cadamba Bark

Anthocephalus cadamba, an important plant in the traditional system of medicine in India, is reported to possess anticancer activity. Guided by bio-assay tests using human colorectal (HCT116) and hepatocellular carcinoma (HepG2) cell lines, it has been shown to contain three active constituents, the triterpenoid saponins 3- O-[α-L-rhamnopyranosyl]-quinovic acid (1) and 3- O-[α-L-rhamnopyranosyl]-quinovic acid 28- O-[β-D-glucopyranosyl] ester (2), and the alkaloid cadambine (3). The structures of the isolated compounds were established using spectroscopic techniques. The isolated compounds demonstrated concentration dependent inhibition of both the cell lines, where compound 3 proved to be the most potent inhibitor of cell line HCT116 (IC50 45 ± 4 μg/mL) and compound 2 demonstrated maximum inhibitory activity against HepG2 cell line with an IC50 value of 89 ± 7 μg/mL.

Andrographolide: progression in its modifications and applications - a patent review (2012 - 2014)

INTRODUCTION

Extraction, isolation and modifications of andrographolide (Androg) is extensively investigated and patented. The prominent activities were vastly modified for anticancer and antivirals. Many products related to Androg are commercially available, thus the section 'Interaction of Androg and Andrographis paniculata dried extract with drugs' is included.

AREAS COVERED

The data in this review are searched and selected from SciFinder and Espacenet for the patents, with the keywords: Andrographolide and Andrographolide analogs, and the results were refined by the years.

EXPERT OPINION

Modifications of Androg have been done to nearly all of the possible sites, and now screening tests for any new activities had been settled down. Categorizing the analogs that have been developed is not clear cut since some diseases can develop into others, for example, inflammation and some viral infections can develop into cancer. Currently, investigation of the mode of action and the mechanisms at the molecular level are intensively ongoing. Producing new chemotherapeutic agents from Androg looks promising. The main problem of using Androg in therapeutic applications is its insolubility in aqueous media. Those modified analogs' esters, ethers or salts, have to be considered for the stability of pharmaceutical preparations, and transformation in biological fluids after administration. Further stages of drug development are required for those promising analogs.

Specificity and inhibitory mechanism of andrographolide and its analogues as antiasthma agents on NF-κB p50

Andrographolide (1) is a diterpenoid lactone with an α,β-unsaturated lactone group that inhibits NF-κB DNA binding. Andrographolide reacts with the nucleophilic Cys62 of NF-κB p50 through a Michael addition at the Δ(12(13)) exocylic double bond to form a covalent adduct. Using computer docking, site-directed mutagenesis, and mass spectrometry, the noncovalent interactions between andrographolide and additional binding site residues other than Cys62 were found to be essential for the covalent incorporation of andrographolide. Furthermore, the addition reaction of andrographolide on Cys62 was highly dependent on the redox conditions and on the vicinity of nearby, positively charged Arg residues in the conserved RxxRxR motif. The reaction mechanisms of several of the analogues were determined, showing that 14-deoxy-11,12-didehydroandrographolide (8) reacts with NF-κB p50 via a novel mechanism distinct from andrographolide. The noncovalent interaction and redox environment of the binding site should be considered, in addition to the electrophilicity, when designing a covalent drug. Analogues similar in structure appear to use distinct reaction mechanisms and may have very different cytotoxicities, e.g., compound 6.

Cytotoxic potential of dispirooxindolo/acenaphthoquino andrographolide derivatives against MCF-7 cell line

Dispiro andrographolides induce a caspase-dependent apoptotic cell death pathway in breast cancer (MCF-7) cells.

Gold (I) N-heterocyclic carbene complex inhibits mouse melanoma growth by p53 upregulation

BACKGROUND

Cancer treatment using gold (I) complexes is becoming popular. In this study, a gold (I) N-heterocyclic complex designated as complex 3 was synthesized, its cytotoxicity was examined, and its anti-melanoma activity was evaluated in vitro and in vivo.

METHODS

Viability of cancer cells was determined by MTT assay upon treatment with various concentrations of a gold (I) N-heterocyclic carbene complex (complex 3) in a dose and time dependent manner. Mouse melanoma cells B16F10 were selected for further apoptotic studies, including flowcytometric analysis of annexin binding, cell cycle arrest, intracellular ROS generation and loss in the mitochondrial membrane potential. ELISA based assays were done for caspase activities and western blots for determining the expression of various survival and apoptotic proteins. Immunocytology was performed to visualize the translocation of p53 to the nucleus. B16F10 cells were inoculated into mice and post tumor formation, complex 3 was administered. Immunohistology was performed to determine the expressions of p53, p21, NF-κB (p65 and p50), MMP-9 and VEGF. Student's t test was used for determining statistical significance. The survival rate data were analyzed by Kaplan-Meier plots.

RESULTS

Complex 3 markedly inhibited the growth of HCT 116, HepG2, and A549, and induced apoptosis in B16F10 cells with nuclear condensation, DNA fragmentation, externalization of phosphatidylserine, activation of caspase 3 and caspase 9, PARP cleavage, downregulation of Bcl-2, upregulation of Bax, cytosolic cytochrome c elevation, ROS generation, and mitochondrial membrane potential loss indicating the involvement of an intrinsic mitochondrial death pathway. Further, upregulation of p53, p-p53 (ser 15) and p21 indicated the role of p53 in complex 3 mediated apoptosis. The complex reduced tumor size, and caused upregulation of p53 and p21 along with downregulation of NF-κB (p65 and p50), VEGF and MMP-9. These results suggest that it induced anti-melanoma effect in vitro and in vivo by modulating p53 and other apoptotic factors.

CONCLUSIONS

The gold (I) N-heterocyclic carbene complex (C22H26N6AuO2PF6) designated as complex 3 induced ROS and p53 dependent apoptosis in B16F10 cells involving the mitochondrial death pathway along with suppression of melanoma tumor growth by regulating the levels of pro and anti apoptotic factors (p53, p21, NF-κB, VEGF and MMP-9).

Cytotoxicity of silver(i), gold(i) and gold(iii) complexes of a pyridine wingtip substituted annelated N-heterocyclic carbene

Cl–Ag(i)–NHC, Cl–Au(i)–NHC, and Cl₃–Au(i)–NHC complexes based on the 1-methyl-2-pyridin-2-yl-2H-imidazo[1,5-a]pyridin-4-ylium chloride, were tested for their cytotoxicity towards different cancer cell lines.