Synthesis and cytotoxic activity of the heptaphylline and 7-methoxyheptaphylline series

7-Methoxyheptaphylline Enhances TRAIL-induced Apoptosis of Colorectal Adenocarcinoma Cell via JNK-mediated DR5 Expression

A cytokine known as TNF-related apoptosis-inducing ligand (TRAIL) has the ability to precisely cause the death of cancer cells, while normal cells are left undisturbed. Recent studies show that certain cancer cells are sensitive to the apoptotic effect of TRAIL. In this study, HT29 colorectal adenocarcinoma cells exposed to TRAIL were treated with heptaphylline and 7-methoxyheptaphylline from Clausena harmandiana in an effort to comprehend the mechanisms involved behind this activity. The MTT test was utilized to determine cell survival, and phase contrast microscopy was used to examine cell morphology. Through using real-time RT-PCR, Western blotting, and RT-PCR, the molecular mechanisms were investigated. According to the findings, whilst hepataphylline caused cytotoxicity in normal colon FHC cells, in comparison to healthy colon FHC cells, 7-methoxyheptaphylline inhibited cancer cells in a concentration-dependent manner. Heptaphylline alone or in conjunction with TRAIL showed no discernible effect on TRAL-induced HT29 cell death, but 7-methoxyheptaphylline boosted caspase-3 cleavage. The study showed that the JNK pathway was responsible for the 7-methoxyheptaphylline's enhancement of the DR5 (death receptor 5) mRNA, TRAIL receptor, and protein. The results demonstrated that the 7-methoxyheptaphylline of Clausena harmandiana increased the expression of DR5 via the JNK pathway, intensifying TRAIL-induced HT29 cell death.

Gold (I)-Promoted Intermolecular Cascade Annulation to Access 2-Hydroxybenzocarbazoles via a Meyer-Schuster Rearrangement

An efficient cascade annulation protocol was established to access substituted 2-hydroxybenzocarbazoles from alkynylcyclohexadienones and substituted 2-aminophenols under gold catalysis. In this transformation a new C-C, two C-N bonds were formed sequentially and moderate to excellent yields of 2-hydroxybenzocarbazole derivatives were obtained selectively via Meyer-Schuster rearrangement in one-pot.

Semi-Synthesis of Small Molecules of Aminocarbazoles: Tumor Growth Inhibition and Potential Impact on p53

The tumor suppressor p53 is inactivated by mutation in approximately 50% of human cancers. Small molecules that bind and stabilize those mutants may represent effective anticancer drugs. Herein, we report the tumor cell growth inhibitory activity of carbazole alkaloids and amino derivatives, as well as their potential activation of p53. Twelve aminocarbazole alkaloids were semi-synthesized from heptaphylline (1), 7-methoxy heptaphylline (2), and 7-methoxymukonal (3), isolated from Clausena harmandiana, using a reductive amination protocol. Naturally-occurring carbazoles 1–3 and their amino derivatives were evaluated for their potential effect on wild-type and mutant p53 activity using a yeast screening assay and on human tumor cell lines. Naturally-occurring carbazoles 1–3 showed the most potent growth inhibitory effects on wild-type p53-expressing cells, being heptaphylline (1) the most promising in all the investigated cell lines. However, compound 1 also showed growth inhibition against non-tumor cells. Conversely, semi-synthetic aminocarbazole 1d showed an interesting growth inhibitory activity in tumor cells expressing both wild-type and mutant p53, exhibiting low growth inhibition on non-tumor cells. The yeast assay showed a potential reactivation of mutant p53 by heptaphylline derivatives, including compound 1d. The results obtained indicate that carbazole alkaloids may represent a promising starting point to search for new mutp53-reactivating agents with promising applications in cancer therapy.

Novel Carbazole-Piperazine Hybrid Small Molecule Induces Apoptosis by Targeting BCL-2 and Inhibits Tumor Progression in Lung Adenocarcinoma in Vitro and Xenograft Mice Model

Lung cancer is a type of deadly cancer and a leading cause of cancer associated death worldwide. BCL-2 protein is considered as an imperative target for the treatment of cancer due to their significant involvement in cell survival and death. A carbazole-piperazine hybrid molecule ECPU-0001 was designed and synthesized as a potent BCL-2 targeting agent with effective anticancer cancer activity. Interaction of ECPU-001 has been assessed by docking, molecular dynamics (MD) simulation, and thermal shift assay. Further, in vitro and in vivo anticancer activity was executed by cytotoxicity assay, FACS, colony formation and migration assay, western blotting, immunocyto/histochemistry and xenograft nude mice model. Molecular docking and MD simulation study confirmed that ECPU-0001 nicely interacts with the active site of BCL-2 by displaying a Ki value of 5.72 µM and binding energy (ΔG) of -8.35 kcal/mol. Thermal shift assay also validated strong interaction of this compound with BCL-2. ECPU-0001 effectively exerted a cytotoxic effect against lung adenocarnoma cells A459 with an IC50 value of 1.779 µM. Molecular mechanism of action have also been investigated and found that ECPU-0001 induced apoptosis in A459 cell by targeting BCL-2 to induce intrinsic pathway of apoptosis. Administration of ECPU-0001 significantly inhibited progression of tumor in a xenograft model without exerting severe toxicity and remarkably reduced tumor volume as well as tumor burden in treated animals. Our investigation bestowed ECPU-0001 as an effective tumoricidal agent which exhibited impressive anticancer activity in vitro as well as in vivo by targeting BCL-2 associated intrinsic pathway of apoptosis. Thus, ECPU-0001 may provide a valuable input for therapy of lung adenosarcoma in future, however, further extensive investigation of this compound will be needed.

Synthesis and biological evaluation of sulfur-containing shikonin oxime derivatives as potential antineoplastic agents

As a continuation of our research on developing potent and potentially safe antineoplastic agents, a set of forty five sulfur-containing shikonin oxime derivatives were synthesized and evaluated for their in vitro cytotoxic activity against human colon cancer (HCT-15), gastric carcinoma (MGC-803), liver (Bel7402), breast (MCF-7) cancer cells and human skin fibroblast (HSF) cells. All the synthesized compounds exhibited potent cytotoxic activity selectively towards HCT-15 cells and did not display apparent toxicity to the normal HSF cells, some of which were more or comparatively effective to the parent compound against HCT-15, MGC-803 and Bel7402 cells. The most active agent 9m displayed high potency against human cancer cells with IC₅₀ ranging from 0.27 ± 0.02 to 9.23 ± 0.12 μM. The structure-activity relationships (SARs) studies suggested that the nature of substituent group in the side chain is important for antitumor potency in vitro. Additionally, nitric oxide release studies revealed that the amount of nitric oxide generated from these oxime derivatives was relatively low. Furthermore, cellular mechanism investigations indicated that compound 9m could arrest cell cycle at G1 phase and induce a strong apoptotic response in HCT-15 cells. Moreover, western blot studies revealed that compound 9m induced apoptosis through the down-regulation of Bcl-2 and up-regulation of Bax, caspase 3 and 9. For all these reasons, compound 9m hold promising potential as antineoplastic agent.

Synthesis of hetero annulated isoxazolo-, pyrido- and pyrimido carbazoles: Screened for in vitro antitumor activity and structure activity relationships, a novel 2-amino-4-(3'-bromo-4'-methoxyphenyl)-8-chloro-11H-pyrimido[4,5-a]carbazole as an antitumor agent

Claisen-Schmidt condensation of 2,3,4,9-tetrahydro-1H-carbazol-1-one with 3-bromo-4-methoxy benzaldehyde afforded the 2-(3'-bromo-4'-methoxybenzylidene)-2,3,4,9-tetrahydro-1H-carbazol-1-one 3. Compound 3 was allowed to react with different organic reactants, hydroxylamine hydrochloride, malononitrile and guanidine nitrate through condensation cum cycloaddition reactions to afford a series of the respective novel hetero annulated carbazoles such as isoxazolo-, pyrido- and pyrimido carbazoles. The structures of the compounds were established by FT-IR, ¹H NMR, ¹³C NMR, X-ray diffraction and elemental analysis. The compounds have been screened for in vitro anti-tumor activity by MTT assay and displayed enviable selective growth inhibition on MCF-7 cell line compared to A-549 cell line. Apoptotic morphological changes in MCF-7 and A-549 cells were visualized using fluorescent microscopic technique. The preliminary structure activity relationships were also carried out. Data pointed out that among pyrimido carbazole compounds, 2-amino-4-(3'-bromo-4'-methoxyphenyl)-8-chloro-11H-pyrimido [4,5-a]carbazole could be exploited as an excellent therapeutic drug against cancer cell proliferation.

1,2,4-Triazole/oxime hybrids as new strategy for nitric oxide donors: Synthesis, anti-inflammatory, ulceroginicity and antiproliferative activities

A series of novel nitric oxide (NO) donating triazole/oxime hybrids was prepared and evaluated for their anti-inflammatory activity and antiproliferative activity. Most of the tested compounds showed significant anti-inflammatory activity using carrageenan-induced rat paw edema method compared to indomethacin. Calculation of the ulcer indices and histopathological investigation indicated that the prepared NO-donating oximes exhibited less ulcerogenicity compared to their ketone intermediates and indomethacin. The NO-donating oximes 7i and 7k achieved remarkable cell growth inhibition activity against most of the tested cell lines. Compound 7k was found to be with high selectivity against CNS subpanel with selectivity ratio of 11.99 at GI₅₀ level.

Clauraila E from the roots of Clausena harmandiana and antifungal activity against Pythium insidiosum

A new carbazole alkaloid named clauraila E (1) together with 8 known compounds were isolated from the methanol extract of the roots of Clausena harmandiana. All compounds were evaluated for antifungal activity against Pythium insidiosum using disc diffusion assay. Pythium insidiosum is a fungus-like microorganism, for which antifungals available now are not effective. It was found that compounds 3, 6, 7 and 9 could inhibit the mycelia growth of P. insidiosum. The results show convincingly that they may be lead to compounds for the development of probiotic or novel antifungal drugs.