Novel benzothiazine-piperazine derivatives by peptide-coupling as potential anti-proliferative agents.

In an attempt to develop potential and selective anti-proliferative agents, a series of novel benzothiazine-piperazine derivatives 8a-i and 10a-g were synthesized by coupling of 2H-1,4-benzothiazin-3(4H)-one with various amines 7a-i and 9a-g in excellent yields and evaluated for their in vitro anti-proliferative activity against four cancer cell lines, HeLa (cervical), MIAPACA (pancreatic), MDA-MB-231 (breast) and IMR32 (neuroblastoma). In vitro inhibitory activity indicated that compounds 8a, 8d, 8g, 10a, 10b, 10e, 10f were found to be good anti-proliferative agents. Among them the derivatives 8g, 10e and 10f were found to be the most active members exhibiting remarkable growth inhibitory activity. Molecular docking was undertaken to investigate the probable binding mode and key active site interactions in HDAC8 and EHMT2 proteins. The docking results are complementary to the experimental results.

Luotonin-A based quinazolinones cause apoptosis and senescence via HDAC inhibition and activation of tumor suppressor proteins in HeLa cells.

A series of novel quinazolinone hybrids were synthesized by employing click chemistry and evaluated for anti-proliferative activities against MCF-7, HeLa and K562 cell lines. Among these cell lines, HeLa cells were found to respond effectively to these quinazolinone hybrids with IC50 values ranging from 5.94 to 16.45 µM. Some of the hybrids (4q, 4r, 4e, 4k, 4t, 4w) with promising anti-cancer activity were further investigated for their effects on the cell cycle distribution. FACS analysis revealed the G1 cell cycle arrest nature of these hybrids. Further to assess the senescence inducing ability of these compounds, a senescence associated ß-gal assay was performed. The senescence inducing nature of these compounds was supported by the effect of hybrid (4q) on p16 promoter activity, the marker for senescence. Moreover, cells treated with most effective compound (4q) show up-regulation of p53, p21 and down-regulation of HDAC-1, HDAC-2, HDAC-5 and EZH2 mRNA levels. Docking results suggest that, the triazole nitrogen showed Zn(+2) mediated interactions with the histidine residue of HDACs.

Design and synthesis of 3-(3-((9H-carbazol-4-yl)oxy)-2-hydroxypropyl)-2-phenylquinazolin-4(3H)-one derivatives to induce ACE inhibitory activity.

In an attempt to develop a new class of cardiovascular drugs, a series of novel carbazolyloxy phenylquinazoline derivatives 9a-g have been synthesized and evaluated as angiotensin converting enzyme (ACE) inhibitors. Most of these compounds exhibited activity as significant ACE inhibitors and three compounds (9b, 9c & 9e) showed maximum inhibitory potency in enzyme based assays. To render support to the experimental results, a series of quinazolinone derivatives were docked into active site of ACE and identified the probable binding modes compared to Lisinopril. Also we have identified common pharmacophore hypothesis (AAADDRR) among the best docked conformers of most potent compounds in a series of compounds. The most potent 9b, 9c, 9e compounds shared common active site with the Lisinopril binding site and retained the key active site residue interactions. The obtained results from pharmacological and molecular modeling studies can be utilized for further optimization of identified hits for selective inhibition of ACE.