title: Synthesis of β-carboline-benzimidazole conjugates using lanthanum nitrate as a catalyst and their biological evaluation.
abstract: A series of β-carboline-benzimidazole conjugates bearing a substituted benzimidazole and an aryl ring at C3 and C1 respectively were designed and synthesized. The key step of their preparation was determined to involve condensation of substituted o-phenylenediamines with 1-(substituted phenyl)-9H-pyrido[3,4-b]indole-3-carbaldehyde using La(NO3)3·6H2O as a catalyst and their cytotoxic potential was evaluated. Conjugates 5a, 5d, 5h and 5r showed enhanced cytotoxic activity (GI50 values range from 0.3 to 7.1 μM in most of the human cancer cell lines) in comparison to some of the previously reported β-carboline derivatives. To substantiate the cytotoxic activity and to understand the nature of interaction of these conjugates with DNA, spectroscopy, DNA photocleavage and DNA topoisomerase I inhibition (topo-I) studies were performed. These conjugates (5a, 5d and 5r) effectively cleave pBR322 plasmid DNA in the presence of UV light. In addition, the effect of these conjugates on DNA Topo I inhibition was studied. The mode of binding of these new conjugates with DNA was also examined by using both biophysical as well as molecular docking studies, which supported their multiple modes of interaction with DNA. Moreover, an in silico study of these β-carboline-benzimidazole conjugates reveals that they possess drug-like properties.
authors.affiliation: Medicinal Chemistry and Pharmacology, CSIR - Indian Institute of Chemical Technology, Hyderabad 500 007, India. ahmedkamal@iict.res.in.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Kamal
authors.forename: M P Narasimha
authors.initials: MP
authors.lastname: Rao
authors.forename: P
authors.initials: P
authors.lastname: Swapna
authors.forename: Vunnam
authors.initials: V
authors.lastname: Srinivasulu
authors.forename: Chandrakant
authors.initials: C
authors.lastname: Bagul
authors.forename: Anver Basha
authors.initials: AB
authors.lastname: Shaik
authors.forename: Kishore
authors.initials: K
authors.lastname: Mullagiri
authors.forename: Jeshma
authors.initials: J
authors.lastname: Kovvuri
authors.forename: Vangala Santhosh
authors.initials: VS
authors.lastname: Reddy
authors.forename: K
authors.initials: K
authors.lastname: Vidyasagar
authors.forename: Narayana
authors.initials: N
authors.lastname: Nagesh
mesh_terms: D000042:Absorption; D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001562:Benzimidazoles / Q000737:chemistry*; D002243:Carbolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002384:Catalysis; D002417:Cattle; D045744:Cell Line, Tumor; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D053837:DNA Cleavage / Q000187:drug effects; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D006801:Humans; D007364:Intercalating Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D007811:Lanthanum / Q000737:chemistry*; D062105:Molecular Docking Simulation; D009690:Nucleic Acid Conformation; D013329:Structure-Activity Relationship; D059004:Topoisomerase I Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D001562:Benzimidazoles; D002243:Carbolines; D007364:Intercalating Agents; D059004:Topoisomerase I Inhibitors; C016534:lanthanide nitrate; D007811:Lanthanum; D004247:DNA; C427203:calf thymus DNA; D004264:DNA Topoisomerases, Type I