title: Topoisomerase I and II Inhibitors: A Patent Review.
abstract: BACKGROUND
  Topoisomerases are a set of nuclear enzymes that play a vital role in handling of topological consequences of DNA during various genetic activities necessary for vitality of cell. Inhibition of these enzymes consequently leads to the blockage of ligation step of the cell cycle which generates single and double strand breakage in DNA strand. Introduction of these breaks subsequently leads to programmed cell death (Apoptosis).
  
  
  OBJECTIVE
  In the past several years, topoisomerases have become one of the most expedient and strategic molecular targets for anticancer drugs and numerous patents have been filed and published on topoisomerase inhibitors. This review compiles the patent literature up to 2016 embracing topo I and II inhibitors as well as dual inhibitors which are structurally adjacent to camptothecin (CPT), natural products such as lamellarins and synthetic trisubstituted pyridines. The present assemblage can be extremely advantageous for the medicinal chemists who are in crave for the development of potential anticancer agents targeting topoisomerases.
  
  
  CONCLUSIONS
  Recent patents indicated that some of the nitrogen containing heteroaromatic compounds have immense potential to inhibit topoisomerase enzyme. In particular, fused N-Heterocycles can be anticipated for their promising therapeutic potential alone or in combination with other anticancer agents. Naphthyridinone and indenoisoquinoline derivatives, described in the preceding sections of this review, are endowed with significant potency against topoisomerase I which clearly indicates the need of preclinical and clinical studies to place them in forefront as potential future drug candidates.
authors.forename: Arshdeep
authors.initials: A
authors.lastname: Singh
authors.forename: Navdeep
authors.initials: N
authors.lastname: Kaur
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Singh
authors.forename: Pooja
authors.initials: P
authors.lastname: Sharma
authors.forename: Pms
authors.initials: P
authors.lastname: Bedi
authors.affiliation: Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, Punjab, India. ss.gq2009@gmail.com.
authors.forename: Sahil
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Pharmaceutical Chemistry, ISF College of Pharmacy, Moga, Punjab, India. kunal_8855@rediffmail.com.
authors.forename: Kunal
authors.initials: K
authors.lastname: Nepali
mesh_terms: D000818:Animals; D055808:Drug Discovery; D006801:Humans; D015394:Molecular Structure; D009369:Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000473:pathology; D010330:Patents as Topic; D013329:Structure-Activity Relationship; D059004:Topoisomerase I Inhibitors / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use*; D059005:Topoisomerase II Inhibitors / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use*
chemical_list: D059004:Topoisomerase I Inhibitors; D059005:Topoisomerase II Inhibitors