Floyd A. Beckford
Lyon College
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Featured researches published by Floyd A. Beckford.
Journal of Inorganic Biochemistry | 2011
Floyd A. Beckford; Deidra Dourth; Michael Shaloski; Jacob Didion; Jeffrey Thessing; Jason Woods; Vernon Crowell; Nikolay Gerasimchuk; Antonio González-Sarrías; Navindra P. Seeram
The synthesis and characterization of a number of organometallic ruthenium(II) complexes containing a series of bidentate thiosemicarbazone ligands derived from piperonal is reported. The structure of compounds have been confirmed by spectroscopic analysis (IR and NMR) as well as X-ray crystallographic analysis of [(η⁶-p-cymene)Ru(pPhTSC)Cl]Cl (4) (pPhTSC is piperonal-N(4)-phenylthiosemicarbazone). The interaction of the complexes ([(η⁶-p-cymene)Ru(pEtTSC)Cl]Cl) (3) (pEtTSC is piperonal-N(4)-ethylthiosemicarbazone) and 4 with calf thymus DNA, human serum albumin (HSA) and pBR322 plasmid DNA were studied by spectroscopic, gel electrophoresis and hydrodynamic methods. The apparent binding constant for the interaction with DNA was determined to be 3.97×10³ M⁻¹ and 4.07×10³ M⁻¹ at 293 K for 3 and 4 respectively. The complexes bind strongly to HSA with binding constants of 2.94×10⁴ M⁻¹ and 12.2×10⁴ M⁻¹ at 296 K for 3 and 4 respectively. The in vitro anticancer activity of 3 and 4 has been evaluated against two human colon cancer cell line (HCT-116 and Caco-2) with IC50 values in the range of 26–150 μM. Both 3 and 4 show good activity as a catalytic inhibitor of human topoisomerase II at concentrations as low as 20 μM. The proficiency of 3 and 4 to act as antibacterial agents was also evaluated against six pathogenic bacterial strains with the best activity seen against Gram-positive strains.
Metallomics | 2011
Floyd A. Beckford; Jeffrey Thessing; Jason Woods; Jacob Didion; Nikolay Gerasimchuk; Antonio González-Sarrías; Navindra P. Seeram
We have synthesized and evaluated the biological properties of a compound of the type [η(6)-p-cymene)Ru(EtATSC)Cl]Cl (1) where EtATSC = 2-anthracen-9-ylmethylene-N-ethylhydrazinecarbothioamide, a thiosemicarbazone. The complex has been characterized by elemental analysis, spectroscopically (NMR, UV-Vis, and IR) and structurally by XRD. The in vitro anticancer activity of 1 has been evaluated against two human colon cancer cell lines. The IC(50) value for activity against HCT-116 was 224 ± 7 μM and 205 ± 5 μM against the Caco-2 cell line. The proficiency of 1 as an antibacterial agent was also evaluated against six bacterial strains. The minimum inhibitory concentration for Bacillus cereus was determined to be 5 μM and for Enterococcus faecalis it was 20 μM. At the maximum concentration tested the complex showed no activity against the Gram-negative strains. The complex binds strongly to human serum albumin with a binding constant of 1.37 ± 0.02 M(-1) at 308 K on a single binding site. It is also a strong binder to DNA with an apparent binding constant of 2.82 × 10(5) M(-1) at 308 K. 1 shows very good activity as a catalytic inhibitor of human topoisomerase II at concentrations as low as 20 μM.
International Journal of Inorganic Chemistry | 2010
Floyd A. Beckford
The reaction of [(eta(6)-p-cymene)Ru(ATSC)Cl]PF(6) (ATSC = 9-anthraldehyde thiosemicarbazone) with human serum albumin was investigated at different temperatures using fluorescence and infrared spectrophotometry. The binding constant, K, for the reaction was determined using a number of different methods. Using a modified Stern-Volmer equation, K was determined to be 9.09 x 10(4), 12.1 x 10(4), and 13.1 x 10(4) M(-1) at 293 K, 298 K, and 308 K, respectively. A thermodynamic analysis showed that the reaction is spontaneous with DeltaG being negative. The enthalpy of reaction DeltaH = 16.5kJ mol(-1) and the entropy of reaction DeltaS = 152 Jmol(-1)K(-1). The values of DeltaH and DeltaS suggest that hydrophobic forces are dominant in the mode of interaction and that the process is mostly entropy driven.
International Journal of Inorganic Chemistry | 2011
Marc-Andre LeBlanc; Antonio González-Sarrías; Floyd A. Beckford; P. Canisius Mbarushimana; Navindra P. Seeram
A novel thiosemicarbazone from 2-acetonaphthone (represented as acnTSC) has been synthesized and its basic coordination chemistry with zinc(II), cobalt(II), and copper(II) explored. The complexes were characterized by elemental analysis and various spectroscopic techniques and are best formulated as [M(acnTSC)(2)Cl(2)] with the metal likely in an octahedral environment. The anticancer activity of the complexes was determined against a panel of human colon cancer cells (HCT-116 and Caco-2). The compounds bind to DNA via an intercalative mode with binding constants of 9.7 × 10(4) M(-1), 1.8 × 10(5) M(-1), and 9.5 × 10(4) M(-1) for the zinc, cobalt, and copper complexes, respectively.
Interdisciplinary Journal of Chemistry | 2016
Floyd A. Beckford; Alyssa Stott; P. Canisius Mbarushimana; Marc-Andre LeBlanc; Kinsey Hall; Samantha Smith; Jimmie L. Bullock; Dennis J Houghton; Alvin A. Holder; Nikolay Gerasimchuk; Gonzalez Sarrías; Navindra P. Seeram
A series of half-sandwich ruthenium complexes, two containing an arene face-cap and the other a thiacrown ether face-cap were synthesized to investigate the necessity of the arene for anticancer activity in this class of compounds. The complexes are formulated as [(η-p-cymene)Ru(dmabTSC)Cl]PF6, [(η6-benzene) Ru(dmabTSC)Cl]PF6 (arene complexes), and [([9]aneS3(dmabTSC)Cl]PF6 (dmabTSC = dimethylaminobenzaldehye thiosemicarbazone). It was observed that none of the complexes showed good anticancer activity in vitro against HCT-116 and Caco-2 (colon adenocarcinoma) cells. All three complexes can bind strongly to calfthymus DNA with binding constants on the order of 105 M-1. In addition they all bind strongly to human serum albumin with binding constants between 105 and 106 M-1. There appears to be a single binding site on the protein for these complexes. A computational investigation of these complexes and their hydrolysis products was carried out by molecular docking with DNA and topoisomerase II. From this analysis it is noted that the type of face-capping ligand had different effects on the two macromolecules. It is therefore noted that the knowledge gained from this study will be useful in identifying the type of complexes in this class that show useful metallodrug potential. Correspondence to: Floyd A Beckford, The University of Virginia’s College at Wise, 1 College Avenue, Wise, VA 24293, USA, Tel: (276) 376-4657; Fax: (276) 307-7496; E-mail: [email protected]
Dalton Transactions | 2009
Floyd A. Beckford; Michael Shaloski; Gabriel LeBlanc; Jeffrey Thessing; Lesley C. Lewis-Alleyne; Alvin A. Holder; Liya Li; Navindra P. Seeram
Inorganic Chemistry Communications | 2009
Floyd A. Beckford; Gabriel LeBlanc; Jeffrey Thessing; Michael Shaloski; Brian J. Frost; Liya Li; Navindra P. Seeram
European Journal of Inorganic Chemistry | 2012
Nerissa A. Lewis; Fange Liu; Luke Seymour; Anthony R. Magnusen; Travis R. Erves; Jessa Faye Arca; Floyd A. Beckford; Ramaiyer Venkatraman; Antonio González-Sarrías; Frank R. Fronczek; Donald G. VanDerveer; Navindra P. Seeram; Aimin Liu; William L. Jarrett; Alvin A. Holder
Inorganic Chemistry Communications | 2012
Floyd A. Beckford; Jeffrey Thessing; Alyssa Stott; Alvin A. Holder; Oleg G. Poluektov; Liya Li; Navindra P. Seeram
Journal of Molecular Structure | 2011
Floyd A. Beckford; Jeffrey Thessing; Michael Shaloski; P. Canisius Mbarushimana; Alyssa Brock; Jacob Didion; Jason Woods; Antonio González-Sarrías; Navindra P. Seeram