Two galactomannan preparations from seeds from Mimosa scabrella (bracatinga): Complexation with oxovanadium(IV/V) and cytotoxicity on HeLa cells.
Two galactomannans, GALMAN-A and GALMAN-B, were isolated from seeds of Mimosa scabrella (bracatinga), with deactivation and exposure to native enzymes, respectively. They were treated with oxovanadium(IV) and oxovanadium(V), designated (VO(2+)/VO(3+)) to form GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) complexes, respectively. The potentiometric studies provided the binding constants for the complexes and the resulting complexed species were a function of pH. (51)V NMR spectra of GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) at pH 7.8 and at 30 degrees C indicated the occurrence of two types of complexes formed by oxovanadium ions and galactomannans. GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) caused loss of HeLa cells viability at concentrations of 50-200microg/mL. GALMAN-A:VO(2+)/VO(3+) exhibited low toxicity for 24h, although GALMAN-B:VO(2+)/VO(3+) was extremely toxic, since 50microg/mL was sufficient to decrease HeLa cell viability after 48h by 60%. GALMAN-A gave rise to a slight increase in cell proliferation after 48h at 100microg/mL, whereas GALMAN-B promoted a slight decrease at concentrations of 50-100microg/mL. GALMAN-A:VO(2+)/VO(3+) and GALMAN-B:VO(2+)/VO(3+) exhibited a significant decrease in cell proliferation after 48h, each reaching 60% inhibition at 5-10microg/mL. The complexes which caused this effect were at concentrations 10 times lower than the uncomplexed polymers.
Noleto
Guilhermina Rodrigues
GR
Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Jardim das Americas, Curitiba, PR, Brazil. guinoleto@yahoo.com.br
Petkowicz
Carmen Lucia O
CL
Mercê
Ana Lucia Ramalho
AL
Noseda
Miguel Daniel
MD
Méndez-Sánchez
Stelia Carolina
SC
Reicher
Fany
F
Oliveira
Maria Benigna M
MB
D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects*; D005690:Galactose / Q000031:analogs & derivatives; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008351:Mannans / Q000302:isolation & purification* / Q000494:pharmacology*; D031298:Mimosa / Q000737:chemistry*; D011199:Potentiometry; D012639:Seeds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014638:Vanadates / Q000737:chemistry
D008351:Mannans; C012990:galactomannan; C075743:oxovanadium IV; D014638:Vanadates; D005690:Galactose