Two galactomannan preparations from seeds from Mimosa scabrella (bracatinga): Complexation with oxovanadium(IV/V) and cytotoxicity on HeLa cells

Aminoacid-derivatized oxidovanadium complexes: Synthesis, structure and bromination reaction activity

“…It is found that ( Table 6): (i) the reaction orders of the oxidovanadium complex in bromination reaction are all close to 1, confirming the first-order dependence on vanadium; (ii) the order of the reaction rate constant for them is VOSO 4 Á1.5H 2 O > 4 > 1 > 2 > 3; (iii) mimcing catalysis activity of the starting material (VOSO 4 Á1.5H 2 O) is more higher than that of the aminoacid-derivatized oxidovanadium complexes, revealing that the forming speed of peroxidovanadium intermediate [VO(O 2 )L 2 ] moiety through VOSO 4 Á1.5H 2 O is faster than that of the oxocomplexes with aminoacid derivative, which is probably due to the steric hindrance of the ligands in the complexes. Nevertheless, it is well known that when the central vanadium complexed with organic ligands, it can give more soluble and less toxic compounds than the inorganic vanadium material [38,39], which is being considered less toxic from the biological point of view [40][41][42]; (iv) complex 4 is active markedly in comparison to other oxidovanadium complexes, probably because containing Lhistidine-salicylaldehyde in 4 makes it more close to the active center of the VHPO; (v) the order of the reaction rate constant for other complexes is 1 > 2 > 3, which is may related to that the difference of aminoacid-derivatized ligands and the steric bulk of ancillary ligands. Since the real mechanism by which the bromide oxidation takes place is not very clear at the moment, it is wise to consider aminoacid-derivatized oxidovanadium complexes as good structural models for VHPO.…”

Potential for Biomedical Applications of Galactomannans and Xyloglucans from Seeds: An Overview

“…This possibility is in progress in our group. cells [29]. Only the complexed forms promoted cytotoxicity against this cell line and GALMAN-B:VO 2+ /VO 3+ was ~3-fold more potent than GALMAN-A:VO 2+ /VO 3+ .…”

“…Galactomannans and their derivatives oxovanadium (IV/V)complexes were evaluated for cytotoxicity against tumor cell lines [29], immunomodulation, and leishmanicidal activities [26]. Native galactomannans (GALMAN-A) isolated from seeds of M. scabrella and its enzymatically hydrolyzed form (GALMAN-B), as well as their oxovanadium(IV/V) complexes designated GALMAN-A:VO 2+ /VO 3+ and GALMANB:VO 2+ /VO 3+ , respectively, were evaluated in HeLa Xyloglucan from Tropaeolum majus seeds inhibited the effect of the carcinogen 1-nitropyrene [47].…”

Are Structurally Modified Galactomannan Derivatives Biologically Active?

“…Biological activities of polysaccharides are affected by several factors, among them, monosaccharide composition, molecular weight, molecular structure, functional groups, degree and pattern of substitution, flexibility, and chain configuration [4,19,20]. In addition to the evident biological activity of natural polysaccharides, derivatives obtained by hydrolysis, complexation, or chemical modifications, such as sulfation, phosphorylation, oxidation, and carboxymethylation, were also considered in many studies as successful bioactive derivatives [5,[21][22][23].…”

“…Polysaccharides are suitable binders for complexation reactions with the cationic form of vanadium due to the affinity of this metal for hydroxyl groups free of these polyhydroxyl compounds. Complexation of vanadium (IV, V) with monosaccharides is facilitated by the presence of ligands containing vicinal cis-OH groups [19,32]. Anticancer and antileishmanial activities are recognized as examples of the success of galactomannans complexed with vanadium [19,33].…”