Anticancer effects of two complexes derived from naringin and oxidovanadium(IV) cation

GONZALO RESTREPO; GOITIA SEMECO, HELEN; LUCIANA NASO; EVELINA FERRER; PATRRICIA WILLIAMS

Conferencia; VII Latin American Conference on Biological Inorganic Chemistry; 2021

Two different solid complexes with the glycosilated flavonoid naringin (naringenin (7-Oneohesperidoside)) and the oxidovanadium(IV) cation were prepared and characterized.Complex (1), [VO(Nar)2].8H2O (VONar), was prepared as previously reported [1] using adifferent synthetic method. The solid obtained at pH 9 coordinates through the flavonoid moiety(C=O and O- groups of rings A and C, respectively). FTIR: νC=O shifted from 1645 cm-1 to1638 cm-1 and νV=O, 980 cm-1. Electronic spectrum (DMSO): 598 nm, 810.Spectrophotometric titration: L/M, 2/1. Conductivity measurements, DMSO: 0.000 Ω-1mol1cm2. The complex remained stable at least for 1h (conductivity, UV-vis measurements). Beingnaringin a glycosylated flavonoid, its oxidovanadium(IV) complex may result more cytotoxicagainst A549 human lung cancer cell line. But the complexation did not take place through thesugar moiety while the flavonoid could not allow resonance between rings B and C due to theabsence of the double bond between C2 and C3. Measurements of cell viability showed a 20 %viability reduction at 100 μM concentrations for VONar (naringin and oxidovanadium(IV)cation resulted non cytotoxic). Therefore, we synthesized the VO(IV)/Nar complex at pH 13 inwhich the metal coordinates to the sugar moiety of the glycoflavonoid, complex (2),K2[VO(Nar)(H2O)2]. FTIR: νC=O remained at 1645 cm-1 and νV=O, 921 cm-1. Electronicspectrum: 720 nm. Spectrophotometric titration: L/M, 1/1. Conductivity: 282 (Ω-1mol-1cm2),indicating a 1:2 electrolyte. To avoid instability of the complex in aqueous solutions, complex(2) has been dissolved at pH 13 (KCl-NaOH buffer solution pH 13) and fresh solutions wereused for the anticancer determinations. It displayed more cytotoxic effects on lung A549 cancercells than complex (1) (44 % inhibition in cell viability at 100 μM). The coordination throughthe sugar moiety of the glycosilated flavonoid produced a greater anticancer activity (likehesperidin [2] and diosmin [3] VO(IV) complexes).