The Potentiation of Anti-inflammatory Effect and INOS and COX-2 Gene Expression Inhibition by Rut in When Complexed with Cooper

Aims: The aim of this study was to evaluate both the antioxidant effect and anti-inflammatory activity of a new transition metal coordinated rut in compound, Rutin-Cu2 complex.
Study Design: Flavonoids have proven antioxidant and anti-inflammatory activities. Moreover, recent researches demonstrate that the antioxidant activity of flavonoids is believed to increase when they are coordinated with transition metal ions. Our group has recently synthesized new compounds by the reaction of rut in (a flavonoid) with divalent metal salts (copper acetate, nickel acetate or iron sulfate), rendering new transitional metal coordinated rut in compounds, named R-Fe1 [(FeC27H32O21S)2], R-Cu2 [C31H32O18Cu.2H20] and R-Ni2 (C31H42O23Ni). In order to investigate the ability of these new compounds in modulating biological activity and to compare if metal coordinated rut in could increase anti-inflammatory activity of rut in alone, we used murine experimental model of peritonitis to measured cell migration and In vitro models of antioxidant activity to evaluate radical superoxide scavenging activity and of macrophage cell line culture to quantify nitric oxide production and iNOS and COX-2 gene expression.
Methodology: To characterize physical-chemical the new generated compounds we used elemental analysis, FT-IR and UV/Vis. The antioxidant effect was evaluate by radical superoxide scavenging assay, using NBT methodology. The anti-inflammatory activity of the new compounds were investigated by peritonitis models induced by carrageenan (1%, 4h), bradikynin (10nmol/cavity, 1h), histamine (100µg/cavity, 1h), substance P (20nmol/cavity, 1,5h) and PGE2 (10nmol/cavity, 1h). Total and leucocytes subtypes numbers were evaluated in harvest cells from mice peritoneum after phlogistic agents administration, in controls groups (not treated or treated with dexamethasone or rut in alone) or tested groups (treated with metal coordinated compounds). RAW 264.7 cells were stimulated with LPS on the absence or presence of rut in alone (0.01–90mMr), or Rutin-Cu2 complex (0.01–90mM). The production of NO was measured in culture supernatant after 24h of cell incubation, by Griess assay. And iNOS and COX-2 transcripts were quantified by real time PCR with SYBR GREEN, on cDNAs obtained after 24h of cell incubation, in a step one instrument (Applied bio systems).
Results: Complex formation was also verified by 1H RNM, using DMSO-d6 as solvent. The proton signals from Hydroxyl groups 5-OH, 7-OH, 3’-OH and 4’-OH shifted to lower and broader frequencies in coordinated complex R-Fe1, R-Cu2 and R-Ni2, compared with signals from free rut in. The results showed that R-Cu2 complex presented a higher superoxide scavenging effect when compared with rut in alone (6.95% and 46.42%, at 10µM; and 51.80% and 71.32%, at 100µM, respectively). The results also showed that R-Cu2 inhibited significantly (P<0.05; ANOVA) cell migration (neutrophils, lymphocytes and monocytes) in peritonitis induced by carrageenan, bradikynin and PGE2, in mice, when compared to controls ones (without treatment or Ru alone treatment). Furthermore, rutin and R-Cu2 significantly (P<0.05, paired t test) inhibited iNOS and COX-2 gene expression in LPS-induced macrophage cells.
Conclusions: Taken together, our results show for the first time that the R-Cu2 complex, a metal coordinated rut in compound, produces anti-inflammatory effects in mice, at least in part, by means of increasing the antioxidant activity and inhibition of iNOS and COX-2 gene expression. We suggest that cooper coordinated rut in compound can potentiates some biological properties of this flavonoid and could be more effective for therapeutic treatment of diseases related to oxidative stress.