| Inorganic arsenicals, including arsenite(AsIII) and arsenate(AsV) are well-knownhuman carcinogens. Recently, research studies have indicated that arsenictriglutathione (As(GS)3) is unstable in an aqueous solution. The present study wasdesigned to evaluate the degradation process of As(GS)3in an aqueous solution usinghigh-performance liquid chromatography-electrospray ionisation mass spectrometry(HPLC-ESI-MS). Using acetonitrile (0.1%formic acid, v/v) and an aqueous solution(0.1%formic acid, v/v) as the mobile phase. Two new substances were discovered inthis study. Based on the fragments obtained from MS2and MS3spectrum, wepredicted the structures of these. One of the newly discovered compounds was anisomer of glutathione, it was from the condensation of α-carboxyl and amino. And theother was obtained after cleavage of the glutamyl from oxidised glutathione.Weperformed a contrast experiment under the same conditions as the previousexperiment. After24hours, the compounds were not observed on the chromatogramTherefore, the two new peaks have no relationship to the instability of glutathione,they were caused by the interaction of As and glutathione. The formation of the twonew compounds will influence the genetic and metabolic process of the organism.GSH is an important free radical scavenger in organism. Study on thescavenging effects of GSH to DPPH free radical and the influence of arsenicals(As~Ⅲ,As~Ⅴ,MMA~Ⅴ) in the scavenging processes using UV-Vis spectrophotometer andHPLC-ESI-MS.GSH had the obvious ability of scavenging the free radical by UV-Visspectrophotometer. Through determination of the scavenging effects of GSH/As~Ⅴ、GSH/MMA~Ⅴand GSH/As~Ⅲto DPPH free radical, we could get the regressionequation of GSH/As~Ⅴ、GSH/MMA~Ⅴ、GSH/As~Ⅲof different ratio. Then calculatedthe half elimination ratio(IC50) of them by regression equation. According to the IC50,we concluded that arsenicals(As~Ⅲ， As~Ⅴ， MMA~Ⅴ)could improve the ability ofscavenging DPPH free radical by GSH. The strength of scavenging effects of everysolution was: GSH/As~Ⅴ>GSH/MMA~Ⅴ>GSH/As~Ⅲ.In order to further analysis the influence of arsenicals(As~Ⅲ, As~Ⅴ,MMA~Ⅴ)in thescavenging processes of DPPH free radical by GSH, using HPLC-ESI-MS toresearch the mixed solutions of GSH and arsenicals(As~Ⅲ, As~Ⅴ,MMA~Ⅴ). Based on the scanning results of HPLC-ESI-MS, the arsenicals (As~Ⅲ, As~Ⅴ, and MMA~Ⅴ) could reactwith GSH in mixed solutions and produced GSSG. And GSSG had synergistic effectin the process of scavenging DPPH free radical by GSH. Thus, the arsenical couldimprove the ability of scavenging DPPH free radical by GSH due to the formation ofGSSG. Study on the influence of arsenicals for free radical scavenging by GSH ishelpful to the metabolism in vivo and toxic mechanism of arsenicals. |
PDF Full Text Request