4种Keggin型磷钼酸盐对蘑菇酪氨酸酶活性和黑色素生成的抑制及抗氧化作用

合成并表征了4种过渡金属钒取代的Keggin型磷钼酸盐Na_3+nPMo_12-nV_nO₄₀(PMo_12-nV_n)(n=2, 3, 4, 5). 酶动力学实验结果表明, 4种多酸对酪氨酸酶的抑制类型为可逆的混合型抑制, 过渡金属钒取代的个数会影响酪氨酸酶的抑制效果. 当所加酶量为500 U/mL时, PMo₁₀V₂, PMo₉V₃, PMo₈V₄和PMo₇V₅对酪氨酸酶的半抑制率(IC₅₀)分别为(7.046±0.506), (12.128±0.574), (12.362±0.802)和(9.860±1.490) mmol/L. 分子对接研究表明， 化合物与酪氨酸酶之间主要存在氢键和范德华力. 细胞实验结果表明, 在0~200 μmol/L范围内, 4种多酸未对B16黑素瘤细胞产生细胞毒性, 且能显著抑制黑色素的生成. 此外, 1,1-二苯基-2-三硝基苯肼(DPPH)与2,2'-联氮-双-3-乙基苯并噻唑啉-6-磺酸(ABTS)自由基清除实验显示， 4种多酸具有良好的抗氧化能力, 清除DPPH自由基能力优于ABTS.

Inhibitory Effect of Four Kinds of Keegin-type Phosphomolybdate on Tyrosinase and Melanin Formation and Its Antioxidant Activities

Four kinds of transition metal V substituted Keggin type phosphomolybdate Na_3+nPMo_12-nVnO₄₀ （abbreviated as PMo_12-nV_n）（n=2， 3， 4， 5） were synthesized and characterized. The kinetic enzymatic method suggested that the inhibition type of four compounds on tyrosinase was reversible mixed inhibition， and the number of transition metal vanadium substitution would affect the inhibition effect of tyrosinase. When the enzyme content was 500 U/mL， the inhibition rates of PMo₁₀V₂， PMo₉V₃， PMo₈V₄ and PMo₇V₅ on tyrosinase were （7.046±0.506）， （12.128±0.574）， （12.362±0.802）， （9.860±1.490） mmol/L， respectively. The molecular docking experiment confirmed that there was hydrogen bond and van der Waals force interaction between the compound and tyrosinase. The four compounds did not produce cytotoxic effects on B16 melanoma cells， and could significantly inhibit the production of melanin. In addition， 1，1-diphenyl-2-picrylhydrazyl radical 2，2-diphenyl-1-（2，4，6-trinitrophenyl）hydrazyl（DPPH） and 2，2'-azinobis-（3-ethylbenzthiazoline-6-sulphonate）（ABTS） free radical scavenging experiments confirmed that polyoxometalates had good antioxidant capacity. What’s more， they have stronger DPPH radical scavenging ability.