In this work, corn stalk was subjected to steam explosion (SE) pretreatment, and the hydrolysate in post-washing liquor of steam exploded corn stalk was assayed for anti-tyrosinase activity for the first time. The hydrolysate showed strong anti-tyrosinase activity with an IC₅₀ of 2.17 mg/mL (inhibitor concentration when 50% of tyrosinase activity is inhibited) at SE severity of 4.20 (198 °C, 20 min). Through hydrolysate component profiles and model substance analysis, phenolic compounds (especially lignin-derived H-unit monomers and phenolic acids) were confirmed to be the major tyrosinase inhibitors in hydrolysate. To further improve the inhibitory activity, an enrichment process of phenolic compounds by ethyl-acetate fractionation of hydrolysate was employed. Ethyl-acetate soluble fraction exhibited significantly enhanced anti-tyrosinase activity (IC₅₀, 0.29 mg/mL), which was even better than p-coumaric acid (a typical tyrosinase inhibitor with IC₅₀ of 0.31 mg/mL). Additionally, the mixed-type inhibition of hydrolysate on tyrosinase was illustrated by kinetics study and the interaction between hydrolysate and tyrosinase was confirmed by fluorescence quenching measurement. Consequently, this work aims to evaluate and improve the anti-tyrosinase activity of hydrolysate from steam explosion processing of corn stalk, which opens new perspectives in potential application of currently underused corn stalk hydrolysate as a value-added tyrosinase inhibitor.

在这项工作中，对玉米秸秆进行蒸汽爆炸（SE）预处理，并首次测定了蒸汽爆炸的玉米秸秆洗后液中的水解产物的抗酪氨酸酶活性。水解产物具有很强的抗酪氨酸酶活性，IC ₅₀在SE严重度为4.20（198°C，20分钟）时为2.17 mg / mL（当抑制50％酪氨酸酶活性时的抑制剂浓度）。通过水解产物的成分分析和模型物质分析，酚类化合物（尤其是木质素衍生的H单元单体和酚酸）被证实是水解产物中主要的酪氨酸酶抑制剂。为了进一步提高抑制活性，采用了通过水解产物的乙酸乙酯分级分离富集酚类化合物的方法。乙酸乙酯可溶级分显示出显着增强的抗酪氨酸酶活性（IC _50为0.29 mg / mL），甚至优于对-香豆酸（具有IC ₅₀的典型酪氨酸酶抑制剂）0.31 mg / mL）。另外，通过动力学研究说明了水解产物对酪氨酸酶的混合型抑制，并且通过荧光猝灭测量证实了水解产物与酪氨酸酶之间的相互作用。因此，这项工作旨在评估和改善玉米秸秆蒸汽爆破过程中水解产物的抗酪氨酸酶活性，这为目前未充分利用的玉米秸秆水解产物作为增值酪氨酸酶抑制剂的潜在应用开辟了新的前景。