In the screening of natural products for the development as cosmetic ingredients, the EtOAc-soluble fraction of Humulus japonicus showed tyrosinase inhibitory activity. HPLC-MS/MS coupled online tyrosinase assay of EtOAc-soluble fraction of H. japonicus characterized the twenty-eight constituents including two unknown ones and their tyrosinase inhibitory activity. Fractionation of H. japonicus using various chromatographic techniques yielded thirty-eight compounds. The chemical structures of isolated compounds were identified by spectroscopic analysis. As characterized by HPLC-MS/MS analysis, we isolated twenty-four predicted compounds and further identified two unknown ones, named humulusides A (1) and B (2). Additional ten compounds were also identified by purification. Tyrosinase inhibitory activity of isolated compounds were evaluated, which was closely correlated with the results from HPLC-MS/MS coupled online tyrosinase assay. Consistent with predicted data, two major compounds, trans-N-coumaroyltyramine (14) and cis-N-coumaroyltyramine (15) showed tyrosinase inhibition with IC₅₀ values of 40.6 and 36.4 μM. Taken together, H. japonicus is suggested as whitening ingredient in cosmetic products. In addition, HPLC-MS/MS coupled tyrosinase assay is powerful tool for predicting active compounds with short time and limited amounts, although identification of new compounds and verification of predicted data are also needs to be demonstrated by further experiment.

在筛选天然产物作为化妆品成分的过程中，Hum草的EtOAc可溶级分显示出酪氨酸酶抑制活性。HPLC质谱/质谱联用技术对日本血吸虫的EtOAc可溶级分进行在线酪氨酸酶测定，表征了28种成分，其中包括两个未知成分，以及它们的酪氨酸酶抑制活性。使用各种色谱技术对日本血吸虫进行分馏，得到38种化合物。分离的化合物的化学结构通过光谱分析鉴定。根据HPLC-MS / MS分析的特征，我们分离出了24种预测化合物，并进一步鉴定出两个未知化合物，即草苷A（1）和B（2）。还通过纯化鉴定了另外十种化合物。评估了分离的化合物的酪氨酸酶抑制活性，这与HPLC-MS / MS偶联在线酪氨酸酶测定的结果密切相关。与预测的数据，两个主要的化合物，一致的反式- ñ -coumaroyltyramine（14）和顺式- ñ -coumaroyltyramine（15）表现出酪氨酸酶抑制与IC ₅₀ 40.6 36.4μM的值。总之，日本血吸虫建议用作化妆品中的美白成分。此外，虽然还需要通过进一步的实验来证明新化合物的鉴定和预测数据的验证，但HPLC-MS / MS酪氨酸酶测定法是预测短时间和有限量的活性化合物的有力工具。