Simultaneous Determination of Six Isoflavones from Puerariae Lobatae Radix by CPE-HPLC and Effect of Puerarin on Tyrosinase Activity

Abstract

Tyrosinase inhibitors with excellent inhibitory activities and lower side effects have promising applications in the fields of medicine, agriculture, food sciences and cosmetics. In this study, a method for simultaneous separation and determination of six target compounds (puerarin, daidzin, genistein, daidzein, genistin, and formononetin) in Puerariae Lobatae Radix was established by cloud point extraction (CPE) and concentration combined with high performance liquid chromatography (HPLC). To achieve high extraction yields, an ultrasound-assisted extraction method was developed based on a salt-modified Triton X-100 system. The optimal extraction conditions are: surfactant Triton X-100 concentration 0.07 g/mL, liquid-solid ratio 80:1 (mL/g), NaCl addition amount 0.6 g, equilibrium time 40 min, equilibrium temperature 70 °C. Under the optimal conditions, the total maximum extraction yield of the six target isoflavones reached 8.92 mg/g. Using l-tyrosine and l-dopa as substrates, the effects of puerarin on the monophenolase and diphenolase activity of tyrosinase activity were investigated by the enzyme kinetics method. The results showed that puerarin inhibited monophenolase activity with an IC50 of 0.537 mg/mL and activated diphenolase activity. The inhibition type of puerarin on monophenolase and the activation type of puerarin on diphenolase were analyzed by Lineweaver-Burk plots which show that puerarin showed mixed inhibition on monophenolase and mixed activation on diphenolase. Therefore, puerarin can be used as both a tyrosinase inhibitor and a tyrosinase activator.

Anti-tyrosinase and antioxidant activity of proanthocyanidins fromCinnamomum camphora

“…Moreover, PAs extracted from leaves have a better inhibitory effect on tyrosinase monophenolase activity than those from branches. Qu et al [26] reported the effects of puerarin on the tyrosinase monophenolase activity with an IC 50 value of 0.537 mg/mL. Cui et al [27] reported that T. grandis "Xiangyafei" seed oil (XYSO) exhibited the highest activities in the tested seed oils against tyrosinase monophenolase (IC 50 = 817.5 μg/mL).…”

Structural Characterization and Assessment of Anti-Inflammatory and Anti-Tyrosinase Activities of Polyphenols from Melastoma normale

“…Inflammation, as a common clinical pathological process, is closely related to many diseases such as arthritis, psychosis, cardiovascular and cerebrovascular diseases, and cancer [ 1 ]. Tyrosinase is the key enzyme of melanin synthesis, and its overexpression can lead to pigmentation diseases such as freckles, chloasma and melanoma [ 2 ]. At present, anti-inflammatory drugs such as glucocorticoids, insulin, and tyrosinase inhibitors such as kojic acid have been proven to have significant side effects [ 3 , 4 ].…”

Anti-Tyrosinase and Antioxidant Activity of Proanthocyanidins From Cinnamomum Camphora

“…Both of them had good inhibitory activity on tyrosinase diphenolase, especially the extract of PAs from leaves of C. camphora. Qu et al (23) reported the effects of puerarin on the monophenolase activity with an IC value of 0.537 mg/mL. Cui et al ( 9) reported that T. grandis "Xiangyafei" seed oil (XYSO) exhibited the highest activities in the tested seed oils against tyrosinase monophenolase ( IC 50 = 817.5 μg/mL).…”