Kojic acid

Pharmacological agents were EGCG (98%, Yuanye, Shanghai, China), GCG (98%, Yuanye, Shanghai, China), TFDG (99.12%), and TSA (91.4%) as test samples (generous gifts from the Tea Research Institute of Chinese Academy of Agricultural Sciences, Hangzhou, China) and kojic acid (99%, Macklin, Shanghai, China) as a positive control.
Unless specified otherwise, all chemicals and laboratory ware used for cell culture were purchased from GIBCO (Grand Island, NY, USA), Corning (Corning, NY, USA), GENOM (Jiaxing, China), and Beyotime (Shanghai, China). α-MSH (A1025) was purchased from Apexbio (Houston, TX, USA), and L-DOPA was purchased from Macklin (Shanghai, China). EASY spin Plus cell RNA rapid extraction kit was purchased from Aidlab (Beijing, China). The reverse transcription kit (MR05201M) and fluorescence quantitative kit (MQ00401S) were purchased from Monad (Suzhou, China). Primary antibodies against TYR (TU343218), TRP1 (TD13325), TRP2 (TA5303), MITF (TU326886), p-MITF (Ser180, TA3027), and MC1R (TD4992) were purchased from Abmart (Shanghai, China). Primary antibodies against glyceraldehyde-3-phosphate dehydrogenase (GAPDH, AG019), secondary antibodies of goat anti-mouse IgG labeled with horseradish peroxidase (HRP), goat anti-rabbit IgG labeled with HRP, and other relevant reagents used for protein expression detection were purchased from Beyotime (Shanghai, China).

Kojic acid (≥99%) and L-DOPA were purchased from Macklin (Shanghai, China). L-(-)-tyrosine were purchased from TCI (Shanghai) Development Co., Ltd. Commercial MTYR (S10171-100KU-1), α-arbutin (≥98%), β-arbutin (≥99%), and deoxyarbutin (≥99%) was purchased from Shanghai Yuanye Bio-Technology Co., Ltd. (Shanghai, China). Chemical structures of α-arbutin, β-arbutin, deoxyarbutin, and Kojic acid were shown in Figure 1.

Sargassum pallidum was obtained from Weihai, China, in September 2021. It was identified as Sargassum pallidum by Jinyang Shen of Jiangsu Ocean University. Acarbose was purchased from the National Institutes for Food and Drug Control, China. α-amylase (from porcine pancreas) and α-glucosidase (from saccharomyces cerevisiae) were purchased from Sigma-Aldrich, USA. Tyrosinase was purchased from Shanghai Yuanye, China. Anhydrous ethanol, folinol, soluble starch and sodium hydroxide were purchased from Sinopsin Group Chemical Reagent Co., LTD., China. Gallic acid was purchased from Shanghai Aladdin Biochemical Technology Co., LTD., China. Anhydrous sodium carbonate was purchased from Tianjin Yongda Chemical Reagent Co., LTD., China. Methanol, dinitrosalicylic acid (DNS), 4-nitrobenzene-α-D-glucoside (PNG), glycerol, disodium hydrogen phosphate (Na2HPO4), and dipotassium hydrogen phosphate (K2HPO4) were all analytically pure and purchased from Shanghai Macklin Biochemical Co., Ltd., China. Tyrosinase (BR), L-Dopa, Kojic acid, acetylcholinesterase (derived from electric eel), thio-acetylcholine iodide (ATCI), Dithio-dinitroformic acid (DTNB), Donepiperazine hydrochloride were purchased from Shanghai Macklin Biochemical Co., Ltd., China. Chromatographic grade formic acid, acetonitrile and ammonium formate were purchased from Merck KGaA, Germany.