α secretase

Nobiletin (>98% purity) was purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA). Tangeretin, sinensetin, (>95% purity), and resveratrol (>99% purity) were obtained from Sigma-Aldrich (St. Louis, MO, USA). BACE1 inhibition was determined by enzymatic assay using the fluorescent resonance energy transfer (FRET)-based BACE1 kit from Invitrogen (Pan Vera, Madison, WI, USA). α-Secretase (tumor necrosis factor-α converting enzyme, TACE) and substrate were obtained from R&D Systems (Minneapolis, MN, USA). Trypsin, chymoTrypsin, elastase, and their substrates were obtained from Sigma-Aldrich (St. Louis, MO, USA). The measurement of fluorescence and optical density was performed with a BioTEK ELISA microplate fluorescence reader FLx 800 and BioTEK ELx 808 (Winooski, VT, USA), respectively.

Baicalein (≥98% purity) was obtained from Chemfaces (Wuhan, China). Resveratrol (>99% purity), galantamine, and 5,5′-dithiobis-(2 nitrobenzoic acid) (DTNB) were obtained from Sigma-Aldrich (St. Louis, MO, USA). α-Secretase (TACE) and its substrate were purchased from R&D Systems (Minneapolis, MN, USA). The BACE1 FRET assay kit was purchased from Invitrogen (Pan Vera Co., Madison, WI, USA). AChE, chymotrypsin, trypsin, and elastase, as well as their substrates, were purchased from Sigma-Aldrich (St. Louis, MO, USA).

Hesperetin (>95% purity), naringenin (>95% purity), hesperidin (>97% purity), resveratrol (>99% purity), galanthamine, AChE, BChE, 5,5′-dithiobis-(2 nitrobenzoic acid) (DTNB), and acetylthiocholine iodide were purchased from Sigma-Aldrich (St. Louis, MO, USA). The BACE1 kit from Invitrogen (Pan Vera, Madison, WI, USA) was used for the measurement of BACE1 activity. α-Secretase (tumor necrosis factor-α converting enzyme, TACE) and its fluorogenic substrate were purchased from R&D Systems (Minneapolis, MN, USA). Elastase, chymotrypsin, trypsin, and their substrates were obtained from Sigma-Aldrich.