Bio a

PCSEE and BIO-A were concurrently run on a silica gel matrix (5 × 10 cm²) containing a fluorescent indicator with 254 nm excitation on aluminum foil (Sigma-Aldrich) for thin-layer chromatography (TLC) identification. On replicate TLC matrices, 5 μL of a 1 cm short band of 20 mg/mL PCSEE, and 1 and 5 mM BIO-A (Sigma-Aldrich) ethanol stock solution were directly deposited at 0.5 cm or more from TLC plate lower edge. After ethanol evaporation, TLC plate was slowly placed and developed in a clean glass developing chamber saturated with a miscible solvent system (water: acetone: ethanol of 5: 3: 1 ratio), 0.5 cm deep or less. Plates were taken out after 50-60 min incubation at RT, or when solvent front reached 1 cm from the upper TLC edge (approximately 8.5 cm height). Dried developed TLC plates were then visualized under short (254 nm) and long (366 nm) UV lights. Retention factor (R_f) of BIO-A band and a matching band were quantified.

The tested pure PCS constituents (≥95%) of PS and PSD and the standard selective MAO-AI clorgyline (CLORG) were obtained from Santa Cruz Biotechnology Inc. (Dallas, TX, USA). Hank's Balanced Salt Solution (HBSS), HEPES, benzylamine HCl, IPS, 6-PN, NBI, BIO-A, the selective MAO-BI standard selegiline (Deprenyl®) (DEP), and other chemicals and chromatography supplies were purchased from Sigma-Aldrich (St Louis, MO, USA). Human MAO-A and MAO-B, derived from a recombinant baculovirus infected insect cells, and measured in active units (U) were purchased from Sigma-Aldrich and received in a buffer solution at pH 7.4. The China originated PCS were obtained from East Earth Trade Winds (Redding, CA, USA), and the MAO-Glo™ kits from Promega (Madison, WI, USA).