Table 1. Analytical conditions of HPLC

Parameters	Conditions
Instrument	HPLC system (Shiseido, Nanospace SI-2)
Detector	PDA detector (254 nm)
Column	Capcellpak C18 Type MGⅡ, 5 μm, 4.6×250 mm (Shiseido)
Temperature	40°C
Injection volume	10 μL
Flow rate	1.0 mL/min
	A: 0.1% formic acid in water
	B: Acetonitrile/MeOH (85:15 v/v)
Mobile phase	Gradient	Time (min)	% A	% B
		0	85	15
		24	76	24
		30	20	80
		32	85	15
		40	85	15
Run time	40 min