Optimization of a CUPRAC-Based HPLC Postcolumn Assay and Its Applications for Ginkgo biloba L. Extracts

Table 2

TEAC values (µmol g⁻¹ of dry weight) of Ginkgo biloba L. leaf in CUPRAC postcolumn assay.

Peak number	Analytes	Cultivation source
		(min)	Sample 1	Sample 2	Sample 3	Sample 4	Sample 5	Sample 6	Sample 7
1	Quercetin	13.7	6.79 ± 0.12^b	11.19 ± 0.2^c	3.04 ± 0.04^a	12.22 ± 0.18^d	19.50 ± 0.1^f	3.12 ± 0.04^a	13.74 ± 0.18^e
2	Kaempferol	19.2	2.48 ± 0.05^b	2.40 ± 0.1^b	1.44 ± 0.03^a	3.12 ± 0.04^c	5.59 ± 0.3^e	1.68 ± 0.01^a	3.98 ± 0.05^d
3	Isorhamnetin	20.4	nd	0.37 ± 0.01^bc	0.26 ± 0.01^a	0.40 ± 0.01^cd	0.90 ± 0.03^e	0.44 ± 0.02^d	0.32 ± 0.01^b
Total			9.27 ± 0.16^b	13.96 ± 0.30^c	4.74 ± 0.08^a	15.74 ± 0.25^d	25.99 ± 0.42^f	5.24 ± 0.07^a	18.04 ± 0.27^e

: retention time; nd: not detected.
Notes. (1) Averages marked in different letters in the lines show statistically significant difference (at ).
(2) Values are expressed as mean quantities with standard deviation.