Antioxidant Characterization of Oak Extracts Combining Spectrophotometric Assays and Chemometrics

Table 1

Total phenol, tannin, flavonoid, proantocyanidine, chlorophyll a and b, carotenoid, and proline contents in oak twigs, leaves, and acorns of two Serbian oak species Quercus robur L. and Quercus petraea L.

Plant organ	Locality	TPC (mg catechin/g)	TAC (mg catechin/g)	FLC (mg rutin/100 g)	PAC (mg leukocyani-dine/100 g)	Chla (mg/g)	Chlb (mg/g)	Car (mg/g)	Pro. (μg/g)
Twigs	Q. robur	12.86^a	9.094^a	22.06^a	148.9^a	0.033^a	0.027^a	0.029^a	0.083^a
	Q. petraea	7.44^b	4.667^b	19.12^a	79.04^b	0.035^a	0.042^b	0.018^b	0.053^b
Leaves	Q. robur	32.37^c	22.47^c	290.2^b	1102^c	0.115^b	0.091^c	0.175^c	0.067^c
	Q. petraea	35.52^d	26.24^d	306.1^c	757.6^d	0.229^c	0.164^d	0.147^d	0.075^d
Acorns	Q. robur	16.25^e	11.76^e	26.17^a	612.4^e	0.016^d	0.017^e	0.009^e	0.077^ad
	Q. petraea	15.90^e	12.65^e	73.81^d	163.6^a	0.026^a	0.032^a	0.023^ab	0.041^e

∗Values with the same letter, in each colon, are not significantly different according to Duncan test (𝑃<0.05).
**TPC: total phenolic content; TAC: tannin content; FLC: flavonoid content; PAC: proanthocyanidin content; Chla and Chlb: chlorophyll a and b contents; Car: carotenoid content; Pro: proline content.