Phenolic compounds and antioxidant activity of tuberous root leaves

Figures & data

Figure 1. Chromatogram of the standard solution of phenolic compounds (1) Gallic acid, (2) Catechin, (3) Chlorogenic acid, (4) Caffeic acid, (5) Vanillin, (6) p-coumaric acid, (7) Ferulic acid, (8) m-coumaric acid, (9) o-coumaric acid, (10) Rosmarinic acid, (11) Quercetin (12) Trans-cinnamic acid (4 x 10-5 mol L-1) (A) and methanol extracts of leaves of carrot (B), beet (C), sweet potato (D), yam (E), radish (F). Identified peaks: (B): 1) Gallic acid, (2) Catechin, (3) Chlorogenic acid, (4) Caffeic acid, (5) Vanillin, (6) p-coumaric acid, (7) Ferulic acid, (9) o-coumaric acid, (10) Rosmarinic acid, (11) Quercetin, (12) Trans-cinnamic acid. (C): 1) Gallic acid, (2) Catechin, (3) Chlorogenic acid, (4) Caffeic acid, (5) Vanillin, (6) p-coumaric acid, (7) Ferulic acid, (10) Rosmarinic acid, (11) Quercetin (12) Trans-cinnamic acid. (D): (1) Gallic acid, (2) Catechin, (3) Chlorogenic acid, (4) Caffeic acid, (5) Vanillin, (6) p-coumaric acid, (7) Ferulic acid (9) o-coumaric acid, (10) Rosmarinic acid, (11) Quercetin (12) Trans-cinnamic acid. (E): (1) Gallic acid, (2) Catechin, (3) Chlorogenic acid, (4) Caffeic acid, (5) Vanillin, (8) m-coumaric acid, (9) o-coumaric acid, (12) Trans-cinnamic acid. (F): 1) Gallic acid, (4) Caffeic acid, (3) Chlorogenic acid, (5) Vanillin, (6) p-coumaric acid, (7) Ferulic acid, (10) Rosmarinic acid, (11) Quercetin (12) Trans-cinnamic acid.

Table 1. Identification and quantification of phenolic compounds in leaf extracts of carrot, beet, sweet potato, yam, and radish.

Compounds (mg/L)	Radish	Yam	Sweet potato	Beet	Carrot
Gallic acid	1.17 ± 0.01	1.94 ± 0.01	5.52 ± 0.01	26.38 ± 0.02	0.89 ± 0.01
Catechin	nd	5.21 ± 0.01	8.05 ± 0.01	1.41 ± 0.01	1.20 ± 0.01
Caffeic acid	1.76 ± 0.01	3.85 ± 0.01	30.25 ± 0.01	1.44 ± 0.01	3.3 ± 0.01
Chlorogenic acid	8.84 ± 0.01	6.12 ± 0.01	401.05 ± 0.04	4.72 ± 0.03	458.79 ± 0.03
Vanillin	0.14 ± 0.01	1.15 ± 0.01	0.53 ± 0.01	0.16 ± 0.01	0.34 ± 0.01
p-coumaric acid	0.49 ± 0.01	Nd	0.28 ± 0.01	0.27 ± 0.01	1.39 ± 0.01
m-coumaric acid	nd	0.21 ± 0.01	Nd	nd	nd
o-coumaric acid	nd	1.17 ± 0.01	13.61 ± 0.01	nd	49.94 ± 0.02
Ferulic acid	0.65 ± 0.01	Nd	0.23 ± 0.01	1.84 ± 0.01	0.46 ± 0.01
Rosmarinic acid	21.20 ± 0.01	Nd	222.05 ± 0.01	134.76 ± 0.02	65.71 ± 0.02
Quercetin	0.48 ± 0.01	nd	292.42 ± 0.01	176.99 ± 0.01	5.31 ± 0.01
Trans-cinnamic acid	1.38 ± 0.01	1.36 ± 0.01	4.00 ± 0.01	1.53 ± 0.01	1.44 ± 0.01

The results were expressed as mean ± standard deviation (n = 3); nd: not determined.

Table 2. Iron reducing antioxidant power (FRAP), total compounds, phenolics, β-carotene, scavenging activity of free radicals (DPPH/IC₅₀).

SAMPLES	Total phenolics (mg GAE/g)	FRAP (μM ferrous sulfate/g)	β¯Carotene (IC50) (mg/L)	DPPH (IC50) (μg/g)
RADISH	91.8 a ± 2.9^a	6,658.5 ± 22.5^a	290.7 ± 5.4^d	422.7 ± 6.9^e
YAM	80.4 ± 1.8^b	1,679.9 ± 56.9^b	431.1 ± 38.3^c	1,068.3 ± 28.4^c
BEET	63.2 ± 2.2^c	1,290.0 ± 1.0^c	280.2 ± 15.1^d	739.7 ± 3.9^d
SWEET POTATO	49.3 ± 1.3^d	987.1 ± 1.9^d	550.6 ± 9.8^b	1,540.8 ± 4.8^b
CARROT	41.2 ± 2.4^e	690.3 ± 2.3^e	2,495.0 ± 79.5^a	1,577.7 ± 17.5^a

Means followed by the same letter in the column are significantly different (p < 0.05) according to the Scott-Knott test (n = 3). The results are expressed based on dry matter.

Table 3. Correlation coefficient (p value) between the analysis and the antioxidant capacity of the studied leaves.

	PHENOLICS
DPPH	−0.85
	(0.00)
FRAP	0.63
	(0.00)
β-CAROTENE	−0.60
	(0.015)
PHENOLICS	1

Significant correlations are shown in bold (p < 0.05).