J Food Bioact

Journal of Food Bioactives, ISSN 2637-8752 print, 2637-8779 online

Journal website www.isnff-jfb.com

Original Research

Volume 1, March 2018, pages 124-133

Epigallocatechin gallate (EGCG) esters with different chain lengths fatty acids and their antioxidant activity in food and biological systems

Figure 2.
Chemical structures of EGCG-3′,5′,3″,5″-O- tetracaproylate.

Figure 3.
DPPH radical scavenging activities of epigallocatechin gallate (EGCG) and its esters. [(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].

Figure 4.
β-carotene bleaching as affected by epigallocatechin gallate (EGCG) and its derivatives. [(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].

Figure 5.
Inhibition of LDL choleterol peroxidation by EGC and its derivatives. [(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].

Figure 6.
Inhibition of hydroxyl (A) and peroxyl (B) radicals induceed DNA scissionby EGC and its derivatives. Lanes 1-Blank (DNA only); 2-Control; 3-EGCG; 4-EGCG-C2; 5-EGCG-C3; 6-EGCG-C6; 7-EGCG-C8; 8-EGCG-C12; 9-EGCG-C18; 10-EGCG-DHA. [(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].

**Table 1.** ¹H and ¹³C chemical shift (δ ppm) of epigallocatechin gallate (EGCG) and EGCG-3′, 5′, 3″, 5″-O-tetracaproylate
	EGCG	EGCG-C6
C/H position	¹³C	¹H	¹³C	¹H
2	77.66	4.96	77.59	4.97
3	69.14	5.36	69.18	5.39
4	26.86	2.65	26.81	2.67
		2.93		2.96
5	156.8		156.77
6	95.46	5.83	95.45	5.83
7	158.62		158.64
8	96.68	5.93	96.71	5.94
9	157.61		157.63
10	98.5		98.47
1′	129.71		129.61
2′	106.61	6.39	106.65	6.48
3′	146.52		150.72
4′	133.47		131.77
5′	146.52		150.72
6′	106.61	6.39	106.61	6.48
1″	120.42		120.44
2″	109.81	6.82	109.41	6.86
3″	146.76		151.26
4″	139.64		137.14
5″	146.76		151.26
6″	109.78	6.77	106.54	6.86
COO	166.38		166.36

Table 1. ¹H and ¹³C chemical shift (δ ppm) of epigallocatechin gallate (EGCG) and EGCG-3′, 5′, 3″, 5″-O-tetracaproylate

EGCG

EGCG-C6

C/H position

¹³C

¹H

¹³C

¹H

77.66

4.96

77.59

4.97

69.14

5.36

69.18

5.39

26.86

2.65

26.81

2.67

2.93

2.96

156.8

156.77

95.46

5.83

95.45

5.83

158.62

158.64

96.68

5.93

96.71

5.94

157.61

157.63

98.5

98.47

1′

129.71

129.61

2′

106.61

6.39

106.65

6.48

3′

146.52

150.72

4′

133.47

131.77

5′

146.52

150.72

6′

106.61

6.39

106.61

6.48

1″

120.42

120.44

2″

109.81

6.82

109.41

6.86

3″

146.76

151.26

4″

139.64

137.14

5″

146.76

151.26

6″

109.78

6.77

106.54

6.86

COO

166.38

166.36

**Table 2.** Lipophilicity and protection factor (PF) of epigallocatechin gallate (EGCG) and esters
#	Compound*	Lipophilicity (Octanol-water partition coefficient, P)	Protection factor**
Values (mean ± SD of three replicates) with different letters were significantly different at P < 0.05.
*[(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].
**In stripped corn oil at 0.5 µmol/g of oil.
1	EGCG	0.38 ± 0.06^d	1.51±0.30^c
2	EGCG-C2	0.43 ± 0.04 ^a	1.12±0.45^e
3	EGCG-C3	0.45 ± 0.06 ^a	1.08±0.68^e
4	EGCG-C6	0.55 ± 0.38 ^a	1.85±0.05^b
5	EGCG-C8	0.70 ± 0.38 ^b	2.26±0.75^a
6	EGCG-C12	0.77 ± 0.38 ^b	2.38±0.40^a
7	EGCG-C18	1.07 ± 0.38 ^c	2.23±0.35^a
8	EGCG-DHA	1.38 ± 0.30 ^c	1.94±0.25^b

Table 2. Lipophilicity and protection factor (PF) of epigallocatechin gallate (EGCG) and esters

Compound*

Lipophilicity (Octanol-water partition coefficient, P)

Protection factor**

Values (mean ± SD of three replicates) with different letters were significantly different at P < 0.05.

*[(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].

**In stripped corn oil at 0.5 µmol/g of oil.

EGCG

0.38 ± 0.06^d

1.51±0.30^c

EGCG-C2

0.43 ± 0.04 ^a

1.12±0.45^e

EGCG-C3

0.45 ± 0.06 ^a

1.08±0.68^e

EGCG-C6

0.55 ± 0.38 ^a

1.85±0.05^b

EGCG-C8

0.70 ± 0.38 ^b

2.26±0.75^a

EGCG-C12

0.77 ± 0.38 ^b

2.38±0.40^a

EGCG-C18

1.07 ± 0.38 ^c

2.23±0.35^a

EGCG-DHA

1.38 ± 0.30 ^c

1.94±0.25^b

**Table 3.** Inhibitory effect of epigallocatechin gallate (EGCG) and its derivatives against β-carotene bleaching and TBARS formation in cooked ground meat
#	Compound*	Inhibition (%)
Values (mean ± SD of three replicates) with different letters were significantly different at P < 0.05.
1Inhibition (%) calculated at the end of the incubation period (105 min).
2Inhibition (%) calculated at the end of storage period (day 14).
*[(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].
1	EGCG	13.27 ±0.75^e	64.45±1.65^d
2	EGCG-C2	20.53 ±0.50^d	66.77±0.78^d
3	EGCG-C3	22.24 ±0.45^d	65.43±0.65^d
4	EGCG-C6	40.63 ±0.21^c	88.78±0.45^a
5	EGCG-C8	48.25 ±0.34^b	89.65±1.23^a
6	EGCG-C12	54.49 ±0.75^a	90.75±0.43^a
7	EGCG-C18	47.26 ±0.24^b	87.45±2.45^b
8	EGCG-DHA	46.66 ±0.22^b	84.22±1.38^b
	BHA	–	82.76±1.56^c

Table 3. Inhibitory effect of epigallocatechin gallate (EGCG) and its derivatives against β-carotene bleaching and TBARS formation in cooked ground meat

Compound*

Inhibition (%)

β-carotene bleaching

TBARS formation in cooked pork

Values (mean ± SD of three replicates) with different letters were significantly different at P < 0.05.

1Inhibition (%) calculated at the end of the incubation period (105 min).

2Inhibition (%) calculated at the end of storage period (day 14).

EGCG

13.27 ±0.75^e

64.45±1.65^d

EGCG-C2

20.53 ±0.50^d

66.77±0.78^d

EGCG-C3

22.24 ±0.45^d

65.43±0.65^d

EGCG-C6

40.63 ±0.21^c

88.78±0.45^a

EGCG-C8

48.25 ±0.34^b

89.65±1.23^a

EGCG-C12

54.49 ±0.75^a

90.75±0.43^a

EGCG-C18

47.26 ±0.24^b

87.45±2.45^b

EGCG-DHA

46.66 ±0.22^b

84.22±1.38^b

BHA

–

82.76±1.56^c

**Table 4.** DNA retention (%) in hydroxyl and peroxyl radical-induced oxidative scission
#	Compound*	DNA retention (%)
Values (mean ± SD of three replicates) in the same column with different letters were significantly different at P < 0.05.
*[(2) EGCG-C2, EGCG tetraacetate; (3) EGCG-C3, EGCG tetrapropionate; (4) EGCG-C6, EGCG tetracaproylate; (5) EGCG-C8, EGCG tetracapryloylate; (6) EGCG-C12, EGCG tetralauroylate; (7) EGCG-C18, EGCG tetrastearoylate; and (8) EGCG-DHA, EGCG tetradecosahexaenoate].
	Control	27.87 ±0.45^e	23.27 ±0.75^f
1	EGCG	43.27 ±1.75^c	81.45±1.65^a
2	EGCG-C2	29.53 ±0.50^e	56.77±0.78^e
3	EGCG-C3	30.28 ±0.95^e	55.43±0.65^e
4	EGCG-C6	34.43 ±0.21^d	68.78±0.45^c
5	EGCG-C8	48.27 ±0.34^b	69.65±1.23^c
6	EGCG-C12	55.49 ±0.85^a	70.75±0.43^c
7	EGCG-C18	40.26 ±1.24^c	78.45±2.45^b
8	EGCG-DHA	36.65 ±0.22^d	64.22±1.38^d

Table 4. DNA retention (%) in hydroxyl and peroxyl radical-induced oxidative scission

Compound*

DNA retention (%)

Hydroxyl radical

Peroxyl radical

Values (mean ± SD of three replicates) in the same column with different letters were significantly different at P < 0.05.

Control

27.87 ±0.45^e

23.27 ±0.75^f

EGCG

43.27 ±1.75^c

81.45±1.65^a

EGCG-C2

29.53 ±0.50^e

56.77±0.78^e

EGCG-C3

30.28 ±0.95^e

55.43±0.65^e

EGCG-C6

34.43 ±0.21^d

68.78±0.45^c

EGCG-C8

48.27 ±0.34^b

69.65±1.23^c

EGCG-C12

55.49 ±0.85^a

70.75±0.43^c

EGCG-C18

40.26 ±1.24^c

78.45±2.45^b

EGCG-DHA

36.65 ±0.22^d

64.22±1.38^d