J Food Bioact

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

Journal website www.isnff-jfb.com

Original Research

Volume 13, March 2021, pages 82-92

Synergies of herbal teas on improved plasma antioxidant capacity and postprandial hypoglycemic response in healthy adults

Figure 1. (a) Mean plasma glucose concentration of healthy adults (herbal tea × time); (b) Comparison of glycemic response of test herbal teas with the control (If an interval does not contain zero, the corresponding mean is significantly different from the control mean). CFT, Cassia flowers tea; CJT, Cassia flowers and Jackfruit leaves mix tea; JLT, Jackfruit leaves tea.

**Table 1.** Phenolic compounds identified and their contents (µg/100 g) in test herbal extracts
Compound	[M-H]⁻ (m/z)	Other product ions (m/z)	Cassia flowers and buds	Jackfruit leaves
Data represent mean values for each sample ± standard deviations (n = 3). Means followed by the same letter within a column are not significantly different (p > 0.05). *Quantified as equivalent of catechin. nd: not detected.
Ellagic acid	301	283	1.23 ± 0.06	0.17 ± 0.01
Gallocatechin*	305	289	272.6 ± 21.2	nd
Isorhamnetin derivative	461	317	3726 ± 52.2	nd
Myricetin derivative	509	317	130.6 ± 8.75	nd
Phloridzin derivative	529	435	982.4 ± 36.9	nd
Epigallocatechin derivative*	579	305, 179	nd	436.4 ± 8.00
Dimeric gallocatechin*	609	305	1,450 ± 90.8	nd
Trimeric Propelargonidin*	849	561, 407, 289	367.0 ± 0.80	nd

Table 1. Phenolic compounds identified and their contents (µg/100 g) in test herbal extracts

Compound

[M-H]⁻ (m/z)

Other product ions (m/z)

Cassia flowers and buds

Jackfruit leaves

Data represent mean values for each sample ± standard deviations (n = 3). Means followed by the same letter within a column are not significantly different (p > 0.05). *Quantified as equivalent of catechin. nd: not detected.

Ellagic acid

301

283

1.23 ± 0.06

0.17 ± 0.01

Gallocatechin*

305

289

272.6 ± 21.2

Isorhamnetin derivative

461

317

3726 ± 52.2

Myricetin derivative

509

317

130.6 ± 8.75

Phloridzin derivative

529

435

982.4 ± 36.9

Epigallocatechin derivative*

579

305, 179

436.4 ± 8.00

Dimeric gallocatechin*

609

305

1,450 ± 90.8

Trimeric Propelargonidin*

849

561, 407, 289

367.0 ± 0.80

**Table 2.** Phenolic contents and antioxidant activities (per g) of extract of herbal teas
	Cassia flowers and buds	Senescent jackfruit leaves
Abbreviations: Total phenolic content, TPC; Total flavanoid content, TFC; Trolox equivalent antioxidant capacity, TEAC; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, DRSA; Reducing power, RP; Ferrous ion chelating ability, FICA; and Ethylenediaminetetraacetic acid, EDTA Values with the same letters in each raw for tested herbal extracts are not significantly different (p > 0.05).
TPC ( µmol gallic acid equiv)	549.6 ± 4.7^a	68.8 ± 4.3^b
TFC ( µmol catechin equiv)	102.2 ± 2.3^a	8.3 ± 2.4^b
TEAC (µmol trolox equiv)	523.9 ± 12.0^a	23.4 ± 6.6^b
DRSA ( µmol trolox equiv)	567.7 ± 7.9^a	27.1 ± 2.8^b
RP ( µmol ascorbic acid equiv)	693.8 ± 5.7^a	143.0 ± 5.1^b
FICA ( µmol EDTA equiv)	0.03 ± 0.01^b	0.09 ± 0.01^a

Table 2. Phenolic contents and antioxidant activities (per g) of extract of herbal teas

Cassia flowers and buds

Senescent jackfruit leaves

Abbreviations: Total phenolic content, TPC; Total flavanoid content, TFC; Trolox equivalent antioxidant capacity, TEAC; 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, DRSA; Reducing power, RP; Ferrous ion chelating ability, FICA; and Ethylenediaminetetraacetic acid, EDTA Values with the same letters in each raw for tested herbal extracts are not significantly different (p > 0.05).

TPC ( µmol gallic acid equiv)

549.6 ± 4.7^a

68.8 ± 4.3^b

TFC ( µmol catechin equiv)

102.2 ± 2.3^a

8.3 ± 2.4^b

TEAC (µmol trolox equiv)

523.9 ± 12.0^a

23.4 ± 6.6^b

DRSA ( µmol trolox equiv)

567.7 ± 7.9^a

27.1 ± 2.8^b

RP ( µmol ascorbic acid equiv)

693.8 ± 5.7^a

143.0 ± 5.1^b

FICA ( µmol EDTA equiv)

0.03 ± 0.01^b

0.09 ± 0.01^a

**Table 3.** Mean scores for sensory attributes and Friedman test ranks for different preparations of herbal teas
Cassia flowers and buds tea (CFT)
All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).
	459	353	721
Colour	5.7 ± 1.1^a	4.4 ± 1.4^b	4.4 ± 1.4^b
Taste preference	5.9 ± 1.1^a	4.7 ± 1.3^b	3.8 ± 1.2^c
After taste	5.5 ± 1.0^a	4.7 ± 1.1^a	3.6 ± 1.1^b
Overall acceptance	5.3 ± 1.1^a	5.3 ± 1.2^a	3.3 ± 1.3^b
Willingness to drink regularly	5.2 ± 1.3^a	5.2 ± 1.3^a	3.5 ± 1.1^b
Friedman test mean rank	2.43	2.06	1.51
All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).
	824	276	599
Colour	5.8 ± 1.5^a	4.7 ± 1.1^b	4.8 ± 1.3^b
Taste preference	5.4 ± 1.1^a	3.7 ± 1.3^b	4.8 ± 1.0^c
After taste	5.6 ± 0.9^a	4.4 ± 1.1^b	5.3 ± 0.9^ab
Overall acceptance	5.2 ± 1.2^a	4.9 ± 1.4^a	5.0 ± 1.4^a
Willingness to drink regularly	5.3 ± 1.1^a	4.3 ± 1.0^b	4.8 ± 1.3^ac
Friedman test mean rank	2.26	1.87	1.87
All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).
	602	411	905
Colour	6.1 ± 1.5^a	5.2 ± 1.1^b	5.5 ± 1.3^b
Taste preference	5.9 ± 1.2^a	4.6 ± 1.3^b	3.7 ± 1.0^c
After taste	5.4 ± 1.2^a	4.4 ± 1.3^b	3.5 ± 1.4^c
Overall acceptance	5.6 ± 1.1^a	5.4 ± 1.3^a	3.8 ± 1.4^b
Willingness to drink regularly	5.5 ± 1.1^a	5.2 ± 1.0^a	4.3 ± 1.1^c
Friedman test mean rank	2.45	1.95	1.60

Table 3. Mean scores for sensory attributes and Friedman test ranks for different preparations of herbal teas

Cassia flowers and buds tea (CFT)

All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).

459

353

721

Colour

5.7 ± 1.1^a

4.4 ± 1.4^b

Taste preference

5.9 ± 1.1^a

4.7 ± 1.3^b

3.8 ± 1.2^c

After taste

5.5 ± 1.0^a

4.7 ± 1.1^a

3.6 ± 1.1^b

Overall acceptance

5.3 ± 1.1^a

5.3 ± 1.2^a

3.3 ± 1.3^b

Willingness to drink regularly

5.2 ± 1.3^a

3.5 ± 1.1^b

Friedman test mean rank

2.43

2.06

1.51

Jackfruit leaves tea (JLT)

All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).

824

276

599

Colour

5.8 ± 1.5^a

4.7 ± 1.1^b

4.8 ± 1.3^b

Taste preference

5.4 ± 1.1^a

3.7 ± 1.3^b

4.8 ± 1.0^c

After taste

5.6 ± 0.9^a

4.4 ± 1.1^b

5.3 ± 0.9^ab

Overall acceptance

5.2 ± 1.2^a

4.9 ± 1.4^a

5.0 ± 1.4^a

Willingness to drink regularly

5.3 ± 1.1^a

4.3 ± 1.0^b

4.8 ± 1.3^ac

Friedman test mean rank

2.26

1.87

Jackfruit leaves & Cassia flowers mixed tea (JCT)

All values are mean ± SD; n = 50; Values in each row having the same letter are not significantly different (p > 0.05).

602

411

905

Colour

6.1 ± 1.5^a

5.2 ± 1.1^b

5.5 ± 1.3^b

Taste preference

5.9 ± 1.2^a

4.6 ± 1.3^b

3.7 ± 1.0^c

After taste

5.4 ± 1.2^a

4.4 ± 1.3^b

3.5 ± 1.4^c

Overall acceptance

5.6 ± 1.1^a

5.4 ± 1.3^a

3.8 ± 1.4^b

Willingness to drink regularly

5.5 ± 1.1^a

5.2 ± 1.0^a

4.3 ± 1.1^c

Friedman test mean rank

2.45

1.95

1.60

**Table 4.** Total phenolic content and antioxidant activity (per 250 mL of serving) of test herbal teas
	Total phenolic content (µmol gallic acid equiv)	Trolox equivalent antioxidant capacity (µmol trolox equiv)
Values in each column having the same letters are not significantly different (p > 0.05).
Cassia flowers tea (CFT)	1843.9 ± 16.4^a	1880.8 ± 40.5^a
Jackfruit leaves + Cassia flowers tea (JCT)	1722.0 ± 14.8^b	421.6 ± 26.8^b
Jackfruit leaves tea (JLT)	670.1 ± 3.1^c	49.7 ± 2.5^c

Table 4. Total phenolic content and antioxidant activity (per 250 mL of serving) of test herbal teas

Total phenolic content (µmol gallic acid equiv)

Trolox equivalent antioxidant capacity (µmol trolox equiv)

Values in each column having the same letters are not significantly different (p > 0.05).

Cassia flowers tea (CFT)

1843.9 ± 16.4^a

1880.8 ± 40.5^a

Jackfruit leaves + Cassia flowers tea (JCT)

1722.0 ± 14.8^b

421.6 ± 26.8^b

Jackfruit leaves tea (JLT)

670.1 ± 3.1^c

49.7 ± 2.5^c

**Table 5.** Difference of postprandial plasma glucose response of healthy adults on herbal teas compared to the control
	0 min	30 min	45 min	60 min	90 min	120 min
Values are mean difference (SEM); n = 14; *Difference from control is significant (p < 0.05).
Cassia flowers tea (CFT)	−4.9 ( 3.8)	10.3 ( 7.2)	7.8 (7.9)	18.5 ( 7.3)	8.2 ( 7.4)	4.9 ( 5.1)
Jackfruit leaves tea (JLT)	−4.9 ( 4.2)	20.0* ( 9.4)	28.1* ( 7.8)	28.8* (5.5)	23.2* (3.8)	3.9 ( 3.2)
Jackfruit leaves + Cassia flowers tea (JCT)	−8.5 ( 3.6)	20.1* ( 6.7)	29.6 * ( 9.1)	31.7* (8.5)	16.2 ( 5.8)	2.4 ( 5.0)

Table 5. Difference of postprandial plasma glucose response of healthy adults on herbal teas compared to the control

0 min

30 min

45 min

60 min

90 min

120 min

Values are mean difference (SEM); n = 14; *Difference from control is significant (p < 0.05).

Cassia flowers tea (CFT)

−4.9 ( 3.8)

10.3 ( 7.2)

7.8 (7.9)

18.5 ( 7.3)

8.2 ( 7.4)

4.9 ( 5.1)

Jackfruit leaves tea (JLT)

−4.9 ( 4.2)

20.0* ( 9.4)

28.1* ( 7.8)

28.8* (5.5)

23.2* (3.8)

3.9 ( 3.2)

Jackfruit leaves + Cassia flowers tea (JCT)

−8.5 ( 3.6)

20.1* ( 6.7)

29.6 * ( 9.1)

31.7* (8.5)

16.2 ( 5.8)

2.4 ( 5.0)

**Table 6.** Plasma antioxidant capacity (µmol trolox equiv/L) of healthy adults at baseline and 120 min after ingestion of herbal teas
	Baseline	End (120 min after ingestion)	Difference between baseline and end	Percentage change (%) compared to baseline at the end
All values are mean ± SEM; n = 14; Values in each column with the same letter are not significantly different (p > 0.05); Values in each row having the same letter are not significantly different (p > 0.05). *Percentage increment of plasma antioxidant capacity of each tea compared to the respective baseline is significant (p > 0.05).
Control	206.9 ± 44.1^a	196.1 ± 43.5^a	−10.8	–
Jackfruit leaves tea (JLT)	237.7 ± 26.2^a	325.5 ± 54.2^b	87.8	37.7*
Cassia flowers tea (CFT)	207.7 ± 28.4^a	342.2 ± 36.0^b	134.5	67.0*
Jackfruit leaves + Cassia flowers tea (JCT)	204.8 ± 38.4^a	338.9 ± 64.4^b	134.1	71.1*

Table 6. Plasma antioxidant capacity (µmol trolox equiv/L) of healthy adults at baseline and 120 min after ingestion of herbal teas

Baseline

End (120 min after ingestion)

Difference between baseline and end

Percentage change (%) compared to baseline at the end

All values are mean ± SEM; n = 14; Values in each column with the same letter are not significantly different (p > 0.05); Values in each row having the same letter are not significantly different (p > 0.05). *Percentage increment of plasma antioxidant capacity of each tea compared to the respective baseline is significant (p > 0.05).

Control

206.9 ± 44.1^a

196.1 ± 43.5^a

−10.8

–

Jackfruit leaves tea (JLT)

237.7 ± 26.2^a

325.5 ± 54.2^b

87.8

37.7*

Cassia flowers tea (CFT)

207.7 ± 28.4^a

342.2 ± 36.0^b

134.5

67.0*

Jackfruit leaves + Cassia flowers tea (JCT)

204.8 ± 38.4^a

338.9 ± 64.4^b

134.1

71.1*