Phenolic compounds and the biological effects of Pu-erh teas with long-term storage

Figures & data

Table 1. Retention times, MS spectral characteristics, and identify of phenolic compound present in 15 Pu-erh teas.

Peak	Retention time (min)	Identified compounds	[M–H]^– (m/z)	MS^Citation2 (m/z)
1	1.184	Ethyl 3,4-dihydroxybenzoate	181.068	135.9104
2	1.299	Quinic acid	191.0559	127.0389
3	1.734	Purpurogallin	221.0256	113.0205
4	2.757	Unknown	151.0263	108.0209
5	4.053	Gallic acid	169.0147	125.0239
6	5.505	3-O-galloylquinic acid	343.0676	191.0557
7	9.511	GC	305.0668	167.0336, 165.0161
8	16.242	(Epi)theaflagalli	399.1055	275.1064, 110.0260
9	16.893	Unknown	194.0417	108.0464
10	17.505	Unknown	465.1066	331.0780, 245.0806
11	17.546	3-p-coumaroylquinic acid	337.0908	119.0500, 163.0387, 191.026
12	17.861	Caffeic acid	179.0580	135.0308, 164.0328, 107.0125, 122.0358
13	17.894	4-p-coumaroylquinic acid	337.0919	163.0035, 125.0259
14	17.973	C	289.0731	123.0450
15	18.155	EGC	305.0669	219.0645, 167.0348, 165.0212
16	18.142	(Epi)catechin(epi)catechin	577.1380	289.0709, 125.0231, 407.0747
17	18.400	(Epi)catechin(epi)catechin	577.1337	407.0780, 289.0716, 125.0247
18	18.7	Unknown	209.0636	137.0239
19	19.042	Unknown	545.1238	125.0365
20	19.313	Dihydromyricetin	319.0416	203.0337, 175.0404,137.0263, 109.0304
21	19.417	(Epi)catechin(epi)catechin	577.1279	289.0658, 407.0719, 125.0210
22	19.505	Unknown	465.103	331.0819, 205.0502, 123.0444, 179.0344
23	19.612	Unknown	361.0561	165.0189, 137.0289, 123.0463, 109.0307
24	19.975	3-caffeoylquinic acid	353.0872	191.0553, 179.0367, 173.0452, 135.0449
25	20.573	EG C G	457.0769	305.0606, 169.0136
26	20.963	Unknown C-glycosylated flavones	595.1636	475.1165, 383.0935, 355.0826
27	20.837	EC	289.0714	137.0241, 203.0678, 123.0446, 125.0238
28	21.764	5-p-coumaroylquinic acid	337.0926	191.0556, 173.0447, 163.0381
29	22.4	6,8-C-diglucosylapigenin	593.1544	473.1105, 413.0821, 383.0786, 353.0680
30	22.749	ECG	441.0857	289.0694, 169.0129
31	23.051	CG	441.0820	289.0701, 169.0141
32	23.575	6-C-arabinosyl-8-C-glucosyl apigenin	563.1396	473.1096, 443.0984, 413.0889, 383.0756, 353.0644
33	23.833	8-C-arabinosyl-6-C-glucosyl apigenin	563.1426
34	24.522	Myricetin 3-O-galactoside	479.0816	316.0220, 317.0247
35	24.756	Unknown	400.142	205.0505, 203.0691, 161.0599, 123.0452, 137.0218
36	24.917	Vitexin	431.0989	311.0553, 283.0599
37	24.736	2’-O-galloylhyperin	615.0925	463.0774, 301.0267
38	25.241	Unknown	400.1398	205.0496, 161.0599, 123.0492
39	25.315	Isovitexin	431.0996	311.0510, 283.0592
40	25.715	Apigenin 6,8-C-depentoside	533.1318	473.1049, 443.0953, 413.0793, 383.0763, 353.0643
41	25.961	Quercetin-3-O-dirhamnosylglucoside	755.1969	609.1176, 301.0321
42	26.147	Rutin	609.1448	301.0333
43	26.374	Ellagic acid	300.9992
44	26.831	Kaempferol-3-O-rhamnosyl-galactoside	593.1435	285.0354
45	27.137	Kaempferol-rhamnose-hexose-rhamnose conjugate	739.2004	593.1507, 285.0440
46	27.190	Myricetin	317.0309	151.0025, 137.0235, 109.0296
47	27.281	Kaempferol-3-O-rhamnosyl-glucoside	593.1440	285.0342
48	27.71	Unknown	401.0908	341.0692, 233.0438, 191.0344, 163.0375, 151.0396, 123.0452
49	29.379	Quercetin	301.0349	151.0033, 121.0297, 107.0141
50	29.902	Quercetin-3-O-p-coumaroyl-rhamnosyl-arabinosyl-hexoside	887.2237	741.1873,595.1124, 301.0348
51	30.332	Quercetin-3-O-p-coumaroyl-dirhamnosylhexoside	901.2346	755.1764, 609.1458, 301.0336
52	31.172	Kaempferol	285.0388
53	36.377	Trigalloylglucose	635.0416	112.9858

Table 2. IC₅₀ values of DPPH and ABTS assay of 15 Pu-erh teas.

Pu-erh tea type	Number	IC50 mmol TEAC/g
		DPPH	ABTS
Bowl tea	T1	2.12 ± 0.03	1.43 ± 0.08
	T2	2.08 ± 0.01	1.74 ± 0.06
	T3	1.83 ± 0.03	2.10 ± 0.10
Cake tea	P1	1.13 ± 0.01	2.07 ± 0.15
	P2	1.28 ± 0.02	1.97 ± 0.06
	P3	1.62 ± 0.01	2.67 ± 0.02
	P4	1.17 ± 0.01	1.40 ± 0.06
	P5	1.18 ± 0.01	1.36 ± 0.03
	P6	1.48 ± 0.00	1.90 ± 0.10
	P7	1.10 ± 0.01	1.27 ± 0.06
Brick tea	B1	1.79 ± 0.01	1.36 ± 0.13
	B2	1.95 ± 0.02	2.13 ± 0.04
	B3	1.44 ± 0.04	2.23 ± 0.12
	B4	0.99 ± 0.04	0.97 ± 0.02
	B5	1.74 ± 0.03	2.23 ± 0.14

Table 3. IC₅₀ values of MTT assay of 15 Pu-erh teas.

Pu-erh tea type	Number	IC50 μg/mL
Bowl tea	T1	508.88 ± 11.21
	T2	467.1 ± 7.56
	T3	96.94 ± 2.15
Cake tea	P1	384.62 ± 12.30
	P2	289.02 ± 7.06
	P3	160.12 ± 9.1
	P4	404.67 ± 19.41
	P5	191.09 ± 15.89
	P6	65.88 ± 3.53
	P7	154.39 ± 14.67
Brick tea	B1	477.87 ± 4.20
	B2	208.93 ± 7.34
	B3	250.15 ± 16.51
	B4	414.89 ± 19.36
	B5	163.18 ± 27.88

Figure 1. Effects of 15 Pu-erh tea extracts at various concentrations on relative viability of SMMC-7721 cells 24 h after treatment (n = 5).

Table 4. The contents of the total polyphenols, total flavonoids, total catechins, free amino acid, total soluble saccharides, purine alkaloids, and gallic acid.

Pu-erh tea	Number			mg/g DW
		Total polyphenols	Total flavonoids	Free amino acid	Total solublesaccharides	Gallic acid	Totalcatechins	Purinealkaloidal
Bowl tea	T1	47.02 ± 0.30^c	14.04 ± 0.61^ab	3.86 ± 0.25^bc	26.46 ± 1.86^ab	0.17 ± 0.01^ij	1.94	20.59
	T2	38.82 ± 0.44^ef	10.66 ± 0.32^g	3.88 ± 0.03^bc	21.76 ± 1.15^bc	0.60 ± 0.01^hi	1.43	18.69
	T3	58.92 ± 0.71^b	11.79 ± 1.40^cd	4.15 ± 0.14^a	22.47 ± 0.54^bc	10.12 ± 0.3^a	0.9	26.32
Cake tea	P1	29.66 ± 1.70^h	12.16 ± 0.67^cd	3.79 ± 0.04^cd	14.72 ± 3.12^d	1.41 ± 0.35^g	0.29	23.8
	P2	41.50 ± 0.49^de	12.29 ± 1.33^cd	3.67 ± 0.07^cd	27.64 ± 0.66^a	2.60 ± 0.34^e	1.15	26.55
	P3	63.91 ± 3.22^a	12.72 ± 1.08^bc	3.69 ± 0.01^cd	29.04 ± 4.12^a	5.81 ± 0.82^b	0.96	27.18
	P4	32.33 ± 1.73^h	14.26 ± 1.77^a	3.51 ± 0.19^ef	14.30 ± 1.32^d	0.28 ± 0.05^ij	0.89	28.29
	P5	25.76 ± 1.81^i	10.90 ± 0.37^fg	3.42 ± 0.07^g	6.20 ± 1.38^e	0.14 ± 0.02^j	0.43	26.45
	P6	37.56 ± 1.72^fg	12.86 ± 0.98^bc	3.87 ± 0.02^bc	22.26 ± 4.75^bc	1.51 ± 0.30^g	1.02	26.23
	P7	23.96 ± 1.09^i	11.25 ± 1.06^ef	3.58 ± 0.02^de	13.25 ± 1.31^d	0.91 ± 0.07^h	0.63	30.29
Brick tea	B1	25.21 ± 0.40^i	11.45 ± 0.41^de	3.90 ± 0.14^bc	13.83 ± 1.50^d	0.54 ± 0.08^hi	0.70	19.3
	B2	42.99 ± 1.81^d	13.02 ± 0.41^ab	4.04 ± 0.21^ab	21.42 ± 0.12^b	3.09 ± 0.72^d	0.73	21.90
	B3	35.34 ± 3.30^g	12.94 ± 0.311^ab	3.61 ± 0.15^de	28.75 ± 0.42^a	4.01 ± 0.19^c	0.98	23.46
	B4	17.34 ± 1.88^j	8.99 ± 1.41^h	3.45 ± 0.02^fg	6.16 ± 0.96^e	0.13 ± 0.01^j	0.27	22.94
	B5	64.33 ± 3.98^a	13.90 ± 0.34^ab	3.74 ± 0.02^cd	17.46 ± 1.23^cd	2.06 ± 0.26^f	0.72	23.7

The difference letter in the same row indicated that the difference among the tea samples is significantly through Duncan test (p < 0.05).

Table 5. Average contents of the main active compounds of Pu-erh tea at four different storage stages.

Storage time	Number of samples	mg/g DW
		total polyphenols	total flavonoids	gallic acid	total catechins
Short turn (10–30 year)	P5, P6, P7, T3	36.55 ± 16.08^a	11.70 ± 0.85^a	3.17 ± 4.66^a	0.75 ± 0.27^a
Middle turn (40–60 year)	B5, P4	48.33 ± 22.63^a	14.08 ± 0.25^a	1.17 ± 1.26^a	0.81 ± 0.12^a
Longer turn (70–90 year)	B3, B4, T1, T2, P1, P2, P3	39.08 ± 14.50^a	11.97 ± 1.66^a	2.10 ± 2.16^a	1.00 ± 0.60^a
Long turn (>100 year)	B1, B2	34.10 ± 12.57^a	12.24 ± 1.11^a	1.82 ± 1.80^a	0.72 ± 0.02^a

The letter “a” in the same row indicated that there is no significant difference among the tea samples (p > 0.05).

Table 6. Correlation coefficients between antioxidant and anticancer activities and the main active compound contents.

	Correlation coefficientof IC50 (DPPH)	Correlation coefficientof IC50 (ABTS)	Correlation coefficientof IC50 (MTT)
Total polyphenols	0.585*	0.770**	–0.399
Total flavonoids	0.321	0.467	–0.124
Gallic acid	0.257	0.666**	–0.561*
Total catechins	0.676**	0.136	0.251

Significant correlation by Student t-test.

*p < 0.05; **p < 0.01.

Fan, J.P.; Fan, C.; Dong, W.M.; Gao, B.; Yuan, W.; Gong, J.S. Free Radical Scavenging and Anti-Oxidative Activities of an Ethanol-Soluble Pigment Extract Prepared from Fermented Zijuan Pu-Erh Tea. Food and Chemical Toxicology 2013, 59, 527–533.

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