Table 2.

Different chemical components of three species of rhubarb identified in negative ion mode.

Nol.	R.T. (min)	Mass (m/z)	Name	Formula	MS/MS	VIP	P
1	7.56	566.1958	4-(4-Hydroxyphenyl)-2-butanone O-[2,6-digalloylglucoside]	C30H30O15	[M-H]−	1.15	≤0.001
2	28.32	205.1603	(-)-Epicatechin	C15H14O6	[M-H]−	1.20	≤0.001
3	6.53	886.1869	(-)-Epicatechin gallate	C22H18O10	[M-H]−	1.24	≤0.001
4	15.05	939.1112	Pentagalloylglucose	C41H32O26	[M-H]−	1.21	≤0.001
5	19.17	255.0692	5,8-Dihydroxyflavanone	C15H12O4	[M-H]−	1.12	≤0.001
6	4.73	390.1415	7,12-Dioxo-5a-cholan-24-oic acid	C24H36O4	[M-H]−	1.11	≤0.001
7	2.32	189.0554	7-Ethoxycoumarin	C11H10O3	[M-H]−	1.05	0.02
8	10.08	311.0567	Aloe emodin	C17H12O6	[M-H]−	1.46	0.01
9	17.36	609.1686	Apiin	C26H28O14	[M-H]−	1.14	≤0.001
10	6.94	951.1323	Cassiaside	C20H20O10	[M-H]−	1.23	≤0.001
11	6.11	883.1701	Catechin gallate	C22H18O10	[M-H]−	1.24	≤0.001
12	27.79	239.0714	Chrysarobin	C15H12O3	[M-H]−	1.07	≤0.001
13	22.68	239.0713	Chrysophanic acid 9-anthrone	C15H12O3	[M-H]−	1.35	0.02
14	11.07	729.1464	Ent-Epicatechin-(4alpha->8)-ent-epicatechin 3-gallate	C37H30O17	[M-H]−	1.25	≤0.001
15	3.64	273.0768	(-)- (2R,3R) Epiafzelechin	C15H14O5	[M-H]−	1.03	0.02
16	19.63	191.0715	Ethyl-p-coumarate	C11H12O3	[M-H]−	1.11	0.04
17	20.04	443.0992	Formononetin 7-O-glucuronide	C21H18O10	[M-H]−	1.11	0.02
18	7.52	125.0251	Gallic acid	C7H6O5	[M-H]−	1.16	≤0.001
19	1.32	602.0134	Gallic-acid-O-galloyl-glucoside	C20H20O14	[M-H]−	1.13	≤0.001
20	26.92	161.0622	Glabranine	C20H20O4	[M-H]−	1.34	≤0.001
21	28.20	255.0662	Isoliquiritigenin	C15H12O4	[M-H]−	1.29	0.02
22	5.58	189.0562	Kaempferol	C15H10O6	[M-H]−	1.02	≤0.001
23	8.04	835.2391	Liquiritin	C21H22O9	[M-H]−	1.11	≤0.001
24	6.78	575.1085	Procyanidin B1	C30H26O12	[M-H]−	1.06	≤0.001
25	2.58	1155.2755	Procyanidin B2	C30H26O12	[M-H]−	1.12	0.03
26	15.03	945.1180	Procyanidin B-2,3,3′-di-O-gallate	C44H34O20	[M-H]−	1.23	≤0.001
27	4.67	730.1512	Procyanidin B4	C30H26O12	[M-H]−	1.29	≤0.001
28	4.67	729.1479	Procyanidin B5	C30H26O12	[M-H]−	1.30	≤0.001
29	8.82	727.0850	Procyanidin B-5,3,3′-di-O-gallate	C44H34O20	[M-H]−	1.03	≤0.001
30	4.89	867.2121	Procyanidin C1	C45H38O18	[M-H]−	1.13	0.01
31	5.05	440.1660	Prunin	C21H20O11	[M-H]−	1.39	≤0.001
32	22.17	549.1775	Quercetin-3-(6″-malonyl)-glucoside	C24H22O15	[M-H]−	1.18	≤0.001
33	11.23	462.1145	Quercetin-3,4′-O-di-beta-glucopyranoside	C27H30O17	[M-H]−	1.10	0.01
34	27.06	610.2032	Vincetoxicoside A	C27H30O16	[M-H]−	1.24	≤0.001
35	6.09	980.1351	Resveratrol-4′-O-(6″-galloyl)-b-d-glucopyranoside	C27H26O12	[M-H]−	1.03	≤0.001
36	19.37	696.1174	Sennoside A	C42H38O20	[M-H]−	1.06	≤0.001
37	28.22	247.1000	Torachrysone 8-glucoside	C20H24O9	[M-H]−	1.07	≤0.001
38	3.13	179.0350	Trans-2,3-Dihydroxycinnamate	[C9H7O4]−	[M-H]−	1.08	0.01