Effect of Ethanol/Water Solvents on Phenolic Profiles and Antioxidant Properties of Beijing Propolis Extracts

Table 1

Phenolics identified in propolis samples and their UV and MS characteristics.

	Phenolics	UV λmax (nm)	Mw	[M + H]^+	[M + Na]^+	Reference
1	3,4-Dihydroxybenzaldehyde	280, 311	138	139.0387	—	[11]
2	Vanillic acid	260, 292, 369	168	169.0489	—	[12]
3	Caffeic acid	322	180	181.0501	—	[11]
4	Vanillin	280, 309	152	153.0549	—	[12]
5	p-Coumaric acid	309	104	165.0548	187.0366	[11]
6	Ferulic acid	323	194	195.0655	217.0474	[11]
7	Isoferulic acid	303, 323	194	195.0657	217.0477	[11]
8	Benzoic acid	273	122	123.0437	—	[12]
9	3,4-Dimethoxycinnamic acid	321	208	209.0816	231.0638	[11]
10	Cinnamic acid	276	148	149.0234	—	[11]
11	4-Methoxycinnamic acid	230, 309	178	179.0700	201.0509	[12]
12	Cinnamylideneacetic acid	311	174	175.0758	—	[11]
13	Benzyl caffeate	232, 328	270	—	293.0792	[11]
14	Phenethyl caffeate	301, 328	284	285.1122	307.0948	[11]
15	Benzyl p-coumarate	232, 313	254	255.0660	277.0482	[11]
16	Cinnamyl cinnamate	328	296	—	319.0946	[11]
17	5-Methoxy pinobanksin	232, 287	286	287.092	309.0741	[11]
18	Pinobanksin	291	272	273.076	295.0585	[11]
19	Quercetin	292, 365	302	303.0502	325.032	[11]
20	Alpinetin	286	270	271.0972	293.0795	[11]
21	Kaempferol	266, 296, 366	286	287.0554	309.0375	[11]
22	Apigenin	267, 338	270	271.064	—	[11]
23	Isorhamnetin	293, 370	316	317.0665	339.0489	[11]
24	Pinocembrin	290	256	257.0816	—	[11]
25	Pinobanksin-3-O-acetate	294	314	315.0868	337.0688	[11]
26	Chrysin	268, 313	254	255.0663	277.0844	[11]
27	Galangin	264, 357	270	271.0955	—	[11]
28	Pinostrobin	289	270	271.0974	293.0787	[12]
29	Tectochrysin	268, 311	268	269.0817	291.0635	[12]

Note: —: not detected.