Comparison of Chemical Compositions and Antioxidant Activities of Fresh and Dried Rosa roxburghii Tratt Fruit

Abstract

Fresh fruit of Rosa roxburghii Tratt has attracted great interest and is used in many functional products in China. However, fresh fruits are perishable products with quite short shelf lives and few studies have focused on dried fruits. Therefore, this study aimed to explore whether the drying process can be used to preserve bioactive components of R roxburghii fruits by comparing phytochemical profiles and antioxidant activities between fresh and dried fruit. As result, a total of 95 compounds, mainly including organic acids, phenols, and flavonoids, were identified in fresh and dried fruits by using ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry. The relative quantitative result showed that contents of phenols and acylamide were significantly higher (p < .05) in dried fruit. Furthermore, dried fruit showed stronger antioxidant activity by using 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability and ferric reducing antioxidant power. This research suggested that dried R roxburghii fruit could be considered a more effective and economical health and functional source for functional food and industry.

Keywords

ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-ToF/MS)fresh and dried fruits antioxidant activities chemical constituents

Introduction

Rosa roxburghii Tratt is mainly found in the south and southwest of China. Over recent decades, many research studies have shown that the fruit of R roxburghii owns significant radiation protection, antitumor, antioxidant, and antiinflammatory properties. It has been widely used in functional foods and cosmetic products. These health benefits are attributable to the biologically active components, including L-ascorbic acid, superoxide dismutase, flavonoids, phenols, polysaccharides, organic acids, and amino acids.¹ However, fresh fruit can only be stored for up to 15 days at room temperature because of high respiration and water loss rates after harvest.² Furthermore, common low-temperature storage techniques are expensive and need specialized equipment, which has limitations in some areas.³ Hence, an appropriate drying method is a suitable alternative to reduce the loss and preserve the fruit quality. Drying process could reduce moisture, weight, and volume of fresh materials, largely increasing their shelf-life and facilitating their transportation in a mountainous area.⁴

According to previous studies, drying can lead to composition changes, such as degradation of the total polyphenolic compounds, carotenoids, and total anthocyanin content.^5,6 To date, there are few in-depth studies on the active components of dried R roxburghii fruit. And, in previous studies, components in the dried fruits were mainly evaluated by high-performance liquid chromatography with diode-array detection, refractive index detector, ultraviolet spectrophotometer, and atomic absorption spectrophotometer.^7–9 However, these methods are either time-consuming or have low sensitivity. In recent years, ultrahigh-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-ToF/MS) has been widely used to identify constitutions in complex extract due to its high sensitivity, selectivity, and separation efficiency.¹⁰

To explore the effect of drying on the composition and efficacy of fruits, in this paper, the components of fresh and dried R roxburghii fruits were identified and compared by using UHPLC-Q-ToF/MS. Besides, in vitro antioxidant activity was also investigated by using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•) scavenging ability and ferric reducing antioxidant power (FRAP).

Results and Discussions

Component Difference Between Fresh and Dried R roxburghii Fruits by Using UHPLC-Q-ToF/MS

In this study, a total of 95 compounds were identified in 2 fruits. The representative chromatographs and information on identified compounds are shown in Figure 1 and Table 1, respectively.

Figure 1.

Representative base peak chromatograms (BPCs) of Rosa roxburghii fruits: (A, B) BPCs of fresh and dried fruits in positive mode. (C, D) BPCs of fresh and dried fruits in negative mode.

Table 1.

Compounds Identified in the Rosa roxburghii Fruit Extracts.

No.	Rt (min)	Molecular formula	Selected ion	Experimentalm/z	MS/MS ions	Identification	Chemical type	Source
1	0.77	C₆H₁₄N₄O₂	[M + H]⁺	175.1186	158.0927, 130.0978, 116.0807	Arginine	Amino acid	FF, DF
2	0.85	C₁₇H₁₆O₁₀	[M + H]⁺	381.0781	321.0262, 263.0784, 245.0657, 130.0856, 118.0862	1,1′-(1,3-Propanediyl) bis(34,5-trihydroxybenzoate)	Phenol	FF, DF
3	0.89	C₆H₁₂O₆	[M − H]⁻	179.0557	161.0454, 149.0451, 125.0241, 119.0334, 89.0224, 71.0140, 59.0143	Glucose	Monosaccharide	FF
4	0.91	C₁₂H₂₂O₁₁	[M − H]⁻	341.1082	179.0567, 119.0354, 89.0249	Sucrose	Disaccharide	FF
5	0.92	C₆H₈O₆	[M + H]⁺	177.0392	141.0182, 129.0182, 113.0233	Ascorbic acid	Organic acid	FF, DF
6	0.93	C₄H₈O₅	[M − H]⁻	135.029	117.0194, 89.0246, 75.0092	Threonic acid	Small molecule organic acid	FF
7	0.93	C₇H₁₂O₆	[M − H]⁻	191.0561	173.0446, 127.0381, 85.0724	Quinic acid	Small molecule organic acid	FF, DF
8	0.93	C₅H₁₀O₆	[M − H]⁻	165.0394	147.0287, 135.6368, 129.0191, 75.0088	Xylonic acid	Small molecule organic acid	FF, DF
9	0.97	C₅H₁₁NO₂	[M + H]⁺	118.0851	72.0809, 59.0493, 43.0546	Valine	Amino acid	FF, DF
10	1.01	C₆H₈O₇	[M − H]⁻	191.0173	173.0071, 129.0166, 111.0066, 85.0276	Citric acid	Small molecule organic acid	FF, DF
11	1.07	C₅H₅N₅	[M + H]⁺	136.0617	119.0353, 92.0245, 81.0700	Adenine	Nucleobases	FF, DF
12	1.1	C₁₂H₁₆O₁₂	[M − H]⁻	351.0571	157.0120, 127.0018, 115.0014, 87.0068	4-O-(4-Deoxy-α-L-erythro-hex-4- enopyranuronosyl)-α- L-gulopyranuronic acid	Organic acid	FF
13	1.14	C₄H₆O₅	[M − H]⁻	133.0132	115.0013, 89.0223, 71.0117	Malic acid	Small molecule organic acid	FF, DF
14	1.2	C₂₀H₁₈O₁₄	[M − H]⁻	481.0608	445.5222, 300.9963, 275.0181	2,3-(S)-hexahydroxydiphenoyl-D-glucose	Organic acid	FF, DF
15	1.21	C₆H₈O₇	[M − H]⁻	191.0176	173.0066, 154.9971, 111.0063, 87.0064	Isocitric acid	Small molecule organic acid	FF, DF
16	1.22	C₉H₁₁NO₃	[M + H]⁺	182.081	165.0442, 147.0335, 136.0656	Tyrosine	Amino acid	FF, DF
17	1.25	C₁₂H₂₃NO₇	[M + H]⁺	294.1538	276.1446, 258.1338, 248.1497, 230.1391, 212.1277, 88.0394	Fructose-leucine	Amino acid	FF, DF
18	1.3	C₁₃H₁₆O₁₀	[M − H]⁻	331.0657	169.0127, 125.0225,	Galloyl-glucose	Phenol	FF, DF
19	1.39	C₆H₁₃NO₂	[M + H]⁺	132.1019	115.0744, 105.0698	Isoleucine or isomer	Amino acid	FF, DF
20	1.45	C₇H₆O₅	[M − H]⁻	169.0145	151.0018, 125.0243, 107.0133, 97.0293	Gallic acid	Phenolic acid	FF, DF
21	1.5	C₆H₁₃NO₂	[M + H]⁺	132.1019	115.0744, 105.0698	Isoleucine or isomer	Amino acid	FF
22	1.55	C₉H₁₈N₂O₃	[M + H]⁺	203.1385	185.0429, 162.1020, 86.0963	L-Alanyl-L-leucine	Amino acid	FF, DF
23	1.67	C₁₂H₁₄O₉	[M + H]⁺	303.0709	285.0594, 267.0495, 257.0647, 127.0382	β-D-Glucopyranosiduronic acid, 2,3-dihydroxyphenyl	Phenol	FF, DF
24	1.72	C₅H₆O₃	[M + H]⁺	115.0385	87.0483, 59.0491, 43.0180	β-Acetylacrylic acid	Organic acid	FF, DF
25	1.79	C₁₀H₂₀N₂O₃	[M + H]⁺	217.154	121.0505, 86.0599, 72.0808	L-valine anhydride	Small molecule organic acid	DF
26	1.89	C₁₅H₂₁NO₇	[M + H]⁺	328.1393	310.1279, 292.1175, 264.1217, 246.1116, 178.0856	Fructose-phenylalanine	Small molecule organic acid	DF
27	2.05	C₉H₁₁NO₂	[M + H]⁺	166.086	149.0592, 131.0484, 120.0804, 107.0485, 103.0537	Phenylalanine	Amino acid	FF, DF
28	2.3	C₇H₆O₄	[M − H]⁻	153.0191	123.0449, 109.0296, 81.0351,	Protocatechuic acid	Phenolic acid	FF, DF
29	2.34	C₂₇H₂₂O₁₈	[M − H]⁻	633.0737	481.0609, 463.0512, 343.0098, 300.9990, 275.0192, 169.0136, 125.0237	Galloyl-hexahydroxydiphenoyl-glucose or isomer	Phenolic acid	FF, DF
30	2.39	C₉H₈O₅	[M − H]⁻	195.0295	179.0346, 165.0198, 151.0405, 123.0455	3,4,5-Trihydroxycinnamic acid	Phenolic acid	FF
31	2.44	C₁₅H₁₄O₆	[M + H]⁺	291.1071	273.0753, 237.1110, 209.1177, 153.0524	Catechin or isomer	Flavone	FF, DF
32	2.63	C₁₁H₂₀N₂O₃	[M + H]⁺	229.1543	211.0513, 190.0498, 167.0704, 116.0704, 86.0963, 70.0648	Leucylproline	Amino acid	DF
33	2.63	C₂₀H₂₀O₁₀	[M + H]⁺	421.1127	403.1020, 385.0921, 357.0970, 271.0609	3,4′,5′,6,8-Penta-Me ether-3, 3′,4′,5,5′,67,8-Octahydroxyflavone	Flavone	FF, DF
34	2.65	C₃₀H₂₆O₁₂	[M − H]⁻	577.136	407.0776, 339.0887, 289.0720, 245.0824, 161.0241, 125.0245	Procyanidin B1 or isomer	Flavone	FF, DF
35	2.75	C₃₀H₂₆O₁₂	[M + H]⁺	579.1491	561.1391, 427.1028, 409.0917, 291.0866, 289.0705	Procyanidin B1 or isomer	Flavone	FF, DF
36	2.8	C₃₀H₂₆O₁₂	[M − H]⁻	577.136	407.0776, 339.0887, 289.0720, 245.0824, 161.0241, 125.0245	Procyanidin B1 or isomer	Flavone	FF, DF
37	2.82	C₁₅H₂₀O₄	[M + H]⁺	265.1432	247.1333, 229.1210, 201.1260, 187.1107	Abscisic acid	Organic acid	FF, DF
38	2.82	C₂₃H₃₀O₁₀	[M + H]⁺	467.1892	305.0657, 287.1223, 259.0595, 153.0618	2-(4-Hydroxyphenyl)ethyl (2S,3E,4R)-3- ethylidene-2-(β-D- glucopyranosyloxy)-3,4-dihydro-2H-pyran-4-acetate	Ester	FF, DF
39	2.9	C₃₀H₂₆O₁₂	[M + H]⁺	579.1491	561.1391, 427.1028, 409.0917, 291.0866, 289.0705	Procyanidin B1 or isomer	Flavone	FF, DF
40	2.9	C₁₅H₁₂O₆	[M + H]⁺	289.0706	259.0598, 179.0329, 163.0390, 151.0382, 149.0235, 139.0390, 135.0436	Eriodictyol or isomer	Flavone	FF, DF
41	2.9	C₁₃H₁₆O₉	[M + H]⁺	317.0872	299.0762, 253.0684, 141.0543	2,6-anhydro-1-O-(34,5-trihydroxybenzoyl)-D-mannitol or isomer	Phenolic acid	FF
42	2.9	C₁₁H₁₂N₂O₂	[M + H]⁺	205.0971	188.0700, 159.0912, 146.0600	Tryptophan	Amino acid	FF, DF
43	2.93	C₁₅H₁₈O₉	[M − H]⁻	341.0879	179.0352, 135.0452	Caffeic acid hexoside	Organic acid	FF
44	2.96	C₂₇H₂₂O₁₈	[M − H]⁻	633.0737	481.0609, 463.0512, 343.0098, 300.9990, 275.0192, 169.0136, 125.0237	Galloyl-hexahydroxydiphenoyl-glucose or isomer	Phenolic acid	FF, DF
45	2.98	C₁₃H₁₆O₉	[M + H]⁺	317.0865	299.0762, 253.0684, 141.0543	2,6-anhydro-1-O-(34,5- trihydroxybenzoyl)-D-mannitol or isomer	Phenolic acid	FF
46	3	C₂₁H₂₀O₁₂	[M + H]⁺	465.1027	303.0124	Isoquercetin	Flavone glycoside	FF, DF
47	3	C₃₀H₂₆O₁₁	[M + H]⁺	563.155	427.1002, 411.1053, 393.0955, 291.0852, 273.0753, 255.0624	Epiafzelechin-(4β→8)-epicatechin or isomer	Flavone	FF, DF
48	3	C₄₅H₃₈O₁₈	[M + H]⁺	867.2134	579.1528, 425.0884, 409.0947, 397.0918, 289.0717	Procyanidin C₁	Flavone	FF, DF
49	3	C₁₅H₁₄O₆	[M − H]⁻	289.072	247.0248, 191.0349, 173.0242, 151.0398, 145.1096, 123.0296, 109.0294	Catechin or isomer	Flavone	FF, DF
50	3.04	C₇H₆O₃	[M + H]⁺	139.0387	111.0435, 93.0331, 72.9352, 65.0377, 56.9644	4-Hydroxybenzoic acid	Phenolic acid	FF, DF
51	3.07	C₁₃H₈O₈	[M − H]⁻	291.0149	247.0240, 219.0294, 191.0344	Brevifolincarboxylic acid	Phenolic acid	FF
52	3.1	C₁₅H₂₀O₄	[M + H]⁺	265.1429	247.1330, 229.1219, 217.1225, 201.1268, 187.1119	Abscisic acid	Organic acid	FF, DF
53	3.17	C₁₅H₁₄O₆	[M + H]⁺	291.1071	273.0753, 237.1110, 209.1177, 153.0524	Catechin or isomer	Flavone	FF
54	3.2	C₄₅H₃₈O₁₈	[M + H]⁺	867.2126	579.1475, 289.0709	Procyanidin C₁	Flavone	FF, DF
55	3.2	C₂₁H₂₀O₁₂	[M + H]⁺	465.1021	303.0501	Isoquercetin	Flavone glycoside	FF, DF
56	3.2	C₁₅H₁₂O₆	[M + H]⁺	289.0705	259.0598, 179.0329, 163.0390, 151.0382, 149.0235, 139.0390, 135.0436	Eriodictyol	Flavone	FF, DF
57	3.38	C₉H₈O₃	[M + H]⁺	165.0543	147.0438, 123.0389, 119.0484	p-Hydroxy-cinnamic acid	Phenolic acid	FF, DF
58	3.38	C₁₇H₁₆O₈	[M + H]⁺	349.0895	303.0883, 289.9267	Dryopteric acid	Flavone	FF, DF
59	3.39	C₂₀H₁₈O₉	[M − H]⁻	401.0878	301.0696, 289.0699, 203.0703, 151.0394, 137.0236, 109.029	(Epi)catechin derivative	Flavone	FF, DF
60	3.4	C₄₅H₃₈O₁₈	[M + H]⁺	867.2107	579.1475, 289.0709	Procyanidin C₁	Flavone	FF, DF
61	3.4	C₉H₈O₃	[M + H]⁺	165.0545	147.0389, 123.0389, 119.0441	p-Hydroxy-cinnamic acid or isomer	Phenolic acid	FF, DF
62	3.45	C₂₁H₁₀O₁₃	[M − H]⁻	469.005	300.9978, 270.9899,	Flavogallonic acid	Phenol	FF, DF
63	3.5	C₃₀H₂₆O₁₁	[M + H]⁺	563.155	427.1002, 411.1053, 393.0955, 291.0852, 273.0753, 255.0624	Epiafzelechin-(4β→8)-epicatechin or isomer	Flavone	FF
64	3.5	C₄₅H₃₈O₁₈	[M + H]⁺	867.2122	579.1475, 289.0709	Procyanidin C₁	Flavone	FF, DF
65	3.55	C₃₀H₂₆O₁₂	[M − H]⁻	577.136	407.0776, 339.0887, 289.0720, 245.0824, 161.0241, 125.0245	Procyanidin B1 or isomer	Flavone	FF, DF
66	3.57	C₁₅H₁₄O₆	[M − H]⁻	289.0719	271.0618, 245.0817, 189.0527, 151.0398,	Catechin or isomer	Flavone	FF, DF
67	3.73	C₂₁H₂₀O₁₂	[M + H]⁺	465.1025	303.0501	Isoquercetin	Flavone glycoside	FF
68	3.75	C₃₀H₂₆O₁₂	[M + H]⁺	579.1491	561.1391, 427.1028, 409.0917, 291.0866, 289.0705	Procyanidin B1 or isomer	Flavone	FF, DF
69	3.8	C₃₇H₃₀O₁₆	[M − H]⁻	729.1458	407.0780, 289.0729, 169.0149, 125.0251	Gallocatechin-(4α->8)-catechin	Flavone	FF, DF
70	3.8	C₂₁H₂₈O₈	[M + H]⁺	409.1831	247.1299, 203.0518, 185.0409	Vernoflexuoside	Sesquiterpene	FF, DF
71	3.82	C₄₀H₅₈O₁₆	[M + H]⁺	795.3782	409.1838, 303.0141	6-[6-carboxy-2-[(11-carboxy-6a, 6b,8a,11,14b-pentamethyl-14-oxo-1,2,3,4,4a,5,6,7,8,9,10, 12,12a,14a-tetradecahydropicen-3-yl)oxy]-4,5- dihydroxyoxan-3-yl]oxy-34,5-trihydroxyoxane-2-carboxylic acid	Triterpenoid glycoside	FF, DF
72	4.15	C₁₁H₂₀O₂	[M + Na]⁺	207.1375*	189.1264, 161.1318, 149.0954, 147.1163, 135.1162, 123.0799	Xi-γ-Undecalactone	Ester	FF, DF
73	4.16	C₂₀H₁₆O₁₂	[M − H]⁻	447.0573	300.9978, 216.0062	Ellagic acid-4-O-L-rhamnoside	Flavone glycoside	FF
74	4.27	C₁₉H₂₈O₁₀	[M + H]⁺	417.1735	249.0392, 231.1697	Phenethanol β-vicianoside	Alcohol	FF, DF
75	4.32	C₁₄H₆O₈	[M − H]⁻	300.9997	283.9963, 254.9928, 229.0142, 201.0192, 173.0245, 145.0296	Ellagic acid	Phenol	FF, DF
76	4.78	C₂₆H₃₆O₁₁	[M + H]⁺	525.231	363.1355, 335.0924	Secoisolariciresinol 4-O-β-D-glucopyranoside	Lignan	FF, DF
77	4.82	C₂₇H₂₈O₁₆	[M − H]⁻	607.1309	463.0876, 300.0274, 289.5069, 271.0246, 151.0040	Quercetin 3-O-[(X-O- 3-hydroxy-3-methylglutaryl)-β-glucoside]	Flavone glycoside	FF, DF
78	5.17	C₂₇H₂₈O₁₅	[M − H]⁻	591.1358	529.1361, 489.1044, 447.0942, 285.0418	Kaempferol 3-O-[(X-O-3-hydroxy-3- methylglutaryl)-β-glucoside] or isomer	Flavone glycoside	FF
79	5.37	C₂₇H₂₈O₁₅	[M − H]⁻	591.1358	529.1361, 489.1044, 447.0942, 285.0418	Kaempferol 3-O-[(X-O-3- hydroxy-3-methylglutaryl)-β- glucoside] or isomer	Flavone glycoside	FF
80	5.66	C₁₁H₂₂O₂	[M + Na]⁺	209.1531*	191.1424, 165.1269, 149.1323, 135.0796	Methyl decanoate	Ester	FF, DF
81	6.46	C₃₀H₂₆O₁₃	[M − H]⁻	593.1303	447.0952, 284.0328, 255.0298, 145.0302	Kaempferol-3-O-b-D-(6″- (E)-p-coumaroyl)-glucopyranoside	Flavone glycoside	FF, DF
82	6.53	C₁₅H₁₀O₇	[M − H]⁻	301.0355	257.1551, 203.0169, 178.9988, 151.0036, 121.0295	Quercetin	Flavone	FF, DF
83	6.56	C₂₁H₂₈O₉	[M + H]⁺	425.1802	407.1689, 389.1589, 371.1485, 263.1274, 245.1167, 233.1168, 215.1062	Crepidiaside B	Sesquiterpene	FF
84	6.56	C₂₁H₂₆O₈	[M + H]⁺	407.1706	389.1586, 371.1487, 245.1171	Threo-guaiacylglycerol-sinapyl ether	Lignan	FF
85	6.81	C₃₃H₃₆O₁₁	[M + H]⁺	609.2304	414.1636, 217.0837, 203.0667, 189.0511	2′¢¢-O-Cinnamoyloregonin	Phenolic acid	FF, DF
86	6.91	C₃₈H₅₆O₁₁	[M + H]⁺	689.3877	527.3356, 185.0410	(4R)-4-[(3S,7R,8R,9S,10S,13R,14S,17R)-7-Hydroxy-3-(4- methoxybenzoyl)-10,13-dimethyl-3-[(3R,4S,5S,6R)-34,5-trihydroxy- 6-(hydroxymethyl) oxan-2-yl]oxy-1,2,4,5,6,7,8,9,11,12,14,15,16,17- tetradecahydrocyclopenta[a]phenanthren-17-yl]pentanoic acid	Steroidal glycoside	FF, DF
87	7.31	C₃₆H₅₈O₁₀	[M+COOH]⁻	695.4012^#	649.3947, 487.3430	Kaji-ichigoside F1 or its isomer	Triterpenoid glycoside	FF, DF
88	7.43	C₃₆H₅₈O₁₀	[M + COOH]⁻	695.4012^#	649.3947, 487.3430	Kaji-ichigoside F1 or its isomer	Triterpenoid glycoside	FF, DF
89	7.58	C₃₆H₅₈O₁₀	[M + COOH]⁻	695.4012^#	649.3947, 487.3430	Kaji-ichigoside F1 or its isomer	Triterpenoid glycoside	FF, DF
90	8.05	C₃₈H₅₆O₁₀	[M + H]⁺	673.3933	511.338	Chol-4-en-6-one, 3-(β-D-glucopyranosyloxy)- 20-hydroxy-16-(6-methoxy-3-oxo-1,5- cyclohexadien-1-yl)-23-methyl-, (20ξ)-(9CI)	Steroidal glycoside	FF, DF
91	8.44	C₃₆H₅₆O₁₀	[M + H]⁺	671.3792	509.3234	Oligoporin C	Triterpenoid glycoside	FF, DF
92	9.35	C₃₀H₄₆O₅	[M − H]⁻	485.3272	467.3164, 425.3049, 375.3079	2α,19α-Dihydroxy-3-oxo-urs-12-en-28-oic acid or isomer	Triterpenoid	FF, DF
93	9.65	C₃₀H₄₈O₅	[M − H]⁻	487.3429	469.3320, 443.3518, 423.3228, 407.3309, 371.2963	Euscaphic acid or isomer	Triterpenoid	FF, DF
94	10.68	C₃₀H₄₆O₅	[M − H]⁻	485.3272	467.3156, 425.3061, 375.3079	2α,19α-Dihydroxy-3-oxo-urs-12-en-28-oic acid or isomer	Triterpenoid	FF
95	10.78	C₁₆H₂₅NO	[M + H]⁺	248.2018	230.1886, 194.1530, 180.1378, 175.1104, 167.1298, 152.1066, 81.0698, 72.0806, 57.0700	(2E,4E,8Z,10Z)-Nisobutyl-dodeca-2,4,8,10-tetraenamide or isomer	Acylamide	DF

Abbreviations: FF, fresh fruit extract; DF, dried fruit extract.

Organic acids were the most abundant components in R roxburghii.^10,11 In the present study, 10 compounds (5-8, 10, 12, 15, 24-25, 43) were annotated as organic acids. Among them, compound 5 was identified as L-ascorbic acid by comparing the MS and MS² data with standard (Figure S1A). Other 9 compounds were identified by comparing the molecular formula of the deprotonated molecule [M + H]⁺ and [M − H]⁻ and neutral loss (H₂O, HCOOH, CO₂, and glucosyl groups) during fragmentation to previous reports.^10,12

Flavonoids also were important constituents.¹⁰ Thirty-one compounds were identified as flavonoids (31, 33, 34-36, 39, 40, 46-49, 53 −56, 58-60, 63-69, 73, 77-79, 81, 82) in fresh and dried fruits. Compounds 36, 40, 46, 49, and 82 were identified as procyanidin B1, eriodictyol, isoquercitrin, catechin, and quercetin, respectively, by comparing with the reference standards (Figure S1C-F and H). And, compounds 31, 53, and 66 were tentatively identified as catechins and their isomers, while compounds 34, 35, 39, 47, 59, 63, 65, 68, 69, and 77, which contained catechin unit, were further identified by comparing with database and previous reports.^10,11 Furthermore, compounds 48, 54, 58, 60, and 64 could generate procyanidin B1 and eriodictyol unit, and compounds 55 and 67 contained a quercetin unit in MS² spectra, which were characteristic ions and as a basis of identification.^10,13,14

Compounds 1, 16, 17, 19, 21, 27, and 32 were identified as amino acids. The characteristic fragment ions were produced by neutral losses of H₂O, HCOOH, and NH₃ groups. For example, compound 27 with protonated [M + H]⁺ ion at m/z 166.08, suggests the molecular formula of C₉H₁₁NO₂. Fragment ions at m/z 149.05, 131.04, 120.08 correspond to the neutral losses of NH₃, H₂O, and HCOOH groups. Then, by referring to the literature, it was identified as phenylalanine—an essential amino acid (Figure S1B).^10,15

Seventeen phenols, including 2, 18, 20, 23, 28, 29, 30, 41, 44, 45, 50, 51, 57, 62, 73, 75, and 85, were annotated. Among them, compound 75 was identified as ellagic acid by comparing to standard (Figure S1G). In addition, compounds 29, 44, 62, and 73 produced base peak ions at m/z 300.99 in MS² spectra, which indicated an ellagic acid unit. Finally, these compounds were further identified by comparing to a database and previous reports.⁷

Compound 87 was identified as Kaji-ichigoside F1 comparing to standard (Figure S1I, which was a characteristic and main triterpenoid in R roxburghii fruit. Compounds 71, 88, 89, 91-94, 70, and 83 yield characteristic ions (neutral losses of glucosyl group, H₂O, and HCOOH groups) in MS/MS spectra and were identified as triterpenoids and sesquiterpenes.¹⁰ Compound 95 was identified as an acylamide. It showed [M + H]⁺ at m/z 248.20, [M + Na]⁺ at 270.18 in MS spectra, and produced MS/MS ions at m/z 230.18, 175.11, 167.12, 152.10, 81.06, 72.08, and 57.07 (Figure S1J). Then, it was tentatively identified as (2E,4E,8Z,10Z)-nisobutyl-dodeca-2,4,8,10-tetraenamide or an isomer.¹⁶

The chemical profiles were quite similar between fresh and dried fruits (Table 1). More specifically, L-ascorbic acid, flavonoids, and phenols, which contribute more to the antioxidant activities, were identified in both fresh and dried fruits. These results indicated that functional components might be preserved in the dried fruit. However, considering the antioxidant capacity was influenced by not only component difference but also their amount, it is still necessary to know the difference in the content of these components between fresh and dried fruits.

Component Content Difference Between Fresh and Dried R roxburghii Fruits

Relative quantification was performed to compare the difference of identified compounds between fresh and dried fruits by using lLC-MS peak areas. Ionization mode with the best MS response was selected for the calculation of the detected compounds: [M − H]⁻ ions were used for phenols, catechins, flavonoids, terpenoids, and organic acids, while [M + H]⁺ ions for amino acids and acylamides.

As shown in Table 2, relative contents of each type of compound in fresh and dried fruits are: amino acids (21.34% and 34.39%), acylamide (0% and 11.29%), flavonoids (35.00% and 22.13%), organic acids (60.37% and 52.81%), phenols (3.88% and 19.10%), terpenoids (16.56% and 13.30%), respectively. Among these compounds, there was no significant difference between fresh and dried fruits, except for acylamide (p < .001) and phenols (p < .05).

Table 2.

Relative LC-MS Peak Areas of Identified Compounds in Fresh and Dried Rosa roxburghii Fruits.

No.	Compound	Fresh fruit（%）	Dried fruit（%）	Fold change^a	P value
1	Arginine	5.54	0.17	−33.07
16	Tyrosine	1.08	4.37	4.06
17	Fructose-leucine	0.09	0.99	11.05
19	Isoleucine or isomer	6.89	6.63	−1.04
21	Isoleucine or isomer	1.89	9.90	5.25
27	Phenylalanine	0.45	6.37	14.16
32	Leucylproline	0.04	0.49	13.66
Total amino acid		21.34	34.39		.32

95	(2E,4E,8Z,10Z)-Nisobutyl-dodeca-2,4,8,10- tetraenamide or isomer	0.00	11.29	∞
Total acylamide		0.00	11.29		<.001

31	Catechin or isomer	0.34	0.10	−3.28
33	3,4′,5′,6,8-Penta-Me ether-3,3′,4′,5,5′,67,8-Octahydroxyflavone	0.06	0.49	7.90
34	Procyanidin B1 or isomer	1.35	0.74	−1.82
36	Procyanidin B1 or isomer	8.96	4.44	−2.01
46	Isoquercetin or isomer	2.29	0.06	−38.72
47	Epiafzelechin-(4β→8)-epicatechin or isomer	0.13	0.29	2.26
48	Procyanidin C1 or isomer	1.72	0.41	−4.16
49	Catechin or isomer	13.25	10.32	−1.28
54	Procyanidin C1 or isomer	0.19	0.04	−4.49
55	Isoquercetin or isomer	0.14	0.00	−∞
56	Eriodictyol	0.13	0.09	−1.52
58	Dryopteric acid	0.00	0.22	∞
59	(Epi)catechin derivative	0.00	0.57	∞
60	Procyanidin C1 or isomer	0.37	0.06	−5.81
63	Epiafzelechin-(4β→8)-epicatechin or isomer	0.62	0.01	−71.04
64	Procyanidin C1 or isomer	0.45	0.11	−3.90
65	Procyanidin B1 or isomer	0.71	0.37	−1.90
66	Catechin or isomer	0.00	0.38	∞
67	Isoquercetin or isomer	0.31	0.10	−3.20
73	Ellagic acid-4-O-L-rhamnoside	1.83	0.92	−1.99
77	Quercetin 3-O-[(X-O-3-hydroxy-3-methylglutaryl)-β-glucoside]	0.11	0.55	4.81
78	Kaempferol 3-O-[(X-O-3-hydroxy-3-methylglutaryl)-β-glucoside] or isomer	0.00	0.21	∞
79	Kaempferol 3-O-[(X-O-3-hydroxy-3-methylglutaryl)-β-glucoside] or isomer	0.00	0.17	∞
Total flavonoid		35.00	22.13		.49

5	L-ascorbic acid	30.80	25.28	−1.22
6	Threonic acid	0.13	1.56	11.90
7	Quinic acid	2.71	4.23	1.56
8	Xylonic acid	1.46	5.58	3.81
10	Citric acid	7.28	7.92	1.09
12	4-O-(4-Deoxy-α-L-erythro-hex-4-enopyranuronosyl)-α-L-gulopyranuronic acid	8.79	0.94	−9.35
15	Isocitric acid	7.62	6.00	−1.27
24	β-Acetylacrylic acid	0.37	0.10	−3.55
25	L-valine anhydride	0.00	0.0032	∞
43	Caffeic acid hexoside	0.25	0.10	−2.48
Total organic acid		60.37	52.81		.84

2	1,1′-(1,3-Propanediyl) bis(34,5-trihydroxybenzoate)	1.20	0.07	−18.38
18	Galloyl-glucose	0.00	0.81	∞
20	Gallic acid	0.00	4.54	∞
23	β-D-Glucopyranosiduronic acid, 2,3-dihydroxyphenyl	0.00	0.18	∞
28	Protocatechuic acid	0.00	0.31	∞
29	Galloyl-hexahydroxydiphenoyl-glucose or isomer	0.00	2.04	∞
30	3,4,5-Trihydroxycinnamic acid	0.00	1.55	∞
50	4-Hydroxybenzoic acid	0.11	0.19	1.68
51	Brevifolincarboxylic acid	0.0065	1.73	267.20
62	Flavogallonic acid	0.043	1.15	26.43
75	Ellagic acid	1.31	4.84	3.71
Total phenol		3.88	19.10		.02

88	Kaji-ichigoside F1	11.35	8.19	−1.39
Total Terpenoid		16.56	13.30		.81

11	Adenine	0.13	1.02	7.61
72	xi-γ-Undecalactone	4.85	1.83	−2.65
80	Methyl decanoate	1.65	0.11	−15.31
86	(4R)-4-[(3S,7R,8R,9S,10S,13R,14S,17R)-7-Hydroxy-3-(4-methoxybenzoyl)-10,13-dimethyl-3-[(3R,4S,5S,6R)-34,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-1,2,4,5,6,7,8,9,11,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl]pentanoic acid	0.12	0.29	2.40
Total others		10.50	6.90		.47

Positive fold change value means a relatively higher content in dried fruit, while negative value means higher content in fresh fruit. All the tests were performed in triplicate.

The high content of L-ascorbic acid (compound 5) in R roxburghii was known to provide noticeable antioxidant activities.^10,11 In Table 2, L-ascorbic acid showed no significant difference between the 2 fruits (fold change <1.5), which indicated that the antioxidant activities in the dried fruit could not be significantly diminished.

Flavonoids are also known for their antioxidant activity in R roxburghii.^10,11 As shown in Table 2, total flavonoid was lower in dried fruit, but with no significant difference (p > .05). More specifically, the most abundant flavonoids are catechin (compound 49), procyanidin B1 (compound 36), and/or their isomers, accounting for 70% of the total flavonoids in both fresh and dried fruits. According to previous studies focusing on the thermal treatment of teas and blueberries, heating could lead to the loss of catechin and procyanidin due to chemical reactions with other compounds or oxidations.^17,18 In this study, the lower content of catechin and procyanidin in dried fruit might be caused by a similar reason. Catechin was reported to have antioxidant and antitumor activities, and procyanidin B1 also has antioxidant activity.^10,11 Thus, the reduction of total flavonoid contents might lead to a diminishment of antioxidant activities in dried fruit.

Interestingly, the content of total phenol was significantly higher (p < .05) in dried fruit. More specifically, the content of ellagic acid (compound 75) and gallic acid (compound 20) were the main and characteristic phenols in dried fruit (fold change: 3.75/∞; relative area ratio: 4.84%/4.54%). The increase of the gallic acid content was also reported in a previous study on potato after the heating process, due to the breakdown of complex components.¹⁹ And, the amount of ellagic acid could increase after heating,¹⁹ due to the hydrolysis of the precursors. In our study, the high content of gallic and ellagic acids in dried fruit might come from a similar way. Both gallic acid and ellagic acid are strong antioxidants sourced in plants.^19,20 Therefore, these results suggested that the higher phenols in dried fruits might enhance their antioxidant activity.

As shown in Figure 1 and Table 2, the content of (2E,4E,8Z,10Z)-Nisobutyl-dodeca-2,4,8,10-tetraenamide (compound 95) was significantly higher in dried fruit (p < .001). This compound is known as the main alkylamide in Echinacea species plants, which have immunomodulatory and antiinflammatory actions.^21,22 Besides, the content of the total amino acid was also higher in dried fruit (34.39%). Among them, the content of essential amino acids, including tyrosine, isoleucine, and phenylalanine, were the main amino acids in dried fruit, which suggested that the nutritional benefits would be improved.

In this study, total organic acid and flavonoid contents were lower, whereas total amino acid, acylamide, and phenol contents were higher in dried fruits. Since L-ascorbic acid, flavonoids, and phenols all contribute to the antioxidant capacities, the difference of the bioactivity between fresh and dried fruit was still unclear. Thus, the DPPH• scavenging assay and FRAP were performed.

Antioxidant Activities of R roxburghii Fruits

Based on the different mechanism-based methods, DPPH• scavenging ability and FRAP are widely used to detect the in vitro antioxidant activity of the specific compound or extracts from plants or foods.²³ In this experiment, the DPPH• scavenging activities and FRAP of the fresh and dried fruits were also determined, and L-ascorbic acid was used as a positive control. As shown in Table 3, the scavenging activity of DPPH• assay showed that dried fruit was with slightly higher AAEs and lower IC₅₀ compared to fresh fruit, indicating it had better antioxidant activity. The result of the ferric reducing capacity of dried fruit also gave a higher value.

Table 3.

DPPH• Scavenging Capacity and FRAP of Fresh and Dried R. roxburghii Fruits.

Sample	DPPH		FRAP (mmol Fe²⁺/100 g)
Sample	(mg AAE/g)	IC₅₀ (mg/mL)	FRAP (mmol Fe²⁺/100 g)
FF	2.92 ± 0.59	4.21 ± 1.03	110.62 ± 35.38
DF	5.05 ± 0.83	3.69 ± 1.25	187.30 ± 49.16
L-Ascorbic acid	nt	0.026 ± 0.009	1882.72 ± 202.91

Abbreviations: DPPH•, 1,1-diphenyl-2-picrylhydrazyl radical; FRAP, ferric reducing antioxidant power; AAE, L-ascorbic acid equivalents; FF, fresh fruit extract; DF, dried fruit extract; nt, not tested.

All values are expressed as mean ± SD of three independent measurements.

The above results indicated that dried R roxburghii fruit still has strong antioxidant activity. Previous studies have reported that L-ascorbic acid, flavonoids, and phenols showed strong antioxidant activity.^10,24–30 The analysis of relative amounts of identified compounds, phenols in dried fruits were significantly higher, which might explain the strong antioxidant activity of dried R roxburghii fruit.

Conclusion

In conclusion, the constituents and in vitro antioxidant activities of fresh and dried R roxburghii fruit were evaluated and compared for the first time. The dried fruit showed stronger antioxidant activities by scavenging free radical and ferric reducing capacity assays. The high content of phenols in dried fruit might explain the above results. Overall, this study suggested that dried R roxburghii fruit could preserve the bioactive and functional compounds. Therefore, dried fruit could be considered a more effective and economical health and functional supplement for food and healthcare industries.

Experimental

Chemicals and Reagents

Acetonitrile (HPLC grade) and methanol (HPLC grade) were obtained from Anaqua Chemicals Supply Inc., Ltd. Deionized water was prepared using a Millipore water purification system (Millipore Corp.). Formic acid (MS grade), 2, 4, 6-tripyridyl-s-triazine (TPTZ), and other chemical reagents were provided by Sigma-Aldrich. 1,1-Diphenyl-2-picrylhydrazyl radical (DPPH•) was purchased from TCI Development Co., Ltd. Reference substances, (+)-catechin, isoquercitrin, quercetin, kajiichigoside F1, and eriodictyol were obtained from Shenzhen hiboled century Biotechnology Co. Ltd), L-ascorbic acid, procyanidin B1, and ellagic acid were supplied by Guangzhou zhuanyan Biological Technology Co. Ltd, and their purities were more than 98.0% by high-performance liquid chromatography analysis.

Plant Materials

The variety of R. roxburghii is Gui Nong Qi Hao, provided by Guizhou Hengliyuan Natural Biotechnology Co. Ltd

Sample Preparation

Dried fruits, which were dried at 37 °C in an oven until the moisture content was <5% (drying time is around 24 h), were exactly weighed and extracted by refluxing with water (1:10, w/v) for 2 h. All supernatant was collected after centrifugation at 15,000 rpm for 5 min for LC-MS analysis and antioxidative assays. Fresh fruit was prepared the same way, except for the drying process. DPPH• solution was prepared by dissolving accurately weighed DPPH (24.6 mg) into a 100 mL brown volumetric flask right with methanol before the experiments and the whole procedure was protected from light. FRAP stock solution contained 2.5 mL of a 10 mM TPTZ solution in 40 mM HCl, 2.5 mL of 20 mM FeCl₃ and 25 mL of 0.3 M acetate buffer, pH 3.6. It was prepared daily and kept in the dark at 37 °C before use.

UHPLC-Q-TOF/MS Analysis

The chromatographic separation was conducted on a Shimadzu LC-30AD LC system (UHPLC) with a Waters BEH-C18 column (2.1 × 100 mm, 1.7 μm). The column temperature was maintained at 40 °C and the auto-sampler was set at 4 °C. Mobile phases A and B were 0.1% formic acid-containing water and 0.1% formic acid-containing acetonitrile, respectively. The gradient was set as follows: 0–5 min, 5–30% B; 5–10 min, 30–37% B; 10–11 min, 70–95% B; 11–12 min, 95–95% B, and 12.1–14 min, 5% B. The injection volume was 2 μL and the flow rate was 0.3 mL/min.

Mass spectrometry was conducted on an AB SCIEX Triple ToF 5600 accurate mass system. The instrument was operated in both positive and negative full scan mode with the following MS parameters: Positive ion mode: dry gas temperature, 150 °C; dry gas flow, 15 L/min; sheath gas temperature, 250 °C; sheath gas flow, 11 L/min; nebulizer pressure, 25 psi; capillary voltage, 4000 V; and nozzle voltage, 500 V; negative ion mode: dry gas temperature, 150 °C; dry gas flow, 15 L/min; sheath gas temperature, 320 °C; sheath gas flow, 11 L/min; nebulizer pressure, 45 psi; capillary voltage, 3500 V; and nozzle voltage, 500 V. Mass spectra were recorded between 50 and 1700 m/z.

LC-MS Data Analysis

LC-MS data was extracted by Peakview (AB SCIEX) to perform meaningful data mining. Then the formula finder was used to extract molecular features and compounds were identified based on the exact masses, MS² spectra, and the database, such as Scifinder (scifinder.cas.org/), HMDB (https://hmdb.ca/), Pubchem (https://pubchem.ncbi.nlm.nih.gov/) and METLIN (https://metlin.scripps.edu/index.php) and previous reports.

Relative LC-MS peak areas were the relative share of each identified compound from the total chromatogram peak area in a sample. The fold change higher than 1.5 was considered statistically significant, and a positive value means a relatively higher content in dried fruits, while a negative value means fresh fruits showed higher content. And all the tests were performed in triplicate. The significance of discriminating each compound with the same type was determined by the t-test device. The difference with p < .05 was considered statistically significant.

Microplate Assay of DPPH• Scavenging Activity

DPPH• scavenging activity was performed using a reported method, with slight modification.²³ Briefly, fresh and dried fruit extracts were adjusted to the same dried weight. Then, 300 μL DPPH• solution was added to a 150 μL extract solution or L-ascorbic acid standard solution (5.3, 10.6, 21.2, 42.4, and 84.8 mg/mL), then stirred. Samples were incubated in the dark at room temperature for 30 min and then detected by measuring the absorbance A_sample+DPPH at 517 nm using a Multiskan Go microplate reader (Thermo). A 150 μL aliquot of each concentration with 300 μL of MeOH was used as the blank, and the absorbance was recorded as A_sample. Similarly, A_DPPH was the absorbance of the mixture of distilled water and DPPH• solution, while A_blank was the absorbance of the mixture of distilled water and MeOH. The natural antioxidant L-ascorbic acid was used as a positive control. The DPPH radical scavenging activity of the sample was expressed as mg of L-ascorbic acid equivalents (AAE) per gram of dried sample (mg AAE/g). All tests were performed in triplicate.

DPPH• scavenging activity was calculated as follow:

\begin{aligned} scavenging activity (%) & = [1 - (A_{sample + DPPH} - A_{sample}) / \\ (A_{DPPH} - A_{blank})] \times 100 % . \end{aligned}

Ferric Reducing/Antioxidant Power Assay

The FRAP assay was carried out as previously described.³¹ Then 50 μL of properly diluted sample was added to 250 μL of freshly prepared FRAP reagent in a 96-well plate and mixed thoroughly. The mixture was incubated at 37 °C for 10 min, and then measured at 593 nm. The FRAP value was calculated as millimoles of Fe²⁺ equivalents per 100 g of sample (mmol Fe²⁺ equiv/100 g) based on a calibration curve plotted using FeSO₄·7H₂O as the standard curve.

Supplemental Material

sj-docx-1-npx-10.1177_1934578X221095350 - Supplemental material for Comparison of Chemical Compositions and Antioxidant Activities of Fresh and Dried Rosa roxburghii Tratt Fruit

Supplemental material, sj-docx-1-npx-10.1177_1934578X221095350 for Comparison of Chemical Compositions and Antioxidant Activities of Fresh and Dried Rosa roxburghii Tratt Fruit by Guanyu Yan, Peiyan Zheng, Shaoquan Weng, Yida Zhang, Wenliu Xu, Jiaying Luo, Jianjun Fei, Jingxian Wang, Hui Zhang, Haisheng Hu and Baoqing Sun in Natural Product Communications

Footnotes

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by the China Evergrande Group, SKLRD Open Project (grant numbers 2020GIRHHMS04 and SKLRD-OP-202108).

Ethical Approval

Not applicable, because this article does not contain any studies with human or animal subjects.

Informed Consent

Not applicable, because this article does not contain any studies with human or animal subjects.

ORCID iD

Guanyu Yan

Supplemental Material

Supplemental material for this article is available online.

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