Optimization of the acid hydrolysis process for the extraction of Rosa roxburghii Tratt-bound phenols and antioxidant, α-glucosidase and lipase inhibitory activities in vitro

Figures & data

Table 1. Factors and levels of L₉(3³) orthogonal experiment.

Level	Factors
	A: time (h)	B: HCl concentration (moL/L)	C: solid-liquid ratio
1	6	5	1:30
2	8	6	1:40
3	10	7	1:50

Figure 1. Effect of different extraction parameters on bound phenolic contents from Rosa roxburghii Tratt (RRT). (a) Effect of different acidolysis time on bound phenolic contents from RRT. (b) Effect of different concentration of HCl on bound phenolic contents from RRT. (c) Effect of solid-to-liquid ratio on bound phenolic contents from RRT. Different letters (a-d) indicated statistically significant differences (p < .05).

Table 2. Results and designs of orthogonal test.

Number	A	B	C	Yield (mgGAE/100gDW)
1	1	1	1	154.91 ± 10.76
2	1	2	2	279.90 ± 12.73
3	1	3	3	469.60 ± 9.23
4	2	1	2	244.55 ± 4.88
5	2	2	3	401.63 ± 11.54
6	2	3	1	416.21 ± 5.29
7	3	1	3	282.80 ± 5.93
8	3	2	1	332.21 ± 10.13
9	3	3	2	444.62 ± 6.04
K1	301.47	227.42	301.11
K2	354.13	337.91	323.02
K3	353.20	443.47	384.68
R	52.66	216.05	83.57

Table 3. Analysis of orthogonal test.

Factors	Square of deviance	df	F	Significance
A:Time(h)	7567.245	2	7.216
B:HCl concentration (moL/L)	80746.633	2	77.001	*
C:Solid – liquid ratio	10507.309	2	10.02
Error	1048.65	2

*means that the differences are extremely significant, p < .05.

Figure 2. Total ion chromatograms of RRT-BPs in negative ion mode based on LC-MS.

Table 4. The phenolic compositions of the acid hydrolysis bound phenols.

Number	Identification	Rt(S)	Formula	m/z		MS fragments (m/z)
Phenolic acids and its derivatives
1	m-Coumaric acid	586.5	C9H8O3	163.0392	[M-H]^−	119.05, 162.94
2	Gallic acid	159.6	C7H6O5	169.0121	[M-H]^−	125.02, 169.01
3	3,4-Dihydroxyhydrocinnamic acid	312.1	C9H10O4	181.0498	[M-H]^−	181.03
4	Vanillic acid	277	C8H8O4	167.0321	[M-H]^−	108.02, 123.04, 152.01, 167.03
5	Caffeic acid	399.3	C9H8O4	163.0396	[M+H-H2O]^+	57.07, 89.05, 107.05, 163.04
6	4-Hydroxyphenylpyruvic acid	439.4	C9H8O4	179.0336	[M-H]^−	180
7	Sinapic acid	312.5	C11H12O5	223.0596	[M-H]^−	164.05, 165.02, 178.03, 183.07, 193.01, 194.06, 208.04
8	3-Hydroxybenzoic acid	230.7	C7H6O3	137.0212	[M-H]^−	93.03, 137.02
9	3-Hydroxyphenylacetic acid	412	C8H8O3	151.0371	[M-H]^−	136.02, 151.04
10	Syringic acid	318.8	C9H10O5	197.0452	[M-H]^−	182.02, 197.04
11	4-Hydroxybenzoic acid	429.1	C7H6O3	137.0232	[M-H]^−	93.03, 137.02
12	Isoferulic acid	375.6	C10H10O4	193.0514	[M-H]^−	178.03, 193.05
13	4-Hydroxycinnamic acid	567	C9H8O3	147.0439	[M+H-H2O]^+	147.04
14	Vanillylmandelic acid	164.8	C9H10O5	197.0439	[M-H]^−	69.16, 111.11
15	2-Hydroxycinnamic acid	630	C9H8O3	163.0368	[M-H]^−	119.05, 162.84
16	Protocatechuic acid	274.5	C7H6O4	155.0347	[M+H]^+	109.08, 110.99, 137.03, 155.03
17	2-Pyrocatechuic acid	262.1	C7H6O4	153.0186	[M-H]^−	109.03, 153.02
18	2-Hydroxyisophthalic acid	214.4	C8H6O5	181.0113	[M-H]^−	93.03, 137.02
19	3,4-Dihydroxymandelic acid	433.7	C8H8O5	167.0345	[M+H-H2O]^+	167.05
20	p-Hydroxyphenylacetic acid	193.4	C8H8O3	153.0605	[M+H]^+	152.09
21	5-Carboxyvanillic acid	245.3	C9H8O6	211.0232	[M-H]^−	108.02, 123.04, 152.01, 167.03
22	Salicylic acid	357.4	C7H6O3	137.0583	[M-H]^−	93.03, 137.02
23	3-Hydroxyanthranilic acid	147.4	C7H7NO3	136.0344	[M+H-H2O]^+	136.05
24	Ellagic acid	386.8	C14H6O8	303.0137	[M+H]^+	303.01
Flavonoids and its derivatives
25	Arbutin	358.9	C12H16O7	271.0866	[M-H]^−	109.03
26	Kaempferide	574.6	C16H12O6	299.1851	[M-H]^−	299.12
27	Astragalin	470	C21H20O11	447.0967	[M-H]^−	284.04, 447.09
28	Cyanidin 3-glucoside	470	C21H21O11	447.0855	[M-H]^−	284.03, 447.09
29	Catechin	378.7	C15H14O6	289.0708	[M-H]^−	109.03, 125.02, 137.02, 151.04, 179.03, 203.07, 205.05, 245.08, 289.07
30	Genistein	792.5	C15H10O5	269.0451	[M-H]^−	269.04
31	Epicatechin	403.3	C15H14O6	291.0875	[M+H]^+	123.04, 139.04
32	Quercetin	573.1	C15H10O7	301.0331	[M-H]^−	139.04
33	Apigenin	716.7	C15H10O5	269.0450	[M-H]^−	269.13
34	Isorhamnetin	625.4	C16H12O7	315.0483	[M-H]^−	300.03
35	Biochanin A	674.9	C16H12O5	283.1910	[M-H]^−	221.19, 265.18, 283.17
36	Eriodictyol	503.9	C15H12O6	287.0545	[M-H]^−	287.14
37	Luteolin	630	C15H10O6	286.0423	[M]^−	285.12
38	Sakuranetin	576.1	C16H14O5	285.0734	[M-H]^−	285.14

Figure 3. Antioxidant activities of RRT-BPs in vitro. (a) DPPH radical scavenging activity, (b) ABTS radical scavenging activity, (c) Ferric reducing antioxidant power assay. Different lowercase letters within the same concentration show differences between samples (p < .05). Different uppercase letters within the same sample indicate statistically significant differences (p < .05).

Figure 4. Inhibition of α-glucosidase by RRT-BPs. (a) Inhibitory effect of acarbose on α-glucosidase, (b) Inhibitory effect of RRT-BPs on α-glucosidase, (c) Reversibility of RRT-BPs mediated inhibition, (d) Lineweaver−Burk plots.

Figure 5. Inhibition of lipase by RRT-BPs. (a) inhibitory effect of orlistat on lipase, (b) inhibitory effect of RRT-BPs on lipase, (c) reversibility of RRT-BPs mediated inhibition, (d) Lineweaver−Burk plots.