Chemical compositions, extraction technology, and antioxidant activity of petroleum ether extract from Abutilon theophrasti Medic. leaves

Figures & data

Table 1. Box–Behnken experimental design and the results for extraction yield of PEE from A. theophrasti leaves (n = 3).

No.	The ratio of solvent to material (X1)/(mL/g)	Extraction time (X2)/(h)	Extraction temperature (X3)/(°C)	Yield of PEE (%)^a
1	20	6	60	2.38
2	22	6	55	1.68
3	20	6	60	2.37
4	18	6	55	1.56
5	18	4	60	2.01
6	20	4	55	1.81
7	22	6	65	1.93
8	20	6	60	2.36
9	20	6	60	2.37
10	22	4	60	2.17
11	20	8	65	2.15
12	18	8	60	2.06
13	20	8	55	1.87
14	20	4	65	2.21
15	18	6	65	1.96
16	22	8	60	2.04
17	20	6	60	2.38

^aEach value is the mean of triplicate measurements.

Figure 1. Effect of ratio of solvent to material (X₁), extraction time (X₂), and extraction temperature (X₃) on the extraction yield of PEE.

Figure 2. (a–c) Response surface plots of ratio of solvent to material (X₁, mL/g), extraction time (X₂, h), and extraction temperature (X₃, ^oC) on the yield of PEE.

Table 2. Yield of PEE, IC₅₀ values for evaluated antioxidant assays and EC₅₀ values reducing power of PEE from A. theophrasti leaves.

No.	Yield of extracts (%)	IC50 DPPH (μg/mL)	IC50 ABTS (μg/mL)	FRAP (mmol Fe^2+/100 μg/mL)
August	2.05 ± 0.02	831.5	278.0	0.15
September	2.39 ± 0.01	327.5	170.1	0.31
October	2.32 ± 0.02	331.5	182.1	0.28
BHT		9.02	21.16	0.33

IC₅₀, inhibition concentration 50%; sample 1, 2, and 3 were collected in August, September, and October 2014.

Table 3. Chemical composition of PEE from A. theophrasti leaves.

Peak no.	Retention time (min)	Compounds	RA^a (%)
			August^b	September	October
1	11.648	Undecanoic acid, 10-methyl-	0.22	0.29	–
2	15.748	Methyl tetradecanoate	1.20	1.34	1.98
3	16.609	Tetradecanoic acid, ethyl ester	–	–	0.27
4	17.721	Pentadecanoic acid	0.17	0.28	0.17
5	19.087	Phenol, 2, 4-bis(1, 1-dimethylethyl)	–	0.62	0.47
6	19.632	Hexadecanoic acid	21.07	17.41	16.39
7	20.282	7-Hexadecenoic acid	1.35	0.77	0.61
8	20.398	Hexadecanoic acid, ethyl ester	1.82	2.59	2.22
9	21.448	Hexadecanoic acid, 14-methyl-	0.19	–	0.20
10	23.215	Octadecanoic acid	2.93	1.60	1.26
11	23.671	9-Octadecenoic acid	1.37	0.57	0.81
12	24.515	8, 11-Octadecadienoic acid	0.25	–	–
13	24.637	9, 12-Octadecadienoic acid	11.36	9.08	8.28
14	25.243	Linoleic acid ethyl ester	0.80	1.02	0.93
15	25.710	Phytol	1.46	–	–
16	25.849	9, 12, 15-Octadecatrienoic acid	43.36	50.42	53.14
17	26.387	9, 12, 15-Octadecatrienoic acid, ethyl ester, (Z,Z,Z)	3.81	7.13	7.50
18	26.521	Eicosanoic acid	0.22	0.21	–
19	27.315	Nonadecane	0.36	–	–
20	27.326	Docosane	–	–	0.46
21	29.460	Folic acid	0.31	–	–
22	29.587	Docosanoic acid	0.51	0.54	0.63
23	30.321	Heneicosane	–	0.71	–
24	30.337	Tetratetracontane	–	–	0.54
25	30.476	Dibutyl phthalate	2.80	0.65	1.17
Total amount			95.56	95.23	97.03

^a Relative area; ^bcollecting season; ^cundetected (<0.1%).

Table 4. Correlation coefficients between antioxidant activities and yield of extracts.

	DPPH	ABTS	FRAP	Yield of extracts (%)
DPPH	1	0.996	−0.986	−0.982
ABTS	–	1	−0.997*	−0.996
FRAP	–	–	1	1.000*
Yield of extracts (%)	–	–	–	1

**significant at p＜0.01; *significant at p＜0.05.

Table 5. Correlation coefficients between antioxidant activities and content of four main components.

	DPPH	ABTS	FRAP	9, 12, 15-Octade-catrienoic acid	Hexadec-anoic acid	9, 12-Octade-cadienoic acid	9, 12, 15-Octadecatrienoic acid, ethyl ester, (Z,Z,Z)
DPPH	1	0.996	−0.986	−0.961	0.977	0.966	−0.995
ABTS	–	1	−0.997*	−0.931	0.952	0.938	−0.981
FRAP	–	–	1	0.900	−0.926	−0.909	0.964
9, 12, 15-Octadecatrienoic acid	–	–	–	1	−0.998*	−1.000*	0.984
Hexadecanoic acid	–	–	–	–	1	0.999*	−0.993
9, 12-Octadecadienoic acid	–	–	–	–	–	1	−0.987
9, 12, 15-Octadecatrienoic acid,ethyl ester, (Z,Z,Z)	–	–	–	–	–	–	1

**significant at p＜0.01; *significant at p＜0.05.