Chemical constituents and biological activities of essential oil from Mentha longifolia: effects of different extraction methods

Figures & data

Table 1. Volatile compounds identified in extracts of Mentha longifolia prepared by different extraction methods

NO	RT	Components	RI	RI^a	Extraction Methods
					SD		LSE		SC-CO2
					A%	g/100 g	A%	g/100 g	A%	g/100 g
1	6.51	α-Pinene	929	932	0.54	0.43	0.28	0.08	-	-
2	7.93	β-Thujene	966	972	0.37	0.28	0.21	0.06	-	-
3	8.03	Sabinene	974	974	0.71	0.53	0.43	0.12	-	-
4	8.60	β-Myrcene	991	990	0.30	0.23	0.14	0.04	-	-
5	10.06	Limonene	1023	1029	30.10	23.14	14.66	4.23	0.23	0.03
6	10.11	Eucalyptol	1032	1030	0.31	0.31	0.65	0.19	-	-
7	10.41	(Z)-Ocimene	1038	1038	0.39	0.30	0.09	0.02	-	-
8	10.81	(E)-Ocimene	1049	1048	0.20	0.15	-	-	-	-
9	12.78	Linalool	1099	1099	-	-	-	-	0.30	0.01
10	14.80	trans-Menthone	1154	1153	0.56	0.54	-	-	-	-
11	15.20	cis-Menthone	1164	1164	-	-	0.12	0.02	-	-
12	15.34	Lavandulol	1170	1167	-	-	0.29	0.05	0.17	0.02
13	16.18	α-Terpineol	1189	1190	1.47	1.43	1.34	0.42	0.79	0.10
14	16.41	1,6-Dihydrocarveol	1195	1196	0.92	0.93	0.20	0.05	0.26	0.03
15	16.57	Dodecane	1200	1200	-	-	0.12	0.03	0.15	0.02
16	17.24	trans-Carveol	1217	1219	0.32	0.31	0.32	0.08	0.43	0.06
17	17.71	cis-Carveol	1229	1232	0.38	0.39	0.39	0.11	0.14	0.02
18	17.97	cis-3-Hexenyl isovalerate	1238	1239	1.01	1.23	-	-	-	-
19	18.25	Carvone	1248	1247	52.81	55.82	47.52	13.18	33.07	4.50
20	18.49	Piperitone	1253	1254	0.27	0.28	1.03	0.27	1.50	0.20
21	19.51	α-Terpinen-7-al	1283	1283	0.23	0.24	-	-	-	-
22	19.75	2-Caren-10-al	-	1290	0.33	0.35	0.05	0.09	0.24	0.03
23	20.14	Carvacrol	1299	1301	-	-	0.13	0.03	0.34	0.05
24	22.22	cis-Carvyl acetate	1362	1364	0.15	0.18	0.10	0.03	0.22	0.03
25	22.64	Copaene	1376	1376	0.19	0.13	0.25	0.06	0.19	0.02
26	22.94	β-Bourbonene	1384	1385	1.12	0.08	0.91	0.21	1.05	0.12
27	23.37	Jasmone	1394	1398	0.24	0.26	0.72	0.19	1.36	0.18
28	23.65	cis-caryophyllene	1406	1407	0.08	0.05	0.10	0.02	0.16	0.02
29	24.05	trans-caryophyllene	1419	1420	2.59	1.88	2.70	0.62	4.87	0.55
30	24.36	β-Copaene	1432	1430	0.12	0.09	0.15	0.03	0.24	0.03
31	24.83	Isogermacrene D	1448	1445	0.10	0.07	0.11	0.03	0.19	0.02
32	25.11	Humulene	1454	1454	0.27	0.19	0.04	0.03	-	-
33	25.23	trans-β-Farnesene	1457	1458	0.07	0.05	1.05	0.24	2.26	0.25
34	25.98	Germacrene D	1481	1482	0.70	0.51	0.99	0.23	2.09	0.24
35	26.46	Bicyclogermacrene	1495	1497	0.26	0.19	0.47	0.11	1.23	0.14
36	27.27	δ-Cadinene	1524	1525	0.11	0.08	0.19	0.04	0.74	0.08
37	28.86	Spathulenol	1577	1579	-	-	0.35	0.08	0.89	0.11
38	29.03	Caryophyllene oxide	1581	1584	0.15	0.13	0.26	0.08	0.77	0.10
39	35.94	Perhydrofarnesyl acetone	-	1840	-	-	4.17	0.11	0.56	0.07

RT: Retention times, RI: Theoretical retention index of compounds on HP-5 apolar capillary column, RI^a: Experimental retention index of compounds on HP-5 apolar capillary column, A%: Relative content of individual compounds calculated by area normalization method, g/100 g: semi-quantitative analysis results of component, each value is represented in terms of average mean (n = 3).

Figure 1. Yield of essential oil extract by different methods, SD was the essential oil obtained by steam-distillation, SC-CO₂ was supercritical CO₂ fluid extraction and LSE was organic solvent extract

Means in the same row followed by different letters are significantly different (p < .05). Each value is represented in terms of mean (n = 3) ± SD (Standard deviation).

Figure 2. Scavenging ability of EOs against DPPH (upper panel) and ABTS (lower panel) free radicals, SD corresponds to the upper X-axis, LSE and SC-CO₂ corresponds to the lower X-axis, the value of each point is represented in terms of mean (n = 3) ± SD (Standard deviation)

Table 2. Numbers of the classes of compounds in extracts obtained by different extraction methods

Classification of compounds	SD		LSE		SC-CO2
	A%	g/100 g	A%	g/100 g	A%	g/100 g
Aldehydes and ketones	54.44	57.49	53.61	13.86	36.73	4.98
Terpenes	38.22	28.38	22.77	6.17	13.25	1.50
Alcohols	3.40	3.37	3.67	1.01	3.32	0.40
Esters	1.16	1.41	0.10	0.03	0.22	0.03
Others	0.15	0.13	0.38	0.11	0.92	0.12
Total	97.37	90.78	80.53	21.18	54.44	7.03

A%: Relative content of individual compounds calculated by area normalization method, g/100 g: semi-quantitative analysis results of component, each value is represented in terms of average mean (n = 3).

Table 3. Antioxidant activities of essential oils extracted by different methods

	Sample	IC50(mg/mL)
		DPPH	ABTS
	SD	15.61 ± 0.16a	2.19 ± 0.11a
	LSE	1.58 ± 0.03b	0.42 ± 0.006 b
	SC-CO2	0.69 ± 0.014d	0.156 ± 0.001 c
	Tocopherol	1.30 ± 0.02 c	0.023 ± 0.0005d

Means in the same row followed by different letters are significantly different (p < 0.01). Each value is represented in terms of mean (n = 3) ± SD (Standard deviation).

Figure 3. The inhibit rate of EOs extracted by different methods on COX-2, means in the same row followed by different letters are significantly different (p < .05), each value is represented in terms of mean (n = 3) ± SD (Standard deviation)