Chemical composition and biological activities of extracts and essential oil of Boswellia dalzielii leaves

Figures & data

Table 1. Extraction yields (%) and chemical composition of B. dalzielii extracts.

Samples	Yields (%)	Phenolics (GAE)^a	Flavonoids (QE)^a	Tannins (CE)^a	Anthocyanins (C3GE)^b	Sugar (GE)
Cyclohexane	3.37^b	3.58 ± 0.09^d	4.09 ± 0.26^d	nd^c	0.82 ± 0.01^a	nd
Dichloromethane	1.57^c	48.23 ± 0.22^c	31.95 ± 0.39^c	10.81 ± 0.72^b	nd^c	nd
Ethyl acetate	0.03^e	148.81 ± 1.44^b	35.26 ± 0.50^b	35.18 ± 0.46^a	0.23 ± 0.00^b	nd
Methanol	16.08^a	315.97 ± 4.12^a	37.19 ± 0.42^a	nd^c	nd^c	nd
Essential oil	1.12^d

nd: not detected. Standard deviations (SD) did not exceed 5%.

^ag/kg dry mass; ^bmg/kg dry mass.

Table 2. Chemical composition of B. dalzielii leaves essential oil.

No.	RI	Noum	%Area
1	939	α-Pinene	15.18
2	953	Camphene	0.26
3	983	E-isolimonene	0.37
4	993	Myrcene	5.72
5	1011	3-Carene	27.72
6	1019	α-Terpinene	0.45
7	1027	p-Cymene	9.54
8	1032	β-Phellandrene	8.48
9	1045	Z-β-ocimene	0.28
10	1057	γ-Terpinene	0.20
11	1084	Isoterpinolene	0.40
12	1093	E-sabinene hydrate	0.67
13	1116	1S-β-Fenchol	0.19
14	1132	3-Terpinenol	0.17
15	1158	E-pinocamphone	0.69
16	1162	Z-chrysanthemol	0.64
17	1167	Lavandulol	0.42
18	1179	Terpinen-4-ol	1.41
19	1189	Methyl salicylate	0.52
20	1221	β-cyclocitral	0.38
21	1230	Z-carveol	0.33
22	1255	Carvenone	0.24
23	1292	Undecan-2-one	0.27
24	1345	α-Cubebene	0.70
25	1354	α-Longipinene	0.23
26	1379	β-Patchoulene	0.25
27	1387	Isolongifolene	6.15
28	1394	Cyperene	0.20
29	1396	Italicene	0.17
30	1418	β-Caryophyllene	0.75
31	1436	E-α-bergamotene	0.20
32	1439	Aromadendrene	0.79
33	1445	Z-β-farnesene	4.53
34	1451	Z-4,5-muuroladiene	0.24
35	1456	α-Patchoulene	0.47
36	1462	β-Santalene	0.91
37	1468	9-Epicaryophyllene	0.23
38	1476	β-Chamigrene	0.43
39	1484	β-selinene	2.13
40	1487	Z-β-guaiene	0.22
41	1493	Viridiflorene	0.16
42	1498	β-Himachalene	0.20
43	1521	Lilial	0.11
44	1548	E-α-bisabolene	0.12
45	1559	Caryophyllene alcohol	0.35
46	1590	Viridiflorol	0.41
47	1598	Widdrol	0.38
48	1621	1,6-Humulanedien-3-ol	1.61
49	1630	γ-Eudesmol	0.53
50	1645	Torreyol-α-cadinol	1.93
		Monoterpene hydrocarbons	68.58
		Monoterpenes oxygenated	5.14
		Sesquiterpeneshydrocarbons	19.07
		Sesquiterpenes oxygenated	5.21
		Others	0.90
		Total	98.87

RI: retention index.

Table 3. Compounds identified for B. dalzielii extracts before and after derivatization.

No.	Tr (min)	Compounds	Structure	Cyclohexane	Dichloromethane	Ethyl acetate	Methanol
				Before derivatization
1	6.35	Tetrahydrofurfuryl acetate			+++
2	7.10	α-Pinene		+++
3	8.56	p-Cymene		+++		++
4	9.46	Z-linalooloxide				++
5	10.80	Thymol				+
6	12.00	(5E)-2,4,4,7-tetramethyl-5,7-octadien-3-ol		+++	++	++
7	13.12	β-Caryophyllene		+++
8	13.57	(−)-β-Copaene			+++
9	13.59	(E)-α-bergamotene		+++
10	14.56	Caryophyllene alcohol		+++	++
11	15.05	α-Cadinol		+++		+
12	16.26	Phytol acetate				++
13	17.89	2-Propenoic acid, 3-[2-(amino carbonyl) phenyl]-, (E)			+++
14	18.02	Methyl 8,11,14-heptadecatrienoate		+++
15	21.05	6-Isopropenyl-4,8a-dimethyl-3,5,6,7,8,8a-Hexahydro-2(H)-naphtalenone		+++		++	+
16	21.35	Urs-12-en-24-oic acid, 3-oxo-,methyl ester				+++
17	22.55	Longipinocarvone		+++			+
18	23.05	1,2,3,5,6,7,8,8a-Octahydronaphthalen-2-yl ester, 3-hydroxy-6-isopropenyl-4,8a-dimethyl, acetic acid				+++
19	24.29	α-d-Mannofuranoside, farnesyl			+++
				After derivatization
1	16.55	2,5-Dihydroxy acetophenone					+++
2	16.62	β-d-Xylopyranose					+++

+++: high presence; ++: average presence; +: low presence.

Table 4. Antioxidant and antixanthine oxidase activities of B. dalzielii extracts and essential oil.

	DPPH^• assay		XOD assay
Sample	% Inhibition (100 mg/L)	IC50 (mg/L)	% Inhibition (100 mg/L)	IC50 (mg/L)
Cyclohexane	17.07 ± 0.43^c	>100^e	15.58 ± 0.06^d	>100^e
Dichloromethane	59.99 ± 0.70^b	78.10 ± 0.10^d	58.54 ± 0.32^c	88.30 ± 1.03^d
Ethyl acetate	95.33 ± 0.13^a	15.20 ± 0.04^c	90.08 ± 0.17^a	30.20 ± 0.04^b
Methanol	96.35 ± 0.10^a	6.10 ± 0.20^b	86.41 ± 0.17^b	35.10 ± 0.06^c
Essential oil	11.54 ± 0.20^d	>100^e	10.74 ± 0.13^e	>100^e
Vitamin C		5.3 ± 0.05^a
Allopurinol				0.95 ± 0.02^a

Table 5. Anti5-lipoxygenase, antiacetylcholinesterase and antisuperoxide dismutase activities of B. dalzielii extracts and essential oil.

	5-lipoxygenase assay		AChE assay		SOD essay
Sample	% inhibition (100 mg/L)	IC50 (mg/L)	% inhibition (100 mg/L)	IC50 (mg/L)	% inhibition (100 mg/L)
Cyclohexane	29.39 ± 1.20^e	>100^f	22.79 ± 0.04^e	>100^e	13.96 ± 0.04^a
Dichloromethane	83.63 ± 3.30^b	58.01 ± 0.16^d	45.79 ± 0.01^d	>100^e	4.14 ± 0.01^c
Ethyl acetate	94.12 ± 3.05^a	45.10 ± 0.01^c	59.92 ± 0.04^b	76.20 ± 0.02^c	8.27 ± 0.01^b
Methanol	78.87 ± 3.55^c	28.01 ± 1.07^b	53.30 ± 0.02^c	85.01 ± 0.02^d	8.03 ± 0.02^b
Essential oil	57.53 ± 1.73^d	70.01 ± 0.15^e	85.37 ± 0.01^a	67.10 ± 0.03^b	nd^d
Nordihydroguaiaretic acid		1.60 ± 0.01^a
Galanthamine				1.30 ± 0.01^a

nd: not determined.

Figure 1. IGROV-1 cell line inhibition (a) and OVCAR-3 cell line inhibition (b) by cyclohexane (CH), dichloromethane (DCM), ethyl acetate (EAC) and methanol (MeOH) extracts of B. dalzielii at 50 mg/L. Tamoxifen was tested at 0.2 mg/L.