Volatile composition, antidiabetic, and anti-obesity potential of Brassica incana leaf and flowering top extracts

Figures & data

Table 1. Composition as volatile constituents and classes of substances of B. incana leaf hydroalcoholic extract.

Compound	LRI^a on DB-5ms	LRI^a on VF-WAXms	Amount^b	Percentage
Sulphur compounds
Dimethyl disulphide	742	1080	3959	1.99
Isobutyl isothiocyanate	929	1322	610	0.31
Dimethyl trisulphide	969	1388	21,163	10.66
3-Butenyl isothiocyanate	973	1462	85,532	43.10
Methyl methylthiomethyl disulphide	1135	1665	520	0.26
All			111,784	56.33
Nitriles
4-Pentenenitrile	745	1279	5254	2.65
Heptanenitrile	991	1408	120	0.06
All			5374	2.71
Aldehydes
(E)-2-Pentenal	758	1131	387	0.19
Heptanal	904	1186	776	0.39
(E)-2-Heptenal	958	1329	571	0.29
Octanal	1004	1290	1116	0.56
(E)-2-Octenal	1058	1433	140	0.07
Nonanal	1105	1396	4201	2.12
Decanal	1207	1501	7448	3.75
Undecanal	1307	1606	240	0.12
Dodecanal	1408	1711	1174	0.59
Tridecanal	1510	1817	559	0.28
Tetradecanal	1610	1922	1058	0.53
β-Cyclocitral	1220	1624	1388	0.70
Safranal	1200	1649	1071	0.54
All			20,128	10.14
Ketones
6-Methyl-5-hepten-2-one	985	1340	249	0.13
All			249	0.13
Alcohols
1-Hexanol	870	1347	188	0.09
1-Octen-3-ol	980	1448	233	0.12
2-Ethyl-1-hexanol	1028	1489	484	0.24
(Z)-2-Octen-1-ol	1060	1620	356	0.18
(E)-2-Octen-1-ol	1068	1616	101	0.05
1-Octanol	1071	1557	171	0.09
1-Nonanol	1173	1659	363	0.18
Dodecanol	1475	1966	15,106	7.61
Tetradecanol	1576	2171	5164	2.6
All			22,165	11.17
Acids
Butanoic acid	779	1636	5276	2.66
Hexanoic acid	978	1851	7856	3.96
Octanoic acid	1171	2064	3707	1.87
Hexadecanoic acid	1960	3000	2426	1.22
All			19,264	9.71
Esters
3-Methyl-1-butyl acetate	876	1121	829	0.42
Hexyl acetate	1011	1270	3001	1.51
1-Methylbutyl butanoate	1015	1208	509	0.26
Butyl hexanoate	1185	1412	664	0.33
Hexyl butanoate	1194	1415	228	0.11
Methyl hexadecanoate	1926	2216	3268	1.65
All			8498	4.28
Terpenes
Limonene	1029	1193	4363	2.20
(Z)-Calamenene	1531	1835	1335	0.67
Guaiol	1597	2087	2333	1.18
Bulnesol	1667	2208	2391	1.20
All			10,423	5.25

^aLinear retention indexes calculated according to the Van Den Dool and Kratz equation.

^bPeak area arbitrary scale.

Table 2. Composition as volatile constituents and classes of substances of B. incana flowering top hydroalcoholic extract.

Compounds	LRI^a on DB-5ms	LRI^a on VF-WAXms	Amount^b	Percentage
Sulphur compounds
Dimethyl disulphide	742	1080	32,307	18.96
Isobutyl isothiocyanate	929	1322	137	0.08
Dimethyl trisulphide	969	1388	63,208	36.62
3-Butenyl isothiocyanate	973	1462	995	0.57
Dimethyl tetrasulfide	1216	1750	14,244	8.16
All			112,673	64.40
Nitriles
3-Methyl-3-butenenitrile	759	–	28,026	16.06
Benzyl nitrile	1136	1893	1442	0.83
Benzenepropanenitrile	1237	2041	119	0.07
1H-Indole-3-acetonitrile	1807	–	1028	0.59
All			30,495	17.54
Aldehydes
Hexanal	803	1085	683	0.39
Heptanal	904	1186	110	0.06
(E)-2-Heptenal	958	1329	299	0.17
Benzaldehyde	962	1530	231	0.13
(E.E)-2.4-Heptadienal	1000	1508	92	0.05
Octanal	1004	1290	400	0.23
Phenylacetaldehyde	1044	1645	336	0.19
Nonanal	1105	1396	1150	0.66
Decanal	1207	1501	356	0.20
All			3657	2.10
Ketones
1-Penten-3-one	721	1020	3405	1.95
6-Methyl-5-hepten-2-one	985	1340	251	0.14
6-Methyl-3.5-heptadien-2-one	1096	1582	532	0.30
6.4.10-Trimethyl-2-pentadecanone (hexahydrofarnesyl acetone)	1844	2119	2302	1.32
All			6490	3.72
Alcohols
1-Octen-3-ol	980	1448	1871	1.07
(E)- 2-Octen-1-ol	1068	1616	867	0.50
1-Octanol	1071	1557	1945	1.11
1-Nonanol	1173	1659	98	0.06
All			4781	2.74
Acids
3-Methylbutanoic acid	834	1681	417	0.24
2-Methylbutanoic acid	845	1687	874	0.50
(Z)-3-Hexenoic acid	992	1940	80	0.05
2-Methyl-4-pentenoic acid	996	–	315	0.18
2-Ethylhexanoic acid	1115	1129	165	0.09
Octanoic acid	1171	2064	665	0.38
Nonanoic acid	1268	2165	836	0.48
Decanoic acid	1365	2267	386	0.22
All			3738	2.14
Esters
3-Methyl-1-butyl acetate	876	1121	290	0.17
Pentyl 2-methylpropanoate	1056	1243	254	0.15
Phenyl acetate	1064	1660	86	0.05
Methyl octanoate	1127	1411	1162	0.67
Carveyl acetate	1314	2071	150	0.09
Octyl 2-methylpropanoate	1347	1547	89	0.05
Benzyl 3-methylbutanoate	1392	1852	121	0.07
1-Methylethyl decanoate	1428	1615	409	0.23
1-Octen-3-yl hexanoate	1507	–	328	0.19
1-Methylethyl tetradecanoate	1826	2017	57	0.03
Methyl hexadecanoate	1926	2216	1563	0.90
Methyl linoleate	2095	2480	76	0.04
Methyl linolenate	2101	2503	357	0.20
All			4790	2.83
Terpenes
α-Pinene	933	1025	149	0.09
β-Pinene	978	1108	333	0.19
p-Cymene	1025	1270	600	0.34
Limonene	1029	1193	3632	2.20
Eucalyptol	1033	1206	715	0.41
α-Isophorone	1124	1621	805	0.46
Safranal	1200	1639	451	0.26
β-Cyclocitral	1220	1623	530	0.30
Citronellol	1232	1757	68	0.04
Carvacrol	1299	2225	110	0.06
Orivone	1354	–	133	0.08
All			7740	4.43
Hydrocarbons
Heptadecane	1700	1700	59	0.03
Octadecane	1800	1800	40	0.02
1-Eicosene	1994	2051	69	0.04
All			168	0.10

*Linear retention indexes calculated according to the Van Den Dool and Kratz equation.

^bPeak area arbitrary scale.

Figure 1. Inhibition of pancreatic lipase (A) and α-glucosidase (B) by B. incana leaf and flowering top hydroalcoholic extracts. Orlistat and acarbose were used as positive control substances.

Table 3. IC₅₀ values for B. incana leaf and flowering top hydroalcoholic extracts and drug compounds used as references.

Samples	IC50 values (mg/mL) in different bioassays
	AGEs	Superoxide	Glucosidase	Lipase
B. incana (leaf)	0.192 ± 0.024^a	0.022 ± 0.003^a	0.968 ± 0.141^a	1.086 ± 0.319^a
B. incana (flowering top)	0.262 ± 0.020^a	0.038 ± 0.012^a	1.921 ± 0.321^a	0.939 ± 0.131^a
AMG	0.0744 ± 0.017^b	–	–	–
Trolox	–	0.028 ± 0.001^a	–	–
Acarbose	–	–	0.306 ± 0.039^b	–
Orlistat	–	–	–	0.0277 ± 0.015^b

Results are expressed as average ± SEM of at least three independent experiments. ^a,b Different letters within the same column indicate significant differences between mean values (P < 0.05). No significant differences were found between leaves and flowering tops using ANOVA and Tukey for multiple comparison statistical analyses.

Figure 2. Inhibition of advanced glycation end-products (AGEs) by B. incana leaf and flowering top hydroalcoholic extracts (A) compared to aminoguanidine (B), used as positive control substance.

Figure 3. Antioxidant activity against superoxide radicals by B. incana leaf and flowering top hydroalcoholic extracts. Trolox was used as positive control substance.