Lavandula angustifolia mill. (Lamiaceae) ethanol extract and its main constituents as promising agents for the treatment of metabolic disorders: chemical profile, in vitro biological studies, and molecular docking

Figures & data

Table 1. HPLC-DAD analysis of selected markers (mg/g extract) of lavender ethanolic extracts.

Compound	La1	La2
Phenolic acids
Caffeic acid	2.5 ± 0.3	4.9 ± 0.3
Chlorogenic acid	75.1 ± 2.5	19.6 ± 1.4
Ferulic acid	0.3 ± 0.02	1.2 ± 0.1
Homovanillic acid	6.9 ± 0.6	13.5 ± 1.2
p-Coumaric acid	0.2 ± 0.02	2.2 ± 0.2
Rosmarinic acid	32.7 ± 2.1	17.2 ± 1.6
Vanillic acid	2.1 ± 0.1	3.6 ± 0.6
Flavonoids
Apigenin	1.2 ± 0.3	3.4 ± 0.2
Luteolin	1.6 ± 0.1	2.2 ± 0.2
Quercetin	4.1 ± 0.5	Nd
Coumarins
Coumarin	0.5 ± 0.2	1.4 ± 0.2
Herniarin	tr	tr

Data are reported as mean ± standard deviation (n = 3). nd: not detected. tr: trace (<0.1 mg/g).

Table 2. Antioxidant effects of lavender ethanolic extracts.

Antioxidant assay	La1	La2	Sign.
ABTS test (IC50 µg/mL)	0.5 ± 0.02	0.4 ± 0.03
DPPH test (IC50 µg/mL)	3.9 ± 0.6^a	4.4 ± 0.4^b	**
FRAp^ test (µM Fe(II)/g)	50.7 ± 1.3^b	31.4 ± 1.1^a	**
β-Carotene bleaching test (IC50 µg/mL)
- Incubation 30 min	12.1 ± 1.4^a	29.6 ± 1.9^b	**
- Incubation 60 min	9.1 ± 1.6^b	6.8 ± 1.2^a	**

Data are expressed as media ± SD (standard deviation) (n = 3).

ABTS test: positive control ascorbic acid, IC₅₀ di 1.1 ± 0.3 µg/mL; DPPH test: positive control ascorbic acid, IC₅₀ of 5.2 ± 0.6 µg/mL; FRAP test: positive control BHT, 8.6 ± 0.7 µM Fe(II)/g, at the concentration of 0.3 mg/mL; β-Carotene bleaching test: positive control propyl gallate, IC₅₀ di 1.3 ± 0.4 µg/mL after 30 min of incubation and IC₅₀ di 1.1 ± 0.3 µg/mL after 60 min of incubation. Differences within and between groups were evaluated by one-way ANOVA followed by Tukey’s multiple range test. Results followed by different letters in a same column are significantly different at **p < 0.01.

^Samples tested at the concentration of 0.3 mg/mL.

Table 3. Enzymes inhibitory activity (IC₅₀, µg/mL) of lavender ethanolic extracts.

Assay	La1	La2	Sign.
α-Glucosidase	2.5 ± 0.2^a	2.1 ± 0.3^a
α-Amylase	6.8 ± 0.6^a	14.8 ± 2.4^b	**
Pancreatic lipase	30.5 ± 3.1^a	44.5 ± 3.2^b	**

Positive controls: α-glucosidase inhibitory activity test, acarbose (IC₅₀ 35.5 ± 1.2 µg/mL); α-amylase inhibitory activity test, acarbose (IC₅₀ 50.2 ± 1.9 µg/mL); lipase inhibitory activity test, orlistat (IC₅₀ 37.1 ± 1.1 µg/mL). Data are expressed as media ± standard deviation (n = 3). Differences within and between groups were evaluated by One-way ANOVA followed by Tukey’s multiple range test. Results followed by different letters in a same column are significantly different at **p < .01.

Table 4. Enzymes inhibitory activity of the main identified phenolic acids and flavonoids of lavender extracts.

	α-Glucosidase		α-Amylase		Lipase
Compound	IC50 (mM)	Ref	IC50 (mM)	Ref	IC50 (mM)	Ref
Caffeic acid	27.6 × 10^−3	53	20.4 × 10^−3	53	0.18	54
p-Coumaric acid	> 30	55	> 30	56	0.17	57
Chlorogenic acid	10.6 × 10^−3	58	5.2 × 10^−3	58	0.27	54
Ferulic acid	4.9	55	9.5	55	0.12	59
Rosmarinic acid	12.0 × 10^−3	58	2.5 × 10^−3	58	0.35	54
Vanillic acid	0.27	60	27.9	60	8.9	60
Apigenin	> 0.20	61	> 0.5	61	0.38	62
Luteolin	0.10	58	0.07	58	0.099	63
Quercetin	7 × 10^−3	61	0.50	61	6.1 × 10^−3	57

Figure 1. Crystallographic structure of α-glucosidase, α-amylase and pancreatic lipase, corresponding to the PDB entries (A) 3TOP, (B) 4W93 and (C) 1LPB; (D) re-docking score values for crystallographic ligands.

Table 5. Chemical structures, dihedral angles, complexes binding energy values and key protein residues of α-glucosidase (3TOP) interacting with the ligands.

Ligand	Structure	Dihedral angles	Binding energy Kcal/mol	INTERACTIONS
				Hydrogen Bonds				Hydrophobic Bonds Residues	π -stacking	Salt bridges
				Residues	Distance Å		Donar Angle°
					H-A	D-A
Caffeic acid		5	−6.8	Asp1279 Asp1420 Thr1586	2.49 2.18 2.38	3.06 2.97 2.79	117.31 137.49 105.06	Tyr1251 Trp1355 Trp1355 Phe1559	Phe1559
Ferulic acid		5	−7.1	His1584	2.12	3.07	164.92	Trp1355 Phe1559	Tyr1251
Vanilic acid		4	−6.3					Tyr1251 Tyr1251 Trp1355 Phe1559
Homovanillic acid		4	−6.7	Asp1279	2.16	3.07	155.26	Tyr1251 Tyr1251 Trp1355 Trp1355 Phe1559
p-Coumaric acid		3	−6.4	Thr1586	2.35	2.89	116.38	Tyr1251 Trp1355 Trp1355 Phe1559 Phe1559	Tyr1251
Rosmarinic acid		11	−8.9	Asp1279 Asp1420 Arg1510 Asp1526 Asp1526 Thr1586	2.50 2.28 2.72 2.01 2.69 2.47	2.98 2.88 3.70 2.82 3.58 3.01	110.06 121.89 171.46 137.95 152.81 115.11	Tyr1251 Trp1355 Phe1559 Phe1559 Phe1560 Phe1560	Tyr1251 Phe1559
Chlorogenic acid		5	−8.2	Asp1420 Arg1510 Asp1526 Thr1586	2.98 2.62 3.51 2.91	3.68 3.05 3.82 3.59	133.45 107.06 100.81 119.35	Tyr1251 Trp1355 Trp1355 Phe1559	Tyr1251	Lys1460
Coumarin		0	−6.0					Trp1355 Trp1418 Trp1523 Phe1559	Tyr1251	Arg1510
Herniarin		1	−6.3					Tyr1251 Trp1355 Phe1559		His1584
Apigenin		4	−8.1	Arg1510 Arg1510 Asp1526	1.99 3.49 3.33	2.92 4.09 4.02	156.50 121.42 130.00	Tyr1251 Trp1355 Ile1587	Trp1355 Phe1559
Luteolin		5	−8.2	Asp1420 Arg1510 Arg1510	3.46 1.91 3.48	3.83 2.83 4.06	104.31 153.56 119.34	Tyr1251 Trp1355 Ile1587	Trp1355 Phe1559
Quercetin		6	−8.9	Asp1157 Asp1279 Arg1510 Arg1510	2.80 2.24 2.06 3.26	3.75 2.99 3.04 3.95	176.07 133.18 172.78 128.69	Trp1355 Phe1559	Trp1355 Phe1560

Table 6. Complexes binding energy values and key protein residues of α-amylase (4W93) interacting with the ligands.

Ligand	Binding Energy Kcal/Mol	INTERACTIONS
		Hydrogen Bonds				Hydrophobic Bonds Residues	π-stacking	Salt Bridges
		Residues	Distance Å		Donar Angle°
			H-A	D-A
Caffeic acid	−6.5	Gln63 Arg195 Arg195 Glu233	2.07 3.30 2.15 2.96	2.99 4.00 3.12 3.91	155.49 129.64 167.47 168.34	Trp58 Tyr62 Leu165	Tyr62
Ferulic acid	−6.5	Gln63 Arg195 Arg195 Glu233	2.08 3.35 2.14 2.59	2.99 4.04 3.11 3.00	153.71 129.06 168.24 105.82	Trp58 Tyr62 Leu165	Tyr62
Vanilic acid	−5.5	Tyr62 Arg195 Arg195 Ala198	3.52 3.30 2.09 3.53	4.09 3.98 3.06 3.94	121.52 128.38 167.42 107.51	Trp58 Tyr62	Tyr62
Homovanillic acid	−5.8	Trp59 Arg195 Arg195 Ala198 Glu233	3.41 3.36 2.15 3.70 2.31	4.06 4.06 3.12 4.08 3.00	128.30 128.99 167.90 105.95 127.32	Trp58 Trp59 Tyr62	Tyr62
p-Coumaric acid	−6.2	Gln63 Arg195 Arg195 Glu233	2.02 3.18 2.39 3.47	2.92 3.89 3.27 3.83	151.32 130.13 148.62 104.78	Trp58 Tyr62 Leu165	Tyr62
Rosmarinic acid	−7.9	Trp59 Tyr62 Gln63 Arg195 Arg195 Ala198 Glu233 His299	3.08 3.55 2.43 2.65 2.23 3.64 2.29 3.04	3.40 4.10 3.33 3.34 3.02 4.00 3.03 3.76	101.91 117.70 151.73 127.41 135.90 103.91 132.34 132.18	Trp58 Trp58 Trp59 Leu162 Ala198 Asp300	Tyr62	His101
Chlorogenic acid	−7.4	Gln63 Asn105 Ala106 Thr163 Thr163 Gly164	3.36 2.69 2.37 3.30 1.98 3.04	3.99 3.14 3.30 3.93 2.88 3.43	123.76 107.83 157.56 124.19 152.95 106.70	Tyr62
Coumarin	−5.4	Gln63	2.36	3.27	153.26	Trp58 Tyr62 Leu165	Tyr62
Herniarin	−5.9	Gln63	2.35	3.27	154.08	Trp58 Tyr62 Leu165	Tyr62
Apigenin	−8.6	Trp59 Gln63 Arg195 Arg195 Glu233	2.96 2.35 3.05 2.39 3.06	3.67 2.90 3.81 3.30 3.95	130.51 114.15 134.62 153.18 153.79	Trp58 Tyr62	Phe215 His263
Luteolin	−8.9	Gln63 Arg195 Arg195 Asp197 His299	2.30 3.06 2.35 2.13 2.73	2.87 3.81 3.26 3.07 3.66	115.57 133.72 153.83 166.68 163.26	Trp58 Tyr62	Trp59 Trp59 Tyr62
Quercetin	−8.9	Gln63 His101 Arg195 Arg195 Asp197 Ala198	2.27 3.48 3.10 2.02 2.32 3.60	2.88 3.97 3.81 2.99 2.77 3.98	118.49 114.44 127.74 167.39 107.24 105.57	Trp58 Trp59 Trp59 Tyr62	Trp59 Tyr62

Table 7. Binding energies for and key protein residues of lipase receptor (1LPB) interacting with the ligands.

Ligand	Binding energy Kcal/mol	Interactions
		Hydrogen bonds				Hydrophobic bonds residues	π-stacking	Salt Bridges
		Residues	Distance Å		Donar Angle°
			H-A	D-A
Caffeic acid	−6.3	Gly76 Tyr114 Tyr114 Glu179	3.41 3.65 3.15 3.23	3.80 4.01 4.01 4.02	106.40 105.90 148.46 137.67	Phe77 Phe77 Phe215	Phe215	His151 His263
Ferulic acid	−6.1	Phe77 Ser152 Ser152	3.43 2.48 2.45	4.00 3.25 3.25	118.54 135.79 142.76	Phe77 Phe77 Tyr114 Pro180 Phe215		His151 His263
Vanilic acid	−5.6	Ser152 Ser152	1.88 2.16	2.76 2.76	149.59 120.74	Phe77 Tyr114 Pro180 Phe215		His263
Homovanillic acid	−5.8	Ser152	2.04	2.97	161.11	Phe77 Tyr114 Pro180 Phe215 Phe215		His263
p-Coumaric acid	−6.2	Ser152 Ser152	3.40 3.64	4.10 4.10	131.00 111.17	Phe77 Phe77 Tyr114 Tyr114 Phe215 Phe215		His151 His263
Rosmarinic acid	−8.4	Gly76 Phe77 Phe77 Asp79 Tyr114 His151 Ser152 Ser152	2.53 2.60 2.53 2.76 2.44 2.46 1.87 2.91	3.27 3.07 3.28 3.13 3.22 3.24 2.70 3.67	132.26 109.81 133.89 104.19 136.64 135.64 141.82 135.57	Phe77 Tyr114 Phe215 Phe215 Ala260 Leu264	Phe215
Chlorogenic acid	−8.8	Gly76 Phe77 His151 Ser152	3.13 3.21 2.55 2.17	3.90 3.77 3.21 2.98	136.11 118.28 123.97 140.76	Phe77 Phe77 Tyr114 Pro180 Phe215	Tyr114	Arg256 His263
Coumarin	−7.0	Ser152	2.90	3.81	157.12	Phe77 Ala178 Pro180 Phe215	Phe215 Phe215	His263
Herniarin	−6.7	Phe77 Ser152	3.50 2.95	3.96 3.69	110.94 133.24	Phe77	Phe215 Phe215	His151 His263
Apigenin	−9.3	Gly76 Asp79 His151	2.29 2.56 2.23	3.09 3.01 3.06	137.06 110.30 141.92	Phe77 Phe215 Leu264	Phe215 His263
Luteolin	−9.6	Gly76 Phe77 Asp79 Tyr114 Tyr114 Tyr114 His151 Glu179	2.33 3.49 2.52 3.61 3.21 3.28 2.24 3.25	3.13 3.94 2.97 3.94 3.94 4.04 3.07 4.03	138.00 110.39 109.52 103.79 133.15 136.71 141.49 137.19	Phe77 Phe215 Leu264	Phe215 His263
Quercetin	−9.3	Gly76 Asp79 Asp79 Tyr114 His151 Phe215	2.25 2.48 2.56 3.69 2.15 2.44	3.07 2.96 2.96 4.06 3.00 2.94	139.41 112.22 104.40 106.85 143.85 111.38	Phe77 Phe215 Leu264	Phe215 His263