Antioxidant, α-amylase, and acetylcholinesterase inhibitory activities of Hertia cheirifolia essential oils: Influence of plant organs and seasonal variation

Figures & data

Table 1. The main climatic conditions throughout the seven months of collection.

Period of collection	Average rainfall (mm)	Average temperature (°C)	Average relative humidity (%)
September	36.80	26.35	72
October	18.80	25.10	71
November	37.00	17.55	64
December	86.40	14.20	72
January	33.20	13.80	65
February	26.60	14.80	67
March	50.60	14.75	72

Figure 1. The collection periods of samples according to the three major phenological stages of Hertia cheirifolia.

Figure 2. The main development stages of Hertia cheirifolia throughout the months of collection. Le: leaves; Fb: flower bud; Fl: flowers (inflorescence); Fr: fruit.

Table 2. Essential oil composition (%) of leaves, flower buds, flowers, and fruits of Hertia cheirifolia.

Compounds	RI	Leaves*	Flower buds	Flowers	Fruits
α-pinene	938	35.63 ± 1.40^a	12.67 ± 0.22^c	15.59 ± 0.15^b	33.17 ± 0.07^a
Sabinene	978	0.77 ± 0.04^a	0.34 ± 0.02^b	0.43 ± 0.03^b	0.62 ± 0.08^a
β-pinene	982	0.27 ± 0.03^b	0.14 ± 0.01^c	0.23 ± 0.01^b	0.42 ± 0.01^a
β-myrcene	995	0.25 ± 0.02^a	0.13 ± 0.02^b	0.17±0.04^b	0.16 ± 0.03^b
Limonene	1034	0.15 ± 0.03^a	0.09 ± 0.01^ab	0.14 ± 0.02^a	tr^b
Campholene aldehyde	1132	0.24 ± 0.02^a	tr^b	tr^b	tr^b
Camphene hydrate	1152	0.04 ± 0.01^a	tr^b	tr^b	tr^b
Verbenone	1217	0.03 ± 0.01^a	tr^b	tr^b	tr^b
β-bourbonene	1386	0.08 ± 0.02^a	tr^b	tr^b	tr^b
β-elemene	1400	1.30 ± 0.06^a	1.18 ± 0.08^a	1.10 ± 0.11^a	0.26 ± 0.01^b
β-caryophylene	1429	0.65 ± 0.02^a	0.59 ± 0.04^ab	0.50 ± 0.02^b	tr^c
Alloaromadendrene	1481	0.08 ± 0.01^a	0.07 ± 0.01^a	0.05 ± 0.01^a	tr^b
ɣ-Curcumene	1486	0.20 ± 0.03^a	0.16 ± 0.05^ab	0.14 ± 0.01^b	tr^c
Germacrene D	1492	11.41 ± 0.30^b	12.80 ± 0.46^a	13.18 ± 0.05^a	5.25 ± 0.20^c
α-amorphene	1498	0.48 ± 0.07^b	0.89 ± 0.05^a	0.80 ± 0.02^a	tr^c
Bicyclogermacrene	1507	0.78 ± 0.05^b	0.73 ± 0.05^b	0.90 ± 0.02^a	tr^c
Germacrene A	1516	0.04 ± 0.01^b	0.17 ± 0.02^a	0.16 ± 0.01^a	tr^c
δ-cadinene	1535	0.14 ± 0.02^a	0.07 ± 0.00^b	0.13 ± 0.01^a	tr^c
Caryophyllene oxide	1596	0.40 ± 0.08^a	tr^b	tr^b	tr^b
Cadalene	1687	1.01 ± 0.05^a	tr^b	0.96 ± 0.03^a	tr^b
Anthracene,1,2,3,4,5,6,7,8- octahydro-9,10-dimethyl	1817	1.27 ± 0.09^a	0.24 ± 0.02^c	0.37 ± 0.01^b	tr^d
Drimane type sesquiterpene**	1927	13.81 ± 0.23^d	34.08 ± 0.26^a	30.92±0.20^b	27.19 ± 0.23^c
Drimenin	1934	27.29 ± 1.32^d	32.53 ± 0.37^a	32.55 ± 0.15^a	30.67 ± 0.46^b
Total identified (%)		96.31 ± 1.07	96.89 ± 0.32	98.31 ± 0.77	97.74 ± 0.68
Mh (%)		38.61 ± 0.12^a	13.61 ± 0.17^d	17.92 ± 0.22^c	34.36 ± 0.41^b
Om (%)		0.31 ± 0.01^a	tr^b	tr^b	tr^b
Sh (%)		16.17 ± 0.41^a	16.66 ± 0.14 ^a	17.92 ± 0.31^a	5.51 ± 0.16^b
Os (%)		0.40 ± 0.08^a	tr^b	tr^b	tr^b
Sl (%)		41.10 ± 0.95^d	66.61 ± 0.21^a	63.46 ± 0.18^b	57.86 ± 0.22^c

RI: Retention indices relative to n-alkanes (C9-C24) on HP-5MS column; *: Average over all the seven months; tr: trace (<0.01%); Mh: monoterpene hydrocarbons; Om: oxygenated monoterpenes; Sh: sesquiterpene hydrocarbons; Os: oxygenated sesquiterpenes; Sl: sesquiterpenes lactones.

**Mass spectra of the drimane-type sesquiterpene, M⁺ m/z 234; m/z (%): 109 (100), 108 (56), 159 (49), 145 (43), 111 (38), 216 (29), 199 (23), 214 (15), 91 (15), 110 (14).

Values followed by different letters within the same row are significantly different (p < 0.05).

Figure 3. Mass spectra of the drimane-type sesquiterpene lactone (a) and drimenin (b).

Table 3. Variation of leaf essential oil composition (%) at different phenological stages of Hertia cheirifolia.

	Vegetative stage		Flowering stage		Fruiting stage
Compound	September	October	November	December	January	February	March
α-pinene	53.44 ± 3.68^a	52.95 ± 2.64^a	31.44 ± 1.25^c	30.78 ± 0.12^c	19.49 ± 0.25^e	37.06 ± 1.16^b	24.24 ± 0.68^d
Sabinene	1.24 ± 0.10^a	1.24 ± 0.12^a	0.56 ± 0.01^c	0.54 ± 0.02^c	0.38 ± 0.01^d	0.83 ± 0.04^b	0.58 ± ± 0.03^c
β- pinene	0.46 ± 0.03^a	0.46 ± 0.04^a	0.21 ± 0.01^c	tr ^e	0.14 ± 0.00^d	0.39 ± 0.02^b	0.23 ± 0.04^c
β- myrcene	0.49 ± 0.04^a	0.49 ± 0.05^a	0.25 ± 0.01^b	tr ^e	0.13 ± 0.01^d	0.19 ± 0.01^c	0.20 ± 0.03^bc
Limonene	0.29 ± 0.03^a	0.22 ± 0.11^ab	0.16 ± 0.03^b	tr ^d	0.08 ± 0.01^c	0.19 ± 0.01^b	0.08 ± 0.05^c
Campholene aldehyde	0.60 ± 0.06^a	0.59 ± 0.07^a	0.06 ± 0.03^b	tr ^c	tr ^c	0.45 ± 0.01^b	tr ^c
Camphene hydrate	tr ^b	tr ^b	0.27 ± 0.04^a	tr ^b	tr ^b	tr ^b	tr ^b
Verbenone	0.22 ± 0.02^a	0.16 ± 0.08^a	tr ^c	tr ^c	tr ^c	0.05 ± 0.01^b	tr ^c
β- bourbonene	0.26 ± 0.04^a	0.10 ± 0.01^b	0.18 ± 0.02^a	tr ^c	tr ^c	tr ^c	tr ^c
β-elemene	1.48 ± 0.13^bc	1.46 ± 0.17^bc	1.97 ± 0.04^a	1.65 ± 0.02^b	0.66 ± 0.02^d	0.59 ± 0.01^d	1.33 ± 0.02^c
β-caryophylene	0.72 ± 0.03^bc	0.63 ± 0.07^c	0.95 ± 0.03^a	0.80 ± 0.03^b	0.29 ± 0.01^e	0.42 ± 0.01^d	0.76 ± 0.02^bc
Alloaromadendrene	0.21 ± 0.02^a	0.14 ± 0.07^a	0.18 ± 0.01^a	tr ^b	tr ^b	tr ^b	tr ^b
ɣ-Curcumene	0.30 ± 0.03^b	0.22 ± 0.03^c	0.46 ± 0.02^a	tr ^e	0.10 ± 0.01^d	0.09 ± 0.02^d	0.25 ± 0.00^bc
Germacrene D	6.67 ± 0.73^e	6.64 ± 0.85^e	11.96 ± 0.24^c	15.06 ± 0.52^b	10.07 ± 0.18^c	8.28 ± 0.11^d	21.18 ± 0.11^a
α-amorphene	0.80 ± 0.08^a	0.72 ± 0.02^a	0.80 ± 0.03^a	tr ^c	0.51 ± 0.03^b	tr ^c	0.56 ± 0.32^b
Bicyclogermacrene	0.50 ± 0.06^c	0.36 ± 0.04^d	1.03 ± 0.05^b	1.03 ± 0.02^b	0.65 ± 0.05^c	0.61 ± 0.03^c	1.28 ± 0.03^a
Germacrene A	0.07 ± 0.01^b	tr^c	0.24 ± 0.01^a	tr ^c	tr ^c	tr ^c	tr ^c
δ-cadinene	0.27 ± 0.02^a	0.20 ± 0.10^ab	0.24 ± 0.02^a	tr ^d	0.06 ± 0.00^c	tr ^d	0.18 ± 0.03^b
Caryophyllene oxide	1.35 ± 0.26^a	1.29 ± 0.31^a	0.18 ± 0.00^b	tr ^c	tr ^c	tr ^c	tr ^c
Cadalene	0.30 ± 0.04^e	0.23 ± 0.11^e	1.30 ± 0.06^c	1.90 ± 0.03^a	0.80 ± 0.06^d	1.02 ± 0.05^d	1.51 ± 0.03^b
Anthracene,1,2,3,4,5,6,7, 8-octahydro-9,10-dimethyl	2.30 ± 0.26^a	2.25 ± 0.33^a	1.35 ± 0.02^c	1.89 ± 0.02^b	0.18 ± 0.01^e	0.47 ± 0.03^d	0.42 ± 0.01^d
Drimane type sesquiterpene	tr ^f	tr ^f	10.72 ± 0.67^e	22.88 ± 0.44^b	29.14 ± 0.06^a	18.83 ± 0.52^c	15.09 ± 0.30^d
Drimenin	22.42 ± 3.04^d	22.41 ± 3.35^d	31.06 ± 1.14^b	22.50 ± 0.55^c	36.16 ± 0.44^a	27.16 ± 0.92^c	29.33 ± 0.33^b
Total identified (%)	94.39 ± 2.02	92.75 ± 1.23	95.58 ± 1.14	99.01 ± 1.96	98.83 ± 1.24	96.61 ± 0.97	97.22 ± 1.86
Mh (%)	58.22 ± 0.87^a	57.61 ± 1.41^a	33.97 ± 0.92^c	33.22 ± 0.53^c	20.04 ± 0.45^e	39.12 ± 0.23^b	25.75 ± 0.37^d
Om (%)	0.82 tr ^d	0.75 ± 0.08^b	0.33 ± 0.03^a	tr ^d	tr ^d	0.5 ± 0.01^c	tr ^d
Sh (%)	11.59 ± 0.13^c	10.70 ± 0.24^c	19.31 ± 0.87^b	20.44 ± 0.46^b	13.14 ± 0.23^c	11.01 ± 0.11^d	27.05 ± 0.41^a
Os (%)	1.35 ± 0.26^a	1.29 ± 0.31^a	0.18 ± 0.00^b	tr ^c	tr ^c	tr ^c	tr ^c
Sl (%)	22.42 ± 3.04^d	22.41 ± 3.35^d	41.78 ± 0.86^c	45.38 ± 0.51^b	65.30 ± 0.21^a	45.99 ± 0.89^b	44.41 ± 0.26^b

tr: trace (<0.01%); Mh: monoterpene hydrocarbons; Om: oxygenated monoterpenes; Sh: sesquiterpene hydrocarbons; Os: oxygenated sesquiterpenes; Sl: sesquiterpenes lactones.

Values followed by different letters within the same row are significantly different (p < 0.05).

Figure 4. Variation of the percentages of α-pinene, germacrene D, drimane type, and drimenin during the three phenological stages. For each compound, bars with different letters are significantly different (p < 0.05).

Table 4. Correlation coefficients (R) between major components and climatic parameters.

	Rainfall	Temperature	Humidity
Major compounds
α-pinene	−0.379	0.920**	0.432
Germacrene D	0.627	−0.612	0.226
Drimane type	0.414	−0.928**	−0.397
Drimenin	−0.216	−0.600	−0.768*
Terpenic classes
Monoterpene hydrocarbons	−0.341	0.904**	0.445
Sesquiterpene hydrocarbons	0.601	−0.343	0.329
Sesquiterpene lactones	0.244	−0.912**	−0.542

*, **: Significant at p < 0.05 and p < 0.01, respectively.

Table 5. Antioxidant, acetylcholinesterase, and α-amylase inhibitory activities of leaves, flower buds, flowers, and fruits.

	Leaves*	Flower buds	Flowers	Fruits
Radical scavenging activity (mg Eq trolox/gEO)	15.6 ± 1.7^a	5.07 ± 1.3^b	1.35 ± 0.3^c	4.4 ± 0.5^b
Ferrous ion chelating activity (mg Eq EDTA/gEO)	6.39 ± 0.6^b	6.99 ± 0.2^b	8.42 ± 0.4^a	4.95 ± 0.2^c
β-carotene bleaching test (mgEq BHT/gEO)	31.9 ± 5.7^a	15.7 ± 2.1^b	38.6 ± 4.1^a	10.2 ± 6.8^c
Ferrous reducing power (µmol Fe^2+/gEO)	166.7 ± 8.3^a	67.5 ± 4.1^b	70.2 ± 2.11^b	64.9 ± 5.4^b
AChE inhibitory activity (mg Eq donepezil/gEO)	1.47 ± 0.4^b	1.86 ± 0.2^a	0.62 ± 0.1^c	1.43 ± 0.4^a
α-amylase inhibitory activity (mg Eq acarbose/gEO)	8.32 ± 1.6^a	2.75 ± 0.04^c	5.85 ± 0.3^b	8.84 ± 0.9^a

*: Average over all the seven months

Values followed by different letters within the same row are significantly different (p < 0.05).

Table 6. Antioxidant, acetylcholinesterase, and α-amylase inhibitory activities of leaf essential oil at different phenological stages.

	Vegetative stage		Flowering stage		Fruiting stage
	Sep	Oct	Nov	Dec	Jan	Feb	Mar
Radical scavenging activity (mg Eq trolox/gEO)	15.1 ± 0.7^d	18.9 ± 0.2^b	17.2 ± 0.2^c	22.3 ± 1.1^a	11.1 ± 0.2^e	9.9 ± 0.4^f	14.8 ± 0.6^d
Ferrous ion chelating activity (mg Eq EDTA/gEO)	6.6 ± 0.2^b	8.4 ± 0.7^a	8.3 ± 0.5^a	5.8 ± 0.4^bc	5.6 ± 0.8^c	4.6 ± 0.5^c	5.4 ± 0.9^c
β-carotene bleaching test (mg Eq BHT/gEO)	51.6 ± 3.7^a	44.9 ± 1.4^b	31.8 ± 2.3^d	37.8 ± 4.5^c	25.6 ± 3.1^e	11.9 ± 2.3^g	19.7 ± 3.8^f
Ferrous reducing power (µmol Fe^2+/gEO)	191.1 ± 3.1^c	213.2 ± 4.7^b	225 ± 2.1^a	162 ± 5.9^d	167.1 ± 2.8^d	84.5 ± 3.3^f	123.7 ± 2.7^e
AChE inhibitory activity (mg Eq donepezil/gEO)	0.82 ± 0.2^d	0.86 ± 0.5^d	1.33 ± 0.4^c	2.91 ± 0.3^a	2.25 ± 0.4^b	1.6 ± 0.2^c	0.53 ± 0.1^e
α-amylase inhibitory activity (mg Eq acarbose/gEO)	8.29 ± 0.3^c	8.33 ± 0.2^c	11.56 ± 0.9^b	14.4 ± 0.8^a	8.12 ± 0.15^c	4.44 ± 0.7^d	3.07 ± 0.2^e

Values followed by different letters within the same row are significantly different (p < 0.05).

Table 7. Correlation coefficients (R) between oil compounds and antioxidant, acetylcholinesterase, and α-amylase inhibitory activities.

	α-pinene	Germacrene D	Drimane type	Drimenin	Mh	Sh	Sl
Scavenging activity	0.241	0.206	−0.284	−0.588*	0.262	0.323	−0.419
Chelating activity	0.472	−0.318	−0.660*	−0.207	0.486	−0.139	−0.563*
β−carotene bleaching inhibition	0.682**	−0.411	−0.655*	−0.599*	0.697**	−0.280	−0.697**
Reducing power	0.351	−0.310	−0.505	−0.112	0.369	−0.134	−0.414
AChE inhibitory activity	−0.445	0.020	0.744**	0.136	−0.446	−0.039	0.600*
α−amylase inhibitory activity	0.046	−0.121	0.063	−0.234	0.061	−0.002	−0.036

Mh: monoterpene hydrocarbons; Sh: sesquiterpene hydrocarbons; Sl: sesquiterpenes lactones

*, **: Significant at p < 0.05 and p < 0.01, respectively.