Advertisement

SN Applied Sciences

, 1:1606 | Cite as

Effect of drying on the essential oil traits and antioxidant potential J. regia L. leaves from Kumaun Himalaya

  • Lalit M. Tewari
  • Lata Rana
  • Santosh K. Arya
  • Geeta TewariEmail author
  • Neha Chopra
  • Naveen C. Pandey
  • Penny Joshi
  • Rekha Gahtori
Research Article
  • 88 Downloads
Part of the following topical collections:
  1. Materials Science: Recent Advances in Natural and Nanostructured Functional Materials

Abstract

Drying is an ancient technique adopted to reduce moisture, preserve aroma profile and increase the shelf life of the food products. During drying, the chemical, nutritional and antioxidant properties of the food can get altered as compared to the fresh material. Natural shade drying is the most accepted storage method for aromatic medicinal herbs because of its low cost and minimum loss of volatile constituents. In the present investigation, the effects of shade drying on the volatile components and antioxidant potential of walnut leaves (Juglans regia) have been studied. For this purpose, fresh walnut leaves were shade dried and hydrodistilled using Clevenger apparatus. The extracted oil was analysed by GC and GC/MS. The antioxidant potential of the oils was evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging activity. The GC and GC/MS analysis identified 46 and 42 compounds representing 89.29% and 96.38% of the total fresh and dried oils, respectively. The composition of the five major components namely (E)-caryophyllene, germacrene D, α-zingiberene, δ-cadinene and (E)-β-farnesene was observed to significantly increase after shade drying. Drying caused appearance of four components with complete loss of eight components. Fresh oil showed better antioxidant activity as compared to the shade dried oil.

Keywords

Juglans regia Essential oil Drying (E)-caryophyllene Germacrene D Monoterpene Antioxidant activity 

1 Introduction

Juglans regia L., an aromatic indigenous plant of southeastern Europe, Asia, northern America, North Africa, India and China, belongs to the family Juglandaceae. It is commonly known as walnut “akhrot” (in Hindi) [1]. The essential oil of J. regia is an ingredient of dry skin creams, anti-ageing and anti-wrinkle products as it shows moisturizing properties along with free radical scavenging activity [2]. All the plant parts like green husks, leaves, green walnuts, bark and shells have been used in the pharmaceutical and cosmetic industries [3]. Highly nutritious seeds of the walnut tree are consumed as royal food across the globe. These are rich in protein, carbohydrates, unsaturated fatty acids, vitamins, minerals (copper, iron, magnesium, phosphorus, potassium and sulphur) flavonoids, sterols, phenolic acids and fibres [4, 5, 6]. The stem bark of the plant is reported to show anthelmintic, astringent, bactericide, detergent, depurative, digestive, diuretic, insecticidal and laxative properties [7]. The leaves have been used as folk medicine due to their anthelmintic, astringent, antidiarrheic, fungicidal and insecticidal properties [4, 5, 6]. The oil is a rich source of (E)-caryophyllene, caryophyllene oxide, β-pinene, germacrene D and carvacrol which are accountable for various biological activities.

High demand of preserved and processed food products requires high-quality raw materials. Drying is a post-harvest technique which is used for preservation, microbial decontamination, increase shelf life and disinfections of herbs [8]. It includes natural (sun, shade), hot air, microwave and freeze drying. Drying affects the content of flavour constituents of aromatic and medicinal plants which are considered as antioxidant and antimicrobial agents [9]. Drying may upgrade aroma quality of the plants either by esterification/oxidation/formation of new compounds or loss of volatile components [10]. A number of reports are available on the effect of drying on the essential oil composition of various aromatic species like Thymus vulgaris [11], Murraya koenigii [12], Ocimum americanum [13, 14], Ocimum gratissimum [15] and Origanum vulgare [16].

Reports are available on the volatile composition of J. regia leaves from Egypt [17], India [18, 19, 20], Tunisia [21], Iran [22] and the nuts from Pakistan [23]. There are few reports on the antioxidant potential evaluation of leaf oil of J. regia [18, 20, 23].

Existing literature data revealed that no work has been reported on the effect of drying on the essential oil composition and antioxidant activity of J. regia leave oil. Therefore, the present work aims to explore the impact of natural shade drying on the aroma profile and antioxidant potential of J. regia L. oil from the Himalayan region of, Uttarakhand.

2 Materials and methods

2.1 Collection of plant

Fresh leaves of Juglans regia were collected from Padli, Ratighat (Bhowali), Nainital (Latitude: 29°23°410′ N; Longitude: 79°30′546″ E; Altitude: 1700 m) in the month of August 2017.

2.2 Extraction of oil

Two-kilogram fresh leaves of J. regia were subjected to hydrodistillation using Clevenger apparatus for 5 h. Five kilograms of fresh leaves were shade dried up to the constant weight and 500 g of dried material was hydrodistilled in Clevenger for 5 h. The oils were dried over anhydrous sodium sulphate and kept in Biological Oxygen Demand (BOD) incubator at 4 °C prior to analysis.

2.3 Analysis of oil

The extracted oil was analysed on a Shimadzu 2010 GC, fitted with Rtx-5 column (30 m × 0.25 mm, i.d. 0.25 μm) and flame ionization detector (FID) using Nitrogen/air as the carrier gas. The column was programmed at 50 °C with a hold time of 2 min to 210 °C at a rate of 3 °C/min and increased to 280 °C at 8 °C/min rate and at 280 °C; the sample was hold for 16 min. Nitrogen was adjusted at 30 mL/min column head pressure. The temperature of injector and FID was adjusted to 260 °C and 270 °C, respectively. The split ratio was 1:40, and injection volume was 0.2 μL neat oil. The GC/MS unit was GCMS-QP2010 Ultra consisted of Rtx-5 column (30 m × 0.25 mm, i.d. 0.25 μm). Helium was used as a carrier gas. The mass spectrum was recorded at 70 eV and 40–650 amu. Conditions for GC/MS analysis were similar to that of GC.

2.4 Identification of the components

The identification of the individual constituent was done by comparing the fragmentation pattern of the mass spectral data with literature data [24] and by comparing with NIST (NIST version 2.1) and Wiley (7th edition) mass spectral database. The retention index (RI) of each constituent was calculated by comparing with n-alkane series (C9C33). The relative percentage of each compound in the oil was attained on the basis of FID response without using a correction factor.

2.5 Antioxidant activity measurement

The antioxidant potential of the oils was determined in terms of their radical scavenging activity by the bleaching of purple coloured methanolic solution of 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) [25]. Ascorbic acid was used as standard. One mL solution of oil and standard comprising of different concentrations in methanol (50, 100, 200, 400, 800, 1000 µg/mL for fresh oil; 10, 20, 40, 80, 160 mg/mL for dry oil and 10, 20, 40, 80, 160 µg/mL for ascorbic acid) were mixed with 5 mL methanolic solution of DPPH (0.2 mM). A control was also run without oil under similar conditions. All the samples were incubated for 30 min in the dark at room temperature. The test was performed in triplicate, and the data were represented as mean ± standard deviation (SD) values. The DPPH radical scavenging effect was calculated as “percentage inhibition” according to the equation:
$$\% {\text{DPPH}}\,{\text{scavenging}}\,{\text{activity = }}\frac{{(A_{\text{o}} - A_{\text{t}} )}}{{A_{\text{o}} }} \times 100$$
where Ao is the absorbance of control sample at 517 nm and At is the absorbance value of oil at 517 nm.

2.6 Statistical analysis

All the analysis of the present study was carried out in triplicate, and the mean ± SD was calculated by MS Excel. Two-tailed paired t test was performed to compare mean content of major essential oil constituents of fresh and dried J. regia leaves using MS Excel at probability level of p < 0.05 and p < 0.01. The data were subjected to one-way ANOVA to evaluate significant difference between different treatment groups (significance level of p < 0.05).

3 Results and discussion

3.1 Essential oil composition

A total of 46 and 42 compounds were identified on the basis of GC (Figs. 1, 2) and GC/MS analysis which represented 89.29% and 96.38% of the total fresh and dried oils, respectively. The essential oil yield was 0.02% (v/w). The major components in the fresh leave oil of J. regia were (E)-caryophyllene (13.30%), β-pinene (11.63%), germacrene D (9.31%), β-selinene (7.77%), α-zingiberene (6.74%), α-pinene (6.22%) and δ-cadinene (5.38%) (Table 1; Fig. 3).
Fig. 1

Gas chromatogram of fresh J. regia oil

Fig. 2

Gas chromatogram of dried J. regia oil

Table 1

Previous reports on J. regia essential oil

S. no.

Collection site

Plant part

Major constituents

References

1.

Kentucky, USA

Leaf

Germacrene D (28.6%) and methyl salicylate (16.8%)

[17]

2.

Kashmir

Leaf

β-Pinene (30.5%), α-pinene (15.1%), β-caryophyllene (15.5%) and germacrane D (14.4%)

[18]

3.

India (Western Himalaya)

leaf

(E)-Caryophyllene (47.9%), β-pinene (39.5%), germacrene D (23.3%), α-pinene (18.1%), α-humulene (11.8%), α-zingiberene (11.3%), α-copaene (10.1%), limonene (8.6%), caryophyllene oxide (8.6%), ar-curcumene (7.2%), δ-cadinene (6.7%), (E)-β-farnesene (5.9%) and 1,8-cineole (5.4%)

[19]

4.

Tunisia

Leaf

Caryophyllene oxide (27.4%) β–caryophyllene (22.5%), germacrene D (9.4%) and β-pinene (9.5%)

[21]

5.

Iran

Walnut hydrosol

Carvacrol (33.21%), thymol (16%) and homoveratrole (15.83%)

[22]

6.

Pakistan

Nuts oil

Benzyl alcohol (18.14%), nerolidol (13.54%), globulol (10.95%) and p-cymene (10.94%)

[23]

Fig. 3

Variation in the major constituents of fresh and dried J. regia

Previous study on J. regia fresh leaf oil from Indian Western Himalaya also reported the high percentage of (E)-caryophyllene, β-pinene, germacrene D and α-zingiberene [19] (Table 1; Fig. 4). Another report on the leaf essential oil of J. regia from USA suggested the presence of germacrene D and methyl salicylate as major constituents [17]. Furthermore, the leaf essential oil from Kashmiri akhrot was predominated by β-pinene, α-pinene, β-caryophyllene and germacrene D [18]. A previous study from Pakistan reported the high percentage of benzyl alcohol, nerolidol, globulol and p-cymene in the nuts oil of J. regia. Moravej et al. [22] examined the essential oil composition of walnut hydrosol from Iran and observed the composition to be entirely different from leaf oil. The main components of the hydrosol oil were oxygenated monoterpenes such as thymol and carvacrol (Table 1).
Fig. 4

Comparative essential oil composition of J. regia oil

In the present study, the major volatile components in the shade dried oil were (E)-caryophyllene (18.88%), germacrene D (18.53%), α-zingiberene (9.88%), β-pinene (8.27%), (E)-β-farnesene (7.73%), δ-cadinene (6.81%) and α-pinene (5.04%). In a previous report from Tunisia [21], caryophyllene oxide, (E)-caryophyllene, germacrene D and β-pinene were obtained as major components in the shade dried J. regia leaf oil (Table 1; Fig. 4). Eight components including camphene, (3E)-hexenyl acetate, methyl salicylate, bornyl acetate, β-selinene, trans-muurola-4(14), 5-diene, α-bulnesene and elemol were present only in fresh oil. Out of these, β-selinene was present as major component. In addition, α-terpineol, spathulenol, globulol and salvia-4(14)-en-1-one were present only in the dried sample. The mean percentage of six components namely β-pinene (11.63–8.27% at p < 0.05), β-selinene (7.77–0.00%), α-pinene (6.22–5.04% at p < 0.05), methyl salicylate (4.02–0.00%), caryophyllene oxide (1.56–0.84% at p < 0.01) and 1,8-cineole (1.47–1.15% at p < 0.01) significantly decreased on drying. It was observed that drying led to the significant increase in the percentage of five major compounds including (E)-caryophyllene (13.30–18.88% at p < 0.01), germacrene D (9.31–18.53% at p < 0.01), α-zingiberene (6.74–9.88% at p < 0.01), δ-cadinene (5.38–6.81% at p < 0.05) and (E)-β-farnesene (4.57–7.73% at p < 0.05). Four common constituents present in less than 0.20% amount were neryl acetate (0.02–0.04%), linalool (0.06–0.14%), β-sesquiphellandrene (0.09–0.12%) and α-cubebene (0.16–0.19%) (Table 1). The present study identified β-selinene (7.77%), α-bisabolol (0.99%), geranyl acetate (0.57%), 2-undecanone (0.36%), β-gurjunene (0.29%), humulene epoxide II (0.23%), 1,10-di-epi-Cubenol (0.25%) and 1-epi-cubenol (0.17%) in significant amount for the first time in the dried oil of J. regia.

Sesquiterpene hydrocarbon was the predominating class of volatile compounds in the fresh and dried oil collected from Bhowali (Fig. 5). The result was in good agreement with those obtained by Verma et al. [19]. Kashmiri akhrot oil was rich in monoterpene hydrocarbons (α-pinene and β-pinene) and sesquiterpene hydrocarbons (β-caryophyllene and germacrene D) [18]. Furthermore, the oil from Tunisia was found to be rich in oxygenated sesquiterpene (caryophyllene oxide) and sesquiterpene hydrocarbon (β-caryophyllene) [21] (Fig. 6). The difference in the percentage of the compounds depends upon environmental (seasonal, geographical, climatic), genetic factors, distillation and post-harvest technique (drying, storage conditions) [12, 13, 14, 15, 26]
Fig. 5

Variation in the class of terpenoids in fresh and dried J. regia

Fig. 6

Comparative class of compounds in J. regia

3.2 Antioxidant activity

The DPPH radical scavenging activity of J. regia leaf oils and standard (ascorbic acid) is shown in Tables 2, 3 and Table 4. The results revealed that the samples exhibited concentration-dependent DPPH radical scavenging activity. The antioxidant activity of the fresh oil (IC50: 923.49 µg/mL) was found to be ten times less than the standard (IC50 (92.78 µg/mL) (Tables 3, 5). The results were in good agreement with the previous report on Ocimum gratissimum in which the fresh oil showed better DPPH radical scavenging activity as compared to the dried oil [15]. The dried oil showed moderate antioxidant activity with IC50 value of 48.77 mg/mL (Table 4). Similar to the present study, fresh material of Camellia sinensis was observed to have higher antioxidant content as compared to the dried plant material. This could be attributed degradation caused by the process of drying [27]. On the contrary, study by Pinela et al. has shown that the dried plant material has higher antioxidant content than the fresh plant material [28].
Table 2

Variation in the essential oil composition of fresh and dried J. regia

S. no.

Calculated retention index

Retention index [24]

Name of component

Retention time of components in fresh Juglans regia leaves (minutes)

Mean per cent ± SD (fresh Juglans regia leaves)

Retention time (GC) of components in dried Juglans regia leaves (minutes)

Mean per cent ± SD (dried Juglans regia leaves)

1.

929

932

α-Pinene

9.19

6.22 ± 0.26

9.17

5.04* ± 0.44

2.

945

946

Camphene

9.78

0.07

ND

3.

969

969

Sabinene

10.93

0.14

10.97

0.47

4.

974

974

β-Pinene

11.21

11.63 ± 0.92

11.17

8.27* ± 0.31

5.

987

988

Myrcene

11.77

0.48 ± 0.14

11.78

0.40

6.

1003

1001

(3E)-Hexenyl acetate

12.66

0.49

ND

7.

1029

1026

1,8-Cineole

13.70

1.47 ± 0.06

13.68

1.15** ± 0.05

8.

1044

1044

(E)-β-Ocimene

13.89

0.29 ± 0.01

13.88

1.25** ± 0.09

9.

1082

1086

Terpinolene

14.75

1.19 ± 0.33

14.73

0.58 ± 0.10

10.

1099

1095

Linalool

15.27

0.06

15.28

0.14

11.

1178

1174

Terpinen-4-ol

21.34

0.24

21.31

0.17

12.

1185

1186

α-Terpineol

ND

21.94

0.17

13.

1190

1190

Methyl salicylate

22.29

4.02 ± 0.17

ND

14.

1281

1284

Bornyl acetate

25.50

0.06

ND

15.

1291

1293

2-Undecanone

26.22

0.36 ± 0.10

26.20

0.17 ± 0.01

16.

1344

1345

α-Cubebene

28.94

0.16

28.91

0.19

17.

1350

1356

Eugenol

29.47

2.01 ± 0.09

29.40

1.65 ± 0.18

18.

1357

1359

Neryl acetate

29.58

0.04

29.56

0.02

19.

1373

1374

α-Copaene

30.24

3.71 ± 0.26

30.18

3.54 ± 0.05

20.

1377

1379

Geranyl acetate

30.46

0.57

30.43

0.10

21.

1379

1387

β-Cubebene

30.57

0.35

30.53

0.18

22.

1386

1389

β-Elemene

30.85

0.84 ± 0.05

30.82

1.07 ± 0.06

23.

1401

1390

7-epi-Sesquithujene

31.46

0.18

31.44

0.24

24.

1411

1411

(Z)-α-Bergamotene

31.96

0.29

31.94

0.35

25.

1417

1417

(E)-Caryophyllene

32.33

13.30 ± 0.26

32.30

18.88** ± 0.92

26.

1425

1430

β-Copaene

32.51

0.28

32.49

0.43

27.

1432

1431

β-Gurjunene

32.85

0.29

32.82

0.24

28.

1453

1454

(E)-β-Farnesene

33.59

4.57 ± 0.31

33.56

7.73* ± 0.87

29.

1473

1478

γ-Muurolene

33.64

0.02

33.64

0.70

30.

1479

1484

Germacrene D

34.89

9.31 ± 0.60

34.94

18.53** ± 1.01

31.

1485

1489

β-Selinene

35.01

7.77 ± 0.20

ND

32.

1488

1493

trans-Muurola-4(14),5-diene

35.11

0.07

ND

33.

1494

1493

α-Zingiberene

35.39

6.74 ± 0.67

35.37

9.88** ± 0.34

34.

1498

1505

(E,E)-α-Farnesene

35.82

1.29 ± 0.29

35.79

1.32 ± 0.16

35.

1505

1509

α-Bulnesene

35.97

0.05

ND

36.

1509

1513

γ-Cadinene

36.14

0.46

36.13

0.63

38.

1516

1521

β-Sesquiphellandrene

36.89

0.09

36.87

0.12

39.

1521

1522

δ-Cadinene

36.57

5.38 ± 0.13

36.53

6.81* ± 0.27

40.

1545

1548

Elemol

37.08

0.10

ND

41.

1559

1561

(E)-Nerolidol

38.00

0.09

37.99

0.32

42.

1573

1577

Spathulenol

ND

38.38

0.09

43.

1576

1582

Caryophyllene oxide

39.13

1.56 ± 0.10

39.07

0.84** ± 0.05

44.

1581

1590

Globulol

 ND

39.25

0.05

45.

1587

1594

Salvial-4(14)-en-1-one

 ND

39.46

0.28

46.

1603

1608

Humulene epoxide II

39.90

0.23

39.89

0.22

47.

1611

1618

1,10-di-epi-Cubenol

40.13

0.25

40.11

0.23

48.

1623

1627

1-epi-Cubenol

40.83

0.17

40.81

0.64

49.

1640

1644

α-Muurolol

41.06

0.51

41.01

0.04

50.

1652

1652

α-Cadinol

41.40

0.90 ± 0.10

41.41

1.57 ± 0.06

51.

1684

1685

α-Bisabolol

41.94

0.99 ± 0.09

41.95

1.68** ± 0.17

Total

   

89.29

96.38

ND, Not detected

Mean values ± SD (standard deviation) followed by ** and * indicated significance difference between pairs (fresh and dried) at p < 0.01 and p < 0.05, respectively

Table 3

Antioxidant activity of J. regia fresh oil

S. no.

Oil concentration (µg/mL)

% Inhibition ± SD

1

50

13.77a ± 0.41

2

100

16.04b ± 0.30

3

200

18.39c ± 0.31

4

400

23.98d ± 0.35

5

800

47.14e ± 0.31

6

1000

53.29f ± 0.40

IC50

 

923.49 µg/mL

The mean values followed by different alphabets (a–f) at superscript are significantly different at p < 0.05 according to Duncan’s Test

Table 4

Antioxidant activity of dried J. regia oil

S. no.

Concentration (mg/mL)

% Inhibition by oil ± SD

1

10

26.73a ± 0.87

2

20

40.35b ± 0.56

3

40

57.37c ± 0.33

4

80

66.43d ± 0.60

5

160

80.43e ± 0.40

IC50

 

48.77 mg/mL

The mean values followed by different alphabets (a–e) at superscript are significantly different at p < 0.05 according to Duncan’s Test

Table 5

Antioxidant activity of ascorbic acid

S. no.

Concentration (µg/mL)

% Inhibition by ascorbic acid ± SD

1

10

4.78a ± 0.48

2

20

27.33b ± 0.15

3

40

38.61c ± 0.17

4

80

47.45d ± 0.43

5

160

72.73e ± 0.25

IC50

 

92.78 µg/mL

The mean values followed by different alphabets (a–e) at superscript are significantly different at p < 0.05 according to Duncan's Test

The IC50 value of fresh J. regia oil from Kashmir was 34.5 µg/mL [18]. The compounds present in the Kashmiri Juglans were also present in our collection in significant amounts. Some authors have observed the antioxidant properties of monoterpenes in essential oils. The antioxidant potential of Retama raetam oil could be attributed to the relatively high percentage of monoterpenes [29]. Rather et al. [18] reported that the antimicrobial and antioxidant activity of J. regia could be attributed to the synergetic effect of the bioactive constituents. The antioxidant capacity of Schinus molle L. could be explained by the presence of monoterpenes (β-carotine) [30].

4 Conclusion

From the study, it can be concluded that drying has impact on the essential oil composition, number of components and the antioxidant potential of J. regia. The plant could be a potential natural resource for high value aroma chemicals such as (E)-caryophyllene, germacrene D, β-pinene, β-selinene and α-zingiberene. The results showed that the shade drying of J. regia decreased its antioxidant power.

Notes

Acknowledgements

The authors are grateful to the IERP, GBPNIHSED, Kosi, Karmal (Grant No. GBPI/IERP-NMHS/15-16/48) for financial assistance and The Head, Department of Botany, Kumaun University Nainital for providing necessary laboratory facilities.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

References

  1. 1.
    Tsamouris G, Hatziantoniou S, Demetzos C (2002) Lipid analysis of Greek Walnut oil (Juglans regia L.). Z Naturforschung 57c:51–56.  https://doi.org/10.1515/znc-2002-1-209 CrossRefGoogle Scholar
  2. 2.
    Espin JC, Soler-Rivas C, Wichers HJ (2000) Characterization of the total free radical scavenger capacity of vegetable oils and oil fractions using 2,2-di-phenyl- 1-picrylhydrazyl radical. J Agric Food Chem 48(3):648–656.  https://doi.org/10.1021/jf9908188 CrossRefGoogle Scholar
  3. 3.
    Oliveira I, Sousa A, Ferreira I, Bento A, Estevinho L, Pereira JA (2008) Total phenols, antioxidant potential and antimicrobial activity of walnut (Juglans regia L.) green husks. Food Chem Toxicol 46(7):2326–2331.  https://doi.org/10.1016/j.fct.2008.03.017 CrossRefGoogle Scholar
  4. 4.
    Prasad RBN (2003) Walnuts and pecans. In: Caballero B, Trugo LC, Finglas PM (eds) Encyclopaedia of food sciences and nutrition. Academic Press, London, pp 6071–6079CrossRefGoogle Scholar
  5. 5.
    Labuckas DO, Maestri DM, Perello M, Martinez ML, Lamarque AL (2008) Phenolics from walnut (Juglans regia L.) kernels: antioxidant activity and inter-actions with proteins. Food Chem 107(2):607–612.  https://doi.org/10.1016/j.foodchem.2007.08.051 CrossRefGoogle Scholar
  6. 6.
    Pereira JA, Oliveira I, Sousa A, Ferreira I, Bento A, Estevinho L (2008) Bioactive properties and chemical composition of six walnut (Juglans regia L.) cultivars. Food Chem Toxicol 46(6):2103–2111.  https://doi.org/10.1016/j.fct.2008.02.002 CrossRefGoogle Scholar
  7. 7.
    Chopra RN, Nayar SL, Chopra RC (1986) Glossary of Indian medicinal plants (including the supplement). New Delhi, Council of Scientific and Industrial Research, p 11Google Scholar
  8. 8.
    Sourestani MM, Malekzadeh M, Tava A (2014) Influence of drying, storage and distillation times on essential oil yield and composition of anise hyssop Agastache foeniculum (Pursh.) Kuntze. J Essent Oil Res 26:177–184.  https://doi.org/10.1080/10412905.2014.882274 CrossRefGoogle Scholar
  9. 9.
    Capecka E, Mareczek A, Leja M (2005) Antioxidant activity of fresh and dry herbs of some Lamiaceae species. Food Chem 93(2):223–226.  https://doi.org/10.1016/j.foodchem.2004.09.0120 CrossRefGoogle Scholar
  10. 10.
    Hossain MB, Barry-Ryan C, Martin-Diana AB, Brunton NP (2010) Effect of drying method on the antioxidant capacity of six Lamiaceae herbs. Food Chem 123(1):85–91.  https://doi.org/10.1016/j.foodchem.2010.04.003 CrossRefGoogle Scholar
  11. 11.
    Calín-Sánchez Á, Figiel A, Lech K, Szumny A, Carbonell-Barrachina ÁA (2013) Effects of drying methods on the composition of thyme (Thymus vulgaris L.) essential oil. Dry Technol 31(2):224–235.  https://doi.org/10.1080/07373937.2012.725686 CrossRefGoogle Scholar
  12. 12.
    Rani A, Bisht M, Pande C, Tewari G, Bhatt S, Matiyani M (2017) Effect of drying on the volatiles of leaves of Murraya koenigii (L.). J Essent Oil Bear Plant 20(2):552–558.  https://doi.org/10.1080/0972060X.2017.1317606 CrossRefGoogle Scholar
  13. 13.
    Bhatt S, Tewari G, Pande C, Rana L (2018) Impact of drying methods on essential oil composition of Ocimum americanum L. from Kumaun Himalayas. J Essent Oil Bear Plant 21(5):1385–1396.  https://doi.org/10.1080/0972060X.2018.1543031 CrossRefGoogle Scholar
  14. 14.
    Bisht M, Rana L, Tewari G, Pande C, Bhatt S (2019) Effect of natural drying methods on flavour profile of camphor rich Ocimum americanum L. from North India. Asian J Chem 31(2):1321–1326.  https://doi.org/10.14233/ajchem.2019.21862 CrossRefGoogle Scholar
  15. 15.
    Bhatt S, Bisht M, Tewari G, Pande C, Prakash O, Rana L (2019) Evaluation of antioxidant potential and quality of volatile constituents of fresh and sun dried Ocimum gratissimum. J Indian Chem Soc 96:297–304Google Scholar
  16. 16.
    Bhatt S, Tewari G, Pande C, Prakash O, Tripathi S (2019) Aroma profile and antioxidant potential of Origanum vulgare L.: impact of drying. J Essent Oil Bear Plant 22(1):214–230.  https://doi.org/10.1080/0972060X.2019.1599736 CrossRefGoogle Scholar
  17. 17.
    Farag MA (2008) Headspace analysis of volatile compounds in leaves from the Juglandaceae (Walnut) family. J Essent Oil Res 20(4):323–327.  https://doi.org/10.1080/10412905.2008.9700023 MathSciNetCrossRefGoogle Scholar
  18. 18.
    Rather MA, Dar BA, Dar MY, Wani BA, Shah WA, Bhat BA, Ganai BA, Bhat KA, Anand R, Qurishi MA (2012) Chemical composition, antioxidant and antibacterial activities of the leaf essential oil of Juglans regia L. and its constituents. Phytomedicine (15) 19(13):1185–1190.  https://doi.org/10.1016/j.phymed.2012.07.018 CrossRefGoogle Scholar
  19. 19.
    Verma RS, Padalia RC, Chauhan A, Thul ST (2013) Phytochemical analysis of the leaf volatile oil of walnut tree (Juglans regia L.) from western Himalaya. Ind Crop Prod 42:195–201.  https://doi.org/10.1016/j.indcrop.2012.05.032 CrossRefGoogle Scholar
  20. 20.
    Shah TI, Sharma E, Ahmad G (2014) Juglans regia Linn. A phytopharmacological review. World J Pharm Sci 2(4):363–373Google Scholar
  21. 21.
    Abdallah IB, Baatour O, Mechrgui K, Herchi W, Albouchi A, Chalghoum A, Boukhchina S (2016) Essential oil composition of walnut tree (Juglans regia L.) leaves from Tunisia. J Essent Oil Res 28(6):545–550.  https://doi.org/10.1080/10412905.2016.1166157 CrossRefGoogle Scholar
  22. 22.
    Moravej H, Salehi A, Razavi Z, Moein MR, Etemadfard H, Karami F, Ghahremani F (2016) Chemical composition and the effect of walnut hydrosol on glycemic control of patients with type 1 diabetes. Int J Endocrinol Metab 14(1):e34726.  https://doi.org/10.5812/ijem.34726 CrossRefGoogle Scholar
  23. 23.
    Abbasi MA, Raza A, Riaz T, Shahzadi T, Rehman A, Jahangir M, Shahwar D, Siddiqui SZ, Chaudhary AR, Ahmad N (2010) Investigation on the volatile constituents of Juglans regia and their in vitro antioxidant potential. Proc Pak Acad Sci 47(3):137–141Google Scholar
  24. 24.
    Adams RP (2007) Identification of essential oil components by gas chromatography/mass spectrometry. Allured Publishing Corp, Carol StreamGoogle Scholar
  25. 25.
    Singh G, Marimuthu P, Murali HS, Bawa AS (2005) Antioxidative and antibacterial potential of the essential oils and extract isolated from various spices material. J Food Saf 25(2):130–145.  https://doi.org/10.1111/j.1745-4565.2005.00564.x CrossRefGoogle Scholar
  26. 26.
    Singh S, Tewari G, Pande C, Singh C (2013) Variation in essential oil composition of Ocimum americanum L. from Kumaun north-western Himalayan region. J Essent Oil Res 25(4):278–290.  https://doi.org/10.1080/10412905.2013.775079 CrossRefGoogle Scholar
  27. 27.
    Pinela J, Barros L, Duenas M, Carvalho AM, Santos-Buelga C, Ferreira IC (2012) Antioxidant activity, ascorbic acid, phenolic compounds and sugars of wild and commercial Tuberaria lignosa samples: effects of drying and oral preparation methods. Food Chem 135:1028–1035.  https://doi.org/10.1016/j.foodchem.2012.05.038 CrossRefGoogle Scholar
  28. 28.
    Roshanak S, Rahimmalek M, Goli SAH (2016) Evalation of seven different drying treatments in respect to total flavonoid, phenolic, vitamin C content, chlorophyll, antioxidant activity and color of green tea (Camellia sinensis or C. assamica) leaves. J Food Sci Technol 53(1):721–729.  https://doi.org/10.1007/s13197-015-2030-x CrossRefGoogle Scholar
  29. 29.
    Edziri H, Mastouri M, Cheraif I, Aouini M (2010) Chemical composition and antibacterial, antifungal and antioxidant activities of the flower oil of Retama raetam (Forssk.) Webb from Tunisia. Nat Prod Res 24:789–796.  https://doi.org/10.1080/14786410802529190 CrossRefGoogle Scholar
  30. 30.
    Martins MDR, Arantes S, Candeias F, Tinoco MT, Cruz-Morais J (2014) Antioxidant, antimicrobial and toxicological properties of Schinus molle L. essential oils. J Ethnopharmacol 151:485–492.  https://doi.org/10.1016/j.jep.2013.10.063 CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Botany, D. S. B. CampusKumaun UniversityNainitalIndia
  2. 2.Department of Chemistry, D. S. B. CampusKumaun UniversityNainitalIndia
  3. 3.Department of Biotechnology, Bhimtal CampusKumaun UniversityNainitalIndia

Personalised recommendations