Physiochemical Properties of Essential Oils and Applications

Abstract

Essential oils have received increasing interest due to the high potential of their novel properties, i.e. antibacterial, antifungal and antioxidant activities. Essential oils are obtained from various parts of aromatic cultures, i.e. roots, leaves, seeds, bark, fruits, flowers, stems, etc. by various oil production methods, i.e. field distillation unit (FDU), steam distillation, water and steam distillation & several advanced (supercritical fluid extraction). Therefore, it is necessary to understand the characterization of the essential oils. This study reports on the method of determination of physiochemical properties with the test parameters, i.e. odor, color, optical rotation, solubility, refractive index, specific gravity, acid value, ester value, and ester value after acetylation. There is also discussion about instruments such as gas chromatography-mass spectrometry due to one of the best tools for identifying and quantifying the constituents of essential oils as its simplicity, rapidity, accuracy, and efficiency.

1. Introduction

Essential oils are volatile components of aromatic or aromatic crops that give aroma due to their volatility. Generally, aromatic cultures are those that have aromatic compounds that are volatile at room temperature and give a smell [1]. These compounds are present in essential oils preserved in plant cells, tissues, stomas, and other parts of the plant. Usually, essential oils are stored in the roots, leaves, seeds, bark, fruits, flowers, and stems of plants [2]. The essential oil of the various parts of a plant can be obtained by various distillation methods such as hydro-electric distillation, hydro-vapor distillation, steam distillation, solvent extraction, and supercritical extraction, etc. [3]. Essential oils are the secondary plant metabolites synthesized in different parts of the plant, such as leaves, flowers, stems, roots, and seeds [4]. These are of great importance for perfumery and pharmacy. Natural essential oils are considered biodegradable and have no residual toxicity [5]. Due to the improvement in living standards and taste for natural essential oils as fragrant, flavoring, and pharmaceutical ingredients, the demand for natural essential oils has increased in many ways in the recent past. Many industries use synthetic fragrances that are developed in a laboratory to mimic the aromatic and chemical components of natural oils, based on plants that are more expensive to produce. However, synthetic fragrances may not contain the beneficial aspects of natural plant-based essential oils and may even be dangerous for human applications. Chemicals found in artificial fragrances include, for example, phthalates, endocrine disruptors, and carcinogens known as benzene derivatives [6].

On the other hand, the global market for natural fragrances has grown strongly due to the increasing use of natural fragrances such as essential oils over synthetic fragrances as a result of their associated numerous health benefits associated with them, such as aromatherapy, which will drive market growth in the coming years [7]. The analysis of the essential oil purity test can be confirmed with physiochemical, instrumental analysis. The qualitative and quantitative analysis is carried out to know the components of the oil and the percentage of the components contained in the oil respectively, in doing so, we can know the purity of this particular oil. Only pure oils contain a full range of compounds that simply cannot duplicate cheap imitations.

2. Physico-chemical analysis

2.1 Odor evaluation

Take smelling strips and one end of each odors strip must be clearly marked before use. Now, dip the unmarked end of a strip (about 0.5 to 1.0 ml) in the material under examination and of another strip to the same depth in the standard sample after it has attained room temperature. For certain perfumery materials, such as fatty, absolute, and solid aldehydes, solutions of I to 10 percent solutions in ethyl alcohol or diethyl phthalate for olfactory evaluation [8]. Odorant profile of essential oil can be investigated by gas chromatography (GC)-olfactometry using aroma extract dilution analysis (AEDA) and vocabulary-intensity-duration of elementary odors by sniffing (VIDEO-Sniff) [9]. Table 1 shows the standards for the odor of some essential oils, according to the Bureau of Indian Standards (BIS).

Name of oil	Physical parameters at 27°C						Chemical parameters
	Color	Odor	Solubility	Optical rotation	Refractive index	Relative density	Acid value	Ester value	Ester value after acetylation
1. Oil of Mentha arvensis	Colorless to light yellow	Strong minty, herbal, cooling sensation	2.5–3 volumes of ethyl alcohol (70% by volume)	−35° to −45°	1.456–1.4642	0.8773–0.9123		3–15
2. Oil of Geranium	Yellowish brown	Strong, rose like with a minty top note	3 volumes of ethyl alcohol (70% by volume)	−7° to −11°	1.4630–1.4728	0.8824–0.8966	10 maximum	50–76	205–230
3. Oil of Vetiver	Brown to reddish brown viscous liquid	Characteristic and persistent woody aroma	1–2 volumes in 80% ethanol	+15° to +35°	1.5150–1.5250	0.9850–1.0200	35 maximum	5–16%	110–165%
4. Oil of Citronella (Java)	Pale yellow to light tan clear	Characteristic citrus grassy with rose undernote	1–2 volumes of ethanol (80% by volume)	−0.5° to −5°	1.4624–1.4714	0.8743–0.8893	—	—	—
5. Oil of Eucalyptus globulus	Colorless to pale yellow	Aromatic camphoraceous sharp odor	Equal volume of ethyl alcohol, 80% by volume	−5° to +10°	1.4580–1.4700	1.4561–1.4669	0.9050–0.9250	—	—
6. Oil of Clove bud	Colorless or pale yellow	Sweet fruity, spicy	2 or more volumes of 70% ethanol	0° to −2°	1.5230–1.5310	1.0350–1.0570	—	—	—
7. Oil of Cumin seed	Colorless to pale yellow	Strongly aromatic, spicy	8 volumes of ethanol (80% by volume)	+1° to +8°	1.4792–1.5092	0.8688–0.9187	—	—	—
8. Oil of Pine	—	Pleasant, sweet odor reminiscent of terpineols with mild aromatic	—	—	1.4750–1.4820	0.9080–0.9280	2% maximum	—	—
9. Oil of Cardamom	Colorless to yellow	Spicy and camphorous	2–5 volumes of ethanol (70% by volume)	+16° to +41°	1.4575–1.4605	0.9190–0.9360	7% maximum	92–150%	—
10. Oil of Patchouli	Light yellow to reddish brown	Leafy, slightly camphoraccous	1–10 volumes of ethanol (90% by volume)	−66° to −40°	1.5020–1.5120	0.9480–0.9710	4% maximum	10% maximum	—
11. Oil of Sandalwood	Nearly colorless to golden yellow	Pleasant, sweet, woody, and persistent	5 volumes of ethanol (70% by volume)	−20° to −15°	1.5000–1.5070	0.9635–0.9775	—	7% maximum	—
12. Oil of Ginger	Light yellow to greenish yellow liquid	Sharp lemon top note with persistent dry spicy note	In 1 volume of ethanol	−28° to −48°	1.4860–1.4960	0.8700–0.8820	—	—	—
13. Oil of Palmarosa (var. Motia)	Light yellow to yellow mobile	Rosaceous, with grassy background	2 volumes of ethanol (70% by volume)	−1.4° to +3°	1.4710–1.4780	0.8800–0.8940	1% maximum	7–36%	260–280%
14. Oil of Lemongrass	Dark yellow to light brown-red	Lemon like	3 volumes of ethanol (70% by volume)	−3° to +1°	1.4799–1.4859	0.886–0.896	—	—	—
15. Oil of Basil	—	Spicy herbal, anise like	More than 7 volumes of ethanol (80% by volume)	−6° to +7.5°	1.4580–1.5480	0.9050–0.9620	1% maximum	—	—
16. Oil of Cinnamon leaf	—	—	In 2 volumes of ethanol (70% by volume)	1.5250–1.5360	1.0300–1.0560	—	—	—	—
17. Oil of Dill Seed	—	—	0.5 or more volumes of ethanol (90% by volume)	+50° to +65°	1.4750–1.4870	0.9360–0.9800	—	35–42%	50–65%
18. Oil of Davana	Clear brownish yellow to brown liquid	Sweet, lingering, fruity, balsamic	9 volumes of ethanol (90% by volume)	+34° to +41°	1.4775–1.4995	0.9160–0.9560	3% max	30–45%	—
19. Oil of Celery Seed	Pale yellow to light brown	Very persistent and spicy, pleasing	10 volumes of ethanol (90% by volume)	+50° to +80°	1.4765–1.4865	0.8710–0.9100	3.5% (max.)	—	—
20. Oil of Turpentine	—	—	5 volumes of ethanol (90% by volume), 1 volume of ethanol (95% by volume)	1.4670–1.4770	0.8600–0.8700	—	1% (max.)	—	—
21. Oil of Himalayan Cedarwood	Pale yellow to deep reddish yellow	Woody, balasamic	In all proportion of ethanol (90% by volume)	+55° to +65°	1.5050–1.5132	0.9280–0.9360	1% (max.)	15% (max.)	30% (max.)
22. Oil of Black Pepper	Almost colorless to bluish green liquid	Characteristic, recalling that of whole pepper	Completely soluble in 3 volume of ethanol (95% by volume)	−28° to −3°	1.4730–1.4891	0.8450–0.9265	—	11% (max.)	—
23. Oil of Jamarosa	Colorless to pale yellow	Sweet floral rosy, citrusy, minty top note	One volume of ethanol (80% by volume)	−2° to +2°	1.4680–1.4745	0.8830–0.8890	—	19–33%	—
24. Oil of Rose	Colorless to light yellow	Rosy	IS 15740:2007 (RA 2012)	−2° to −4.5°	1.4520–1.4680	0.8700–0.8800	—	—	—

Table 1.

Physico-chemical properties of essential oils [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17].

2.2 Solubility determination

Take exactly 1.0 ml of the essential oil in the measuring cylinder (Figure 1) and place it in a constant temperature device [10]. Then, maintain the specified temperature as mentioned in the specification. Now, add the dilute alcohol (as specified) for the particular materials. i.e. 60%, 70%, 80% 90% while shaking. Record the volume of the alcohol required for producing a clear solution. Standards of solubility results for some essential oils are shown in Table 1.

Figure 1.

Measuring cylinder.

2.3 Optical rotation determination

2.3.1 Polarimeter

Switch on the light source and wait until full luminosity is obtained (Figure 2a) [11]. Then put the blank cell (Figure 2b) for normal sample use (100 mm cell) in the cell compartment to get the cell error whether dextro or levo. Now fill up the cell with sample. After that rotate the analyzer knob for alignment with polarized light.

Figure 2.

(a) Polarimeter and (b) sample cell.

2.3.2 Digital polarimeter

Switch on the power input in the instrument (Figure 3) then switch on the light source (sodium vapor lamp) knob of the instrument and wait until the energy (70–80 i.e. full intensity of the lamp) is obtained. Now, check the cell error (dextro or levo) then fill the sample in the cell. Put the cell in the cell compartment of the instrument and note the reading, directly from the display of instrument. Optical oration results of some essential oils are shown in Table 1.

Figure 3.

Digital polarimeter.

2.4 Refractive index determination

Sample should be free from moisture and any other residual matters and record the ambient temperature [12]. Then open the prism of ABBE type refractometer (Figure 4) and clean it with soft cotton. Now, place some drops of the oil to be tested on the lower part of the prism and close the refractometer. Then, observe through the eyepiece and turn the dispersion correction compensator knob until the colored indistinct boundary seen between the light and darkfield becomes a sharp line. Now, adjust the knurled knob until the sharp line exactly intersects the midpoint of the cross wires in the image. Read the refractive index from the magnifier in the pointer and record the reading. RI results of some essential oils are shown in Table 1.

Figure 4.

Abbe type refractometer.

2.5 Specific gravity determination

The sample should be free from moisture and any other residual matters [13]. Then, carefully wash and clean the pyknometer (Figure 5) or specific gravity bottle and dry the interior with a current of dry air. Now, weigh the pyknometer or specific gravity bottle and record the weight and fill the pyknometer or specific gravity bottle with distilled water and record the weight with temperature. Then again clean the pyknometer/specific gravity bottle and dry the interior with a current of dry air. Now, again fill the same pyknometer/specific gravity bottle with the material under test and record the weight with temperature.

Figure 5.

Pyknometer/specific gravity bottle.

It can be calculated by the equation as under.

$$\mathrm{d}=\frac{W1-W}{W2-W}$$E1

where, d = density, W = weight of pycnometer or relative density bottle, W1 = weight of sample, W2 = weight of distilled water. The relative densities value of some essential oils is shown in Table 1.

2.6 Acid value determination

Sample should be free from moisture and any other residual matters [14]. Weigh about 2.5 g of sample material. Then, dissolve the sample in 20 ml rectified spirit (neutralized). Now, titrate it with potassium hydroxide 0.1 N solution (aqueous/alcoholic) using phenolphthalein indicator until the solution remains faintly pink after 10 s of shaking. Now, note the volume of KOH consumed and put the value in the formula.

$$\text{Acid value}=\frac{56.1\times \mathrm{V}\times \mathrm{N}}{\mathrm{M}}$$E2

where V = volume of KOH consumed, N = normality of KOH solution, M = weight of material (grams) taken.

2.7 Ester value determination

Take an appropriate sample of the material reserved from the acid value determination [15]. Now, add 25 ml of 0.5 N alcoholic KOH, and reflux it on water bath for 1 h. Then, cool it and add 20 ml distilled water and remove the condenser. Now, add few drops of phenolphthalein as an indicator and titrate it against 0.5 N HCl. Simultaneously, a blank determination is also carried out (conditions remain the same except the material to be tested). Put the values in the following formula.

$$\text{Ester value}=\frac{56.1\times \mathrm{N}\left(\mathrm{V}1-\mathrm{V}2\right)}{\mathrm{M}}$$E3

where N = normality of HCl, V1 = vol. in ml of HCl used for blank determination, V2 = vol. in ml. of HCl used in determination to neutralize the excess alkali after hydrolysis, M = weight in g of the material taken.

2.8 Ester value after acetylation determination

Take 10 ml of sample and 20 ml acetic anhydride and 2 g of anhydrous sodium acetate in a round bottom flask then add fragments of pumice-stone or porcelain pieces [16]. Now, connect the flask with an air condenser for reflux for 2 h. After this, cool the content. Now, add 50 ml of cold water and heat it at a temperature between 40 and 50°C for 15 min. Then again, cool it and transfer it to a separating funnel. After that, wash the flask twice with 10 ml of distilled water and separate the water layer from the oil layer.

Wash the oil layer by shaking successively with (a) 50 ml of sodium chloride solution (brine solution), (b) 50 ml of sodium carbonate (solution 2% in brine), (c) 50 ml of sodium chloride solution (brine), and (d) 20 ml of distilled water. Now, shake the acetylated sample material vigorously with the distilled water and check the water layer with litmus paper as should be neutral. After that, dry the acetylated sample material by adding anhydrous sodium sulfate for the saponification of the ester hydrolysis process. The saponification process is carried out as under steps needed.

First take 1–1.5 g of acetylated sample material into a flask and add 25 ml of 0.5 N alcoholic KOH solution. Then, reflux it in a water bath for one-hour and cool it then add 20 ml of distilled water from the top of the condenser. Now, titrate it against 0.5 N HCI in the same way, a blank titration is also carried out at the same condition without a sample. Put the value in the following formula for calculation of ester value after acetylation as

$$\text{Ester value after acetylation}=\frac{56.1\times \mathrm{N}\times \left(\mathrm{V}1-\mathrm{V}2\right)}{\mathrm{M}}$$E4

where, N = normality of HCl, V₁ = volume in ml of HCl used for blank determination, V₂ = volume in ml of HCl used in determination to neutralize the excess alkali after hydrolysis, and M = mass in g of the material taken.

2.9 Instrumental analysis

2.9.1 GC-MS (gas chromatography-mass spectrometry)

Gas chromatography-mass spectrometry (GC-MS) analysis is more feasible for the authenticity of essential oil as determining its maximum chemical component. The qualitative GC-MS analysis for the extracted essential oils can be carried out by using HP 6890 gas chromatography coupled with HP 5973 mass selective detector (Figure 6a) operating in 70 eV mode. Samples of 0.2 μL need to inject in the capillary column with the split mode at a ratio of 5:1. The compounds separate on a 30 m long capillary column (HP-5MS), 0.25 mm in diameter, and with 0.25 μm thick stationary phase film (5% phenyl)-methylpolysiloxane). The flow rate of helium into the column needs to be kept at 1.2 mL min⁻¹. Initially, the temperature of the column 45°C, then it increases to 200°C at a rate of 5°C min⁻¹ (kept constant for 10 min), and then heat up to a final temperature of 250°C at a rate of 5°C min⁻¹ (Figure 6b).

Figure 6.

(a) Gas chromatography-mass spectrometry instrument, (b) role of the different parts of gas chromatography-mass spectrometry, and (c) gas chromatography-mass spectrometry-chromatogram.

The oven stays kept at this temperature for 20 min. The solvent delays 4 min. The total running time for a sample is about 70 min. The relative percentage of the essential oil constituents evaluate from the total peak area (TIC) by apparatus software [18]. Essential oil constituents’ identification by comparison of their mass spectra (Figure 6c) with those stored in the libraries i.e. NIST (National Institute of Standards and Technology), flavor, and Adam’s mass spectral libraries using various search engines. Table 2 is an example of some essential oils and their major components.

Name of essential oil	Major chemical constituents of molecule	Reference
1. Oil of Mentha arvensis	Menthol (84.63%), L-menthol (4.58%)	[19]
2. Oil of Geranium	Citronellol (37.5%), geraniol (6.0%), caryophyllene oxide (3.7%), menthone (3.1%), linalool (3.0%), β-bourbonene (2.7%), iso-menthone (2.1%) and geranyl formate (2.0%)	[20]
3. Oil of Vetiver	Vetiverol (45–80%), khusimol (3.4–13.7%), β-vetispirene (1.6–4.5%), vetiselinenol (1.3–7.8%), vetivone (2.5–6.3%)	[21]
4. Oil of Citronella (Java)	Citronellal (29.6%), 2,6-octadienal, 3,7-dimethyl-, (E)-(11%), cis-2,6-dimethyl-2,6-octadiene (6.9%), caryophyllene (6.5%), citronellol (4.8%), limonene (2.7%)	[22]
5. Oil of Eucalyptus globulus	Eucalyptol (51.62%), α-pinene (23.62%), p-cymene (10%), β-myrcene (8.74%), terpinen-4-ol (2.74%) and γ-terpinene (2.59%)	[23]
6. Oil of Clove bud	Eugenol (76.8%), followed by β-caryophyllene (17.4%), α-humulene (2.1%), and eugenyl acetate (1.2%)	[24]
7. Oil of Cumin seed	Cuminaldehyde (36.67%) and caren-10-al (21.34%)	[25]
8. Oil of Pine	α-Terpineol (30.2%), linalool (24.47%), limonene (17.01%), anethole (14.57%), caryophyllene (3.14%), and eugenol (2.14%)	[26]
9. Oil of Cardamom	α-Terpinyl acetate (29.9–61.3%) followed by 1,8-cineole (15.2–49.4%), α-terpineol (0.83–13.2%), β-linalool (0.44–11.0%), and sabinene (1.9–4.9%)	[27]
10. Oil of Patchouli	Patchouli alcohol (42.75%), Delta-Guaiene (28.30), Azulene (20.48%), Trans Caryophyllene (11.84%), Seychellene (CAS) (10.77%), Nephtalene (8.02%), Cycloheptane (6.02%) and Caryophyllene (5, 73%)	[28]
11. Oil of Sandalwood	α-Santalol (59.00%), α-bergamotene (9.68%), and β-santalol (9.02%)	[29]
12. Oil of Ginger	a-Zingiberene (30.06%), β-sesquiphellandrene (10.71%), E–E-a-farnesene (9.75), β-bisabolene (6.53%), y-curcumene (5.90%) and ar-curcumene (5.18%)	[30]
13. Oil of Palmarosa (var. Motia)	(E)-β-Ocimene (1.2–4.3%), linalool (0.8–2.0%), geraniol (70.1–85.3%), geranyl acetate (4.3–14.8%) and (E,Z)-farnesol (1.6–3.4%)	[31]
14. Oil of Lemongrass	Citral-a (33.1%), citral-b (30.0%), geranyl acetate (12.0%) and linalool (2.6%)	[32]
15. Oil of Basil	Methyl cinnamate (70.1%), linalool (17.5%), β-elemene (2.6%) and camphor (1.52%)	[33]
16. Oil of Cinnamon leaf	Eugenol (74.9%), followed by β-caryophyllene (4.1%), benzyl benzoate (3.0%), linalool (2.5%), eugenyl acetate (2.1%) and cinnamyl acetate (1.8%)	[34]
17. Oil of Dill Seed	Carvone (38.9%), apiol (30.8%), limonene (15.9%) and trans-(+)-dihydrocarvone (10.9%)	[35]
18. Oil of Davana	cis-Davanone (45.8%), bicyclogermacrene (9.6%), linalool (2.5%), caryophyllene oxide (2.2%) and phytol (2.1%)	[36]
19. Oil of Celery Seed	Limonene (54.04–58.29%), myrcene (19.51–27.65%), 1,2 ethanediol, 1-phenyl (5.62–7.17%)	[37]
20. Oil of Turpentine	α-Pinene 77% and 89% respectively as the major component	[38]
21. Oil of Himalayan Cedarwood	β-Himachalene (38.3%), α-himachalene (17.1%) and γ-himachalene (12.6%)	[39]
22. Oil of Black Pepper	trans-Caryophyllene (30.33%), limonene (12.12%)	[40]
23. Oil of Jamarosa	Geraniol (80–90%), geranyl acetate (19–33%)	[41]
24. Oil of Rose	Citronellol (15.9–35.3%), geraniol (8.3–30.2%), nerol (4.0–9.6%), nonadecane (4.5–16.0%), heneicosane (2.6–7.9%) and linalool (0.7–2.8%)	[42]

Table 2.

Major constituents of the essential oils.

3. Applications

The applications of essential oils are diverse. Widely used in cosmetics and perfumes, they also have medicinal applications due to their therapeutic properties as well as agro-alimentary uses because of their antimicrobial and antioxidant effects.

1. Oil of Mentha arvensis

   Uses for stomach disorders, inflammation, and treatment of fever headache, cold, and asthma.

2. Oil of Geranium

   Uses for female reproductive disorders, menstrual cramps, infertility, endometriosis, premenstrual syndrome. Menopausal symptoms, circulatory disorders, Raynaud’s disease, varicose veins, hemorrhoids, neuralgia, nervous skin disorders, depression, fatigue, emotional crisis, stress-related conditions, wounds, acne, bruises, minor burns, dermatitis, eczema, ulcers, hemorrhoids, head lice, ringworm, sebum balancing, urinary, and liver tonic.

3. Oil of Vetiver

   Uses for nervous tension, muscular spasm, muscular pain, menstrual cramps, premenstrual syndrome, restlessness, acne, arthritis, cuts, depression, exhaustion, insomnia, muscular aches, oily skin, rheumatism, sores, stress.

4. Oil of Citronella (Java)

   Uses for muscular aches, infectious skin conditions, fevers, heat rash, excessive perspiration, fungal infections, fatigue, insect bites, insect deterrent.

5. Oil of Eucalyptus globules

   Uses for respiratory infection, bronchitis, infectious disease, fever, catarrh, sinusitis, fever, muscular aches and pains, rheumatism, arthritis, urinary infection, cystitis, parasitic infection.

6. Oil of Clove bud

   Uses for cognitive support and brain health, pain relief, bacterial infection, fungal infection, viral skin infection, warts, verrucas, toothache, gum disease, muscle pain, rheumatism, flu, bronchitis, tired limbs, nausea, flatulence, stomach cramp, abdominal spasm, parasitic, infection, scabies, ringworm.

7. Oil of Cumin seed

   Uses for toxin buildup, poor circulation, low blood pressure, colic, stomach cramps, indigestion, gas, fatigue.

8. Oil of Cardamom

   Uses for appetite (loss of), colic, fatigue, stress.

9. Oil of Patchouli

   Uses for treating skin conditions such as dermatitis, acne, or dry, cracked skin, easing symptoms of conditions like colds, headaches, and stomach upset, relieving depression, providing feelings of relaxation and helping to ease stress or anxiety, helping with oily hair or dandruff, controlling appetite, using as an insecticide, antifungal, or antibacterial agent, using as an additive in low concentrations to flavor foods like candies, baked goods, and beverages.

10. Oil of Sandalwood

    Uses for bronchitis, chapped skin, depression, dry skin, laryngitis, leucorrhea, oily skin, scars, sensitive skin stress, stretch marks.

11. Oil of Ginger

    Uses for aching muscles, arthritis, nausea, indigestion, poor circulation, nervous exhaustion.

12. Oil of Palmarosa (var. Motia)

    Uses for sinusitis, excess mucus, cystitis, urinary tract infection, gastrointestinal disorders, scarring, wounds acne, pimples, boils, fungal infection, general fatigue, muscular aches, over-exercised muscles, stress, irritability, restlessness, insect bites, and stings.

13. Oil of Lemongrass

    Uses for muscular aches and pains, gastrointestinal disorders, indigestion, physical and mental exhaustion acne, insect repellent.

14. Oil of Basil

    Uses for bronchitis, colds, coughs, exhaustion, flatulence, flu, gout, insect bites, insect repellent, muscle aches rheumatism, sinusitis.

15. Oil of Cinnamon leaf

    Uses for sluggish digestion, colds/flu exhaustion, lice, circulation, rheumatism, scabies, stress.

16. Oil of Dill seed

    Uses for dyspepsia, flatulence, indigestion, bronchial asthma, dysmenorrhea, and the promotion of lactation.

17. Oil of Davana

    Uses for bacterial infection, bronchial congestion, coughs, colds, influenza, nervous stomach, indigestion, nausea, menstrual cramps, menopausal symptoms, general debility, anxiety, stress, irritability, tension, anxiety, wound healing, antiseptic, coughs.

18. Oil of Himalayan Cedarwood

    Uses for acne, arthritis, bronchitis, coughing, cystitis, dandruff, dermatitis, stress.

19. Oil of Black Pepper

    Uses for aching muscles, arthritis, chilblains, constipation, muscle cramps, poor circulation, sluggish digestion, quitting smoking, and nicotine addiction.

20. Oil of Jamarosa

    Jamarosa essential oil regulates skin moisture & sebum production. Can restore luster to dull aged skin and remove wrinkles & other signs of aging. Has disinfectant, antiseptic properties, and is widely used for treating insect bites and as insect repellents. Aids in repairing the damaged skin cells. Fights anxiety, stress and promotes peaceful sleep.

21. Oil of Rose

    Uses for depression, eczema, frigidity, mature skin, menopause, and stress.

4. Conclusion

This study will facilitate the identification of essential oils or fragrant raw materials purity and quality. Physiochemical methods and their range of value can be utilized by traders of fragrant raw material as avoiding adulteration. GC-MS is an ideal instrumental analysis for maximum major and minor chemical constituents of the essential oils. Advanced analytical techniques for the characterization of essential oils are more reliable by their fruitful results. Since, good quality of the raw material i.e. essential oils can be used in various purposes i.e. antimicrobial, insecticide, antiseptic, antifungal, and analgesic activities, aromatherapy, disease treatments and cosmetics & allied products as desired results. Quality assessment improves the confidence of both producer & consumer as well.

Conflict of interest

The authors have no conflict of interest to declare.