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Thermal, photo-oxidation and antimicrobial studies of linalyl acetate as a major ingredient of lavender essential oil
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Received: ,
Accepted: ,
This article was originally published by Elsevier and was migrated to Scientific Scholar after the change of Publisher.
Peer review under responsibility of King Saud University.
Abstract
Lavender oil, obtained from the flowers of Lavandula angustifolia (Family: Lamiaceae) by steam distillation, The major component of lavender oil is linalyl acetate was isolated and subjected to oxidation thermally and photochemically using (mcpba and H2O2) respectively to produce mixture of 6,7-epoxy-3,7-dimethyl-1-octene-3-yl acetate (3) and 1,2-epoxy-3,7-dimethyl-6-octene-3-yl acetate (4) photochemically, while produced epoxide 4 only thermally. On the other hand, photooxygenation of 1 using different singlet oxygen sensitizers gave two hydroperoxide derivatives of 6-hydroperoxy-3,7-dimethylocta-1,7-diene-3-yl acetate (5) and 7-hydroperoxy-3,7-dimethylocta-1,5-diene-3-yl acetate (6) in the presence of tetraphenyl porphin (TPP), whereas gave hydroperoxide 6 only using hematoporphyrin (HP). Studies on the antimicrobial especially Microsporum canis and Microsprum gallinna showed that linalyl acetate and its epoxide and hydroperoxide derivatives have a good antibacterial action.
Keywords
Medicinal plants
Monoterpene
Linalyl acetate
Essential oil
Epoxidation
Antibacterial
m-Chloroperbenzoic acid
Photooxygenation
Epoxide
1 Introduction
The use of medicinal plants and folk medicine are wide spread in the world. In folk medicines as well as aroma therapy, essential oils and fragrance compounds are being used as therapeutic agents for relieving pain, anxiety reduction and energy enhancement (Kako et al., 2008; Kiecolt-Glaser et al., 2008; Ekor, 2013; Emmanuel et al., 2016). Among them, due to their high volatility, the acyclic monoterpenes are a valuable class of compounds useful for the flavor and fragrance industries (King and Dickinson, 2013; Elsharif et al., 2015).
Lavender is a common and popular aromatic Mediterranean herb belongs to Lamiaceae family growing almost all over the world, it is marked as the fresh or dried plant (Ruriko et al., 2006). It is also considered as a treatment of pain and tremor (Gorji, and Ghadiri, 2002; Gorji, 2003; Vakili, and Gorji, 2006).
Linalyl acetate 1 and linalool 2 are the most important acyclic monoterpene substances which represent about 70% of the terpenoids of floral scents (Cavanagh and Wilkinson, 2002; Stashenko and Martínez, 2008; Skold et al., 2008; Woronuk et al., 2011). They are found in the essential oils of over 200 plant species, belonging to different families (Cavanagh and Wilkinson, 2002). Linalyl acetate 1 and linalool 2 are the main components of lavender oil (Fig. 1) The odor of linalyl acetate is described as floral, sweet and citric, and additionally as minty and slightly caraway-like (d'Acampora et al., 2007).
It was indicated that linalyl acetate plays an important role in the anti-inflammatory activity (Peana et al., 2002). On the other hand, plant monoterpenes are subjected to oxidize, when exposed to air. Oxidation is enhanced by heat, exposure to light or by chemical catalysts. Oxidation may also begin by an attack of reactive singlet oxygen, as in photo-oxidation which provides an important way to produce hydroperoxides in the presence of oxygen, light energy, and photosensitizers (Elgendy and Khayyat, 2008a, 2008b).
As a result, unstable neutral primary oxidation products such as hydroperoxides are formed. Hydroperoxides may give rise to secondary oxidation products having multiple chemical functional groups (hydroxy, oxo, and epoxy derivatives) (Elgendy and Khayyat, 2008a, 2008b). Furthermore, unsaturated trepenes are capable of trapping activated oxygen species in vivo to give intermediate epoxides which can alkylate DNAs, proteins, and other bimolecular (Méou et al., 1999; Richter et al., 2003; Geraghty, 2005). In addition, some monoterpenes undergo oxidation using hydrogen peroxide with different conditions to give terpene epoxide derivatives (Yarovaya et al., 2002; Yarovaya et al., 2003) Hydrogen peroxide is considered as oxidative reagent via thermal or photochemical oxidation reactions to give the corresponding epoxy derivatives (Saddiq and Khayyat, 2010).
In Saudi Arabia, Lavender is growing in some areas such as Albaha and Abha, there are no reported data on Albaha's lavender or its essential oils. In view of the significant therapeutic value of mono-terpene, it was considered worthwhile to investigate some oxidation reaction of linalyl acetate.
2 Materials and methods
2.1 Chemistry
Linalyl acetate was extracted from lavender essential oil. Lavender was collected from Albaha city from Kingdom of Saudi Arabia. IR spectra was performed on a NICOLET IS50 FT-IR spectrophotometer. 1H NMR spectra was obtained in CDCl3 solution with a Brucker Ascend TM 850 MHz apparatus. A Philips G/5812 SON sodium lamp was used as irradiation source in photoinitiated reactions. Thin layer chromatography (TLC) and proparative layer chromatography (PLC): Polygram SIL G/W 254, Mecherey-Nagel. A rotatory evaporator (at 20 °C/15 torr) was used to remove the solvents.
2.1.1 General epoxidation procedures of 1
2.1.1.1 Method A: epoxidations photochemically usind hydrogen peroxide
A solution of H2O2 (2.5 ml, 50%) was added cautiously drop wise over 5 min to a stirred solution of 1 (5 mmol) in ethanol (25 ml) at 0 °C. The mixtures were irradiated using sodium lamp in an atmosphere of nitrogen. The reaction mixture was evaporated under reduced pressure at room temperature which was purified by column chromatography on silica gel adsorbent by eluting with a mixture of petroleum ether 60–80 °C and ethyl acetate (8:2) (Elgendy and Khayyat, 2008a, 2008b). 25 ml of chloroform was added to the crude products. The combined extract was dried over anhydrous Na2SO4 and evaporated under reduced pressure to give crude product, which was purified by column chromatography on silica gel adsorbent. Elution of the column with the solvent mixture of petroleum ether 60–80 °C and diethyl ether (9:2) gave a mixture of 3 and 4. The results were given in Table 1.
| Comp. no. | Start wt. gm | Epoxidation | Solvent | Yield | Epoxid. prod. |
|---|---|---|---|---|---|
| 1 | 2 | Thermally (mcpba) | CHCl3 | 0.83% | 3:80% |
| 1 | 2 | Photochemically (H2O2) | C2H5OH | 0.75% | 3:50% 4:20% |
2.1.1.2 Method B: thermally epoxidations using m-chloroperbenzoic acid
A solution of mcpba (10 mmol, 80%) was added cautiously drop wise over 15 min to a stirred solution of 1 (5 mmol) in chloroform (25 ml) at 0 °C. The mixtures were continue stirred in an atmospheric nitrogen at room temperature (TLC, peroxide test by KI, 10%), after which were carefully washed with a saturated aqueous solution of NaHCO3 (3 × 10 ml), then with distilled water (3 × 10 ml). The organic layers were separated, dried over anhydrous Na2SO4 and evaporated under reduced pressure at room temperature (Khayyat, 2012). The crude residue product was purified by column chromatography on silica gel adsorbent. Elution of the column with the solvent mixture of petroleum ether 60–80 °C and ether (9:2) gave the epoxide derivatives (Table 1).
2.1.2 General photooxygenation of 1
A solution of I (10 mmol) of linalyl acetate in chloroform, according to the type of sensitizers, was irradiated externally by means of sodium lamp at −5 °C. During the irradiation a continuous stream of dry oxygen gas was allowed to pass through the reaction mixtures at a slow rate to avoid evaporation of solvent. The solvent was evaporated at 20 °C/15 Torr. The crude products were purified by column chromatography on silica gel adsorbent by eluting with a mixture of petroleum ether 60–80 °C and ethyl acetate (8:2) (Khayyat, 2011; Khayyat and Al-Zahrani, 2014). The solvents, sensitizers, reaction time, the yields and photo-products were given in Table 2.
| Comp no. | Start wt. gm | Sensitizer | Solvent | Irradiation time | Yield | Photo products |
|---|---|---|---|---|---|---|
| 1 | 1 | TPP | CHCl3 | 12 | 0.70% | 5:30% |
| 6:32% | ||||||
| 1 | 1 | HP | CHCl3 | 12 | 0.55% | 6:50% |
2.2 Spectroscopic data
2.2.1 3,7-Dimethyl-1,6-octadien-3-yl acetate (1)
Colorless liquid, C12H20O2 (M. wt. 196.29). IR (thin film): ν−: 3460, 2973, 2879, 1720, 1736, 1367, 1237, 1110 cm−1. 1H NMR (CDCl3): δ: 1.35 (s, 3H, 10CH3), 1.40 (s, 3H, 9CH3), 1.48 (s, 3H, 8CH3), 1.62 (comp. pat., 2H, H-4), 1.79 (comp. pat., 1H, H-5), 1.94 (s. s, 3H, 12CH3), 4.92 (t, 1H, H-6), 4.95 (dd, 1H, J = 7.2, H-1a), 4.97 (dd, 1H, J = 11.1, H-1b), 5.79 (dd, 1H, J = 11.6, H-2) ppm. 13C NMR spectrum, δ ppm: 17.1 (C12), 21.3 (C5), 21.9 (C8), 23.1 (C10), 25.1 (C9), 39.9 (C4), 81.8 (C3) 111.2 (C1), 122.3 (C6), 133.2 (C7), 141.1 (C2), 169.5 (C11).
2.2.2 6,7-Epoxy-3,7-dimethyl-1-octene-3-yl-acetate (3)
Colorless liquid, C12H20O3 (M. wt. 212.29). IR (thin film): ν−: 3627, 3089, 2979, 2880, 1735, 1451, 1367, 1237, 1118 cm−1. 1H NMR (CDCl3): δ: 1.18 (s, 3H, 9CH3), 1.22 (s, 3H, 8CH3), 1.47 (d, 2H, H-5), 1.52 (comp. pat., 2H, H-4), 1.60 (s, 3H, 10CH3), 1.94 (s. s, 3H, 12CH3), 2.61 (comp. pat., 1H, H-6), 5.04 (dd, 1H, J = 7.1, H-1a), 5.08 (dd, 1H, J = 11.0, H-1b), 5.79 (dd, 1H, J = 11.6, H-2) ppm. 13C NMR spectrum, δ ppm: 17.4 (C12), 18.4 (C5), 21.9 (C8), 22.1 (C9), 23.1 (C10), 36.1 (C4), 57.5 (C7) 63.7 (C6), 77.2 (C3), 114 (C1), 141.1 (C2), 169.5 (C11).
2.2.3 1,2-Epoxy-3,7-dimethyl-6-octene-3-yl acetate (4)
Colorless liquid, C12H20O3 (M. wt. 212.29). IR (thin film): ν−: 3630, 3088, 2980, 2879, 1758, 1455, 1371, 1119 cm−1. 1H NMR (CDCl3): δ: 1.51 (s, 3H, 10CH3), 1.60 (t, 2H, H-4), 1.75 (s, 3H, 8CH3), 1.80 (s, 3H, 9CH3), 2.00 (comp. pat., 1H, H-5), 2.05 (s, 3H, 12CH3),2.70 (comp. pat., 2H, H-1), 3.1 (comp pat., 1H, H-2), 5.45 (comp. pat., 1H, H-6) ppm. 13C NMR spectrum, δ ppm: 17.5 (C5), 18.0 (C12), 19.4 (C9), 20.6 (C10), 25.4 (C8), 36.6 (C4), 39.5 (C1) 63.6 (C2), 78.9 (C3), 126.2 (C6), 133.3 (C7), 171.2 (C11).
2.2.4 6-Hydroperoxy-3, 7-dimethylocta-1,7-diene-3-yl acetate (5)
Colorless liquid, C12H20O4 (M. wt. 228.14). IR (thin film): ν−: 3397, 3089, 2980, 2252, 1716, 1368, 1240, 1019 cm−1. 1H NMR (CDCl3): δ: 1.32 (s, 3H, 10CH3), 1.53 (t, 2H, H-5), 1.72 (s, 3H, 9CH3), 2.0 (d, 2H, H-4), 2.17 (s, 3H, 12CH3), 4.28 (t, 1H, H-6), 5.14 (comp. pat., 1H, H-8), 5.62 (comp. pat, 2H, H-1), 5.98 (q, 1H, H-2), 7.97 (s, 1H, OOH) ppm. 13C NMR spectrum, δ ppm: 17.1 (C9), 22.1 (C12), 23.4 (C10), 24.3 (C5), 35.6 (C4), 77.1 (C3), 89.3 (C6) 113.5 (C8), 137.5 (C2), 141.4 (C1), 143.2 (C7), 170.0 (C11).
2.2.5 7-Hydroperoxy-3,7-dimethylocta-1,5-diene-3-yl acetate (6)
Colorless liquid, C12H20O4 (M. wt. 228.14). IR (thin film): ν−: 3401, 2978, 2753, 1732, 1239, 1368, 1019 cm−1. 1H NMR (CDCl3) : δ : 1.33 (s, 3H, 9CH3), 1.50 (s, 3H, 8CH3), 1.97 (s, 3H, 10CH3), 2.2 (s, 3H, 12CH3), 2.57 (d, 2H, H-4), 5.12 (comp. pat, 2H, H-1), 5.60 (t, 1H, H-6), 5.89 (comp. pat, 1H, H-5), 5.95 (comp. pat, 1H, H-2), 7.8 (s, 1H, OOH) ppm. 13C NMR spectrum, δ ppm: 17.6 (C12), 22.2 (C9), 22.34 (C8), 23.6 (C10), 42.2 (C4), 76.9 (C7), 77.3 (C3) 113.5 (C6), 123.8 (C5), 133.3 (C1), 142.9 (C2), 170.1 (C11).
2.3 Antimicrobial activity
2.3.1 Test organisms
The tested dermatophytes that is used in this study Microsporum canis and Microsprum gallinna were obtained from King Fahad Hospital in Jeddah, Saudi Arabia.
2.3.2 Well-cut diffusion method
Well-cut diffusion technique was used to evaluate the antifungal activities of the tested compounds (El-Masry et al., 2002). The Sabaroud dexterous agar media was inoculated with 1 ml from tested spore suspension, then wells were cut from the plate using a sterile 10 mm cork borer. About 0.5 and 1.0 ml of tested compounds were added into each well. All plates were incubated at 4 °C for 2 h to slow fungal growth. The plates were later incubated at 28 °C for a week (Mtolera and Semesi, 1996). After incubation, the diameter of the growth inhibition zone was measured in mm (Attaie et al., 1987) (Table 3).
| Types of extracts | Concentrations | Inhibition zone diameter (mm) | |
|---|---|---|---|
| M. gallina | M. canis | ||
| Control | 0.0 | – | – |
| Linalyl acetate 1 | 0.5 | 80.00 | 80.00 |
| 1 | 85.00 | 85.00 | |
| Epoxide 3 | 0.5 | 37.00 | 60.00 |
| 1 | 74.00 | 85.00 | |
| Epoxide 4 | 0.5 | 65.00 | 75.00 |
| 1 | 85.00 | 85.00 | |
| Hydroperoxide 5 | 0.5 | 80.50 | 81.00 |
| 1 | 85.00 | 85.00 | |
| Hydroperoxide 6 | 0.5 | 80.00 | 80.50 |
| 1 | 85.00 | 85.00 | |
3 Results and discussion
3.1 Chemistry
Linalyl acetae [3,7-Dimethylocta-1,6-dien-3-yl acetate] (1) is one of the major components of lavender essential oil which can be easily extracted by hydrodistillation from Lavandula (Koulivand et al., 2013; Prusinowska, and Krzysztof, 2014). The chemical structure of 1 was confirmed by spectral measurements. 1H NMR spectrum of 1 showed doublet of doublet at δ 4.95 ppm and 4.97 ppm of protons of C1, and doublet of doublet at δ 5.79 ppm of protons of C2. 13C NMR spectrum of 1, the C1 and C2 signals were located at δc 111.2 and 141.1 ppm, respectively. signal at δc 169.5 ppm for C11 carbonyl group. Thermal epoxidation of linalyl acetate (1) using mcpba in chloroform gave 80% linalyl epoxide (3) (Scheme 1). On the other hand, Photochemical epoxidation of 1 with hydrogen peroxide (H2O2, 30% by volume) in ethanolic medium under irridation with sodium light (irradiation time 15 h) gave 50% of 6,7-epoxy-3,7-dimethyl-1-octene-3-yl acetate (3) and 18% of 1,2-epoxy-3,7-dimethyl-6-octene-3-yl acetate (4) (Scheme 1). The structures of epoxidation products 3 and 4 were established by spectral measurements. IR spectrum of 3 had an absorption band as in the case of 4. 1H NMR spectrum of 3 showed doublet of doublet at δ 5.04 and δ 5.08 from protons Ha-1 and Hb-1 respectively. The other proton spectra as complex pattern at δ 2.61 ppm from H-6 in oxiran ring. Compound 4 displayed in 1H NMR two complex pattern at δ 2.7 ppm and δ 3.1 ppm for two protons of H-1 and one proton of H-2 in oxirane ring respectively. 13C NMR spectrum of 3 showed signals of the oxirane carbon atoms at δ 57.5 (C7) and δ 63.7 ppm (C6). Whereas compound 4 showed signals at δ 39.5 (C1) and δ 63.5 ppm (C2) of oxiran carbon atoms.
The photooxygenation reaction of 1, in the presence of tetraphenyl porphin (TPP) as singlet oxygen sensitizers gave a mixture of 6-hydroperoxy-3, 7-dimethylocta-1,7-diene-3-yl acetate (5) and 7-hydroperoxy-3,7-dimethylocta-1,5-diene-3-yl-acetate (6). However, compound (6) was obtained only by using Hematoporphyrin (HP) as sensitizer. Fortunately, hydroperoxide 5, 6 can be separated in pure case (Scheme 1).
The structures of 5, and 6 were supported by spectral studies. IR spectrum of 5 had almost an absorption band as in the case of 6, 1H NMR spectrum of 5 showed complex pattern at δ 5.14 ppm for H-8 and singlet at δ 7.97 ppm for OOH group. Whereas, The 1H NMR spectrum of 6 showed tertiary signal at δ 5.60 ppm for H-6 and complex pattern at δ 5.89 ppm for H-5 and singlet at δ 7.8 ppm for OOH group. 13C NMR spectrum of 5 showed signals of the ethylene carbon atoms at δ 113.5 and δ 143.2 for (C8 and C7), respectively, Whereas compound 6 showed signals at δ 113.5 for (C6) and signal at δ 123.8 for (C5).
The epoxidation of linalyl acetate (1) using m-chloroperbenzoic acid thermally under carefully controlled gave (3). However, the photo epoxidation of (1) using hydrogen peroxide in ethanolic solution gave a mixture of (3 & 4) in the ratio of 5:2 respectively (Scheme 1).
The probable mechanism for production of epoxide derivatives (3 & 4) is believed to be through the formation of the oxirane intermediates (A & B) via elimination of H2O or m-chlorobenzoic acid [depending on the epoxidizing agents, which were used (H2O2 or mcpba)] (Scheme 2).
On the other hand, our interest was focused on the photooxygenation reaction of linalyl acetae (1) using different singlet oxygen sensitizers which gave a mixture of (6-hydroperoxy-3,7-dimethyl-octa-1,7-diene-3-yl-acetate (5) and 7-hydroperoxy-3,7-di-methyl-octa-1,5-diene-3-yl acetate (6) using TPP while HP gave (6) only (Scheme 1).
The formation of hydroperoxides 5 and 6 may be assumed to proceed via peroxirane transition state (C), which has been done through two probable pathways (Scheme 3).
3.2 Antimicrobial activity
In recent years, most of the essential oils have been reported to be good source of antifungal and antibacterial compounds (Nor Azah et al., 2002; Tabassum, and Vidyasagar, 2002). Many monoterpenes were shown to act effectively in chemoprevention and chemotherapy. Also, the compounds were proved to be active against many pathogenic bacteria (Saddiq, and Khayyat, 2010).
It is known that some monoterpenes and its derivatives have biological activity. Therefore, a comparative test was taken of the linalyl acetate 1 with its epoxide and hydroperoxide derivatives, 3, 4 and 5, 6 against Microsporum canis and Microsprum gallinna which are fungal species that causes numerous forms of disease. They are a part of a group of fungi known as communicable pathogen dermatophytes (Michiko et al., 2013; Shafiee et al., 2014). The results clearly indicated that linalyl acetate 1, epoxides 3, 4 and hydroperoxides 5, 6, strongly inhibited Microsprum canis and Microsprum gallinna grown on the solid media, It showed that all linalyl acetate and its derivatives were effective in reducing the growth of tested fungi, (Table 3 showed all the tested compounds inhibited Microsprum canis and Microsprum gallinna grown completely at 1 mg/ml concentration except epoxide 3 on Microsprum canis. Hydroperoxide 5 was registered a highest antimicrobial activity at 0.5 mg/ml concentration against Microsprum canis and Microsprum gallinna (Table3).
The results indicated that compounds are beneficial to human health, and have the potential to be used for medical purposes.
4 Conclusion
The results of the present study indicated the preventive effect of linalyl acetate and its epoxide and hydroperoxide derivatives against Microsporum canis and Microsprum gallinna on Mueller Hinton media. The results proved that epoxides and hydroperoxides of linalyl acetate are beneficial to human health, having the potential to be used for medical purpose.
Acknowledgement
Manal Al-Kattan is gratefully acknowledged for her valuable help in biological study.
References
- Inhibition of growth of S. aureus during production of acidophilus yogurt. J. Food Prot.. 1987;50:224-228.
- [Google Scholar]
- Biological activities of lavender essential oil. Phytother. Res.. 2002;16(4):301-308.
- [Google Scholar]
- Odour fingerprint acquisition by means of comprehensive two-dimensional gas chromatography-olfactometry and comprehensive two-dimensional gas chromatography/mass spectrometry. J. Chromatogr. A. 2007;1141:279-286.
- [Google Scholar]
- The growing use of herbal medicine: issues relating to adverse reactions and challengesin monitoring safety. Front. Pharmacol.. 2013;4:177-186.
- [Google Scholar]
- Oxidation studies on some natural monoterpenes: citral, pulegone and camphene. Russ. J. Org. Chem.. 2008;44(6):814-822.
- [Google Scholar]
- Oxidation reactions of some natural volatile aromatic compounds: anethole eugenol. Russ. J. Org. Chem.. 2008;44(6):823-829.
- [Google Scholar]
- Synthesis and antimicrobial activity of some new benzimidazole derivatives. Molecules. 2002;5:1429-1438.
- [Google Scholar]
- Structure-odor relationships of linalool, linalyl acetate and their corresponding oxygenated derivatives. Front. Chem.. 2015;3:57-61.
- [Google Scholar]
- Essential oil constituents, anticancer and antimicrobial activity of Ficus mucoso and Casuarina equisetifolia leaves. Am. J. Essent. Oils Nat. Prod.. 2016;4:01-06.
- [Google Scholar]
- History of headache in medieval Persian medicine. Lancet Neurol.. 2002;1(8):510-515.
- [Google Scholar]
- Pharmacological treatment of headache using traditional persian medicine. Trends Pharmacol. Sci.. 2003;24(7):331-334.
- [Google Scholar]
- Geraghty, N., 2005. Photochemistry. In: Dunkin (Ed.), London: Royal Soc. Chem, vol. 27. pp. 35–116.
- Effects of direct exposure of green odour components on dopamine release from rat brain striatal slices and PC12 cells. Brain Res. Bull.. 2008;75:706-712.
- [Google Scholar]
- Photosynthesis of Safrole types potential intercalative and oxidative agent of DN through photooxidation reaction. Aust. J. Bas. App. Sci.. 2011;5(5):78-81.
- [Google Scholar]
- Thermal, photosynthesis and antibacterial studies of bioactive safrole derivative as precursor for natural flavor and fragrance. Arab. J. Chem.. 2014;7:800-804.
- [Google Scholar]
- Olfactory influences on mood and autonomic, endocrine, and immune function. Psychoneuroendocrinology. 2008;33(9):1303.
- [Google Scholar]
- Biotransformation of hop aroma terpenoids by ale and lager yeasts. FEMS Yeast Res.. 2013;3:53-62.
- [Google Scholar]
- Lavender and the nervous system. Evid.-Based Complement. Altern. Med.. 2013;2013:10-20.
- [Google Scholar]
- Oxygen transfer mechanism in the Mn-salen catalysed epoxidation of olefins. J. Mol. Catal. A Chem.. 1999;138(2):221-226.
- [Google Scholar]
- Isolation of Microsporum gallinae from a fighting cock (Gallus gallus domesticus) in Japan. Med. Mycol.. 2013;51(2):144-149.
- [Google Scholar]
- Mtolera, M.S.P., Semesi, A.K., 1996. Antimicrobial activity of extracts from six green algae from Tanzania. Curr. Trends Mar. Bot. Res. East Afr. Reg. pp. 211–217.
- Chemical composition and antimicrobial activities of the essential oils of Cinnamomum aureofulvum GambEssent. Oil Res.. 2002;14:135-138.
- [Google Scholar]
- Anti-inflammatory activity of linalool and linalyl acetate constituents of essential oils. Phytomedicine. 2002;9:721-726.
- [Google Scholar]
- Prusinowska, R., Krzysztof, B., 2014. Composition, biological properties and therapeutic effects of lavender (Lavandula angustifolia L.). A review. Herba Bonica 60(2), 56–66.
- Clerocidin alkylates DNA through its epoxide function: evidence for a fine tuned mechanism of action. Nucl. Acids Res.. 2003;3:5149-5156.
- [Google Scholar]
- Linalyl acetate as a major ingredient of lavender essential oil relaxes the rabbit vascular smooth muscle through dephosphorylation of myosin light chain. J. Cardiovasc. Pharmacol.. 2006;48(1):850-856.
- [Google Scholar]
- Chemical and antimicrobial studies of monoterpene: citral. Pest. Biochem. Physiol.. 2010;98:89-91.
- [Google Scholar]
- Comparative study of Microsporum canis isolates by DNA fingerprinting. Mycoses. 2014;57:507-512.
- [Google Scholar]
- Autoxidation of linalyl acetate, the main component of lavender oil, creates potent contact allergens. Contact Dermatitis. 2008;58:9-14.
- [Google Scholar]
- Sampling flower scent for chromatographic analysis. J. Sep. Sci.. 2008;31:2022-2031.
- [Google Scholar]
- Antifungal investigations on plant essential oils. A review. Int. J. Pharm Pharm. Sci. 2002;5(2):19-28.
- [Google Scholar]
- Psychiatry and psychology in medieval Persia. J. Clin. Psychiatry. 2006;67(12):1862-1869.
- [Google Scholar]
- Biosynthesis and therapeutic properties of lavandula essential oil constituents. Planta Med.. 2011;77(1):7-15.
- [Google Scholar]
- Acid-catalyzed reactions of camphene and α-fenchene epoxide. Russ. J. Org. Chem.. 2002;38:810-822.
- [Google Scholar]
- Synthesis of heterocyclic compounds in acid-catalyzed reactions of citral epoxides. Mendeleev Commun.. 2003;27:1-2.
- [Google Scholar]