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Influence of Air on Essential Oil Constituents
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Darija Gajić, Gerhard Buchbauer
Compared to the previously reviewed studies on terpene oxidation, this study reported that geranial actually follows the third pattern of autoxidation. As discussed, stable primary oxidation products, that is, hydroperoxides, are derived from autoxidation of linalool, limonene, and linalyl acetate. However, along with only a small amount of hydroperoxides, autoxidation of geraniol resulted in the formation of aldehydes as the main oxidation products. Hydroperoxides of geranial, structurally analogous to the ones identified in linalool, linalyl acetate, and geraniol, were not detected in the oxidation mixture. The presence of compound 51 was confirmed in concentrations proportional to those of limonene-7- and limonene-6-hydroperoxide. Furthermore, for the first time, dioxolane structures were detected as a product of an autoxidation of fragrance terpenes. DFT calculations also confirmed that formation of the hypothetical geranial hydroperoxides in C6 or C7 is less favored than the formation of dixolane structures 50 and 51. A thorough study on autoxidation mechanism of geranial was also provided by this research.
Chemical composition and insecticidal properties of essential oils against diamondback moth (Plutella xylostella L.)
Published in Toxin Reviews, 2020
Rajkesh Koundal, Shudh Kirti Dolma, Gopi Chand, Vijai K. Agnihotri, S. G. Eswara Reddy
EO from leaves of C. camphora was rich in camphor (83.8%) followed by limonene (3.1%), sabinene (2.5%) and myrcene (1.4%). Sixteen components identified which account for 95.8% of the total oil. The composition of camphor (84%) is higher in the present study as compared to earlier reports. Frizzo et al. (1999) and Chen et al. (2014) reported 68% and 40.5% camphor in C. camphora, respectively as compared to present studies. Similarly, 9 and 22.9% linalool in C. camphora reported by Frizzo et al. (1999) and Chen et al. (2014), respectively. Leaves of C. flexuosus on hydro distillation yielded geranial (43.1%) as a major compound with other components viz., neral (33.1%), limonene (4.9%), myrcene (1.6%) and β-pinene oxide (1.4%). Nine components identified which account for 85.2% of the total oil. The EOs of seven cultivars of C. flexuosus reported citral (75–85%) and isointermedeol as a major component (Ganjewala et al. 2008; Ganjewala 2009).
Fumigant toxicity of three Satureja species on tomato leafminers, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)
Published in Toxin Reviews, 2021
The chemical components of three Satureja species oils in addition to their amounts analyzed by gas chromatography – mass spectrometry are summarized in Table 1. Geraniol was maximum in all of the three species. The mean composition of the major elements in S. bakhtiarica was Geraniol (30.20%), Neral (12.21%), Geranial (10.24%), and Mentone (10.18%). Also, the main ingredients in S. khuzestanica were Geraniol (31.14%), Nerol (13.58%), Mentone (12.01%), and Geranial (10.91%). Furthermore, in S. rechingeri Geraniol (26.43%), Neral (16.12%), and Geranial (9.24%) were recorded as the major components.
Chemical composition of essential oil and oleoresins of Zingiber officinale and toxicity of extracts/essential oil against diamondback moth (Plutella xylostella)
Published in Toxin Reviews, 2020
G. D. Kiran Babu, Shudh Kirti Dolma, Mohit Sharma, S. G. Eswara Reddy
The EO produced by HD dominated by zingiberene (20.3%), β-sesquiphellandrene (9.4%), (E,E)-α-farnesene (6.6%), ar-curcumene (6.3%), etc. (Table 2). Zingiberene and β-sesquiphellandrene content was high as compared to cultivars from Meghalaya namely Nadia (19.26% and 5.13%) and Varada (17.35% and 6.31%), but low as compared to Mahima (29.89% and 10.1%, respectively). High ar-curcumene and low camphene concentration detected in the present study as compared to Nadia (2.68% and 14.02%), Varada (2.4% and 11.1%) and Mahima (4.65% and 5%, respectively) (Kiran et al. 2013b). The total citral content (neral + geranial) influences the lemony aroma of ginger and has wide applications in the food and cosmetic industries (Yang et al. 2011). Generally, total citral comprises more of geranial than neral. In the present study, the total citral content was 8.2% (5% geranial and 3.2% neral), which was low as compared to cultivars M. Mahima, (14.1 to 17.4%), Varada, (16.4%) and Nadia (16.98%) (Kiran et al. 2013a, 2013b), Bhaisa (9.4%), and Majulay (18.7%) (Sasidharan et al. 2012). Australian gingers are known to be a good source of citral (50 to 70%), while the Jamaican ginger is low in citral content (Wohlmuth et al. 2006). In general, the EO contains sesquiterpenoids as the major group followed by monoterpenoids. On contrary, higher content of monoterpenoids (57%) and lower content of sesquiterpenoids (39%) were reported in the same variety elsewhere (Kiran et al. 2013b). Gingerols, shogaols, paradols, fatty acids, and gingerdiols were not detected in the present trials. Out of 51.5% total SHs, the principal compounds were zingiberene, β-sesquiphellandrene, (E,E)-α-farnesene, and ar-curcumene.