Exogenous Paclobutrazol Reinforces the Antioxidant and Antimicrobial Properties of Lavender <i>(Lavandula officinalis</i> L.) Oil through Modulating Its Composition of Oxygenated Terpenes
Salwa M. El-Sayed,
Karim. M. Hassan,
Ahmed. N. Abdelhamid,
Eman E. Yousef,
Yasmin M. R. Abdellatif,
Samah H. Abu-Hussien,
Mohamed A. Nasser,
Walaa. A. Elshalakany,
Doaa Bahaa Eldin Darwish,
Awatif M. Abdulmajeed,
Nadiyah M. Alabdallah,
Salem Mesfir Al-Qahtani,
Nadi Awad Al-Harbi,
Eldessoky S. Dessoky,
Hatem Ashour,
Mohamed F. M. Ibrahim
Affiliations
Salwa M. El-Sayed
Department of Biochemistry, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Karim. M. Hassan
Department of Horticulture, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Ahmed. N. Abdelhamid
Department of Horticulture, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Eman E. Yousef
Department of Food Science and Technology, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Yasmin M. R. Abdellatif
Department of Agricultural Botany, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Samah H. Abu-Hussien
Department of Microbiology, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Mohamed A. Nasser
Department of Horticulture, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Walaa. A. Elshalakany
Department of Biochemistry, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Doaa Bahaa Eldin Darwish
Botany Department, Faculty of Science, Mansoura University, Mansoura 35511, Egypt
Awatif M. Abdulmajeed
Biology Department, Faculty of Science, University of Tabuk, Umluj 46429, Saudi Arabia
Nadiyah M. Alabdallah
Department of Biology, College of Science, Imam Abdulrahman Bin Faisal University, P.O. Box 1982, Dammam 31441, Saudi Arabia
Salem Mesfir Al-Qahtani
Biology Department, University College of Tayma, University of Tabuk, P.O. Box 741, Tabuk 47512, Saudi Arabia
Nadi Awad Al-Harbi
Biology Department, University College of Tayma, University of Tabuk, P.O. Box 741, Tabuk 47512, Saudi Arabia
Eldessoky S. Dessoky
Department of Biology, College of Science, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
Hatem Ashour
Department of Agricultural Botany, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Mohamed F. M. Ibrahim
Department of Agricultural Botany, Faculty of Agriculture, Ain Shams University, Cairo 11566, Egypt
Plant growth regulators can affect the primary and secondary metabolites of various plant species. However, the effect of paclobutrazol (PBZ) on the composition of lavender oil, especially related to the terpenoid pathway, is still unclear in literatures. In this study, the effect of PBZ as a foliar spray (0.200, 400 and 600 ppm) on the vegetative growth, phytochemical content, and both antioxidant and antimicrobial properties of lavender oil were investigated. The results indicated that all examined PBZ treatments led to a significant (p ≤ 0.05) decrease in growth parameters compared to the untreated plants. Meanwhile, the yield of essential oil was significantly decreased by the treatment of PBZ at 200 ppm compared to the control. In contrast, applied-PBZ significantly enhanced the chlorophyll content and displayed a marked change in the composition of the essential oil. This change included an obvious and significant increase in 3-carene, eucalyptol, γ–terpinene, α-pinocarvone, caryophyllene, β-vetivenene, β-santalol, ledol, geranyl isovalerate, farnesol, caryophyllene oxide, and phytol percentage. Generally, the highest significant values were achieved by the treatment of 400 ppm compared to the other treatments. Furthermore, this treatment showed the highest free radical scavenging activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) by 13% over the control. Additionally, to determine the antimicrobial activities of the extracted oil, each treatment was examined against two strains of Gram positive bacteria (S. aureus and B. cereus), two strains of Gram negative bacteria (S. enteritidis and E. coli), and two fungal species (C. albicans and A. niger) represent the yeast modal and filamentous fungus, respectively. The findings demonstrated that all examined species were more sensitive to the oil that was extracted from lavender plants, treated with 400 ppm PBZ, compared to the other concentrations.
