Biological and chemical characterization of Origanum vulgare and Ocimum Basilicum essential oils and their derived nanoemulsions

To contest the disadvantages of synthetic pesticides, we investigated the essential oils (EOs) of Origanum vulgare and Ocimum basilicum and their nano-formulations as alternative tools for pest management. After conducting assays, we prepare nanoemulsions (Nano-Es) from these essential oils (EOs) and characterized them biologically and chemically. Both EOs and Nano-Es have remarkable suppression activity in the pre-emergence; however, they have fewer inhibition effects as post-emergence applications against Convolvulus arvensis, Lolium temulentum, Chenopodium album, and Cuscuta planiflora weeds. These treatments did not display any observed selectivity and negative effects in the T. alexandrine crop. When EOs and Nano-Es were applied on Fusarium oxysporum, they had EC₅₀ by 114.89 and 54.94 (O. basilicum) and 89.56 and 33.54 (O. vulgare) ‎µl ml¹ respectively. Similarly, when applied to bacteria Erwinia carotovora, the EC₅₀ were 179.76 and 128.65 ‎µl ml^-1 (O. basilicum) and 171.76 and 114.65 (O. vulgare) ‎µl ml^-1, respectively. The GC/MS analyses identified the essential oil constituents, which the major compounds in O. basilicum were geranyl acetate (15.58%), linalool (13.68%), methyl chavicol (9.56%), and terpinene-4-ol (9.10%), beta-myrcene (7.40%), and 1, 8-cineol (6.76%), respectively. The major constituents in O. vulgare of oils were carvacrol (13.565), thymol (11.78%), dihydrocarveol (11.36%), carvacrol methyl ether (7.60%), α-terpinene (7.09%), cymene (6.61%) and pinene (6.03%), respectively. The Nano-Es of O. basilicum and O. vulgare were characterized by their nanoparticle sizes of 13.45 ± 6.3 and 22.4 ± 8.0 nm, and the transmission electron microscopy (TEM) images of 46.76 and 57.32 nm, respectively. In general, the efficacy of EOs of O. vulgare and O. basilicum improved in their Nano-Es, and their characterizations were good for an application that offered promising formulations for pest management programs.