The need to use environmentally friendly substances in agriculture for pest control has become increasingly urgent in recent years. This was generated by humanity’s awareness of the harmful effects of chemicals with increased persistence, which accumulated in nature and harmed living beings. Essential oils are among the most important biopesticides and could significantly contribute to the expansion of ecological agriculture, replacing traditional methods. However, for judicious use, it is necessary to have a thorough knowledge of the mechanisms by which these oils act on both harmful and useful insects. An important step in transitioning from theory to practice is adapting essential oil application technologies for open fields, overcoming the difficulties created by their high volatility and low remanence, which results in a rapid reduction in the toxic effect. The review proposes an in-depth, up-to-date analysis of the existing literature on these subjects, aiming to provide researchers with some potential future study directions and practitioners with a solid base of information regarding the interaction between insects and essential oils.

The emergence of pathogenic multidrug-resistant bacteria demands new approaches in finding effective antibacterial agents. Synthetic flavonoids could be a reliable solution due to their important antimicrobial activity. We report here the potent in vitro antibacterial activity of ClCl-flav—a novel synthetic tricyclic flavonoid. The antimicrobial effects were tested using the minimum inhibitory concentration (MIC), time kill and biofilm formation assays. Fluorescence microscopy and scanning electron microscopy were employed to study the mechanism of action. MTT test was used to assess the cytotoxicity of ClCl-flav. Our results showed that Gram positive bacteria were more sensitive (MIC = 0.24 μg/mL) to ClCl-flav compared to the Gram negative ones (MIC = 3.9 μg/mL). We found that our compound showed significantly enhanced antibacterial activities, 32 to 72-fold more active than other synthetic flavonoids. ClCl-flav showed bactericidal activity at concentrations ranging from 0.48 to 15.62 μg/mL. At twice the MIC, all Escherichia coli and Klebsiella pneumoniae cells were killed within 1 h. Also ClCl-flav presented good anti-biofilm activity. The mechanism of action is related to the impairment of the cell membrane integrity. No or very low cytotoxicity was evidenced at effective concentrations against Vero cells. Based on the strong antibacterial activity and cytotoxicity assessment, ClCl-flav has a good potential for the design of new antimicrobial agents.

Biopesticides, alongside the expansive growth of conventional agriculture, emerged as a hopeful avenue for mitigating the environmental impact of synthetic chemicals. Essential oils derived from various plant species are regarded as environmentally friendly and have been suggested by numerous researchers for combating the pest species. However, in addition to their detrimental effects on harmful species, these essential oils exert varying degrees of impact on non-target species with which they share ecological relationships. This review serves the dual purpose of updating data on the use of the essential oils as biopesticides, considering the substantial increase in research output in the recent years. Simultaneously, it aims to provide a focused synthesis on the essential oils currently approved for commercial use as biopesticides, and shedding light on their impact on beneficial pollinator species, which may inadvertently suffer from the application of substances deemed safe by most users.

In this study the glandular hair morphology, chemical composition and antimicrobial activity of the essential oils from three Ocimum species have been investigated (Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum). The indumentum shows little variation among the investigated species with both glandular and non-glandular hairs presents. Glandular hairs on the three species are peltate and capitate (with various cell numbers in the stalk and gland). The samples of essential oils obtained from the plant aerial organs by hydrodistillation have been analyzed by GC-MS. Linalool (65.38%, 74.22%, 38.60%), eugenol (5.26%, 3.47%, 10.20%) and tau-cadinol (8.18%, 3.47%, 10.20%) appear as the main components in Ocimum basilicum L. var. Genovese, O. gratissimum and O. tenuiflorum. The oils also contain lower levels of α-bergamotene, 1,8-cineole, germacrene D, β-ocimene, α-caryophyllene, camphor, and α-guaiene. All essential oils showed antibacterial activity against Staphylococcus aureus and Escherichia coli depending on their concentration. Ocimum basilicum L. var. Genovese oil produced the strongest antibacterial effect on S. aureus and E. coli.