Impact of elicitors on essential oil compositions and phytochemical constituents in Lavandula stoechas L.

Lavandula stoechas L. (LS) is an aromatic evergreen herb used broadly in the food, pharmaceutical, and perfume industries. However, the inducer effect of elicitors on secondary metabolites (SMs) biosynthesis in LS is nebulous. In addition, the precise mechanism of elicitors in cells remains unexplored. Hence, the primary objective of this study was to analyze the changes in phytochemical compositions of LSs treated with a biotic elicitor (chitin) and an abiotic one (copper nanoparticle) under in vitro and greenhouse conditions, with the aim of choosing an appropriate elicitor type, concentration, and exposure time for this species. In this study, the biochemical function of four chitin concentrations (i.e. 0, 50, 100 & 200 mg L-1) and four copper oxide nanoparticle concentrations (i.e. 0, 25, 50, & 100 mg L-1) at two exposure times (i.e. 5 & 10 days) was investigated in LS so as to compare with the un-elicited explants and the original plant materials. The analysis showed that the highest contents of the total phenolic (4.68 mg g-1 FW), flavonoids (0.68 mg g-1 FW), anthocyanins (36.51 mg g-1 FW), and flavonols (0.29 mg g-1 FW) compounds were observed in the elicited LSs. Besides, the role of elicitors in augmenting the percentage of SMs was intelligible, especially 'lavandulol', '1,8-cineole', 'germacrene D', and '(E)-nerolidol', which increased by 21.68%, 17.21%, 9.33%, and 8.11%, respectively. In conclusion, these findings indicate that utilizing elicitors at optimal concentrations and with timely durations of exposure can largely assist in improving the biotechnological production of SMs in LS, so that their potential for industrial use can be actualized.