Impact of fifteen combinations of the main components of rosemary, lavender and citrus essential oils on in vitro biological activities

Since ancient times, essential oils or their volatiles have been used in food, health and aromatherapy. Essen-tial oils are complex mixtures constituted by dozens of compounds, which makes it difficult to attribute their biological properties to this or that compound or compound combinations. Moreover, the quantification of the volatiles is generally made through their relative percentage abundances. In the present study, the major volatiles isolated from Rosmarinus officinalis, Lavandula angustifolia, and Citrus aurantium essential oils extracted by simultaneous hydrodistillation-steam distillation were quantified through the external standard calibration method. Fifteen volatile mixtures were made using individual volatiles identified in the essential oils (EOs) to better find their role in the biological activities (antioxidant, anti-glucosidase, anti-inflammatory, anti-tyrosinase and anti-acetylcholinesterase activities). For almost mixtures assayed, the in vitro biological activities were generally poorer than those obtained for crude EOs, with the exception of the inhibitory effect on the a-glucosidase activity. In this case, 1,8-cineole and a-terpineol seem to have a positive role in inhibit-ing a-glucosidase activity, in contrast to camphor and borneol, which had the opposite action. Therefore there was a possible antagonist effect of both camphor and borneol in the volatile mixtures assayed on inhibiting the a-glucosidase activity. This approach also permitted us to conclude that there were several other factors not determined in the present work that were responsible for the activities found in the EOs,(c) 2023 SAAB. Published by Elsevier B.V. All rights reserved.