Composition and antimicrobial activity of Rosmarinus officinalis L. and Artemisia monosperma L. leaf essential oils and methanolic extracts from plants grown in normal and saline habitats in Egypt

Abstract

The present work aimed to investigate the effect of salinity in natural habitats in Egypt on the main secondary metabolites of Rosmarinus officinalis L. and Artemisia monosperma L. plants compared to plants grown at normal conditions. Plants grown under salinity were collected from Egyptian Western Coastal region habitats irrigated with underground water. Results showed that salinity increased the essential oil percentage of R. officinalis L. by 52.7% and A. monosperma L by 0.29% in addition to the total phenolics and flavonoids content in dry leaves compared to control plants. GC/MS analysis of rosemary essential oils revealed that salinity decreased the amount of some major oil monoterpenes component as verbenone, with a slight effect on 1,8 cineole and increased Camphor, endo- Boreneol, and linalool in addition to the appearance of new specific components such as Chrysanthenone monoterpene ketone and Caryophyllene sesquiterpene, while, in the case of Artemisia, the GC/MS showed that Artemisia ketone, Camphor, β -phellandrene monoterpenes andα-Bisabolol sesquiterpenewere the major oil components; salinity decreased Camphor and β -phellandrene content and increased artemisia ketone and α-Bisabolol oil content. About 11 new oil constituents were detected such as ( +)-2-Bornanone and Sesquisabinene hydrate. Mineral ions (N, K⁺, Ca⁺², P, and Mg⁺²) uptake by R. officinalis and A. monosperma decreased in plants grown under salinity, while Na content increased compared to corresponding controls. Results demonstrated that both plants could tolerate the high salinity level in natural Western Coastal region soil which promoted more production of valuable secondary metabolites. The antimicrobial effect of R. officinalis L. and A. monosperma L. leaf methanolic extracts, results showed that R. officinalis extracts had an inhibitory response against all tested gram-positive and negative bacteria, in addition to the yeast (Candida albicans), whereas there was no any inhibitory effect concerning A. monosperma L extract on the tested species.