Rosemary leaves as source of bioactive compounds

Abstract

Rosemary (Salvia rosmarinus Spenn., syn. Rosmarinus officinalis L., Lamiaceae) is a perennial evergreen shrub widely distribut ed in the Balkan region. Rosemary leaf is used in traditional medicine as a rubefacient, carminative and emmenagogue. The main biologically active compounds present are phenolic acids (caffeic and rosmarinic acid), flavonoids (luteolin, diosmetin and hespere tin heterosides) and diterpenes (carnosic acid, carnosol). These compounds exhibit a wide range of biological activities, including antimicrobial, anti-inflammatory and antioxidant effects. Although it is widely cultivated in Serbia, phytochemical characterization of rosemary leaf from different localities across the country remains insufficiently explored. The study aimed to characterize the main phytochemical groups in aqueous rosemary leaf extracts and investigate differences between samples from four localities in Serbia (Bor, Užice, Belgrade and Vrbas). Aqueous leaf extracts (1:10) were analyzed by liquid chromatography coupled with mass spectrometry (LC-MS). Analysis identified 20 compounds, predominantly flavonoids and phenolic acids. The main compound was rosmarinic acid, present in samples from Užice (3.83 ± 0.44 mg/g), Vrbas (9.9 ± 1.73 mg/g) and Belgrade (16.02 ± 1.36 mg/g), while it was not detected in the sample from Bor. The principal flavonoid detected was tetrahydroxyflavone hexuronide (5.24 ± 0.12 to 13.62 ± 0.21 mg/g), present in all samples. Phenolic diterpenes were not detected, which is consistent with their predominantly lipophilic character. These findings show that the phytochemical profile of aqueous rosemary leaf extracts from Serbia differs significantly depending on geographical origin, especially in the content of rosmarinic acid, which may affect biological activity.