This work aims to elucidate the chemical composition of two essential oil (EO) samples obtained from the leaves of Thymus vulgaris L. (Lamiaceae) collected in two regions of Northwestern Algeria (Tlemcen and Mostaganem) and to assess their in vivo acute toxicity and anti-inflammatory activity. Sixty-six compounds could be identified by means of simultaneous GC-FID and GC-MS, accounting for 99.3% of total thyme oil of Mostaganem (EO.TM) and 99.0% of Tlemcen (EO.TT). In both samples, thymol was the major component, amounting to 59.5% (EO.TM) and 67.3% (EO.TT) of the total oil. EO.TT proved to be acutely toxic to mice at a dose of 4500 mg/kg p.o., whereas EO.TM did not show signs of acute toxicity, even at the highest dose tested (5000 mg/kg p.o.). Both EO samples were proven to possess anti-inflammatory activities, significantly reducing carrageenan-induced paw edema in mice (after 6 hours at a dose of 400 mg/kg p.o) at 58.4% for EO.TT and 50.4% for EO.TM, respectively. In conclusion, it could be demonstrated that EOs of T. vulgaris exhibit a considerable in vivo anti-inflammatory activity at non-toxic doses.

The essential oils (EOs) obtained by steam distillation from the leaves and the berries of Juniperus phoenicea L., harvested in northwest of Algeria were analyzed and their antimicrobial and anti-inflammatory activities were assessed. 63, 46 and 78 volatile compounds were identified by GC-FID and GC-MS from fresh leaves, dried leaves and berries representing 98.1%, 98.3% and 96.4% of the total oil, respectively. The fresh and dried leaves oils were mainly composed of β-phellandrene (43.9% / 44.9%), α-pinene (25.1% / 20.3%), myrcene (8.5% / 8.2%), α-phellandrene (4.7% / 4.5%) p-cymene (2.7%-3.0%) and limonene (2.3%-2.5%) whereas, the berries oil was mainly composed of α-pinene (43.7%), p-cymene (5.8%), β-phellandrene (4.6%), α-terpineol (4.3%) and α-campholenal (4.0%). The study of the antimicrobial activity showed that the 3 EOs were effective only on B. cereus ATCC 10876 and C. albicans ATCC 10231. No signs of acute toxicity have been noted in mice even at the highest dose tested (5000 mg/kg p.o). The fresh leaves, dried leaves and berries oils reduced the carrageenan-induced paw edema in mice by 16.8%, 15.2% and 6.4%, respectively, after 6 hours at a dose of 400 mg/kg p.o.

Antimicrobial drugs are highly popular in the treatment of infectious diseases and particularly nosocomial infections. However, excessive microbial exposure to drugs has become the most important factor triggering the emergence and spread of multidrug resistance (MDR) of microorganisms (1). This phenomenon has become a pressing global problem for two reasons. Firstly, it increases morbidity and mortality rates and treatment costs. Secondly, it limits the effectiveness of existing drugs and enhances the number of treatment failures (2). Furthermore, in the last few decades, cancer has become one of the most fiercely combated diseases around the world (3). Synthetic drugs are often the only option for cancer chemotherapy (4). However, most of them kill not only tumor cells but also the normal ones (5). Therefore, there is an urgent need for new treatments with few side effects. The use of medicinal plants and especially their secondary metabolites, essential oils (EOs), may pose a viable alternative. Thymus vulgaris L., known as common thyme (Lamiaceae family), is a perennial herb indigenous to the Mediterranean region, Asia, Southern Europe and North Africa (6). It is widely used in folk medicine and also in the food industry as a spice and natural preservative. Its oil is among the top 10 EOs exhibiting various biological activities (7) mainly due to phenols, e.g. thymol and carvacrol (8). This considerable potential of thyme oil encouraged us to analyze its chemical structure by GC-FID and GC-MS and verify its antimicrobial activity against seven reference strains responsible for nosocomial infections. We also assessed its cyto