Consequently, they

are extensively used in medicine, and food and cosmetic industries. In addition to their role as antimicrobial agents,6 they have a role as antioxidant agents.7 For instance, lemon Citrus lemon (L.) Burm. has been used as an antimicrobial,8 anticoccidial,9 and antifungal agent,10 whereas, cinnamon Cinnamomum verum J. Presl has been used only an antimicrobial agent.11 However, nutmeg Myristica fragrans Houtt., peppermint Mentha BIX 01294 molecular weight piperita L., and sweet marjoram Origanum majorana L. have been used as stimulating agents against bacteria,6 and fungus.12 There is, however, no information Inhibitors,research,lifescience,medical about the role of essential volatile oil extracts against intracellular bacteria such as B. abortus 544 inside the human macrophages. Thus, the aim of this study was to assess the efficacy Inhibitors,research,lifescience,medical of several essential volatile oil extracts from C. verum, M. fragrans, M. piperita, C. Lemon or O. Majorana. Such oil extracts arelargely used in Syrian traditional

medicine for the treatment of respiratory and gastrointestinal diseases, against B. abortus 544, inside the human macrophages. Materials and Methods Bacterial Culture For infection experiments, B. abortus 544 was grown for 48 h in 2YT (peptone; 16 g, sodium chloride; 5 g, meat extract; 10 g, distilled water; 1 litre, (Difco, BD, Spars, MD) with 5% sterile horse serum. Bacteria Inhibitors,research,lifescience,medical were suspended in a sterile phosphate-buffered saline (PBS). Abundance of B. Inhibitors,research,lifescience,medical abortus 544 in PBS was monitored by recording optical density (OD) at 590 nm. The exact number of bacteria colony forming units (CFU) was assessed by viable count on 2YT agar (20 g/L) plates. Plates were placed in an incubator for 48 h at 37°C with 10% CO2 tension adjusted automatically. During the contact with the organism, laboratory personnel were wearing impermeable protective clothes, gloves,

and face masks. Plant Samples Collection Leaves samples of M. piperita (Lamiaceae) and O. majorana (Lamiaceae), and peel samples of C. lemon Inhibitors,research,lifescience,medical (Rutaceae) were collected from almost their native growing regions in Syria, while C. verum (Lauraceae) bark samples and M. fragrans (Myristicaceae) fruit samples were purchased from the local markets. Plants characterizations were consigned in table 1. Table 1: Characteristics of plants from which essential oils were derived Essential Volatile Oil Extraction Aerial parts of M. piperita and O. majorana were cleaned and dried prior to steam distillation in a glass apparatus using double distilled water. The plant leaves, which were collected from one station, were separated from the steams and mixed thoroughly to ensure a good homogeneity. Seventy five grams of the dried leaves and 700 ml of water were placed into a distillation flask of one litre capacity, and were extracted for three hours. This process was applied on all plants collection.