Antimicrobial Activity and Toxicity of Ocimum bacillicum Plant Growing In Jeddah

Multiple drug resistance bacteria have been developed due to the indiscriminate use of commercial antimicrobial drugs commonly used in the treatment of infectious diseases. Thus, searching for new antibiotics is of great interest.  Ocimum bacillicum L. (basil) is an annual hairy herb growing up to 1 meter and as one of the most common plants used traditionally in Saudi Arabia to treat many serious diseases. The plant was collected and the essential oil was extracted by either ethanol or methanol using Soxhlet. The oil has a watery viscosity and is pale greenish-yellow in color. The results showed that the methanolic extract of O. bacillicum was more active against pathogenic bacteria compared with ethanol extract. Maximum activity was against skin and respiratory tract relevant bacteria, in particular Gram positive cocci, especially Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Streptococcus mutans and/or Gram negative rod bacteria, in particular Haemophilus influenzae. Moderate antifungal activity was recorded against fungi and no activity was found against the pathogenic yeasts. The minimal inhibitory concentration (MIC) for bacteria was 25-50 µg/ml and was 50-150 µg/ml for fungi. The extracted oil affects the wall composition of the most susceptible bacterium. The oils exhibit excellent antitumor activity against Erlish Ascites Carcinoma and the oil showed no toxicity at different concentrations up to 400 µg/ ml against Artimia salina as test organisms. The chemical composition of Basil oil was determined using Gas chromatography mass spectra. Basil oil has various chemical compounds that include α-pinene, camphene, camphor, methyl cinnamate and eugenol.