The activity of alcoholic extract of Garlic on the growth of Staphylococcus aureus with estimation of median lethal dose in lab. Mice

The study was intended to investigate the in vitro activity of alcoholic extract of Garlic on the inhibition of growth of Staph. aureus which was isolated from skin infections , and determine the median lethal dose ( LD 50 ) of the extract in lab. mice. The Garlic was extracted by ethyl alcohol 95% , the ratio of ethanolic extraction amounted 44% of the weight of dry substance. Graduated concentration were prepared from alcoholic extract of Garlic from 10100 mg/ml. Their activities were checked up against Staph.aureus by agar diffusion method using ethylene glycol as control. The results showed that the sensitivity of the test bacteria was gradually increased with increasing the extract concentration , the concentration 10-30 mg/ml were rather low active in preventing the growing of Staph. aureus in culturing media , the concentrations 40-70 mg/ml were moderately active ,meanwhile the concentrations 80-100 mg/ml were highly active against the growing of Staph.aureus . The results also showed that the LD50 of the ethanolic extract of Garlic when it is orally administered to the lab mice by gradual concentrations was about 8000 mg/kg body weight . The toxic signs during 24 hrs after initial feeding with the extract were rapid breathing followed by dullness , then death . Introduction Many plant-derived substances touted to improve health are sold around the world, Garlic (Allium sativum ) is believed by many people to be useful for diseases prevention. The Garlic belongs to the Family “Liliaceae“, and the important components are : volatile oils that contain diallyl disulfate , alliin and allicin with allinase and many vitamins (Hussein 1986). In ancient Egypt, Garlic was given to laborers and soldiers to mitigate fatigue or to prevent recovery from physical exhaustion (Essman et al 1984 ). Louis Pasteur was the first to describe the antibacterial effect of Garlic juice and found that it exhibit a broad antibacterial spectrum against both Grampositive and Gram-negative bacteria (Sivam et al 2001 ). Garlic also long been known to have anti-fungal , anti-protozoal, antiviral, and anti-bacterial properties (Bakri et al 2005). Researches have been recently focused on the prevention and curative effects of Garlic on cancer (Black et al 1994), cardiovascular disease ( Jacob et al 1993) , and skin disease ( ). The purposes of this study are to detect the in vitro activity of Garlic extract in the growth inhibition of Stapyllococcus aureus isolated from skin diseases , so this study carried out to :1-Prepare alcoholic extraction of Garlic in ethyl alcohol 95% . 2-Detection of inhibitory effects of different concentrations of extract on the growth of Staph. aureus by using agar well diffusion method . 3Determination of median lethal dose ( LD 50 ) of extract in lab. mice . AL-Qadisiya Journal of Vet.Med.Sci. Vol./9 No./2 2010 54 Materials and Methods Materials :1-Culture media : Are prepared according to the producing companies instructions and sterilized in autoclave at 121 C under pressure of 15 pounds/ inche after incubation at 37 C for 24 hrs , used for culture and diagnosis of bacteria used in this study . 2Chemicals and reagents : Specific chemicals and reagents are used for biochemical tests to confirmed the diagnosis of bacteria ( Forbes et al ) . 3Equipments : Different equipments were used such as:analytical balance, autoclave, incubator, microscope, sensitive balance, spectrophotometer, and blender. Methods :1-Preparation of plant : Garlic were collected from the local market and authenticated as Allium sativum (University of Baghdad Herb Centre ) . 2-Extraction methods : Garlic was skinned and sliced, 50 gm sliced Garlic were crushed in awarding blender for 1 minute , then soaked in 450 ml ethanol 95% . It was naturally extracted for 3 months at room temperature , the mixture was separated in test tubes by centrifugation 3000 rpm , the filtrate was dried in oven 37 C for 24 hrs. The final product was stored in freezer at -20 C (Krell et al 1996 ). 3-Culture preparation: The bacteria were activated by re culturing on nutrient agar and kept in the incubator for 24 hrs at 37 C, then transferred in to sterilized tubes containing heart infusion broth , then placed in the incubator for 24-72 hrs at 37 C . Total bacterial count was estimated by using spectrophotometer, the percentages of light transmittance was 26% at a wave length of 580 nanometer, while the light transmittance was 100% for nutrient broth used to prepare the bacteria