Evaluation of antibacterial activity of Coriandrum sativum (L.) against gram – positive and gram – negative bacteria

Background: Most of the present anti-bacterials are either semisynthetic modifications of some natural compound or are synthetic chemicals. All of them have acceptable spectrum of action and efficacy but none of them are devoid of side effects. For this reason a new anti-bacterial is needed which should have same acceptable efficacy with better safety. Coriander (Coriandrum sativum L.) is a well-known herb commonly used in cooking, folk medicine, pharmaceutical and food industries. In this study we have tested anti-bacterial activity of coriander oil against 5 microorganisms and compared the results with ampicillin and genatmicin.Methods: The study was done on five bacteria – Staphylococcus aureus, Escherichia coli, Klebseilla, Pseudomonas and Salmonella. Antibiotic sensitivity testing was done on Mueller Hinton agar plates by Kirby-Bauer disk diffusion method. After application of inoculum antibiotic discs of 2 mm diameter impregnated with ampicillin, gentamicin or coriander oil were placed 2 cm apart from each other. Each drug sample was used in triplicate. Incubation was done for 18-24 hours at 37oC aerobically. The diameters of zones of inhibition were measured in mm and expressed as Mean±SD.Results: Coriander oil expressed highest antibacterial action against E. coli (10.73±0.21) which was better than Gentamicin (9.47±0.45). Coriander also inhibited growth of Salmonella (9.53±0.40) which was slightly less than Ampicillin (10.57±0.21) and least activity was expressed against Klebsiella (7.20±0.17) and that also was close to action of Ampicillin (8.43±0.25).Conclusions: Coriander oil demonstrated good anti-bacterial activity against commonly five occurring microorganisms but further extensive studies are required to isolate the active ingredient responsible for antibacterial action and develop coriander essential oil as a clinically proven antibacterial agent