Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol.4, No.18, 2014 92 Invitro Antimicrobial Activity of Plumbago Zylanica L. Yohannes Weldemariam Getahun (Corresponding author) Department of Chemistry, Adigrat University, P.O. Box 50, Adigrat, Ethiopia E-mail: jonygsfusw@gmail.com Afework Mulugeta, Department of Public Health, Mekelle University, P.O. Box 231, Mekelle, Ethiopia E-mail: afework.mulugeta@gmail.com Gebremedhin Gebremariam Department of Chemistry, Mekelle University, P.O. Box 231, Mekelle, Ethiopia E-mail: ggchem74@gmail.com Abstract Beside the search for new plants; Plants investigated to have medicinal value for particular diseases has been also checked for extra pathogens and further in other biological activities in a search for efficient and effective drug. In this study the in vitro antimicrobial capacity of Plumbago zeylanica L. root extracts were investigated against seven bacterial strains and one fungal strain. Antimicrobial activity was done employing Agar disc diffusion and Minimum inhibitory concentration (MIC) was determined involving broth dilution method. The chloroform crude extracts as well as fractions were more potent than ethanolic extracts. From MIC findings S. entritidis, S. aureus , E.coli were withdrawn from growth at 0.2mg/mL, 1mg/ml and 2mg/ml respectively. In addition, nine pure compounds were isolated and one (PFr 8 ) inhibited a bit higher than the standard drugs. Keywords: Plumbago zeylanica L, antimicrobial activity, minimum inhibitory concentration (MIC), fractionation, invitro test 1. Introduction Extensively more than 85% of deaths attribute to acute respiratory infections, diarrhoeal diseases, measles, AIDS, malaria, and tuberculosis. 1 Of these deaths; about one-half are due to infectious diseases. 2, 3 A study by WHO on conventional antimicrobial drugs such as benzyl pencilin, gentamicin, metronidazole, ampicilin, phenoxy methyl pencilin, and ciprofloxacin revealed that those drugs are no longer very effective due to continually emerging resistance by the pathogens. As people use antimicrobials for treatment of common diseases such as acute respiratory infections antibiotic, resistance is becoming a growing public health concern. 1 The species plumbago zeylanica is very known traditional medicinal plant. 4 Traditionally in India, it has been used against fever and malaria and tumor, 5 against diarrhoea, dyspepsia, piles, and skin diseases including leprotic lesions. In Nepal as an antiviral medicine, in Taiwanese folk medicine for anti-Helicobacter activity, in Assam for family planning and birth control and permanent sterilization. 6, 7, 8, 9 In DR Congo and Gabon, the pounded root is applied to treat itch. In Zambia a root decoction with boiled milk is swallowed to treat inflammation in the mouth, throat, and chest. In southern Africa, a paste of the root in vinegar, milk and water is used to treat influenza and black water fever. Plumbago zeylanica L.root cooked with meat in soup is consumed in Zimbabwe as an aphrodisiac, and it also helps digestion. A root infusion is taken orally to treat shortness of breath. In Madagascar the roots are applied as a vesicant, while in Mauritius and Rodrigues a root decoction is used to treat diarrhoea and dyspepsia. 8, 9, 10, 11 Studies on crude extracts of plumbago species have shown antibacterial, antifungal activities against selected organisms infectious to human as well as anthelmintic, antimalarial, analegesic, anti-inflamatory and antioxidant activities. 10, 11, 12, 13, 14, 15, 16 The plant is also proved to be rich in active metabolites such as flavonoids, saponins, naphthoquinone, linoleic acid, terpenoids and palmitic acid. 7, 15, 16, 17, 18 Plumbago zeylanica L. known by its local name Aftuh (in Tigrigna) and Amera (in Amharic) is a shrub widely distributed in the West and Northwest parts of Ethiopia at 1500–2200m above sea level. Traditionally local healers in Ethiopia use powdered bark, root or leaves to treat gonorrhea, syphilis, tuberculosis, rheumatic pain and swellings wound. 19, 20 Research works which screen plants for chemoterapautic significance in their crude extracts are much more times appear in the literature than those done in a fractionation system. The former ones are simple and cheaper. Thus, less worthed than the later ones. Plumbago zeylanica L is widely found in Asia particularly in China and India with medical value as antimutagenic, 6 antihelicobacter pylori, 7, anti inflammatory, 8, 17, 21 analegesic activity, 22 nephroprotective activity, 23 for cytotoxic effects, 8 larvicidal , 8, 24 as inhibitor of growth,