Quantitative Determination of Free Radical Scavenging, Antitumor and Antimicrobial Activities of Some Myanmar Herbal Plants Myat Myat Mon 1 , Saw Sandar Maw 1+ , Zaw Khine Oo 2 1, 1+ Department of Biotechnology, Mandalay Technological University, Myanmar 2 Department of Biotechnology, Technological University (Taungu), Myanmar Abstract. Various organic and aqueous extracts of leaves of Ardisia japonica Blume, Ageartum conyzoides Linn., and Cocculus hirsutus Linn Diels., obtained by maceration were screened for their antioxidant and anti-tumor and antimicrobial activities in this research. All of these extracts have remarkable antioxidant activities and EC 50 values were 12.72µg/ml for A. japonica, 15.19µg/ml for A. conyzoide and 10.68µg/ml for C. hirsutus respectively. According to results from bioassay with carrot discs infected with Agrobacterium tumefaciens, no gall was detected in carrot disks treated with 100 ppm dose of C. hirsutus and A. japonica crude extracts and 1000ppm dose of A. conyzoides extract after 3 weeks incubation. According to the in vitro brine shrimp larvae lethal toxicity test, the LC 50 value of the crude extract ranged from 890ppm for A. japonica, 768ppm for A. conyzoides and 587ppm for C. hirsutus respectively and that were very much higher than that of potassium dichromate. A. japonica was selected to do further experiments as it has highest LC 50 value among these three plants. In in vivo toxicity test with mice model, there is no toxicity of A. japonica extract dosage up to 2500mg/kg/day indicating its safety for further experiments. According to antagonistic activities against nine different species of food borne and human pathogenic microorganisms by the agar-well diffusion method, the methanol fraction of crude extract of the leaves of A. japonica showed strong inhibitory activity against the food borne pathogenic bacteria Shigella boydii with 34mm in diameter. Ethyl acetate fractions also showed best results against other pathogens. The MIC value was in the ranged from 0.625 to 5.0mg/ml and the MBC value was in the ranged from 0.625 to 10.0mg/ml for these tested microorganisms. Therefore, the research clearly indicates that these herbal plants of Myanmar’s dry farm land are expectionally advantageous for human health especially A. japonica can be used as anti-microbial drug or antioxidant diet or as food preservative. Keywords: antimicrobial, antioxidant, antitumor, pathogen, preservative 1. Introduction Medicinal plants are an important source of practical and inexpensive new drugs. Myanmar is rich in varieties of medicinal as well as aromatic plants due to the presence of different climate zone in the country. There are 7000 different plants growing in Myanmar and most of them have been recognized as medicinal plants. Ever green shrubs, Ardisia japonica Blume; and Ageratum conyzoides L., and ever green climber shrub Cocculus hirsutus (L) Diels are widely growing throughout Myanmar. Although species of Ardisia, Ageratum and Cocculus are rich sources of novel and biologically potent phytochemical compounds, the utilization of Ardisia species or their phytochemical constituents have not been fully explored, resulting in underexploitation of their uses [1]. The aim of my research here is to study on the Myanmar traditional herbs that play a very important role in the development of new drugs. The objective of this research is to find out the potential antioxidant, antitumor and antimicrobial herbal drugs as well as herbal food preservatives. 2. Materials and Methods Myat Myat Mon. Tel.: 95-2-57008; fax: 95-2-57361 E-mail address: myatmyat21@gmail.com. 2011 International Conference on Biomedical Engineering and Technology IPCBEE vol.11 (2011) © (2011) IACSIT Press, Singapore 109