Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol.4, No.12, 2014 62 Chemical compositions, antioxidant and antibacterial activities of essential oils from Anethum graveolens L. and Trachyspermum roxburghianum (DC.) Craib grown in Thailand Nichakan Peerakam 1 , Suchart Punjaisee 2 , Santhana Buamongkol 2 , Panee Sirisa-ard 1 , Jakaphun Julsrigival 1 and Sunee Chansakaow 1* 1. Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand 2. Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai 50200, Thailand *E-mail of the Corresponding Author: chsunee@gmail.com The research is financed by Asian Development Bank. No. 2006-A171(Sponsoring information) Abstract The essential oils from the aerial part of Anethum graveolens L. and Trachyspermum roxburghinum (DC.) Craib were obtained by hydro-distillation. Gas chromatography-mass spectrometry (GC-MS) was employed for the identification of chemical components. Folin-Ciocalteu colorimetric method, DPPH, ABTS and FRAP assays were used to determine total phenolic content and to evaluate antioxidant potential. Agar-well diffusion and agar- dilution methods were used to investigate antibacterial activity. The results indicated that α-phellandrene (61.57%), β-phenandrene (10.39%) and dill ether (8.23%) represented as the major components of A. graveolens while sabinene (28.60%) and α-terpinolene (24.20%) including 3-n-butylphathalide (23.34%) were the main compounds of T. roxburghinum. The essential oils of both plants showed high total phenolic content (GEA= 1.7948-3.0971 mg/mL) and exhibited potent antioxidant activities in DPPH (TEAC= 19.3119 and 357.9297 mg/mL), ABTS (TEAC= 4.6031 and 13.4242 mg/mL) and FRAP assays (TEAC= 0.8327and 27.4173 mg/mL). Moreover, they had an effect on both gram-positive bacteria with MIC 2.66-11.88 µg/mL and gram-negative bacteria with MIC 23.76-85.77 µg/mL, respectively. Keywords: Anethum graveolens L., Trachyspermum roxburghinum (DC.) Craib, essential oil, antioxidant activity, antibacterial activity. 1. Introduction Pak Chi Lao and Pak Chi Rai are the local names of Anethum graveolens L. and Trachyspermum roxburghinum (DC.) Craib, respectively. They are members of family Umbelliferae (Apiaceae) [1] which are a rich source of essential oils and have been extensively cultivated in northern and northeastern regions of Thailand as vegetables. Thai folk wisdom has shown that the seeds of this family can be used to prevent spoilage of fermented food. As well, Thai traditional formularies use some Umbelliferous seeds as an ingredient in Thai tradition medicines, such as “Ya Tart Buun Jop and Ya Hom Intajak” which are used to treat the symptoms of dizziness, vomitting and as a cardiotonic drug. In fact, the uses of the aerial parts of plants have been widely practised to provide flavor in local cuisine, e.g., Mok pla: steamed fish in banana leaf, and several coconut milk-based curries that contain fish or prawns [2]. In addition, it is used as an edible vegetable. Therefore, these plants can be used to eliminate fishy aromas and influence the flavor of food and benefits for health because some phenolic compounds in plants have antioxidant activity. Many ailments such as cancer, cardiovascular disease, inflammation-related diseases, neurodegenerative diseases (Alzheimer’s and Parkinson’s disease) etc. are caused from free radicals which are dangerous molecules that can be generated in human body [3]. Natural sources of antioxidant substances have been discovered from fruits and vegetables, even a small amount of free radical scavenger can prevent and reduce reactive species of free radicals in the human body [4-5]. In Thailand, both plants are widely used in household while the scientific information of plants is still lacking. The study concerning the usefulness of these plants has shown the utility and potential of plants corresponding to phytonutrient consumption. Then, the examination on antimicrobial activity from these sources has been aimed to assess the potential and the uses of medicinal plants to their highest advantage because the natural antimicrobial agents could be a safe alternative for food preservation and human remedies. The aim of this research was to study the chemical compositions, antioxidant potential and antibacterial activity of essential oils