ANTIFUNGAL ACTIVITY OF EXTRACT OF EUGENIA AROMATICA (L.) BAILL. (MYRTACEAE) AGAINST SOME PLANT PATHOGENIC MOLDS

Abstract

Extract of Eugenia aromatica (L.) Baill. (Myrtaceae) was tested for antifungal activity. In this study, phytopathogenic molds, Alternaria sp. and Fusarium sp. causing leafspot and wilt disease in Brassica spp., and Botrytis sp. and Septoria sp., causing gray mold rot in roses and leafspot in chrysanthemums respectively, were used as test organisms. The extract of Eugenia aromatica, 0.01 1.00% concentration incorporated in PDA, provided inhibitory activity against all tested molds. Botrytis sp. and Fusarium sp. were completely inhibited at a concentration of 0.05%, while Alternaria sp. and Septoria sp. were completely inhibited at concentrations higher than 0.30%. Separation by preparative-TLC and confirmation by TLC-bioassay using Cladosporium cladosporioides as a diagnostic fungus distinguished two active compounds, eugenyl acetate and eugenol. INTRODUCTION Eugenia aromatica (L.) Baill. (Myrtaceae, common name: clove) is a tree reaching a height of 5-10 meters. It is native in Malacca and abundant in Malaysia, Sumatra, Africa, South America, and Thailand. In Thailand, flower buds of this species are used as a spice and traditional medicine, mainly as a carminative, stomachic, antidiarrheal, local anesthetic for toothache, and as a gargle for mouth-wash (Mahidol University, 1996). In spite of this widespread use, information concerning a marked antifungal property of the plant extract has been reported only quite recently (Lima et al., 1993; Tragoolpua, 1996; Wilson et al., 1997; Wonggiratthiti, 2000; Costa et al., 2000). In order to determine the antifungal activity, the dichloromethanic extract of Eugenia aromatica was tested against phytopathogenic molds and the active compounds were evaluated and identified. MATERIALS AND METHODS Plant Material Dried flower buds of Eugenia aromatica were obtained from a grocery in Chiang Mai Province Test Organisms The fungi used for testing antifungal activity of the plant extract were: Alternaria sp. and Fusarium sp. causing leaf spot and wilt disease of cruciferous vegetables, Septoria sp. causing leaf spot of chrysanthemums and Botrytis sp. causing gray mold rot of roses. They were cultured on potato dextrose agar and maintained at 4-8°C. Extraction Procedure Dried flower buds of clove were crushed and extracted with dichloromethane using an ultrasonic bath (40°C) for 1 hour. The solvent was removed under reduced pressure in a rotary evaporator to give a dry crude extract, which was dissolved in a small amount of dichloromethane and mixed with sterile distilled water to obtain a 2% stock