Abdullah et al. / Malaysian Journal of Fundamental and Applied Sciences Vol. 15, No. 4 (2019) 597-599

RESEARCH ARTICLE

Potential of zeylanica extract to eliminate E. coli and S. aureus in Corbicula fluminea (“Etak”) tissue

Faizuan Abdullah a , *, Siti Nor Aini Md. Nasir b, Dee Koh Han b, Suganthi Appalasamy b, Maryana Mohamad Nor c, Aweng Eh Rak b, * a Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia b Department of Natural Resources and Sustainability, Faculty of Earth Science, Universiti Malaysia Kelantan, 17600, Jeli, Kelantan, Malaysia c Faculty of Agro Based Industry,Universiti Malaysia Kelantan, 17600, Jeli, Kelantan, Malaysia

* Corresponding author: [email protected], [email protected]

Article history Abstract Received 2 August 2018 Revised 10 September 2018 “Etak” or Corbicula fluminea, is a freshwater mollusc regularly consumed as a popular snack Accepted 26 February 2019 among the Kelantanese in Malaysia. The “etak” is usually heated with traditional smoking process Published Online 25 August 2019 which is considered as half cooked and the smoked C. fluminea is commonly known as “etak salai”. This study focuses on the potential of leaves extract to eliminate the bacteria Graphical abstract content in “etak salai”. Extraction of bacterial genomic DNA w a s performed and confirmed the existence of (E. coli) and (S. aureus) in “etak salai”. Antibacterial properties of L. zeylanica leaves extract was identified using disc diffusion assay and the result obtained exhibit that 70 μg/μL of L. zeylanica extract was the optimum concentration to give E. coli the effect of 11 mm inhibition zone for E. coli and 15 mm inhibition zone for S. aureus. This finding proof that L. zeylanica leaves could be the ingredients in the paste for “etak salai” preparation.

S. aureus Keywords: Corbicula fluminea, etak, Leucas zeylanica, antibacterial, E. coli, S. aureus

L. zeylanica extract

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INTRODUCTION known as Ceylon slitwort and normally used at , as a spices to provide a bitter flavor. It is also applied as a cure for insects and Traditionally, the smoking process of C. fluminea involves three poisonous bite, jaundice, healing wounds and as well as for stomach steps of preparations. The first step is cleaning process to remove all ache relief especially due to roundworms for children. The the mud covered on the “etak” shells. The second step is mixing morphology consists of its leaves, flowers, fruits, stems and roots as process, where the blended spices and salt is prepared as a paste to mix explained in Fig. 2. [6]. wi t h the “etak” for the fl avor. While, the third step is the smoking Therefore, the aim of the study was to evaluate the potential of process of the C. fluminea on the special bench structure with the slow methanolic extract of leaves of L. zeylanica for its antimicrobial burning woods underneath as a smoke source. The temperature of the activity against E. coli and S. aureus. Thus, it could be consider as one “etak salai” during the smoking process was measured below 55 ˚C and of the ingredients for the “etak salai” paste to avoid gastrointestinal normally smoked for maximum time of 45 minutes and must ensure the infection among the consumers. “etak salai” shells are not open when cooked [1]. The previous study identified that the minimum temperature for bacteria killing in food especially mollusk is 70 ˚C, and must cooked until the shells open for EXPERIMENTAL clams and mussel, Thus, the smoking process for “et