Bactericidal efficacy of selected medicinal plant crude extracts and their fractions against common fish pathogens = Keberkesanan bakterisid ialah ekstrak mentah tumbuhan ubatan terpilih dan fraksinya terhadap patogen biasa ikan

• Main Authors: Abdul Razak, Rashidah, Shariff, Mohamed, Md. Yusoff, Fatimah, Ismail, Intan Safinar
• Format: Article
• Language: English; English; English
• Published: Penerbit Universiti Kebangsaan Malaysia 2019
• Subjects: S Agriculture (General); SH Aquaculture. Fisheries. Angling
• Online Access: http://irep.iium.edu.my/79206/1/79206_Bactericidal%20efficacy%20of%20selected%20medicinal.pdf; http://irep.iium.edu.my/79206/2/79206_Bactericidal%20efficacy%20of%20selected%20medicinal_SCOPUS.pdf; http://irep.iium.edu.my/79206/13/79206_Bactericidal%20Efficacy%20of%20Selected%20Medicinal_WOS.pdf; http://irep.iium.edu.my/79206/; http://www.ukm.my/jsm/pdf_files/SM-PDF-48-8-2019/05%20Rashidah%20Abdul%20Razak.pdf

The emergence of new diseases and the increased use of antibiotics have led to the development of resistant bacterial strains. Thus, there is greater attention to seek new antibacterial agents from the natural sources for combating fish diseases in the aquaculture industry. The present study evaluated the bactericidal efficacy of crude methanolic and aqueous extracts from Polygonum chinense, Syzygium polyanthum, Premna foetida, Pimenta dioica, Brucea javanica, Vitex negundo, Alpinia conchigera and Clinacanthus nutans against Vibrio harveyi, Vibrio alginolyticus, Vibrio parahaemolyticus and Aeromonas hydrophila using disc diffusion method. The results showed that methanolic extracts of P. dioica, P. foetida and P. chinense, and aqueous extracts of P. dioica and S. polyanthum showed moderate to strong activity (10.8 to 17.2 mm) against all the tested bacteria. These five potential crude extracts were fractionated using liquid-liquid extraction method to obtain the methanol, dichloromethane and ethyl acetate fractions. Among the fractions, ethyl acetate fraction showed the highest activity against all tested bacteria, with minimum inhibition concentration (MIC) values between 0.625 and 10.000 mg/mL. In addition, the five potential crude extracts had low to moderate toxicity with LC50 >100 µg/ mL using brine shrimp cytotoxicity assays. The results of this study indicated that methanolic extracts of P. chinense and P. foetida that showed high bactericidal activity and low toxicity could be good potentials for use in fish culture. ****************************************************************************************** Kemunculan penyakit baharu dan peningkatan penggunaan antibiotik telah membawa kepada penghasilan strain bakteria yang rintang. Oleh itu, terdapat banyak perhatian untuk mencari agen antibakteria baru daripada sumber semula jadi bagi memerangi penyakit ikan dalam industri akuakultur. Kajian ini telah menguji keberkesanan bakterisid bagi ekstrak mentah metanolik dan akueus daripada Polygonum chinense, Syzygium polyanthum, Premna foetida, Pimenta dioica, Brucea javanica, Vitex negundo, Alphinia conchigera dan Clinacanthus nutans terhadap Vibrio harveyi, Vibrio alginolyticus, Vibrio parahaemolyticus dan Aeromonas hydrophila menggunakan kaedah penyebaran cakera. Hasil kajian telah menunjukkan ekstrak metanolik P. dioica, P. foetida dan P. chinense, dan ekstrak akueus P. dioica serta S. polyanthum mempunyai aktiviti antimikrob sederhana hingga kuat (10.8 hingga 17.2 mm) terhadap semua bakteria yang diuji. Kesemua lima ekstrak mentah yang berpotensi ini seterusnya difraksikan menggunakan kaedah pengekstrakan cecair-cecair untuk mendapatkan fraksi metanol, diklorometana dan etil asetat. Antara fraksi ini, fraksi etil asetat menunjukkan aktiviti tertinggi terhadap semua bakteria yang diuji dengan nilai kepekatan perencatan minimum (MIC) antara 0.625 hingga 10.000 mg/mL. Di samping itu, lima ekstrak mentah yang berpotensi ini mempunyai ketoksikan yang rendah hingga sederhana dengan LC50> 100 μg/mL menggunakan pengasaian kesitotoksikan udang brin. Hasil kajian ini menunjukkan bahawa ekstrak metanolik P. chinense dan P. foetida yang mempunyai aktiviti bakterisid tinggi dan ketoksikan rendah mempunyai potensi yang baik untuk digunakan dalam kultur ikan.