The Single Compound Isolate of Eleocharis dulcis having the Antibacterial activity on Fish Diseases

Abstract

Eleocharis dulcis (Burm.f.) Trin. ex. Hensch. has been used a lot in traditional treatment in China to cure coughing, laryngitis, hepatitis, enteritis, hypertension, and pharyngitis. This research aims to identify the extracts, fractions, and isolates of the active E. dulcis toward the antioxidant and antibacterial activities. The extraction was conducted in levelling (hexane, ethyl acetate, and methanol) by using the method of Ultrasonic Assisted Extraction (UAE). The antibacterial activity was tested against the bacteria causing fish diseases, such as Aeromonas hydrophila, Aeromonas salmonicida, and Streptococcus agalactiae. Minimum Inhibitory Concentration (MIC) was carried out by microdilution and the Minimun Bactericidal Concentration (MBC) being determined by growing the microdilution solution. The antioxidant activity test was conducted with the method of DPPH. The active fraction in the fractionation with column chromatography, and furthermore the antioxidant and antibacterial activities were tested. The active isolate was identified with LCMS, 1H-NMR, 13C-NMR, and HMBC. The fractionation of the N-Hexane (NH) extract produced 6 derivative fractions, but there is no single compound isolate. Meanwhile, the Ethyl Acetate (EA) fraction produced 8 derivative fractions. From the Ethyl Acetate no 1(EA1) fraction there is a single isolate identified as the stigmasterol compound. The stigmasterol compound does not show the antioxidant activity, but it has the antibacterial activity. The stigmasterol compound has the antibacterial activity at the concentration of 62.5ppm toward the bacterium of Aeromonas hydrophila, 125ppm toward the bacterium of Aeromonas salmonicida, and 3.25ppm toward the bacterium of Streptococcus agalactiae. Correlated with the positive control, chloramphenicol antibiotic has the antibacterial activity at the concentration of 30ppm. The research results of the N-Hexane fraction do not identify that there is a single isolate. The conclusion of the Ethyl Acetate fraction shows that there is a single isolate which is the stigmasterol compound having the antibacterial activity on fish diseases that can be developed further for the treatment of the bacteria causing the fish diseases.