Syzygium malaccense memiliki beragam aktivitas biologis diantaranya antibakteri. Penelitian ini dilakukan untuk mengetahui senyawa hasil isolasi ekstrak metanol kulit batang tumbuhan Syzygium malaccense bersifat antibakteri terhadap Escherchia  coli dan aktivitas antibakteri senyawa tersebut. Karakteristik senyawa pada isolat berdasarkan hasil UV-Vis  terdapat serapan pada panjang gelombang maksimal 373 nm dan 246 nm menunjukkan kerangka khas flavonoid, dari analisis FTIR isolat memiliki gugus OH 3421 cm^-1, CH alifatik 2968 -2862 cm^-1, C- H aromatik 866– 742 cm^-1,C=O 1726 cm^-1, C=C Aromatik 1579 -1535 cm^-1, C-O 1273 - 1074 cm^-1, dan  gugus benzen tersubtitusi  742cm^-1yang memiliki kesesuaian dengan senyawa flavonoid golongan flavonon, dan LCMS menghasilkan 20 puncak yang merupakan senyawa flavonoid dan fenolik dengan waktu retensi 3,042; 3,042; 9,375; 9,74; 10,02; 10,336; 11,015; 11,017; 11,02; 11,514; 23,194; 23,705; 24,119; 25,839; 35,646; 35,649; 46,577; 60,009;  60,039; dan 60,063. Penelitian ini menggunakan metode uji antibakteri difusi cakram dengan 3 perlakuan dan 3 kali pengulangan. Konsentrasi isolat yang diujikanyakitu 400 ppm, 600 ppm, dan 800 ppm.  Isolat dari ekstrak kulit batang Syzygium mallacense dengan konsentrasi 400 ppm dan 600 ppm termasuk dalam antibakteri lemah karena menghasilkan diameter zona hambatd <5 mm yakitu 1,33 mm dan 4 mm. Isolat dengan konsentrasi 800 ppm menghasilkan 66,67 mm  sehingga termasuk dalam antibakteri sedang karena termasuk dalam reange diameter zona hambat 6-10 mm. Hasil penelitian menunjukkan bahwa konsentrasi isolat meningkat bersamaan dengan diameter zona hambat bakteri Escherchia  coli yang terbentuk.

Kata kunci: Aktivitas antibakteri, Syzygium malaccense, Difusi cakram

Syzygiummalaccense has a variety of biological activities including antibacterial. This research was conducted to determine was to determine the isolate compound of methanol extract of bark Syzygiummalaccense plant which is antibacterial to Escherchia coli and the antibacterial activity of these compounds. The characteristics of compounds in isolates based on UV-Vis results were absorption at a maximum wavelength of 373 nm and 246 nm indicating a typical framework of flavonoids, from FTIR analysis isolates had OH 3421 cm-1 group, CH aliphatic 2968 -2862 cm-1, aromatic C-H 866-742 cm-1, C = O 1726 cm-1, C = C Aromatic 1579 -1535 cm-1 , CO 1273 - 1074 cm-1, and 742cm-1 substituted benzene group which has suitability to flavonoid compounds in the flavonone group, and LCMS produces 20 peaks which are flavonoid and phenolic compounds with a retention time of 3,042; 3,042; 9,375; 9.74; 10.02; 10,336; 11,015; 11,017; 11.02; 11,514; 23,194; 23,705; 24,119; 25,839; 35,646; 35,649; 46,577; 60,009; 60,039; and 60,063. This study used an antibacterial disc diffusion test method with 3 treatments and 3 repetitions. The concentration of isolates tested was 400 ppm, 600 ppm and 800 ppm. Isolates from extracts of Syzygiummallacense bark with concentrations of 400 ppm and 600 ppm included in the antibacterial were weak because they produced a zone diameter of <5 mm which was 1.33 mm and 4 mm. Isolate with a concentration of 800 ppm produce 66.67 mm, so they are included in the medium antibacterial, because they are included in the diameter range of the inhibition zone of 6-10 mm. The results show that the concentration of isolates was increased coincide with the diameter of the Escherchia coli inhibitory zone formed.