Jambu semarang (Syzygium samarangense) is a plant that has the
potential as traditional medicine, including as a natural antibiotic that can
overcome bacterial infections. The study aimed to determine the molecular
structure of the isolates of dichloromethane extracts from S. samarangense plants stem bark and determine the toxic
effects of isolates with certain concentrations of S. aureus and E.coli
bacterial cultures. The isolation
process begins with the maceration process with dichloromethane solvent for 3 x
24 hours, then evaporated to produce a thick extract. The thick extract was
then separated using TLC, KCV and KKG, then purified by recrystallization. Pure
isolates were then identified by their molecular structure using UV-Vis, FTIR
and NMR spectrophotometry. The results of
isolation that have been tested using UV-Vis, FTIR and NMR spectrophotometry
indicate that the compound which was successfully isolated is a phenolic
compound namely 4-tert-Butylcatechol. This is reinforced by 2D NMR data,
namely HMBC and HSQC. Antibacterial activity testing was carried out using the
disk diffusion method. This study used 3 variations of isolate concentrations
namely 250 ppm, 500 ppm, 1000 ppm, positive control (Amoxcillin 1%) and
negative control (DMSO). The
effect of this isolates on S. aureus
was marked by the formation of inhibitory zones at concentrations (ppm) of 250,
500, 1000, and positive control respectively that is 1,66, 2,83, 5,83 and 11,5
mm whereas negative control had no effect on S. aureus. Using the same method, testing on E. coli at concentrations (ppm) of 250, 500, 1000 and positive
control were 2.83, 5, 7 and 11 mm, respectively while negative
controls did not influence on E. coli. This
research shows that dichloromethane extract isolates of S. samarangense
stem bark have antibacterial activity which the higher the concentration of
antibacterial agent given, the greater the inhibitory zone formed.
Keyword
: Isolation, antibacterial activity, Syzygium samarangense,
Disk diffusion, inhibitory zone.