ABSTRACT
The potential of Garcinia
mangostana as a biological control agent against plant pathogenic bacteria
which decrease the quality and volume of crop production worldwide was
assessed. Mangosteen leaves were extracted by maceration using chloroform, n-hexane, and methanol. For the in vitro antibacterial activity, two
dissimilar species of plant pathogenic bacteria: Pseudomonas syringe pv. tomato and Xanthomonas oryzae pv. oryzae were acquired. Four different
concentrations, 12.5, 25, 50, and 100 mg/ml were obtained through the cup-plate
agar diffusion technique. Streptomycin sulphate at 30 μg/ml concentration was
set as the positive control, whereas every respective solvent used in the leaf
extraction was set as the negative control. The results have shown that, only
methanol extract demonstrated antibacterial activity when tested on the plant
pathogenic bacteria. The highest diameter of inhibition zones was observed in X. oryzae pv. oryzae, at all range of concentrations, followed by P. syringae pv. tomato. The least methanol extract concentration utilised
in determination of minimum inhibitory concentration (MIC) assay was at 1.562 mg/ml, inhibiting X.
oryzae pv. oryzae, followed by
P. syringe pv. tomato at a
concentration 3.125 mg/ml. Antibacterial impacts of the most effectual extract
of mangosteen crude were supported by the existence
of chemical components identified by GC-MS. Cycloartenol, Caryophyllene,
Docosane, Phenol, 4,4-Methylenebis (2,6-di-tert-butylphenol) and Chromium were
noted as key compounds in the
mangosteen leaf extract, which were perhaps causing the antibacterial activity.