Abstract:
The objective of this study was to investigate both antioxidant and antibacterial
activities of Sesbania javanica Miq. that belongs to a family of FABACEAE. The total phenolic
and flavonoid contents were determined and polyphenols were analyzed by thin layer
chromatography (TLC). The antioxidant activity was assayed by 2, 2-diphenyl-1-picrylhydrazyl
(DPPH) radical scavenging effect and the reducing power of iron (FRAP assay). Moreover,
antibacterial activity against four opportunistic bacteria was also investigated by agar diffusion
susceptibility test. The results revealed that the total phenolic contents of leaf and flower extracts
were 35.93±0.0004 and 34.81±0.0008 mg GAE/g extract, respectively. The total flavonoid
contents of leaf and flower extracts were 24.11±0.002 and 23.90±0.004 mg QE/g extract,
respectively. S. javanica Miq. extract contained various flavonoids including methyl
dihydroflavonoid, flavonol O-glycosides and flavonone O-glycosides. Leaf and flower extracts
exhibited the DPPH radical scavenging activity with the IC50 by 2.38 and 2.07 mg/mL,
respectively. For the FRAP assay, leaf and flower extracts showed the FRAP value of
46.89±0.003 and 45.90±0.003 mgFeSO4/g extract, respectively. S. javanica Miq. extracts
displayed the best antibacterial activity against Bacillus subtilis, followed by Escherichia coli
ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853,
respectively (MICs = 20, 40, 40 and 80 mg/mL, respectively) although their activities were not as
good as tetracyclin, an antibiotic drug used currently. However, they have an opportunity to
develop as a functional food in the future