Supayang Voravuthikunchai and Lhin Kitpipit

pp. 525 - 534

Abstract

Aqueous and ethanolic extracts of Acacia catechu, Garcinia mangostana, Impatiens balsamina,
Peltophorum pterocarpum, Psidium guajava, Punica granatum, Quercus infectoria, Tamarindus indica, Uncaria
gambir, Walsura robusta were primarily tested for their antibacterial activities against 35 clinical isolates of
methicillin-resistant S. aureus and S. aureus ATCC 25923 using disc diffusion method (2.5 mg/disc). Almost
all extracts, except Tamarindus indica exhibited antibacterial activity. Both aqueous and ethanolic extracts of
Acacia catechu, Psidium guajava, Punica granatum, Quercus infectoria, and Uncaria gambir, and ethanolic
extracts of Garcinia mangostana, Impatiens balsamina, Peltophorum pterocarpum, and Walsura robusta
demonstrated inhibition zones, ranging from 6 to 22 mm. Determination of minimal inhibitory concentration (MIC) and minimal bactericidal concentration
(MBC) values were performed using agar dilution method. The MIC/MBC values of aqueous extracts of
Quercus infectoria against clinical isolates of MRSA and S. aureus were 0.2 to 0.4/0.4 to 1.6 and 0.2/1.6 mg/
ml, respectively. Ethanolic extracts of Garcinia mangostana, Punica granatum and Quercus infectoria were
demonstrated to be the most effective. The MIC values against MRSA isolates and S. aureus ranged from
0.05 to 0.4 and 0.1, 0.2 to 0.4 and 0.1, 0.2 to 0.4 and 0.2 mg/ml, respectively. The MBC values against MRSA
ranged from 0.1 to 0.4, 0.4 to 1.6, and 1.6 to 3.1 mg/ml and against S. aureus at 0.4, 3.2, and 1.6 mg/ml,
respectively.

Keywords

• methicillin-resistant Staphylococcus aureus
• MRSA
• S. aureus
• medicinal plants
• herbs