Optimization of Antibacterial Activity of <i>Perilla frutescens var. acuta</i> Leaf against <i>Staphylococcus aureus</i> Using Evolutionary Operation Factorial Design Technique

다국어 초록 (Multilingual Abstract)

<P>This study was undertaken to optimize extraction using evolutionary operation-factorial (EVOP) design technique to elicit the antibacterial activity of <I>Perilla frutescens var. acuta</I> leaf against <I>Staphylococcus aureus</I> ATCC6538. Higher antibacterial activity was achieved at higher extraction temperature and over a longer extraction time. Antibacterial activity was not affected by differentiation of the ethanol concentration in the extraction solvent. The maximum antibacterial activity of ethanolic extract of <I>P. frutescens</I> leaf against <I>S. aureus</I> was obtained at 75 °C (R = −0.7904<SUP>**</SUP>) extraction temperature, 24 h (R = −0.7273<SUP>**</SUP>) extraction time, and 45% (R = −0.0635) ethanol concentration. The population of <I>S. aureus</I> was decreased from 7.535 log CFU/mL in the initial set to 4.865 log CFU/mL in the third set by EVOP factorial design technique, as well as to 2.600 log CFU/mL by extraction with ethyl acetate. Further, the ethyl acetate extract revealed the highest phenolic contents (111.3 ± 8.6 mg% of dry sample) as compared to the other extracts. Also, the scanning electronic microscopic study of the ethanolic extract of <I>P. frutescens</I> revealed potential detrimental effect on the morphology of <I>S. aureus</I>.</P>