수종의 한약계를 70% 메탄올로 추출하여 식중독 세균인 Staphylococcus aureus에 대한 항균활성으로 생균수의 측정, 생육저해환의 측정, 최소저해농도와 최소사멸농도를 조사한 결과 이들 추출물의 Staphylococcus aureus에 대한 항균활성의 크기는 Rubus coreanus > Sanguisorba officinalis > Eriobotrya japonica > Prunus mume > Crataegus pinnatifida로 나타났다. 생육저해환은 복분자가 16.5 mm, 지유 14.3 mm, 오매 14.0 mm, 산사 12.7 mm로 측정되었다. MIC는 지유가 5mg / ml로 가장 낮았으며, MBC는 복분자가 10mg / ml로 나타났다. 실험에 사용된 한약재 추출물중 복분자, 비파엽, 산사, 오매, 지유는 Staphylococcus aureus에 대해서 강한 항균활성을 나타내었다. 따라서 이들 추출물을 이용한 천연보존료를 개발하여 식품에 적용한다면 그 기대효과가 상당히 클 것으로 생각된다.
Medicinal plant extracts including Rubus coreanus, Sanguisorba officinalis, Eriobotrya japonica, Prunus mume, Crataegus pinnatifida, Rosa leavaigate Prunus persica, Prunus japonica var. nakaii and Spiraea blumei were prepared for the test of antibacterial activity. Tryptic soy broth (TSB) containing $0{sim}10mg/ml$ of medicinal plant extracts was inoculated with $10^6$ cells/ml of Staphylococcus aureus and incubated at $35^{circ}C$ for 24 hours. The plate counting method and clear zone test were used to test inhibitory effect of the extracts. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was derived from the survival curves of S. aureus. The order of antibacterial activities of medicinal plant extracts on the S. aureus was Rubus coreanus > Sanguisorba officinalis > Eriobotrya japonica > Prunus mume > Crataegus pinnatfida. Minimum inhibitory concentration of Sanguisorba ofEcmalis on the Staphylococcus aureus was 2.5mg/ml and minimum bactericidal concentration of Rubus coreanus was 1.0%. Inhibition zone of Rubus coreanus, Sanguisorba officinalis, Eriobotrya japonica, Prunus mume, and Crataegus pinnatifida was 16.5mm, 14.3mm 11.0mm, 14.0mm and 12.7mm, respectively. The morphology of S. aureus cells treated with medicinal plant extracts showed damage of cell wall and cytoplasmic membrane. Severely damaged cells of S. aureus lost electron dense material and cytoplasm. This result suggests that medicinal plant extracts can be used as an effective natural antibacterial agent in food.
