金黃色葡萄球菌是院內感染的病原菌及感染性心內膜炎、骨髓炎、中毒性休克、食物中毒以及皮膚感染等疾病的致病原。金黃色葡萄球菌能形成多層的生物膜於宿主的組織以及表面上，並且增加抗生素的抵抗力。虎杖在東亞常被使用作為治療炎症、肝炎以及腫瘤疾病的名俗醫學療法草藥。本研究主要探討虎杖根乙酸乙酯分劃物和大黃素對金黃色葡萄球菌生物膜形成的影響。結果顯示，虎杖根乙酸乙酯分離物F3與大黃素都能抑制金黃色葡萄球菌 SA 113 、抗甲氧西林金黃色葡萄球菌 MRSA 16 及 MRSA 17 生物膜形成，抑制 50% 生物膜所需的濃度 (IB50) 分別為 8.1 μg/ml 、7.2 μg/ml 及 6.6 μg/ml 與4.2 μg/ml 、5.1 μg/ml 及 4.5 μg/ml 。此外，也發現 F3 及大黃素在濃度 6.25 μg/ml 分別抑制 62% 及 65% 的細胞間多聚醣黏附素合成；也干擾金黃色葡萄球菌生物膜形成的起始黏附期。反轉錄 PCR 結果顯示在濃度 6.25 μg/ml 的F3能降低幫助細胞間多聚醣黏附素生合成的 icaA 轉錄。這些結果證明虎杖根乙酸乙酯分離物 F3 藉由干擾金黃色葡萄球菌生物膜開始形成的起始黏附期及抑制細胞間多聚醣黏附素生合成，進而導致生物膜形成減少。此外也證明大黃素是参與虎杖根乙酸乙酯分離物 F3 抑制生物膜形成的主要成分。所以虎杖根乙酸乙酯分離物 F3 及大黃素有潛能被開發成防止生物膜相關感染的治療試劑。 Staphylococcus aureus is the pathogen of nosocomial infections and the etiologic agent of a wide range of diseases including endocarditis, osteomyelitis, toxic shock syndrome, food poisoning, and skin infections. S. aureus to form multilayered biofilms on host tissue and other surfaces, exhibits increasing resistance to antibiotics. Polygonum cuspidatum Sieb. et Zucc. (P. cuspidatum) has been used as a folk medicine for inflammatory disease, hepatitis and tumor in East Asia. The investigation is to explore the effect of the ethyl acetate subfraction from Polygonum cuspidatum root and emodin on S. aureus biofilm formation. Results showed that the ethyl acetate subfraction F3 from Polygonum cuspidatum root and emodin inhibited the biofilm formation of the S. aureus SA 113 and methicillin-resistant S. aureus MRSA16 and MRSA17, the concentration that inhibited formation of 50% biofims (IB50) were 8.1μg/ml, 7.2 μg/ml and 6.6 μg/ml, 4.2 μg/ml, 5.1 μg/ml and 4.5 μg/ml, respectively. Besides, we found that 6.25 μg/ml of F3 and emodin inhibited polysaccharide intercellular adhesion (PIA) biosynthesis (62% and 65%, respectively) and interrupted the initial attachment stage of biofilm formation. Reverase-transcriptase-PCR showed that the transcriptional level of icaA, which encodes essential enzyme for PIA biosynthesis, was decreased after the treatment with 6.25 μg/ml of F3. These results suggested that the ethyl acetate subfraction F3 from Polygonum cuspidatum root inhibited the biofilm formation of the S. aureus by inhibiting initial attachment stage and PIA synthesis. Furthermore, Emodin is a main compound involved in F3 inhibiting biofilm formation. This investigation indicated a potential application for Polygonum cuspidatum as an adjuvant therapeutic agent for the prevention of biofilm-related infections.
