Abstract：
Previous studies carried out in our laboratory described the antimicrobial activity of the whole hexanic extract (HE) of Achyrocline satureioides (Lam.) DC against Paenibacillus larvae, the causal agent of American Foulbrood (AFB) a disease of the honey bee larvae. In this study, the HE was partitioned into five main fractions by chromatographic techniques leading to the isolation of four known compounds: two prenylated phloroglucinol α-pyrones (1 and 3), 5,7-dihydroxy-3,8-dimethoxyflavone (gnaphaliin A) (2), and 23-methyl-6-O-demethylauricepyrone (4). Isolated compounds were further analyzed towards structural elucidation using 1H RMN and 13C RMN spectroscopic techniques. For the first time, the antimicrobial activity of the isolated compounds was evaluated against P. larvae strains by broth microdilution method and compared with that of the whole HE. Compounds 1-4 displayed minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging between 0.07 and 62.5 μg/mL and 0.26 and 12.5 μg/mL, respectively. The lowest MIC and MBC values were obtained with compounds 3 and 4, respectively. The antimicrobial activity of each single compound and the combination of them showed that the presence of all compounds is needed for the antimicrobial efficacy of whole HE.
摘要：
在我们实验室进行的先前研究描述了Achyroclinesatureioides（Lam。)DC对类芽孢杆菌幼虫，美国Foulbrood（AFB）的病原体，一种蜜蜂幼虫的疾病。在这项研究中,通过色谱技术将HE分为五个主要部分，从而分离出四个已知化合物：两个异戊烯化间苯三酚α-吡喃酮（1和3），5,7-二羟基-3,8-二甲氧基黄酮（gnapaliinA）（2），和23-甲基-6-O-脱甲基环己酮(4)。使用1HRMN和13CRMN光谱技术进一步分析分离的化合物以进行结构阐明。第一次,通过肉汤微量稀释法评估了分离化合物对P.幼虫菌株的抗菌活性，并与整个HE进行了比较。化合物1-4的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）值在0.07至62.5μg/mL和0.26至12.5μg/mL之间。分别。用化合物3和4分别获得最低的MIC和MBC值。每种单一化合物和它们的组合的抗微生物活性表明,所有化合物的存在对于整个HE的抗微生物效力是需要的。
