Dipartimento di Scienze del Suolo, della Pianta, dell'Ambiente e delle Produzioni Animali, Università di Napoli Federico II, Via Università 100, 80055 Portici, Italy.
J Nat Prod. 2011 Dec 27;74(12):2520-5. doi: 10.1021/np200625m. Epub 2011 Nov 29.
Sphaeropsidin A, the main phytotoxin produced by Diplodia cupressi, as well as the two natural analogues sphaeropsidins B and C and 14 derivatives obtained by chemical modifications were assayed for antibacterial activity against Xanthomonas oryzae pv. oryzae, Pseudomonas fuscovaginae, and Burkholderia glumae, the causal agents of severe bacterial rice diseases. The results showed a strong and specific activity of sphaeropsidin A against X. oryzae pv. oryzae, while no activity was observed against the other two pathogens. The results of structure-activity relationship studies showed that structural features important to impart this antibacterial activity are the presence of the C-7 carbonyl group and the hemiketalic lactone functionality. The C-13 vinyl group, the double bond of ring C, and/or the tertiary C-9 hydroxy group, as well as the pimarane arrangement of the tricylic carbon skeleton, were also important for the antibacterial activity. These findings may be useful in designing novel compounds for practical applications in agriculture.
球腔菌素 A 是由拟茎点霉产生的主要植物毒素，以及两种天然类似物球腔菌素 B 和 C 以及通过化学修饰获得的 14 种衍生物，它们被测定对水稻细菌性病害的病原菌如稻黄单胞菌 pv. 稻致病变种、黄单胞菌 fuscovaginae 和伯克霍尔德氏菌 glumae 具有抗菌活性。结果表明，球腔菌素 A 对稻黄单胞菌 pv. 稻致病变种具有很强的特异性活性，而对其他两种病原菌则没有活性。结构-活性关系研究的结果表明，赋予这种抗菌活性的结构特征是 C-7 羰基和半缩酮内酯官能团的存在。C-13 乙烯基、环 C 的双键和/或 C-9 叔羟基以及三环碳骨架的扁柏烷排列对抗菌活性也很重要。这些发现可能有助于设计用于农业实际应用的新型化合物。
