title: Antifungal quinazolinones from marine-derived Bacillus cereus and their preparation.
abstract: Two new quinazolinones alkaloids, R(+)-2-(heptan-3-yl)quinazolin-4(3H)-one (1) and (2R,3'R)+(2S,3'R)-2-(heptan-3-yl)-2,3-dihydroquinazolin-4(1H)-one (2) (a pair of epimers), as well as seven known analogues, 2-methylquinazolin-4(3H)-one (3), 2-benzylquinazolin-4(3H)-one (4), cyclo-(Pro-Ile), cyclo-(Pro-Leu), cyclo-(Pro-Val), cyclo-(Pro-Phe), and cyclo-(Tyr-Pro) were isolated from the n-butyl alcohol extract of the marine-derived bacterium Bacillus cereus 041381. The new compounds were identified by spectroscopic analysis and chemical synthesis. Four optical isomers 5-8 were also synthesized. Compounds 1-8 all showed moderate antifungal activity against Candida albicans with MIC values of 1.3-15.6 μM. Compound 5 exhibits the most powerful antifungal activity, which may reveal that S-configuration and 2,3-double bond were necessary for antifungal activity, and the racemization at C-2 and C-3' reduced the antifungal activity.
authors: Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, People's Republic of China.
authors: Zhihong
authors: Z
authors: Xu
authors: Yapeng
authors: Y
authors: Zhang
authors: Haichao
authors: H
authors: Fu
authors: Huimin
authors: H
authors: Zhong
authors: Kui
authors: K
authors: Hong
authors: Weiming
authors: W
authors: Zhu