Planta Med 2008; 74 - PB91
DOI: 10.1055/s-0028-1084436

Tajixanthones analogs from a new Emericella sp. strain 25379

M Figueroa 1, CM Cerda-García-Rojas 2, R Mata 1
  • 1Facultad de Química, Universidad Nacional Autónoma de México, México DF 04510, México
  • 2Departamento de Química, Centro de Investigación y de Estudios Avanzados, Instituto Politécnico Nacional, México DF 07000, México

Two new xanthones, 15-chlorotajixanthone hydrate (1) and 14-methoxytajixanthone (2), were isolated from an extract from the mycelium and culture broth of Emericella sp. strain 25379, a new fungus species, along with shamixanthone (3) and tajixanthone hydrate (4) [1]. The stereostructures of the new xanthones were elucidated by spectroscopic and molecular modeling methods. The absolute configuration at the stereogenic centers of 1 was established according to CD measurements while in 2 it was determined by molecular modeling calculations of diasteroisomers 2a-2d at DFT B3LYP/DGDZVP level of theory and by comparison with the experimental 1H-1H coupling constant data and optical rotation values [2]. In addition, the absolute configuration at C-25 in 2 was corroborated by Mosher ester methodology.

Acknowledgements: CONACyT (fellowship), DGSCA (KanBalam system).

References: 1. Malmstrom, J. et al. (2002)J. Nat. Prod. 65: 364–367.

2. Stephens, P. et al. (2008)J. Nat. Prod. 71: 285–288.