Planta Med 2012; 78 - PJ151
DOI: 10.1055/s-0032-1321311

Hydroxylation of kaurenoic acid by Aspergillus terreus

MR Simão 1, TS Porto 1, ME Severiano 2, CHG Borges 1, RA dos Santos 1, RC Veneziani 1, NAJC Furtado 2, S Said 2, SR Ambrósio 1
  • 1University of Franca, Av. Dr. Armando Salles de Oliveira 201, 14404–600, Franca-SP, Brazil
  • 2University of São Paulo, Av. Café s/n, 14040–903, Ribeirão Preto-SP, Brazil

In the present work the microbial transformation of kaurenoic acid (1) was performed using submerged shaken liquid culture of Aspergillus terreus (1.5×107 spores/mL). The microorganism was grown by a two-stage fermentation procedure. Compound 1 was added as a dimethylsulfoxide solution (0.1g/L) and incubated for 14 days. The culture was filtered and the aqueous layer was extracted with ethyl acetate to furnish the extract codified as AtKA. Chemical and NMR studies of AtKA allowed us to isolate and to identify four kaurenoic acid hydroxylated derivatives (Compounds 2–5).

In addition to the microbial transformation studies, the in vitro effect of 1 on cell viability was assessed by the XTT assay using breast tumor cell line (SKBR-3). Compound 1 displayed significant cytotoxicity activity in all evaluated concentrations (12.5, 25.0 and 50.0µM), thus denoting the importance of this kaurane-type diterpene in the search for novel antitumor agents.