Fitoterapia. 2013 Oct;90:220-7. doi: 10.1016/j.fitote.2013.08.002. Epub 2013 Aug 13.

Ophiobolins P-T, five new cytotoxic and antibacterial sesterterpenes from the endolichenic fungus Ulocladium sp.

Wang QX¹, Bao L, Yang XL, Liu DL, Guo H, Dai HQ, Song FH, Zhang LX, Guo LD, Li SJ, Liu HW.

Author information

1: State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, PR China; School of Life Sciences, University of Science and Technology of China, No. 96 Jinzhai-Road, Hefei 230026, PR China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, No.1 Beichen West Road, Chaoyang District, Beijing 100101, PR China.

Abstract

Five ophiobolane sesterterpenes, ophiobolins P-T, and three known compounds, 6-epi-21,21-O-dihydroophiobolin G, 6-epi-ophiobolin G and 6-epi-ophiobolin K, were isolated from the acetone extract of the endolichenic fungus Ulocladium sp. by using OSMAC method. Their structures were elucidated on the basis of spectroscopic analysis. The absolute configuration of the 18,19-diol moieties in ophiobolin Q was assigned using the Frelek's method. The cytotoxic effects on KB and HepG2 cell lines, antibacterial activity against Bacillus subtilis, methicillin-resistant Staphylococcus aureus, and Bacille Calmette-Guerin were evaluated for all isolated compounds. Ophiobolin T and 6-epi-ophiobolin G exhibited the most potent cytotoxic activity against HepG2 with IC₅₀ of 0.24 and 0.37 μM, respectively. In antibacterial assay, ophiobolins P and T showed moderate antibacterial activity against B. subtilis and meticillin-resistant S. aureus. Ophiobolin T also displayed moderate antibacterial activity against the Bacille Calmette-Guerin strain.