Two new metabolites of an undescribed endophytic fungus belonging to the order pleosporales isolated from Alibertia macrophylla (Rubiaceae)

Endophytic fungi, fungi that grow in the intercellular spaces of higher plants, are recognized as one of the most chemically promising groups of fungi in terms of diversity and pharmaceutical potential. A very recent analysis of the magnitude of fungal species suggests that fungal endophytes alone are a hyperdiverse group of fungi with an estimated range of 30–150 species per host. Furthermore, it has been noted that a subset of the endophytic fungi may be host-species specific. Therefore, the entire plant community likely harbors a major portion of fungal diversity, and the extinction of even one plant species could result in the loss of several host-specific fungal endophytes [1]. The isolate (strain AM-02) was obtained from Alibertia macrophylla an endemic species of the Brazilian Cerrado, and appears to represent a new species belonging to the class Dothideomycetes. The crude EtOAc extract of AM-02 cultured in corn, presented, anticholinesterasic, antioxidant, anti HIV activities and a strong antifungal activity against the phytopathogenic fungi C. cladosporioides and C. sphaerospermum, triggering further studies. This extract was fractioned by chromatography in column and C-18 reversed-phase HPLC afforded two new compounds 1 and 2. The structures of these compounds were elucidated through a series of 1D and 2D NMR experiments.

Acknowledgements: Supported by BIOTA/FAPESP grant n ^o 03/02176–7

References: 1. Clardy, J. et al. (2001)J. Nat. Prod. 64: 1006–1009