|Glenn, Anthony - Tony|
|Anaya, Ana Luisa|
Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2008
Publication Date: 6/1/2008
Citation: Macias-Rubalcava, M.L., Hernandez-Bautista, B.E., Jimenez-Estrada, M., Gonzalez-Villasenor, M.C., Glenn, A.E., Hanlin, R.T., Hernandez-Ortega, S., Saucedo-Garcia, A., Muria-Gonzalez, J.M., Anaya, A. 2008. Naphthoquinone spiroketal with allelochemical activity from the newly discovered endophytic fungus Edenia gomezpompae. Phytochemistry. 69:1185-1196. Interpretive Summary: The newly described endophytic fungus Edenia gomezpompae was isolated from the leaves of Callicarpa acuminata (Verbenaceae) from the El Eden Ecological Reserve in Quintana Roo, Mexico. From this fungus four naphthoquinone spiroketals were isolated. Three of these are new compounds and the names preussomerin EG1, preussomerin EG2, and preussomerin EG3 are proposed. Additionally, the compound palmarumycin CP2 was also isolated, and the unpublished X-ray data of this compound are reported. The bioactivity of these compounds was tested against three known endophytic fungi isolated from the same plant species (Colletotrichum sp., Phomopsis sp., and Guignardia manguifera) as well as four plant pathogenic fungi with economic importance (Phytophthora capsici, P. parasitica, Fusarium oxysporum, and Alternaria solani). Preussomerin EG1, EG2, and EG3 displayed significant growth inhibition against all the pathogenic fungi. The compound palmarumycin CP2 was not bioactive. Preussomerin EG1 showed the strongest antifungal activity. Two acetylated derivatives of preussomerin EG1 were synthesized, and all three compounds exhibited significant bioactivity against the three endophytic fungi. This is the first report of allelochemicals with antifungal activity from the new endophytic fungus E. gomezpompae, which may utilize the metabolites to protect its host from disease-causing plant pathogens or from infection by other endophytic fungi.
Technical Abstract: Bioassay-guided isolation from the culture of Edenia gomezpompae, a new endophytic fungus isolated from the leaves of Callicarpa acuminata (Verbenaceae) from the ecological reserve El Eden, Quintana Roo, Mexico, led to the isolation of four naphthoquinone spiroketals, including three new compounds. We elucidated the structures of the new metabolites by extensive NMR studies, including DEPT, COSY, NOESY, HSQC, HMBC, and chiroptical methods. The trivial names proposed for these compounds are preussomerin EG1 (1), preussomerin EG2 (2) and preussomerin EG3 (3). In addition, palmarumycin CP2 (4) was obtained, and the unpublished X-ray data of this last compound are reported. The bioactivity of the organic extracts and the pure compounds was tested against three known endophytic fungi isolated from the same plant species (Callicarpa acuminata): Colletotrichum sp., Phomopsis sp., and Guignardia manguifera, and four phytopathogenic fungi with economic importance: Phytophthora capsici, P. parasitica, Fusarium oxysporum, and Alternaria solani. Preussomerin EG1, EG2 and EG3 (1-3) displayed significant growth inhibition against all the phytopathogenic fungi. The ED50 values for these four species were from 20 to 170 ug/ml. Palmarumycin CP2 (4) was not bioactive. Compound 1 showed the strongest antifungal activity. The acetylated derivatives of Preussomerin EG1 (1), 1a and 1b, were synthesized and their biological activity was tested on endophytic and phytopathogenic fungi. Preussomerin EG1 1, 1a and 1b exhibited significant bioactivity against endophytic fungi: 26 to 100% of growth inhibition at 100 ug/ml. This is the first report of the allelochemicals with antifungal activity from the new endophytic fungus Edenia gomezpompae.