Abstracts - Alany Ingrid Ribeiro

Identification of minority Compounds from Stachybotrys levispora by UPLC-ESI-QTOF technique

Alany Ingrid Ribeiro1*, Joao B. F. da Silva1, Paulo C. Vieira1, Maria F. G. F da Silva1

1 Universidade Federal de São Carlos-Departamento de Química, Universidade Federal de São Carlos-SP 676, São Carlos-SP 13565-905, Brazil

*Correspondence: alanysribeiro@hotmail.com

Saprobic fungi have been used as alternative controls against pests and diseases that affect agriculture and cause financial losses to our economy. Previous studies (in vitro) carried out with saprobes, demostrate that the fungus Stachybotrys levispora formerly classified as memnoniella levispora, was pointed as antagonist of Sclereotinia sclereotinum (pathogen of soybean white mold). More than 200 metabolites including of trichothecene, triprenyl phenol, diterpenoid, isochroman, polyketide, cochlioquinone and cyclic peptide have been discovered until 2014 to genera. Thus, in the attempt to obtain the chemical profile of the levispora species (never previously studied) and to relate the identified substances to the antifungal action, we performed the isolation and identification of the major substances produced by this. Among the compounds isolated previously, using the LC-SPE-NMR technique are griseofulvin and analogous derivatives, whose activity is already well informed in the literature. However, the minor compounds could not be isolated and identified by the aforementioned technique. Thus, the objective of this work is the rapid identification of minority compounds by the UPLC-ESI-QTOF technique. For this, the ethyl acetate extract produced by the growth of the fungus in carrot and corn medium and used in the previous experiment, was diluted (1mg / ml) and analyzed. The Q TOF mass detector provided important information on the protonated molecule and the major fragmentation of íons. Based on this information and the isotopic distribution observed in the mass spectra, it was possible to perform a reliable identification of the compounds detected in the sample. Several compounds were detected in addition to those isolated by LC-SPE-NMR. Basically, 15 peaks were detected. Among them, the mass spectra that related the majoritarian substances that confirmed the presence of the isolated compounds previously. In addition, the most interesting of the whole analysis was the detection of triphenyl phenols, including phenylspyrodriamanes and stachybotrins. This type of structure is a chemotaxonomic marker for Stachybotrys fungi (including Memnoniella), and has more than 80 compounds of this class discovered for this genus. The MS / MS spectra of compounds referring to 11-15 substances suggest metabolites related to phenylspyrodrimes and stachybotrins which have been identified as stachybotramide (11), stachybotrylactam (12), stachybotrylactam acetate (13), F1839-A (14) (isolated from Stachybotrys sp. F1839), 5-O-methyl-SMTP-0 (15a) or 5-O-methyl-8-epi-SMTP-0 (15b). These data, along with the previous ones, point out that fungus S. levispora produces a variety of active substances that can be used in biological control against other pathogens.

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