Chemical Composition and Biological Activities of Endophytic Fungus Talaromyces Wortmannii LGT-4, Cultured in CYM Medium

In the present study, nine compounds (1-9) were isolated from Talaromyces wortmannii LGT-4 (an endophytic fungus from Tripterygium wilfordi) which was cultured in CYM Medium. Their structures were determined as 4-hydroxyphthalide (1), Fumitremorgin C (2), Ergosterol (3), 3-(2-hydroxypropyl)-8-hydroxy-3,4- dihydroisocoumarin (4), Cis-cyclo(L-Ala-L-Pro) (5), 6-Amino-3-(4-hydroxybenzyl)- 1,4-diazonane-2,5-dione (6), Aspergillumarin B (7), Deacetylisowortmin B (8), and Entonaemin A (9) based on NMR spectral data, as well as comparing with previous literature data. This is the first report of the isolation of compounds 1-2 and 4-7 from Talaromyces genus. All compounds were tested for their monoamine oxidase and phosphoinositide 3-kinase (PI3Kα) inhibitory activities. Compound 1, 5 showed moderate anti-monoamine oxidase activity with IC50 value of 35 μg/mL, 28 μg/mL, respectively. Compound 9 showed PI3Kα inhibitory activity with IC50 value of 10.3 μg/mL.


Introduction
Endophytes are microbes that colonise the internal tissues of plants without causing any overt negative effects immediately (1). They are proved to be a new source for natural compounds which have unique structure and wide range of biological activities, such as antitumor, antimicrobial, and antituberculosis (2).
During our research on endophytic fungi living in Tripterygium wilfordii, we isolated an endophytic fungi Talaromyces wortmannii LGT-4 (GenBank Accession No KF850714). In the past studies on this fungus, we have obtained a series of novel furanosteroid including secovironolide (3), wortmannines A-D (4), deacetylisowortmina A and B (5), wortmannolol (6), and wortmannine E (7) by changing culture mediums. Our further analysis work indicated that the altered fermentation media can really change its chemical profiles. In this paper, we reported another nine compounds (1-9) (Figure 1), which was obtained from the organic extract of CYM culture medium. All compounds were evaluated for their monoamine oxidase and
Fungus Material: Talaromyces wortmannii (T. wortmannii) LGT-4 (GenBank accession No. KF850714) was isolated from the healthy tissue of Tripterygium wilfordi (T. wilfordi) and identified as T. wortmannii based on both morphology on PDA and analysis of the DNA sequences of the ITS1-5.8S-ITS2 ribosomal RNA gene region. A GenBank search for DNA sequence similarity revealed that ITS1-5.8S-ITS2 of Lgt-4 was 99% homologous to that of T. wortmannii reference strains (GenBank No. FR667650).
Extraction and Isolation: The fungus LGT-4 was cultured in CYM liquid medium (for 1 L medium: including 12.0 g maltose, 2.0 g peptone, 2 g yeast extract, 0.244 g MgSO 4 , 0.460 g KH 2 PO 4 and 1 L water) for 20d at 28 °C on a 50 L fermenter.
Anti-MAO Bioassay: The procedure of testing MAO inhibiting activity was same with that reported in our previous paper (8).
PI3Kα Biochemical Assay: The procedure of testing PI3Kα inhibiting activity was the same with that reported in literature (9).

Results and Discussion
This study focused on the compounds isolated from Talaromyces wortmannii LGT-4 (an endophytic fungus from Tripterygium wilfordi) which was cultured in CYM medium and evaluated biological activities. Nine compounds (1-9, Figure 1) were isolated. This is the first report of the isolation of compounds 1-2 and 4-7 from Talaromyces genus. Compound 1, 5 showed moderate antimonoamine oxidase activity with IC 50 values of 35 μg/mL, 28 μg/mL, respectively. Compound 9 showed PI3Kα inhibitory activity with IC 50 value of 10.3 μg/mL.