2018 Springer Science+Business Media, LLC
Chemistry of Natural Compounds, Vol. 54, No. 3, May, 2018
A NEW COMPOUND FROM THE ENDOPHYTIC FUNGUS Xylaria sp.
FROM Sophora tonkinensis
Na Zheng, Quan Liu, Dong-Lan He, Yan Liang,
Jun Li, and Rui-Yun Yang*
A new compound, 6-heptanoyl-4-methoxy-2H-pyran-2-one (1), was isolated from the endophytic fungus
Xylaria sp. GDG-102 from the leaf of Sophora tonkinensis. The structure of the new compound was elucidated
on the basis of 1D and 2D NMR spectra. Compound 1 showed antimicrobial activity against E. coli and
S. aureus with MIC values 50
Keywords: Sophora tonkinensis, Xylaria sp., secondary metabolite.
In recent years, secondary metabolites obtained from plant or marine-derived fungi, which provide a large number of
novel and bioactive compounds [1–3], have increasingly been a major hot topic of natural product research. Xylaria sp. is a
genus of ascomycetes commonly found as endophytic fungi in rotten wood . A series of isocoumarins, flavonoids, terpenoids,
benzoquinones, and cyclopentapeptides, with considerable antioxidant , antimalarial , cytotoxic , and antifungal
activities , was isolated from different Xylaria species.
In the course of our studies on the endophytic fungi from the Chinese medicinal plant Sophora tonkinensis, the
fungus Xylaria sp. GDG-102 attracted our attention. In a systemic investigation, a new compound, 6-heptanoyl-4-methoxy-
2H-pyran-2-one (1), was isolated from the mycelium of the endophytic fungus Xylaria sp. from the leaf of S. tonkinensis.
Herein, we describe the isolation and structure of the new compound.
Compound 1 was obtained as a colorless powder. The molecular formula was determined as C
on the basis of
HR-ESI-MS m/z 239.1280 [M + H]
(calcd for C
, 239.1278). Analysis of the
H NMR spectrum (Table 1) of 1
showed that its structure contained a methoxy group (G 3.85), one methyl group (G 0.88), two methine groups (G 5.70, 6.75),
and five methylene groups (G 2.89, 1.65, 1.29, 1.29, 1.29). The
C NMR data (Table 1) of 1 showed that its structure contained
two carbonyl groups (G 194.0 and 162.6), one methoxy group (G 56.4), one methyl group (G 14.2), five methylene groups
(G 38.4, 23.2, 28.8, 31.6. 22.6), and four aromatic carbons (G 93.6, 103.9, 154.8, 170.0).
Many 4-oxy-2-pyrones are known, and the difficulties encountered in accurately assigning resonances due to C-2, C-4,
and C-6 have been discussed . The HMBC experiments (Fig. 1) showed that G
5.70 (H-3) was correlated to G
(C-2), 170.0 (C-4), and 103.9 (C-5), G
6.75 (H-5) was correlated to 170.0 (C-4), 154.8 (C-6), and 194.0 (C-7), and G
) was correlated to 170.0 (C-4), which indicated that 1 contained a 4-oxy-2-pyrone moiety.
H COSY and HMBC
correlations (Fig. 1) revealed that a saturated side chain exists in the structure of 1. Based on the above analysis, the structure
of 1 (Fig. 1) was established as 6-heptanoyl-4-methoxy-2H-pyran-2-one.
The isolates 1 were tested for antimicrobial activities against four bacteria (Escherichia coli, Bacillus paratyphosus
B, Micrococcus luteus, and Staphylococcus aureus) using the double dilution method of a 96 trace orifice plate .
Compound 1 only showed antimicrobial activity against E. coli and S. aureus with MIC values 50 Pg/mL.
State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources, College of Chemistry and
Pharmaceutical Sciences, Guangxi Normal University, 541004, Guilin, P. R. China, e-mail: firstname.lastname@example.org. Published
in Khimiya Prirodnykh Soedinenii, No. 3, May–June, 2018, pp. 380–381. Original article submitted October 25, 2016.