Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus <i>Edenia gomezpompae</i>

Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus Edenia gomezpompae

PDF

Yingzi Tan^a^,¹, Zhikai Guo^b^,^d^,¹, Mengyue Zhu^a, Jing Shi^a, Wei Li^a, Ruihua Jiao^a, Renxiang Tan^a^,^c, Huiming Ge^*^,^a

Chinese Chemical Letters | 2020, 31(6) : 1406 - 1409

Less

Chinese Chemical Letters | 2020, 31(6): 1406-1409

• Communication •

Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus Edenia gomezpompae

Full

Yingzi Tan^a^,¹, Zhikai Guo^b^,^d^,¹, Mengyue Zhu^a, Jing Shi^a, Wei Li^a, Ruihua Jiao^a, Renxiang Tan^a^,^c, Huiming Ge^*^,^a

Affiliations

^a State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, School of Life Sciences, Nanjing University, Nanjing 210023, China

^b Hainan Key Laboratory of Tropical Microbe Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China

^c State Key Laboratory Cultivation Base for TCM Quality and Efficacy, Nanjing University of Chinese Medicine, Nanjing 210023, China

^d Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China

Published: 2020-06-15 doi: 10.1016/j.cclet.2020.03.059

Outline

Abstract

Less

Spirobisnaphthalenes comprise a relatively rare family of natural products that are normally isolated from fungi and occasionally from plants. Here we reported the discovery of seven new preussomerintype spirobisnaphthalenes, preussomerins YT1-YT7 (1-7), and seven known ones (8-14), from the endophytic fungus Edenia gomezpompae, enriching the structural diversity of this family of natural products. Their structures were established by 1D and 2D NMR spectroscopy, HRESIMS analysis and comparison with previously reported compounds, with the absolute configurations of compounds 1 and 2 being further confirmed by single-crystal X-ray diffraction using Cu Kα radiation. The antiinflammatory activities of all isolates were assessed by measuring the production of NO in LPS-induced RAW264.7 macrophage cells. Among them, compounds 8 and 13 exhibited potent inhibitory activities on the production of NO, with IC₅₀ values of 2.61 and 1.32 μmol/L, respectively.

Key words

Endophytic fungus / Spirobisnaphthalene natural products / Preussomerin-type / Structure elucidation / Anti-inflammatory activity

Cite this Article

Yingzi Tan, Zhikai Guo, Mengyue Zhu, Jing Shi, Wei Li, Ruihua Jiao, Renxiang Tan, Huiming Ge. Anti-inflammatory spirobisnaphthalene natural products from a plant-derived endophytic fungus Edenia gomezpompae[J]. Chinese Chemical Letters, 2020 , 31 (6) : 1406 -1409 . DOI: 10.1016/j.cclet.2020.03.059

Full Text

Less

Spirobisnaphthalenes are a growing family of rare natural products containing two naphthalene-derived C10 units bridged through a spiroketal linkage [1]. Members of this family include preussomerins, decaspirones, palmarumycins and spiro-nonadienes which have been mainly isolated from fungi and although occasionally from plant sources [1-3]. The preussomerins belong to a relatively rare class of spirobisnaphthalene possessing a unique structural feature. They consist of two unsaturated bicyclo [4.4.0]decane units connected via three oxygen bridges through two spiroketal carbons [1]. This class of compounds have been reported to possess a variety of biological activities such as antifungal, antibacterial, cytotoxic, anti-inflammatory and antileishmanial activities [2, 4-6]. Microbes derived from unexplored or underexplored ecological niches are becoming to be a potential source for discovering structurally interesting and biologically active natural products [7-10]. During our ongoing search for new bioactive metabolites from plant endophytic fungi [11-13], a fungus strain E. gomezpompae was isolated from an unidentified plant collected from Hainan Province of China. LC–MS analysis of its metabolites revealed a series of compounds with molecular weights ranging from 300 to 400 Dalton and a common maximum UV absorption at around 225 nm. Subsequent chemical investigation of this fungus afforded seven new preussomerin-type spirobisnaphthalenes, preussomerins YT1-YT7 (1-7), and seven known compounds, including preussomerin EG1 (8) [14], preussomerin EG2 (9) [14], preussomerin EG4 (10) [15], palmarumycin SA1 (11) [2], MB7056B (Ⅱ) (12) [16], CJ-12, 371 (13) [17], and palmarumycin CP17 (14) [18] (Fig. 1). In this paper, we report the details of isolation, structural elucidation, and anti-inflammatory activity of all isolates (1-14).

A 40-liter fermentation of the fungus E. gomezpompae was conducted and the broth was filtered and extracted with ethyl acetate. The afforded extract was subjected to silica gel column, Sephadex LH-20 column, reversed-phase ODS column chromatography and further purified by reversed-phase HPLC with a gradient CH₃CN-H₂O system to afford compounds 1–14.

Preussomerin YT1 (1) was obtained as pale yellow crystals, and the molecular formula was determined to be C₂₂H₂₀O₇, corresponding to the [M+Na]⁺ ion at m/z 419.1133 in its HRESIMS, requiring thirteen degrees of unsaturation. The NMR spectra contained characteristic signals for a trisubstituted aromatic ring [δ^H 7.09 (d, J =8.1 Hz, H-7'), 7.40 (t, J =8.0 Hz, H-8') and 7.50 (d, J=7.6 Hz, H-9'); δ^C 121.0 (C-5'), 151.2 (C-6'), 121.0 (C-7'), 130.4 (C-8'), 118.8 (C-9') and 130.8 (C-10')], a tetrasubstituted aromatic ring [δ^H 6.68 (d, J=8.8 Hz, H-7) and 6.78 (d, J =8.8 Hz, H-8); δ^C 118.5 (C-5), 141.6 (C-6), 116.0 (C-7), 118.1 (C-8), 151.0 (C-9), and 122.2 (C-10)] and one phenolic group [br s, δ^H 8.19 (9-OH)] (Tables 1 and 2). Analysis of the ¹³C NMR and HSQC spectra revealed two methoxyl groups at δ^C 56.3 and 58.5, one carbonyl carbon of a ketone at δ^C 193.3, two spiroketal carbons at δ^C 94.1 and 94.9, three methylenes at δ^C 40.6, 22.3 and 28.6 and two oxygenated methines at δ^C 71.6 and 79.6 (Table 2). The partial structures H (1)-H (2)-H (3), H (7)- H (8), H (2')- H (3') and H (7')-H (8')-H (9') were established by their ¹H–¹H COSY correlations (Fig. 2). The key HMBC correlations from H-1 to C-2, C-3, C-5, C-9 and C-10; from H-2 to C-4; and from H-3 to C-4 and C-5 further confirmed the partial structure a (Fig. 3). Similarly, the partial structure b (Fig. 3) was verified by the HMBC correlations of H-9' with C-1' and of H-2', H-3', H-7' and H-9' with C-4'. Clearly, there were two unsaturations left. Thus, substructures a and b must be combined by three oxygens and the structure of 1 could be tentatively determined as shown in Fig. 1. The observation of the coupling constants of 2.4 Hz and 4.6 Hz between H-1 and H- 2 and the coupling constants of 2.8 Hz between H-2' and H-3' proved that H-1 and H-3' both occupied pseudoequatorial orientation. Ultimately, these deductions were strongly proven by single-crystal X-ray diffraction experiment using Cu Kα radiation with the absolute configurations being determined as 1S, 4R, 3'R, 4'S (Fig. 4).

Preussomerin YT2 (2) was isolated as pale yellow crystals and had the same molecular formula of C₂₂H₂₀O₇ as that of preussomerin YT1 (1) deduced from HRESIMS and NMR data (Tables 1 and 2). Analysis of the ¹H, ¹³C NMR, ¹H-¹H COSY, HSQC and HMBC spectra of 2 revealed that all structural units appeared identical with those of 1. Thus, compound 2 should have the same planar structure as 1 based on the above data. However, compounds 1 and 2 exhibited an epimeric relationship at a center, which is further supported by a comparison of their notable chemical shifts of the asymmetric center C-1. Meanwhile, the large ³J_{1H, 2H} of 8.0 Hz suggested the methoxy group at C-1 adopted the pseudoaxial position. Finally, the absolute configuration of 2 was confirmed as 1R, 4R, 3'R, 4'S by single-crystal X-ray diffraction using Cu Kα radiation (Fig. 4), which only differs from 1 at C-1.

Preussomerin YT3 (3) and preussomerin YT4 (4) were determined to have the same molecular formula of C₂₁H₁₈O₇ on the basis of HRESIMS (m/z 405.0953 [M + Na]⁺). They had characteristic bisspirobisnaphthalene NMR signals as found in preussomerin YT1 (1). Their NMR spectra closely resembled those of 1 except the absence of the methoxy group on C-1 in 1. Furthermore, the presence of a hydroxyl group [δ^H 4.79 (d) and 5.34 (d)] instead of a methoxyl group at C-1 established a downfield shift of H-1 (δ^H 5.20, dd, J = 3.2, 6.4 Hz and 5.14, t, J = 7.3, 9.3 Hz) and a upfield shift of C-1 (δ^C 63.0 and 67.2). Their structures were confirmed by ¹H-¹H COSY correlations of H-1 with H-2 and of H-1 with OH-1 and the key HMBC correlations of OH-1 with C-1, C-2, C-10 (Fig. 2). For the stereochemistry of C-1, the hydroxyl group OH-1 in 3 was inferred as being placed in the equatorial position of the pseudochair ring owing to the small coupling constant observed between H-1 and H-2 (³J_{1H, 2H} = 3.2 and 6.4 Hz), which were similar to those of 1. Meanwhile, comparison of the ¹³C NMR data (Table 2) of 3 at C-4, C-3' and C-4' with those of 1 indicated the same configurations as 1. For the stereochemistry of 4, the large coupling constants of H-1 suggested that the hydroxyl group OH-1 was located in the axial position of the pseudochair ring. The ¹³C NMR data (Table 2) of 4 at C-4, C-3' and C-4' were same with those of 2, implying these carbons have same configurations. Thus, combining with the biogenetic consideration, the absolute configurations of 3 and 4 were tentatively assigned as 1S, 4R, 3'R, 4'S and 1R, 4R, 3'R, 4'S, respectively (Fig. 1).

Preussomerin YT5 (5) and preussomerin YT6 (6) were shown to have the same molecular formula of C₂₁H₁₈O₇ based on their HRESIMS data. The ¹H and ¹³C NMR spectra of 5 and 6 (Tables 1 and 2) showed similar chemical shifts to those of preussomerin YT1 (1). Comparison of the ¹H and ¹³C NMR spectra of 5 and 6 with those of 1 indicated the absence of a methoxy group and the presence of an additional hydroxyl group on C-3'. This was confirmed by the correlations (Fig. 2) of the hydroxyl group with its vicinal protons (indicated by ¹H-¹H COSY and HMBC spectra). Through analysis of the ¹³C NMR data of these chiral carbons and the protons coupling constants and from the biogenetic consideration, the absolute configurations of 5 and 6 were established to be the same as compounds 1 and 2, respectively (Fig. 1).

Analysis of preussomerin YT7 (7) by HRESIMS and ¹³C NMR suggested the molecular formula of C₂₀H₁₆O₇. Likewise, the ¹H and ¹³C NMR data (Tables 1 and 2) of 7 displayed a similar pattern to those of 1 except for the absence of two oxygenated methyls on C-1 and C-3'. Comprehensive analysis of the ¹H, ¹³C NMR, HSQC, ¹H-¹H COSY and HMBC spectra of 7 permitted the establishment of the structure of 7 as shown in Fig. 1. The absolute configuration could be deduced from the comparison of the ¹³C NMR data and the protons coupling constants of 7 with those of 6, established to be 1R, 4R, 3'R, 4'S.

Compounds 8-14 were identified as preussomerin EG1 (8) [14], preussomerin EG2 (9) [14], preussomerin EG4 (10) [15], palmarumycin SA1 (11) [2], MB7056B (Ⅱ) (12) [16], CJ-12, 371 (13) [17] and palmarumycin CP17 (14) [18] by comparing their NMR spectroscopic data with those reported in the literature.

Spirobisnaphthalenes have been reported to have anti-inflammatory activity [2, 19]. Thus, all compounds (1-14) were firstly evaluated for their anti-inflammatory activity by monitoring their inhibitory effects on the production of NO in LPS-induced RAW264.7 macrophage cells. Among them, compounds 8 and 13 displayed significant anti-inflammatory activity at concentrations down to 3 μmol/L with IC₅₀ values of 2.61 μmol/L and 1.32 μmol/L, with no obvious cytotoxicity, whereas the cell survival of RAW264.7 was very low in toxicity studies for other compounds as shown in Table 3.

In conclusion, we have identified seven new preussomerin-type spirobisnaphthalenes, preussomerins YT1-YT7 (1-7), and seven known compounds (8-14), from the endophytic fungus E. gomezpompae. Their structures were unambiguously determined by analysis of their NMR and HRESIMS data, with the absolute configurations of compounds 1 and 2 being confirmed by singlecrystal X-ray diffraction. The new modifications of these isolated new compounds expand the chemical diversity of the spirobisnaphthalene family of natural products. Furthermore, antiinflammatory activity assays have showed that compounds 8 and 13 exhibited significant inhibitory activities on the production of NO in LPS-induced RAW264.7 macrophage cells with no obvious cytotoxicity, presenting us with a great opportunity to discover promising natural agents for new anti-inflammatory drugs.

Declaration of competing interest

Less

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

Less

This work was financially supported by MOST (Nos. 2018YFA0902000 and 2018YFC1706200), and National Natural Science Foundation of China (Nos. 81925033, 21861142005, 81773591, 21761142001, 81673333 and 21661140001), the Central Public-interest Scientific Institution Basal Research Fund for CATAS-ITBB (Nos. 1630052020032, 19CXTD-32 and 1630052019011) and the Hainan Provincial Basic and Applied Basic Research Fund for High-Level Talents in Natural Science (No. 2019RC306).

Appendix A. Supplementary data

Less

Supplementary material related to this article canbefound, in the online version, at doi:https://doi.org/10.1016/j.cclet.2020.03.059.

References

Less

[1]

Y.S. Cai, Y.W. Guo, K. Krohn, Nat. Prod. Rep. 27(2010) 1840-1870.

[2]

H. Jiang, S.G. Ma, Y. Li, et al., Bioorg. Med. Chem. Lett. 26(2016) 4832-4836.

[3]

A. Wisetsai, R. Lekphrom, J. Boonmak, et al., Org. Lett. 21(2019) 8344-8348.

[4]

H.A. Weber, J.B. Gloer, J. Org. Chem. 56(1991) 4355-4360.

[5]

S.H. Chen, D.N. Chen, R.L. Cai, et al., J. Nat. Prod. 79(2016) 2397-2402.

[6]

J.Y. Dong, H.C. Song, J.H. Li, et al., J. Nat. Prod. 71(2008) 952-956.

[7]

C.L. Liu, C.L. Yang, Y.J. Zeng, et al., Chin. Chem. Lett. 30(2019) 44-46.

[8]

H. Han, Z.K. Guo, B. Zhang, et al., Chin. J. Nat. Med. 17(2019) 475-480.

[9]

S.Y. Ma, Y.S. Xiao, B. Zhang, et al., Org. Lett. 19(2017) 6208-6211.

[10]

Y.S. Xiao, B. Zhang, M. Zhang, et al., Org. Biomol. Chem. 15(2017) 3909-3916.

[11]

Z.K. Guo, R. Wang, W. Huang, et al., Beilstein J. Org. Chem.10(2014) 2677-2682.

[12]

C.L. Yang, H.M. Wu, C.L. Liu, et al., J. Nat. Prod. 82(2019) 792-797.

[13]

Z.K. Guo, C.J. Gai, C.H. Cai, et al., Mar. Drugs 15(2017) 381.

[14]

M.L. Macías-Rubalcava, B.E. Herna'ndez-Bautista, M. Jime'nez-Estrada, et al., Phytochemistry 69(2008) 1185-1196.

[15]

M.L. Macías-Rubalcava, M.E. Ruiz-Velasco Sobrino, C. Mele'ndez-Gonza'lez, et al., J. Agric. Food Chem. 62(2014) 3553-3562.

[16]

T. Masayuki, W. Hiroshi, H. Kenzo, et al., Jpn. Kokai Tokkyo Koho, JP 2003026684 A, 2003.

[17]

S. Sakemi, T. Inagaki, K. Kaneda, et al., J. Antibiot. 48(1995) 134-142.

[18]

S. Martinez-Luis, G. Della-Togna, P.D. Coley, et al., J. Nat. Prod. 71(2008) 2011-2014.

[19]

K. Pudhom, T. Teerawatananond, J. Nat. Prod. 77(2014) 1962-1966.

Appendix

Less

Year 2020 volume 31 Issue 6

PDF

Cite this Article

BibTeX

Article Info

doi: 10.1016/j.cclet.2020.03.059

Receive Date：2020-02-14
Online Date：2026-01-31
Published：2020-06-15

Article Data

Affiliations

History

Received：2020-02-14
Revised：2020-03-09
Accepted：2020-03-23

Affiliations

^a State Key Laboratory of Pharmaceutical Biotechnology, Institute of Functional Biomolecules, School of Life Sciences, Nanjing University, Nanjing 210023, China

^b Hainan Key Laboratory of Tropical Microbe Resources, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China

^c State Key Laboratory Cultivation Base for TCM Quality and Efficacy, Nanjing University of Chinese Medicine, Nanjing 210023, China

^d Hainan Academy of Tropical Agricultural Resource, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China

References

Share

https://castjournals.cast.org.cn/joweb/ccl/EN/10.1016/j.cclet.2020.03.059

Share to

Scan QR to access full text

Cite this article

BibTeX

Citations

表12种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

关闭全屏

BibTeX
EndNote
RefWorks
TxT

Fig. 1 Structures of compounds 1–14.

Fig. 2 Key ¹H-¹H COSY and HMBC correlations of compounds 1, 3, 5, 7.

Fig. 3 Partial structures a and b.

Fig. 4 X-ray crystallographic analysis of 1 and 2.

Articles: Latest Articles; Most Read; Collections

Updates: Events; News; Multimedia

About: About Us

Contact

No. 86 Xueyuan South Road, Haidian District, Beijing

100081

010-62199257

qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House