1H and 13C-NMR data for novel meroterpenoids isolated from Arnebia euchroma (Royle) Johnst.

The data presented in this article are associated with the research article entitled " Meroterpenoids isolated from Arnebia euchroma (Royle) Johnst. and their cytotoxic activity in human hepatocellular carcinoma cells " [1]. The aim of this data was to provide the 1D-NMR spectrum of novel meroterpenoids from Arnebia euchroma (Royle) Johnst.

Data

In our previous study [1], six previously undescribed naturally occurring meroterpenoids (2, 5–9) together with seven known meroterpenoids (1, 3, 4, 10–13) were isolated from the root plant of Arnebia euchroma. The NMR data of meroterpenoids 1–5 and 8 suggest they were structure analogue, which contain a bridgehead double bond, which has recently attracted substantial interest in the natural product isolation community in terms of Bredt's law. Six previously undescribed naturally occurring meroterpenoids (2, 5–9) were first isolated and identified from Arnebia euchroma (Royle) Johnst.

Experimental design, materials, and methods

Study area description

Arnebia euchroma (Royle) Jonst. (family Boraginaceae) is a small genus of annual or perennial herbs, distributed in Asia and the drier regions of Northern Africa [2]. A. Euchroma is a traditional Chinese herbal medicine (TCM) recorded in the Pharmacopoeia of China and has been extensively used in China and other countries for the treatment of various diseases [3]. In the current study, a further phytochemical investigation on the CHCl3 extract of the roots of A. euchroma led to the isolation and characterization of six (2, 5–9) previously undescribed and seven (1, 3–4, 10–13) known meroterpenoids. Herein, their structure characterization of these meroterpenoids are identified by various chromatography methods including NMR and MS spectrum.

Sample collection

The roots of Arnfebia euchroma were purchased in Haozhou city, Anhui Province, China.

H andC NMR spectrum of meroterpenoids (,–)

The dichloromethane-H2O (1: 1, v/v) extract from the roots of A. Euchroma was successively subjected to column chromatography over silica gel, ODS or Sephadex LH-20, and preparative HPLC to afford six previously undescribed meroterpenoids (2, 5–9) together with seven known meroterpenoids (1, 3–4, 10–13). The known compounds were determined to be 9,17-epoxyarnebinol (1) [4], arnebinol B (3) [5], arnebinone B (4) [6], arnebifuranone (10) [7], shikonofuran A (11) [8], shikonofuran E (12) [8], and arnebinone (13) [9], by comparison of their spectral data with literature values.

Meroterpenoid 2

Colorless crystals (MeOH—CH2Cl2); [α]D20 − 513.4 (c 0.15, CH2Cl2); 1H and 13C NMR spectrum see Fig. 1, Fig. 2.

Fig. 1

1H-NMR spectrum of meroterpenoid 2.

Fig. 2

13C-NMR spectrum of meroterpenoid 2.

Meroterpenoid 5

Red crystal (MeOH—CH2Cl2); [α]D20 + 134.3 (c 0.10, MeOH); 1H and 13C NMR spectrum see Fig. 3, Fig. 4.

Fig. 3

1H-NMR spectrum of meroterpenoid 5.

Fig. 4

13C-NMR spectrum of meroterpenoid 5.

Meroterpenoid 6

White amorphous powder; [α]D20 − 21.4 (c 0.11, MeOH); 1H and 13C NMR spectrum see Fig. 5, Fig. 6.

Fig. 5

1H-NMR spectrum of meroterpenoid 6.

Fig. 6

13C-NMR spectrum of meroterpenoid 6.

Meroterpenoid 7

Yellow amorphous powder; [α]D20 + 196.7 (c 0.10, MeOH); 1H NMR and 13C NMR spectroscopic data of meroterpenoid 7 see Fig. 7, Fig. 8.

Fig. 7

1H-NMR spectrum of meroterpenoid 7.

Fig. 8

13C-NMR spectrum of meroterpenoid 7.

Meroterpenoid 8

Red amorphous powder; [α]D20 + 432.1 (c 0.10, MeOH); 1H NMR and 13C NMR spectroscopic data of meroterpenoid 8 see Fig. 9, Fig. 10.

Fig. 9

1H-NMR spectrum of meroterpenoid 8.

Fig. 10

13C-NMR spectrum of meroterpenoid 8.

Meroterpenoid 9

Red amorphous powder; 1H NMR and 13C NMR spectroscopic data of meroterpenoid 9 see Fig. 11, Fig. 12.

Fig. 11

1H-NMR spectrum of meroterpenoid 9.

Fig. 12

13C-NMR spectrum of meroterpenoid 9.

Specifications table

Subject area	chemistry
More specific subject area	Natural products research
Type of data	Figure, Table
How data was acquired	1H and13C-NMR of meroterpenoids
Data format	Filtered and Analyzed
Experimental factors	First, the Sample were isolated from dichloromethane fraction of the roots of A. Euchroma extracts. Then the samole were dissolved in DMSO‑d6or CD3Cl before NMR test.
Experimental features	Nuclear magnetic resonance (NMR) spectra data of meroterpenoids from the roots of A. Euchroma were recorded on a Bruker DPX-400 spectrometer using standard Bruker pulse programs (Bruker, Karlsruhe, Germany). Chemical shifts were shown as δ-values with reference to tetramethylsilane (TMS) as an internal standard.
Data source location	The herbarium of Key Laboratory for New Drug Research of TCM, Research institute of Tsinghua University in Shenzhen, Shenzhen, China.
Data accessibility	Data is with this article
Related research article	Yang Wang, Yuzhen Zhu, Lingyun Xiao, Lanlan Ge, Xin Wu, Weigang Wu, Haoqiang Wan, Keda Zhang, Jiemei L, Boping Zhou, Jun Tian, Xiaobin Zeng. Meroterpenoids isolated from Arnebia euchroma (Royle) Johnst. and their cytotoxic activity in human hepatocellular carcinoma cells.Fitoerapia. 131 (2018) 236–244.

Value of the data • NMR data of meroterpenoids is useful for elucidating their chemical structures. • NMR data of meroterpenoids is useful for elucidating their chemical analogues. • This information will allow comparisons across different meroterpinoids from algal species or othernatural sources.