Elsevier

Phytochemistry Letters

Volume 15, March 2016, Pages 1-6
Phytochemistry Letters

Withaphysalin-type withanolides from Physalis minima

https://doi.org/10.1016/j.phytol.2015.11.005Get rights and content

Highlights

  • Nine new withaphysalin-type withanolides were isolated from the whole plants of Physalis minima Linn.

  • The structures of these new compounds were determined on the basis of 1D and 2D NMR spectroscopy and HRESIMS.

  • Three compounds showed inhibitory activities with IC50 values of 17.41 ± 1.04, 36.33 ± 1.95 and 21.48 ± 1.67 μΜ.

Abstract

Nine new withaphysalin-type withanolides (19), named physaminimins (G-O) were isolated from the whole plants of Physalis minima Linn. The structures of these compounds were elucidated based on spectroscopic methods (1D NMR, HSQC, HMBC, ROESY) and HRESIMS. Physaminimins G, H, and K showed inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in a macrophage (RAW264.7) cells with IC50 values of 17.41 ± 1.04, 36.33 ± 1.95 and 21.48 ± 1.67 μM, respectively.

Introduction

Physalis minima Linn. (Solanaceae) is an annual herb wildly growing in the southeast of China. The whole plant was traditionally used as antibacterial and anti-inflammatory medicine in China (Chinese Herbal Medicine, 1999). Phytochemical studies revealed that it contains various withanolides, especially physalin-type and withaphysalin-type withanolides as its main constituents (Ma et al., 2007, Sahai and Kirson, 1984, Kirson et al., 1976, Glotter et al., 1975, Oshima et al., 1987). The withaphysalins are a group of naturally occurring withanolides, in which C-18 and C-20 are appropriately oxidized and cyclized in order to form a hemiacetal or a lactone. This type of compounds has only been found in genera Dunalia, Iochroma, Physalis, Vassobia and Acnistus so far (Chen et al., 2011, Guan et al., 2014). Continuing investigation of this plant led to the isolation of nine new withaphysalin-type withanolides (see Fig. 1). Herein, the isolation, identification and bioactivities of these compounds are presented.

Section snippets

Results and discussion

Compound 1 was isolated as a white amorphous powder. The molecular formula of 1 was determined as C30H42O8 based on the [M + Na+] peak at 553.2773 in HRESIMS (calcd. 553.2772). The IR spectrum showed absorption for OH groups (3419 cm−1) and α,β-unsaturated carbonyl group (1687 cm−1). The 13C NMR spectrum, in combination with HSQC, exhibited the presence of 30-carbons, including 6-methyls, 6-methylenes, 10-methines and 8-quaternary carbons. The 1H NMR spectrum showed typical withanolide signals (δH

General experimental procedures

The analysis HPLC was carried out using an Agilent1260 instrument equipped with multiple wavelength diode array detector (DAD). Preparative HPLC was performed on Shimadzu apparatus with a Shim-pack RP-C18 column (20 × 200 mm, i.d.) at a flow rate of 10 mL/min. Optical rotations were obtained on a JASCO P-1020 polarimeter (Na filter, λ = 589 nm). Circular dichroism (CD) spectra were carried out on a JASCO 810 spectropolarimeter. UV spectra were obtained on a Shimadzu UV-2501 PC spectrophotometer. IR

Acknowledgments

This work was supported by the Fundamental Research Funds for the Central Universities (JKZD2013008), New Century Excellent Talents in University (NCET-12-0977) and the Project Founded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).

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