Elsevier

Fitoterapia

Volume 95, June 2014, Pages 154-159
Fitoterapia

Bioactivity-guided isolation of anti-inflammation flavonoids from the stems of Millettia dielsiana Harms

https://doi.org/10.1016/j.fitote.2014.03.008Get rights and content

Abstract

Bioactivity-guided isolation of the EtOAc extract of the stems of Millettia dielsiana Harms yielded two new isoflavones together with nine known ones. Their structures were elucidated by analysis of the spectroscopic data including 2D NMR. All of the isolates were evaluated for their potential to inhibit the LPS-induced production of nitric oxide and TNF-α in murine macrophage RAW 264.7 cells. Among the tested compounds, Millesianin C (1) had the most potent anti-inflammatory effect decreasing NO production similar to that of dexamethasone and decreasing TNF-α secretion better than that of dexamethasone. Their structure–activity relationship was also analyzed.

Introduction

Millettia dielsiana Harms (Family: Leguminosae) is a kind of semi-evergreen perennial woody vine plant and its stems have been widely used by the ethnic minorities (Yi, Miao and Yao) in China to treat muscle aches and pains, rheumatic arthritis and gynecological diseases, such as anemia and amenorrhea [1]. As part of our ongoing research program for the discovery of plant-derived anti-inflammation constituents, we found that the EtOAc extract of the stems of M. dielsiana showed strong inhibitory activity against the production of NO and TNF-α in RAW 264.7 cells. Based on the bioassay-guided fractionation of EtOAc extract, two new isoflavones along with nine known isoflavones were isolated from the bioactive fractions of EtOAc extract from stems of M. dielsiana. Millesianin C (1) showed excellent inhibitory activity towards NO and TNF-α. Their structures were characterized on the basis of spectroscopic methods including extensive 2D NMR and MS spectrometry.

Section snippets

General

Column chromatography was carried out on silica gel 60 (0.2–0.5 mm, 0.040–0.063 mm, Merck, Darmstadt, German). Medium-pressure liquid chromatography (MPLC) (Büchi, Flawil, Switzerland) was performed with a C-605 pump, a C-615 pump manager, a C-635 UV detector, a C-660 fraction collector and a Sepacore record 1.0 workstation. Counter-current chromatography was performed on a Midi-DE centrifuge (Dynamic Extraction, Slough, UK). HPLC was performed on a Waters Alliance 2695 separation module (Empower

Chemistry

Compound 9 was isolated as a white powder. The molecular formula was determined as C22H22O5 by HRESIMS of its [M + H]+ ion peak at m/z = 367.1545 (calcd. 366.1467). The UV spectrum absorption at 256 and 319 nm and 1H (δ 7.99 for H-2) and 13C (δ 152.01 for C-2) NMR spectra showed this compound to be an isoflavone type skeleton. The 1H NMR (Table 1) spectrum displayed ortho-coupled A2B2-type protons at δ 7.50 and 6.98 (each 2H, d, J = 8.4 Hz) assignable to H-2′, 6′ and H-3′, 5′, respectively of ring B

Conclusion

Based on the bioactivity-guided isolation, isoflavones (1–11) were separated from the bioactive fractions of Fr.5, Fr.6 and Fr.8 from EtOAc extract of M. dielsiana Harms, which were then tested for the inhibitory activity of NO production and TNF-α secretion in LPS-stimulated RAW 267.4 cells. Among the tested compounds, Millesianin C (1) with 2,2-dimethylpyran fragment, had the most potent anti-inflammatory effect decreasing NO production similar to that of dexamethasone and decreasing TNF-α

Acknowledgment

The work was supported by Guangdong Innovative Research Team Program (2011Y073), the National Science Foundation for Post-doctoral Scientists of China (2013M530403) and the National Natural Science Foundation of China (81373283). The authors have declared no conflict of interest.

References (21)

There are more references available in the full text version of this article.

Cited by (31)

  • Flavonoids from the stems of Millettia pachyloba Drake mediate cytotoxic activity through apoptosis and autophagy in cancer cells

    2019, Journal of Advanced Research
    Citation Excerpt :

    The 13C NMR spectra of 1 indicated 23 signals, including three methoxy groups [δC 55.3, 56.0 and 61.1] and one γ, γ-dimethylallyl unit [δC 17.9, 22.9, 25.8, 121.5 and 132.7]. Comparison of the NMR data of 1 and millesianin H [2] revealed similar carbon and proton resonances, except that 1 contained one more methoxy group. A further HMBC correlation study (Fig. 2) showed that this methoxy group (δH 3.93) was attached to C-7 (δC 151.9).

  • 21‑Benzylidene digoxin, a novel digoxin hemi-synthetic derivative, presents an anti-inflammatory activity through inhibition of edema, tumour necrosis factor alpha production, inducible nitric oxide synthase expression and leucocyte migration

    2018, International Immunopharmacology
    Citation Excerpt :

    Carrageenan activates macrophages and PMN leucocytes, which secrete numerous pro-inflammatory mediators [39]. In the delayed phase of carrageenan-induced inflammation, PMN leucocyte-derived cytokines such as TNF-α are produced, which have been shown to play an important role in inflammation [40] and the peak of production of this proinflammatory mediator in the paw is observed 3 h following injection of carrageenan [41,42]. Carrageenan also induces peripheral release of nitric oxide (NO), which is sustained by TNF-α, since this cytokine have been shown to induce iNOS expression in a variety of cells [10,43].

View all citing articles on Scopus
1

Both authors have contributed equally to the paper.

View full text