Elsevier

Fitoterapia

Volume 128, July 2018, Pages 180-186
Fitoterapia

Two new flavonoid–triterpene saponin meroterpenoids from Clinopodium chinense and their protective effects against anoxia/reoxygenation-induced apoptosis in H9c2 cells

https://doi.org/10.1016/j.fitote.2018.05.023Get rights and content

Abstract

Two new flavonoid–triterpene saponin meroterpenoids, clinoposides G (1) and H (2) were isolated from the aerial parts of Clinopodium chinense (Benth.) O. Kuntze. Their structures were elucidated through spectroscopic and electronic circular dichroism (ECD) analyses. Compounds 1 and 2 were evaluated for their protective effects against anoxia/reoxygenation(A/R)-induced injury in H9c2 cells. A/R treatment severely injured the H9c2 cells, which was accompanied by apoptosis. Both 1 and 2 pretreatment significantly inhibited cell injury and apoptosis, improved mitochondrial membrane potential, increased activities of antioxidant enzymes, and reduced the levels of the inflammatory cytokines. In addition, the presence of 1 and 2 significantly decreased the protein level of p65 and increased the level of Nrf2 in cell nucleus. Unique chemical structure and good biological activity of 1 and 2 elucidated the potential of meroterpenoids as a promising reagent for treating heart disease.

Introduction

Clinopodium is a genus in the family Lamiaceae, which contains approximately 22 species occurring in tropical and subtropical regions of Southeast Asia [1]. The aerial parts of C. chinense, couple with Clinopodium polycephalum, which are known as “duanxueliu” in China, have been used as a traditional folk medicine for the treatment of hematuria, skin trauma, influenza and allergic dermatitis [2]. Numerous chemical constituents have been reported from the genus Clinopodium including flavonoids [3], triterpenoid saponins [4], phenylpropanoids [5], diterpenes [6] and quinoids [7], as well as volatile and fatty oils, and these components exhibit diverse biological activities, including helostatic [8], anti-hyperglycemic [9], anti-tumour [10] and cardioprotective activity [11].

Our previous studies proved that total flavonoids from Clinopodium chinense (Benth.) O. Kuntze showed significantly protective effect against doxorubicin-induced cardiotoxicity and ischemic heart disease [12]. Further chemical studies found six novel favonoid-triterpene saponin meroterpenoids with unprecedented structures in the aerial parts of Clinopodium chinense [13]. In the present study, we examined the protective effects of two new flavonoid–triterpene saponin meroterpenoids, clinoposides G (1) and H (2) (Fig. 1), against anoxia/reoxygenation(A/R)-induced H9c2 cells injury in vitro. This function relies on the activation of Nrf2 and inhibition of NF-κB.

Section snippets

General experimental procedures

Optical rotation values were determined on a Perkin-Elmer 341 digital polarimeter equipped with a sodium lamp (589 nm) and a 1-dm microcell in MeOH. UV spectra were recorded on a Shimadzu UV2550 spectrometer in MeOH. ECD spectra were measured in MeOH on a JASCO J-815 spectropolarimeter. NMR spectra were acquired on Bruker AV III 600 MHz (the chemical shift values are reported as δ values with TMS as an internal standard). HR-ESI-MS spectra were measured on a LTQ Orbitrap XL mass spectrometer

Results and discussion

Two new flavonoid–triterpene saponin meroterpenoids, clinoposides G (1) and H (2), were obtained from C. chinense after successive separations and purifications using various column chromatography methods.

Clinoposide G (1) possesses a molecular formula of C63H90O23, as was established by the analysis of its HR-ESI-MS (m/z 1213.5829 [M - H], calculated as 1213.5795 for C63H89O23) and 13C NMR data. The 1H NMR spectrum (Table 1) showed the presence of seven methyl groups at δH 1.12 (s, H3-24),

Conflict of interest

The authors declare no competing financial interest.

Acknowledgements

This work was supported by grants (No. 81703689) from the National Natural Sciences Foundation of China and Wenzhou Medical University Research Initiation Fund (No. QTJ16015). Yongxiao Mou from School of Pharmacy, Wenzhou Medical University was also thanked for optimizing spatial structure of compound 1.

References (20)

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

Cited by (16)

  • Potential candidates from marine and terrestrial resources targeting mitochondrial inhibition: Insights from the molecular approach

    2023, Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology
    Citation Excerpt :

    Ainsloside B is also implicated in mitochondrial membrane potential (MMP) reduction (Fang et al., 2017). Besides, clinoposides H and G substantially reduced the p65 protein levels while improving MMP (YinDi et al., 2018). The integrity of the mitochondrial membrane was altered by acovenoside A (El Gaafary et al., 2017) (Fig. 4).

  • Clinopodium vulgare L. (wild basil) extract and its active constituents modulate cyclooxygenase-2 expression in neutrophils

    2019, Food and Chemical Toxicology
    Citation Excerpt :

    The protein sustains neutrophil longevity and prevents constitutive apoptosis by inhibiting pro-apoptotic Bax and Bak proteins (Edwards et al., 2004). Other mechanism, described after the exposure of cells to C. chinense extract, was related to decreased level of p65 subunits of NF-kB that, in turn, restricted the transcription of survival proteins XIAP and A1, and hence activated caspases-3 and -9 (Fox et al., 2010; Zhu et al., 2018). The constituents of the CVE can potentiate the zymosan-induced pro-apoptotic pathways via interference with NF-kB signaling, mitochondrial dysfunction and caspase-3 activation (Watabe et al., 2004) or via regulation of the expression of the death-associated protein kinase 2 (DAPK2), important for neutrophil development (Britschgi et al., 2008).

View all citing articles on Scopus
1

These authors contribute equally to this work.

View full text