Piscroside C, a novel iridoid glycoside isolated from Pseudolysimachion rotundum var. subinegrum suppresses airway inflammation induced by cigarette smoke

Journal of Ethnopharmacology

Volume 170, 21 July 2015, Pages 20–27

• Hyuk-Hwan Song^{a, 1},
• In-Sik Shin^{b, 1},
• So Yeun Woo^{a, c},
• Su Ui Lee^a,
• Min Hee Sung^a,
• Hyung Won Ryu^a,
• Doo-Young Kim^a,
• Kyung-Seop Ahn^a,
• Hyeong-Kyu Lee^a,
• Dongho Lee^c,
• Sei-Ryang Oh^{a, ,}

• 
  

doi:10.1016/j.jep.2015.04.043

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Abstract

Ethnopharmacological relevance

Pseudolysimachion rotundum var. subintegrum (Speedwell, Plantaginaceae) is used as a traditional herbal medicine for treating bronchitis, cough and asthma in Korea, China, Russia, and Europe.

Aim of the study

In this study, we investigated the protective effects of the novel iridoid glycoside, piscroside C (compound 1) isolated from the methanolic extract of P. rotundum var. subintegrum against inflammatory responses using a cigarette smoke induced chronic obstructive pulmonary disease (COPD) and TNF-α-stimulated human airway epithelial NCI-H292 cells.

Materials and methods

The novel iridoid glycoside piscroside C was isolated from the methanolic extract of P. rotundum var. subintegrum. The chemical structure was established by NMR, HRESIMS, and optical rotation. In in vivo experiment, the mice received 1 h of cigarette smoke for 3 days. Piscroside C was administered to mice by oral gavage 1 h before cigarette smoke exposure for 3 days. In in vitro experiment, we evaluated the effect of piscroside C on proinflammatory mediators in H292 cells stimulated with TNF-α.

Results

Piscroside C significantly reduced the neutrophil influx, reactive oxygen species production, IL-6, TNF-α, and elastase activity in bronchoalveolar lavage fluid in COPD animals. In addition, piscroside C attenuated NF-κB and IκB phosphorylation, leading to reduced recruitment of inflammatory cells into the lung tissue. Consistent with the results of in vivo experiment, piscroside C significantly inhibited the expression of inflammatory cytokines (IL-6, IL-8 and IL-1β) by inhibiting NF-κB activation, as resulting decrease in the phosphorylation of IKKβ, IκBα and TAK1 in TNF-α-stimulated H292 cells.

Conclusion

These findings indicate that piscroside C effectively inhibits inflammatory responses, which is an important process in the development of COPD through suppression of IKK/NF-κB activation. Our study suggest that piscroside C might represent a useful therapeutic for the treatment of inflammatory airway disease.

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Graphical abstract

Keywords

• Pseudolysimachion rotundum var. subintegrum;
• Piscroside C;
• Cigarette smoke;
• Inflammation;
• NF-κB

Corresponding author. Tel.: +82 43 240 6110; fax: +82 43 240 6029.

1

These authors contributed equally to this work.

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