Elsevier

Phytomedicine

Volume 17, Issues 8–9, July 2010, Pages 557-562
Phytomedicine

A standardized aqueous extract of Anoectochilus formosanus modulated airway hyperresponsiveness in an OVA-inhaled murine model

https://doi.org/10.1016/j.phymed.2009.12.012Get rights and content

Abstract

Anoectochilus formosanus HAYATA, a Chinese herb, is a valued folk medicine for fever, pain, and diseases of the lung and liver. Allergic asthma is characterized by increased serum IgE level and inflammation of the airways with high levels of interleukin (IL)-4 and IL-5 in bronchoalveolar lavage fluids (BALF). Constriction of airway smooth muscle and development of airway hyperresponsiveness (AHR) are the most important symptoms of allergic asthma. In our previous study, a standardized aqueous extract of A. formosanus (SAEAF) was used to modulate innate immunity of normal mice. In this study, airway inflammatory infiltrations, including T cell differentiation, cytokine modulation, allergic antibodies estimation, pulmonary pathology, and enhanced pause (Penh) of AHR were used to evaluate SAEAF treatment of an ovalbumin (OVA)-inhaled airway allergic murine model. The resulting cytokine profiles demonstrated that SAEAF can significantly reduce Th2 polarization after administration of SAEAF in OVA inhalation. These results also suggest that SAEAF modulates cytokine secretion in allergic asthma. Modulated natural T regulatory cells (CD25+/CD4+, Treg) were also shown to increase immuno-suppression in the allergic lung inflammation and further down-regulate airway inflammatory infiltration in eosinophils and macrophages. Finally, decreased airway anti-OVA IgE secretion and reduced AHR were observed. Our results indicate that the administration of SAEAF can modulate cytokines and T cell subpopulation by regulating inflammatory cell infiltration and modulating the allergic response.

Introduction

The family Orchidaceae is one of the most important agricultural resources in Taiwan. The species Anoectochilus formosanus Hayata1) is very precious in the Taiwanese folk medicine market because of its diverse pharmacological effects. Previous studies, including ours, have indicated that different kinds of extraction of A. formosanus have anti-hyperglycemia (Shih et al., 2002), anti-osteoporosis (Shih et al., 2001), anti-hyperliposis (Du et al., 2003), anti-fatigue (Ikeuchi et al., 2005), and hepatoprotective (Fang et al., 2008; Wu et al., 2007; Shih et al., 2005) effects. Tseng et al. (2006) demonstrated that hot water extraction of Anoectochilus formosanus could enhance the phagocytosis activity of murine peritoneal macrophage, but its active component and mechanism are still not well known.

Allergic asthma is characterized by increased serum IgE antibody level and inflammation of the airways with high levels of interleukin (IL)-4 and IL-5 in bronchoalveolar lavage fluids (BALF) and airways mucosa (Gilmour and Lavender, 2008; Mattes and Foster, 2003). T regulatory cells (Tregs) have been shown to control the disease phenotype in studies of allergic airway inflammation (Jutel et al., 2006; McGee and Agrawal, 2006; Romagnani, 2006). Constriction of airway smooth muscle and development of airway hyperresponsiveness (AHR) are the most important reactions of bronchial asthma in the narrowing of the airway (Berend et al., 2008; Meurs et al., 2008; Cockcroft and Davis, 2006).

In the present study, a standardized aqueous extract of A. formosanus (SAEAF) was prepared without the ethyl acetate fraction to demonstrate the extract's action in the treatment of bronchial asthma. The in vivo effects of SAEAF in mice were investigated by examining the production of allergen-specific IgE antibody, Th1/Th2 cytokines, Treg modulation, and enhanced pause (Penh) of AHR using an ovalbumin (OVA)-sensitized airway allergic murine model.

Section snippets

Preparation of SAEAF

A. formosanus plants were purchased from Innorchid Agriculture Biotech Ltd. (Pu-Li, Taiwan) and identified by the Institute of Chinese Pharmaceutical Sciences, China Medical University (plant specimen number: CMCP 1253). Fresh, whole plants of cultured A. formosanus were extracted with water and partitioned with ethyl acetate. The aqueous fraction was further filtered and evaporated under reduced pressure to yield a purple residue, with the yield approximately 2%. A standardized aqueous extract

Quantitative measurement of kinsenoside using HPLC

The linear relationship and AUC of kinsenoside standard solutions are calculated and shown in Fig. 1A. Kinsenoside is identified using HPLC with RI detector at a retention time of 12.2 min (Fig. 1A). The results from our research indicate that the amounts of the three analytes of SAEAF are 180 mg/g (Fig. 1B). The structure of kinsenoside is presented in Fig. 1C.

Effect of SAEAF administration on cellular distribution in BALF of OVA-inhaled allergic mice

No observable abnormal clinical signs were attributable to the SAEAF dosing, and there was neither loss of body weight nor gross

Discussion

In the treatment of asthma, the emphasis in recent decades has been on the suppression of inflammatory responses and β2-bronchodilator agents to alleviate the occurrence of asthma and airway smooth muscle caused by the contraction symptoms (Papi et al., 2009; Barnes and Adcock, 2009). Steroids and β2-bronchodilators for the control of asthma symptoms and lung function improvement are most effective, but because of potential side effects, these drugs are still a cause for concern. In recent

Acknowledgements

This study was supported by grants from the National Sciences Council of the Republic of China (NSC96-2317-B-039-003, NSC97-2317-B-039-005).

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