S-Petasin, the Main Sesquiterpene of Petasites formosanus, Inhibits Phosphodiesterase Activity and Suppresses Ovalbumin-Induced Airway Hyperresponsiveness

Evidence for a Functional Link Between the Nrf2 Signalling Pathway and Cytoprotective Effect of S-Petasin in Human Retinal Pigment Epithelium Cells Exposed to Oxidative Stress

The retinal pigment epithelium (RPE) is a highly specialised monolayer epithelium subjected to constant oxidative stress, which, in the long term, favours the development of a complex pathological process that is the underlying cause of macular damage. Therefore, counteracting the overproduction of ROS is the best-researched approach to preserve the functional integrity of the RPE. S-Petasin, a secondary metabolite extracted from the plant Petasites hybridus, has numerous biological effects, which highlight its anti-inflammatory and antioxidative properties. The aim of our study is to investigate whether S-Petasin exerts cytoprotective effects by protecting the RPE from oxidative damage. The effects of pretreatment with S-Petasin were assessed by the determination of the cell viability, intracellular ROS levels, activation of the Nrf2 pathway and the resulting post-transcriptional antioxidant/antiapoptotic response. Our results show that S-Petasin pretreatment (1) reduces intracellular ROS levels, improving cell viability of RPE exposed to oxidative damage; (2) activates the Nrf2 signalling pathway, modulating the post-transcriptional response of its antioxidant chemical biomarkers; (3) reduces the Bax levels, and an increase in those of Bcl-2, with a concomitant downregulation of the Bax/Bc-2 ratio. Overall, our results provide the first evidence that S-Petasin is able to protect the RPE from oxidative damage.

Biochanin A as a modulator of the inflammatory response: an updated overview and therapeutic potential

Uncontrolled inflammation and failure to resolve the inflammatory response are crucial factors involved in the progress of inflammatory diseases. Current therapeutic strategies aimed at controlling excessive inflammation are effective in some cases, though they may be accompanied by severe side effects, such as immunosuppression. Phytochemicals as a therapeutic alternative can have a fundamental impact on the different stages of inflammation and its resolution. Biochanin A (BCA) is an isoflavone known for its wide range of pharmacological properties, especially its marked anti-inflammatory effects. Recent studies have provided evidence of BCA's abilities to activate events essential for resolving inflammation. In this review, we summarize the most recent findings from pre-clinical studies of the pharmacological effects of BCA on the complex signaling network associated with the onset and resolution of inflammation and BCA's potential protective functionality in several models of inflammatory diseases, such as arthritis, pulmonary disease, neuroinflammation, and metabolic disease.

Therapeutic effects of s-petasin on disease models of asthma and peritonitis

To explore the anti-allergic and anti-inflammatory effects of extracts of Petasites genus, we studied the effects of s-petasin, a major sesquiterpene from Petasites formosanus (a butterbur species) on asthma and peritonitis models. In an ovalbumin-induced mouse asthma model, s-petasin significantly inhibited the accumulations of eosinophils, macrophages, and lymphocytes in bronchoalveolar fluids. S-petasin inhibited the antigen-induced degranulation of β-hexosamidase but did not inhibit intracellular Ca(2+) increase in RBL-2H3 mast cells. S-petasin inhibited the LPS induction of iNOS at the RNA and protein levels in mouse peritoneal macrophages. Furthermore, s-petasin inhibited the production of NO (the product of iNOS) in a concentration-dependent manner in the macrophages. Furthermore, in an LPS-induced mouse model of peritonitis, s-petasin significantly inhibited the accumulation of polymorpho nuclear and mononuclear leukocytes in peritoneal cavity. This study shows that s-petasin in Petasites genus has therapeutic effects on allergic and inflammatory diseases, such as, asthma and peritonitis through degranulation inhibition in mast cells, suppression of iNOS induction and production of NO in macrophages, and suppression of inflammatory cell accumulation.

Dietary acacetin reduces airway hyperresponsiveness and eosinophil infiltration by modulating eotaxin-1 and th2 cytokines in a mouse model of asthma

A previous study found that eosinophil infiltration and Th2 cell recruitment are important causes of chronic lung inflammation in asthma. The plant flavonoid acacetin is known to have an anti-inflammatory effect in vitro. This study aims to investigate the anti-inflammatory effect of orally administered acacetin in ovalbumin- (OVA-) sensitized asthmatic mice and its underlying molecular mechanism. BALB/c mice were sensitized by intraperitoneal OVA injection. OVA-sensitized mice were fed acacetin from days 21 to 27. Acacetin treatment attenuated airway hyperresponsiveness and reduced eosinophil infiltration and goblet cell hyperplasia in lung tissue. Additionally, eotaxin-1- and Th2-associated cytokines were inhibited in bronchoalveolar lavage fluid and suppressed the level of OVA-IgE in serum. Human bronchial epithelial (BEAS-2B) cells were used to examine the effect of acacetin on proinflammatory cytokines, chemokines, and cell adhesion molecule production in vitro. At the molecular level, acacetin significantly reduced IL-6, IL-8, intercellular adhesion molecule-1, and eotaxin-1 in activated BEAS-2B cells. Acacetin also significantly suppressed the ability of eosinophils to adhere to inflammatory BEAS-2B cells. These results suggest that dietary acacetin may improve asthma symptoms in OVA-sensitized mice.

Anti-inflammatory, immunomodulatory, and heme oxygenase-1 inhibitory activities of ravan napas, a formulation of uighur traditional medicine, in a rat model of allergic asthma

Ravan Napas (RN) is a traditional formula used to treat pulmonary symptoms and diseases such as coughing, breathing difficulty, and asthma in traditional Uighur medicine. The purpose of this study was to investigate the anti-inflammatory, and immuno-modulatory activity of RN in a well-characterized animal model of allergic asthma. Rats were sensitized with intraperitoneal (ip) ovalbumin (OVA) and alum, and then challenged with OVA aerosols. The asthma model rats were treated with RN; saline- and dexamethasone- (DXM-) treated rats served as normal and model controls. The bronchoalveolar lavage fluid (BALF) cellular differential and the concentrations of sICAM-1, IL-4, IL-5, TNF-α, INF-γ, and IgE in serum were measured. Lung sections underwent histological analysis. The immunohistochemistry S-P method was used to measure the expression of ICAM-1 and HO-1 in the lung. RN significantly reduced the number of inflammatory cells in BALF and lung tissues, decreased sICAM-1, IL-4, IL-5, TNF-α, and IgE in serum, and increased serum INF-γ. There was a marked suppression of ICAM-1 and HO-1 expression in the lung. Our results suggest that RN may have an anti-inflammatory and immuneregulatory effect on allergic bronchial asthma by modulating the balance between Th1/Th2 cytokines.