Inhibitory effects of Pycnogenol® (French maritime pine bark extract) on airway inflammation in ovalbumin-induced allergic asthma

Pycnogenol (R) (PVC) is a standardized extracts from the bark of the French maritime pine (Pinus maritime) and used as a herbal remedy for various diseases. In this study, we evaluated the effects of PVC on airway inflammation using a model of ovalbumin (OVA)-induced allergic asthma and RAW264.7 cells. PVC decreased nitric oxide production and reduced the interleukine (IL)-1 beta and IL-6 levels in LPS-stimulated RAW264.7 cells. PVC also reduced the expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase (MMP)-9 and enhanced the expression of hemeoxygenase (HO)-1. In the in vivo experiment, PVC decreased the inflammatory cell count and the levels of IL-4, IL-5, IL-13, and immunoglobulin (Ig) E in BALF or serum. These results are consistent with the histological analysis findings, which showed that PYC attenuated the airway inflammation and mucus hypersecretion induced by OVA challenge. In addition, PVC enhanced the expression of HO-1. In contrast, PVC inhibited the elevated expression of iNOS and MMP-9 proteins induced by OVA challenge. In conclusion, PVC exhibits protective effects against OVA-induced asthma and LPS-stimulated RAW264.7 cells. These results suggest that PVC has potential as a therapeutic agent for the treatment of allergic asthma. (C) 2013 Elsevier Ltd. All rights reserved.