Pycnogenol® Augments Macrophage Phagocytosis and Cytokine Secretion

Abstract

We previously reported that Pycnogenol^®, procyanidins extracted from the bark of French maritime pine (Pinus maritima Aiton; the official botanical name is now Pinus pinaster Aiton) is a potent free radical scavenger. It has been shown to inhibit macrophage oxidative burst. Macrophages carry out their microbicidal and tumoricidal activities via oxygen-dependent and oxygen-independent mechanisms. The present study investigated the effects of Pycnogenol^® on oxygen-independent killing mechanisms of macrophages, with particular interest in phagocytosis and cytokine release. J774 cells, a murine macrophage cell line, were preincubated with Pycnogenol^® and then exposed to fluorescein-conjugated Escherichia coli particles for phagocytosis. Pycnogenol^® significantly enhanced the phagocytosis by J774 cells. Incubation with Pycnogenol^® resulted in a significant increase in cell size indicating macrophage activation. J774 cells were treated with Pycnogenol^® for 22 hr and the supernatants were tested for the release of tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β). Pycnogenol^® significantly increased the secretion of both TNF-α and IL-1β . These results suggest that Pycnogenol^® can enhance the macrophage function by increasing its ability to phagocytosis and secretion of TNF-α and IL-1β . These two cytokines may provide costimulatory signals to enhance both the humoral and cellular immune responses to promote host defense.