Anti-inflammatory effects of natural product formulations on murine dendritic cells

The popularity and availability of herbal extracts has increased dramatically over the last decade, providing an inexpensive manner of self-medication. Although the efficacy of individual extracts is currently being studied intensively, research regarding complex mixtures is limited. Therefore, we evaluated the effects of three complex formulations, including BRC-301, a polyherbal extract; BRC-304, a mixture of vitamins, minerals, antioxidant enzymes, botanical extracts, and carotenoids; and BRC-306, a proprietary blend of Uncaria tomentosa (cat's claw) and Phytolens® on murine dendritic cells (DCs). We hypothesized that these formulations would decrease the inflammatory responsiveness and innate function of DCs. In order to address this hypothesis, we evaluated the effects of BRC-301, BRC-304, and BRC-306 on DC2.4 cells and assessed the effects of BRC-301 on bone marrow-derived DCs (bmDCs). Lipopolysaccharide (LPS) stimulation of DC2.4 cells and bmDCs induced production of nitric oxide (NO), TNF-α, and IL-6, a response that was modulated by concomitant treatment with non-cytotoxic concentrations of BRC-301. In contrast, only the production of NO or IL-6 by LPS-activated DC2.4 cells was affected by BRC-304 or BRC-306, respectively. Flow cytometric evaluation following concurrent BRC-301 and LPS treatment revealed an increased relative expression of CD11c, CD86, and CD54 on bmDCs and an increased frequency of bmDCs expressing MHC II. Finally, BRC-301 enhanced the uptake of fluorescein isothiocyanate-conjugated ovalbumin by bmDCs. Taken together, these results suggest that these commercially available formulations modulate the innate responsiveness of murine DCs and may enhance their ability to initiate T cell-mediated immunity.