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 NOor 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.

Anti-inflammatory effects of natural product formulations on murine macrophages.

The popularity of herbal supplements, especially those with purported anti-inflammatory effects, has drastically increased in recent years as more people have turned to natural therapeutics. As the supplement industry is loosely regulated, the safety and efficacy of these products is poorly understood. In the present study, we examined the effects of natural product formulations prepared by the Biotics Research Corporation (BRC) on cyclooxygenase (COX) enzyme activity. We also evaluated the immune responsiveness of RAW264.7 macrophages, a key cell population involved in the inflammation, to those formulations. As a result, three supplements, BRC-301, BRC-304, and BRC-306, selectively inhibited COX-2, the inducible isoform involved in inflammation. Further evaluation of these three products indicated that BRC-304 and BRC-306 produced minimal effects on the production of inflammatory mediators by lipopolysaccharide (LPS)-stimulated macrophages. BRC-301 decreased the LPS-induced production of nitric oxide and IL-6, as well as CD40 expression. Collectively, these results suggest that the BRC-301 extract, comprising several polyphenolic natural products, may have a protective effect in chronic inflammatory disorders.

Toll-like receptor ligand-induced activation of murine DC2.4 cells is attenuated by Panax notoginseng.

The medicinal herb, Panax notoginseng, has been used for thousands of years in traditional Chinese medicine and possesses anti-inflammatory properties. Dendritic cells (DCs) play a central role in the regulation of both inflammation and adaptive immunity. The aim of this study was to investigate the potential for notoginseng extracts to modulate Toll-like receptor (TLR) ligand-induced activation of cultured DC2.4 cells. Following stimulation with LPS, CpG or poly(I:C) and treatment with 0-50micorg/ml notoginseng extract for 24 h, DCs were evaluated for various phenotypic and functional readouts. Notoginseng reduced the LPS-, CpG- and poly(I:C)-induced production of TNF-alpha by DC2.4 cells. Also, IL-6 production by notoginseng-treated cells stimulated with LPS and CpG but not poly(I:C) was reduced when compared to controls. TLR ligand-induced CD40 expression was attenuated by notoginseng. In contrast, notoginseng decreased CD86 levels on DCs activated with LPS and poly(I:C) but not CpG. Inhibition of TNF-alpha production was time-dependent in LPS-stimulated cells, occurring only with pretreatment or concurrent treatment of notoginseng but not after delayed addition of the herbal extract. Additionally, ginsenoside Rg1 more effectively inhibited LPS-stimulated cytokine production by DC2.4 cells than ginsenoside Rb1. Taken together, these results demonstrate that notoginseng inhibits the production of specific inflammatory molecules and innate immune responsiveness by DCs following TLR activation.

Panax notoginseng attenuates LPS-induced pro-inflammatory mediators in RAW264.7 cells.

Herbals or dietary supplements are not regulated as drugs by the United States Food and Drug Administration (USFDA) although many may have associated therapeutic effects and toxicities. Therefore, the immunomodulatory effects of the herbal extract Panax notoginseng on cultured macrophages (RAW264.7 cells) were investigated to address potential therapeutic or toxic effects. Cells were stimulated with LPS (1 microg/ml) and treated with notoginseng at 5, 25 and 50 microg/ml. Notoginseng inhibited the LPS-induced production of TNF-alpha and IL-6 by the cultured macrophages in a concentration-dependent manner. The expression of COX-2 and IL-1 beta mRNA was also attenuated by notoginseng. TNF-alpha production was inhibited in samples treated with notoginseng 24h before, or at the same time as LPS stimulation, but not in samples treated 8h after LPS stimulation. Notoginseng reduced expression of the accessory molecules CD40 and CD86 on the RAW264.7 cells while CD14 and TLR4 expression remained unaffected. Furthermore, Rb1 and Rg1 ginsenosides also inhibited macrophage production of TNF-alpha, but to a lesser extent than did the whole notoginseng extract. Collectively, these results indicate that notoginseng inhibits LPS-induced activation of RAW264.7 macrophages and demonstrates that notoginseng possesses anti-inflammatory and immunosuppressive properties in vitro.