Inhibition of microglial activation by elderberry extracts and its phenolic components

• DOI: 10.1016/j.lfs.2015.01.037
• Publication Date: 2015-03-02T02:00:46Z
• Authors: Agnes Simonyi; Zihong Chen; Jinghua Jiang; Yijia Zong; Dennis Y. Chuang; Zezong Gu; Chi-Hua Lu; Kevin L. Fritsche; C. Michael Greenlief; George E. Rotting...; Andrew L. Thomas; Dennis B. Lubahn; Grace Y. Sun
• Keywords: Lipopolysaccharides; 0301 basic medicine; Cell Survival; Plant Extracts; Nitric Oxide; 3. Good health; Anthocyanins; Mice; 03 medical and health sciences; Phenols; Sambucus; Animals; Quercetin; Microglia; Reactive Oxygen Species; Cells, Cultured

Elderberry (Sambucus spp.) is one of the oldest medicinal plants noted for its cardiovascular, anti-inflammatory, and immune-stimulatory properties. In this study, we investigated the anti-inflammatory and anti-oxidant effects of the American elderberry (Sambucus nigra subsp. canadensis) pomace as well as some of the anthocyanins (cyanidin chloride and cyanidin 3-O-glucoside) and flavonols (quercetin and rutin) in bv-2 mouse microglial cells.The bv-2 cells were pretreated with elderberry pomace (extracted with ethanol or ethyl acetate) or its anthocyanins and flavonols and stimulated by either lipopolysaccharide (LPS) or interferon-γ (IFNγ). Reactive oxygen species (ROS) and nitric oxide (NO) production (indicating oxidative stress and inflammatory response) were measured using the ROS detection reagent DCF-DA and the Griess reaction, respectively.Analysis of total monomeric anthocyanin (as cyanidin 3-O-glucoside equivalents) indicated five-fold higher amount in the freeze-dried ethanol extract as compared to that of the oven-dried extract; anthocyanin was not detected in the ethyl acetate extracts. Elderberry ethanol extracts (freeze-dried or oven-dried) showed higher anti-oxidant activities and better ability to inhibit LPS or IFNγ-induced NO production as compared with the ethyl acetate extracts. The phenolic compounds strongly inhibited LPS or IFNγ-induced ROS production, but except for quercetin, they were relatively poor in inhibiting NO production.These results demonstrated differences in anti-oxidative and anti-inflammatory effects of elderberry extracts depending on solvents used. Results further identified quercetin as the most active component in suppressing oxidative stress and inflammatory responses on microglial cells.