Volume 128, 1 May 2015, Pages 30–38
Inhibition of microglial activation by elderberry extracts and its phenolic components
- doi:10.1016/j.lfs.2015.01.037
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Abstract
Aims
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.
Main methods
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.
Key findings
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.
Significance
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.
Keywords
- Elderberry;
- Lipopolysaccharide;
- Quercetin;
- Microglia;
- Nitric oxide;
- Reactive oxygen species
- Corresponding
author at: Department of Biochemistry, 117 Schweitzer Hall, University
of Missouri, Columbia, MO 65211, USA. Tel.:
+ 1 573 882-5377; fax: + 1 573 882 5635.
