To evaluate the protective effects of purple sweet potato ( Ipomoea batatas
Convolvulaceae) extract (IBE) in stimulated BV-2 microglial cells and its anti-oxidant properties.
Cell viability assessment was performed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium
bromide (MTT) assay. Lipopolysaccharide (LPS) was used to activate BV-2 microglia. Nitric
oxide (NO) levels were measured using Griess assay. Inducible NO synthase (iNOS) and
cyclooxygenase (COX)-2 expressional levels were measured by Western blot analysis. Tumor necrosis
factor-alpha (TNF-α) production was evaluated by enzyme-linked immunosorbent assay (ELISA). Antioxidant
properties were evaluated by 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay.
LPS-activated excessive release of NO in BV-2 cells was significantly inhibited by IBE
(p<0.001 at 100 μg/mL). Increased production of inflammatory mediators such as iNOS, COX-2 and
TNF-α (p < 0.01 and p < 0.001 at 100 and 200 μg/ml, respectively) was attenuated by IBE
concentration-dependently. IBE also scavenged DPPH radicals in a dose-dependent manner (p < 0.05
at 10 μg/ml and p < 0.001 at 20 - 200 μg/ml).
These results indicate that IBE attenuated neuroinflammatory responses in LPS-activated
BV-2 microglia by inhibiting excessive production of pro-inflammatory mediators such as NO, iNOS,
COX-2 and TNF-α. The anti-neuroinflammatory potential of IBE may be related to its strong antioxidant