Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Protective Effect of Purple Sweet Potato (Ipomoea batatas Linn, Convolvulaceae) on Neuroinflammatory Responses in Lipopolysaccharide-Stimulated Microglial Cells

Hyun Kang¹ , Yeon-Gil Kwak², Sushruta Koppula³

¹Department of Medical Laboratory Science, College of Health Science, Dankook University, Cheonan-si, Chungnam, 330-714; ²Research Institute of Natural Food & Pharmaceutical Corp., O-Chang Science Industry Plaza 319-11 Songdaeri, O-changmyon, chongwongun Chungbuk, 363-883; ³Department of Biotechnology, College of Biomedical and Health Science, Konkuk University, Chungju-si, Chungbook, 380-701, Republic of Korea.

For correspondence:- Hyun Kang Email: hkang@dankook.ac.kr Tel:+82415501452

Received: 14 May 2014 Accepted: 14 July 2014 Published: 18 August 2014

Citation: Kang H, Kwak Y, Koppula S. Protective Effect of Purple Sweet Potato (Ipomoea batatas Linn, Convolvulaceae) on Neuroinflammatory Responses in Lipopolysaccharide-Stimulated Microglial Cells. Trop J Pharm Res 2014; 13(8):1257-1263 doi: 10.4314/tjpr.v13i8.9

© 2014 The authors.
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Abstract

Purpose: To evaluate the protective effects of purple sweet potato (Ipomoea batatas Linn, Convolvulaceae) extract (IBE) in stimulated BV-2 microglial cells and its anti-oxidant properties.

Methods: Cell viability assessment was performed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyl-tetrazolium 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). Anti-oxidant properties were evaluated by 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging assay.

Results: 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).

Conclusion: 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 properties.

Keywords: Ipomoea batatas, DPPH radicals, Anti-oxidant, Neuroinflammation, BV-2 microglia, Nitric oxide