Anti-inflammatory and anti-oxidative activities of Stephania pierrei extracts

Abstract

A tuber of Stephania pierrei Diels (Menispermaceae) has been used as a traditional medicine for edema, migraine, and heart related to inflammation. The objective of this study was to determine the anti-oxidative and anti-inflammatory activities of S. pierrei tuber extracts including hot water extract (SH) and ethanolic extract (SE). Hydroxyl radical and superoxide radical scavenging activities were used to analyze their anti-oxidative activities Reverse Transcriptase-polymerase chain reaction (RT-PCR) was used to investigate the gene expression of pro-inflammatory mediators including IL-1β, COX-2, TNF-α, IL-6, and iNOS compared with a housekeeping gene, β-actin.  In addition, the cytotoxicity of extracts against RAW264.7 macrophages was also determined by using an MTT assay..  The results showed that both SE and SH showed high anti-oxidative activity. The SE showed slightly stronger superoxide radical scavenging activity than SH.  For cytotoxic effect, SE showed higher cytotoxicity than SH with IC₅₀ of 96.14±1.79 μg/ml and 191.80±6.08 μg/ml, respectively.  Both extracts as well as the standard compounds, significantly suppressed the gene expression of all pro-inflammatory mediators.  The SE effectively suppressed COX-2 gene expression to the same degree as the SH (IC₅₀ of 50.85±2.15 μg/ml and 56.54±0.97 μg/ml, respectively).   Moreover, the SE showed a stronger inhibitory effect than the SH on the gene expression, especially IL-1β, IL-6 and TNF-α genes.  These results indicated that S. pierrei tuber extracts might decrease inflammation via suppression of pro-inflammatory mediator gene expression and their anti-oxidative activity. Therefore, S. pierrei tubers can be a good candidate for the development of anti-inflammatory health products.