The three-stage of in vitro digestion model system simulating human digestive fluids was employed to determine changes in the profile of phenolic compounds, antioxidant activity and total phenolic content by digestion. The composition of total phenolic compounds in leaf, root and stem detected by gas chromatography-mass Spectroscopy method was 44.27, 19.31 and 8.59%, respectively, and 3-hydroxy-benzoic acid was found as a predominant phenolic compound identified in all parts of Smilax china. Both 2, 2-diphenylpicrylhydrazyl free radical scavenging effect (8.66 mg/mL for IC50) and total phenolic content (2,383.55 µg gallic acid equivalent/mL) using Folin–Ciocalteu method were remarkably high in leaf of Smilax china. Bioaccessible antioxidative effect and digestive stability of total phenolic content in leaf were also significantly higher than those of other parts.


Our study determined the relationship among phenolic compounds' composition, antioxidative effect or total phenolic content. Positive relationship was observed between antioxidative effect and total phenolic content in each part of Smilax china under in vitro physiological condition. As a result, total phenolic content determined after digestion of each part of Smilax china could be regarded as a major contributor for predicting antioxidant activity in human body. Our results provide information that Smilax china may be a useful substance for the application of natural antioxidant.