Isolation, purification and characterization of schisantide from schisandra chinensis

• Main Author: Lee, Cheryl Jia Wen
• Other Authors: James P Tam
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Science::Biological sciences
• Online Access: https://hdl.handle.net/10356/143384
• Institution: Nanyang Technological University

Five-flavour berries (Schisandra chinensis) are classic herbs taken in traditional Chinese medicine to treat and prevent various diseases. Modern research has also revealed the therapeutic effects of their various biologically active components. However, their biologically active peptides and proteins remain underexplored. The use of peptides and proteins is becoming popular in the development of oral drugs due to the advantages they have over their small-molecule counterparts. One family of peptides in particular, the cysteine-rich peptides (CRPs) features high stability and small sizes that make them perfect scaffolds for orally active drugs. CRPs found in plants are between 2–6 kDa, and contain 3–5 disulfide bonds that connect in different ways to give them their stable structures. In this paper, we report the discovery and characterization of schisantide, a first-in-class hyperstable CRP found in the fruits of S. chinensis. Our results revealed that schisantide is a small peptide with a hyper-disulfide constrained structure that displayed high resistance to heat and acid degradation. It also contained a novel cysteine spacing that has not been discovered in planta. Together, this work expands the current knowledge on CRPs and S. chinensis, in particular their application in oral pharmaceutics.