NTU Undergraduates' research April 2014 - Biosciences | Seite 85

Project abstract
Flavonoids are low molecular weight secondary plant metabolites that have a large
number of roles in plant survival including UV filtration and pollination. Tissue
transglutaminase (TG2) is a calcium dependent enzyme that cross links proteins, it is
found commonly throughout mammals tissues and has been linked to several
diseases including celiac disease. Given the properties of flavonoids as being antiinflammatory and anti-cancer and TG2 being linked to inflammation and cancer it
was decided to extract quercetin from red onion and test if it would affect the
enzyme activity of TG2. Quercetin was extracted from red onion by vacuum freeze
drying and concentrated using reflux, TG2 was taken from guinea pig liver by
centrifugation. Tests carried out included protein assays, BCA assays, western
blotting and HPLC (High performance liquid chromatography) using TG2, extracted
quercetin and standard quercetin. There was mixed success with these tests with the
BCA assay and western blot failing, however the protein assays were partially
successful and the HPLC worked fine. The HPLC confirmed successful extraction of
quercetin from the red onion and the protein assays showed that TG2 was not
affected by quercetin.