טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentChefetz Ilana
SubjectThe Antioxidant Activity of Rhus coriaria Fruit Extracts
DepartmentDepartment of Biotechnology and Food Engineering
Supervisors Professor Yuval Shoham
Mr. Ishak Neeman (Deceased)


Abstract

The aim of this research was to investigate the antioxidant potential of fruit extracts from Rhus coriariaRhus coriaria (Sumac) is well-known spice in the Middle East that is being used as a folk medicine for the treatment of diarrhea, bleeding, and as an antiseptic.  The dry fruits were separated to pericarps and kernels and were extracted with various organic solvents or water. Radical scavenging antioxidant activity was quantified by the ABTS assay. Rhus coriaria extracts were shown to scavenge directly the stable ABTS radicals over a concentration of 8 ppm to 16 ppm.  The antioxidant's potential has also been determined using the ferric reducing antioxidant power (FRAP) assay.  Buthanol fraction of pericarps was the most active of all fractions.  To observe the base modification of the amino acid side chains induced by radical reaction, the fluorescence intensity of bi-tyrosine and N-Formyl kynurenine was measured.  Ethanol- and water-extracts decreased considerably the damage caused to a model protein, BSA.  To detect DNA strand breakage the mobility of different forms of plasmid DNA was examined following radical treatment with AAPH.   Rhus coriaria water-extracts decreased DNA strand breakage at a concentration of 13 and 33 ppm.  The preventive action against deoxyribose damage was accomplished using an AAPH-reaction-based assay.  DNA damage was estimated from thiobarbituric acid-reactive substances (TBARS) at 532 nm.  Again, the addition of Rhus coriaria extracts decreased the MDA (melon di-aldehyde) concentration in the DNA solution considerably.  In conclusion, extracts of Rhus coriaria fruits showed high antioxidant activities in different assay systems and thus may provide a useful source for natural antioxidants.