چکیده (انگلیسی):

Objective: To investigate the antioxidant activity, total phenolic and total tannin content
of the pericarp and the seed of Coffea benghalensis (C. benghalensis) and Coffea liberica
compared to Coffea arabica (C. arabica).
Methods: The antioxidant potential, total tannin and polyphenol contents of the
immature and mature seed and pericarp of C. benghalensis and Coffea liberica were
quantified and compared to C. arabica. Enhanced chemiluminescence (ECL), 2,2-
diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity, Folin-
Ciocalteau method and total tannin content assays were used.
Results: Trolox equivalent (TE/g plant material) values obtained by ECL and DPPH
methods showed loose correlation (r2 = 0.587) while those measured by oxygen radical
absorbance capacity assay were higher without correlation in each plant. A closer correlation
was detected between the ECL method and the percentage antioxidant activity of
the DPPH technique (r2 = 0.610 7) in each species, however the immature pericarp of
C. benghalensis showed much higher DPPH scavenging potential than was seen in the
ECL assay. The immature pericarp of C. benghalensis expressed the highest tannin and
polyphenol content, and a high polyphenol level was also detected in the immature seed
of C. arabica. The immature pericarp of Bengal and Liberian coffees showed the largest
amount of phenolic contents.
Conclusions: The obtained data highlight the potential role of C. benghalensis as a new
source of natural antioxidants and polyphenols compared to C. arabica.