sample (up to 35%), while the Arabica spent coffee inhibition
percentage ranged from 12 to 26%.With regard to coffee brews,
Robusta had a protective effect between 20 and 23%, whereas
Arabica coffee brew had the least antimutagenic effect, showing
no significant differences. These results suggest that the components
in spent coffee extracts and coffee brews are active
against the mutagenic action of NPD. First, phenolic compounds
might have a positive contribution; in fact, previous
findings have reported that these compounds might play an
important role in the antimutagenic activity of fruit, vegetables
or herbs (Edenharder et al., 2002). Similar concentrations
of the main bioactive compounds in spent coffee extracts and
coffee brews were tested to determine their role in antimutagenic
activity (Table 3). The results indicated that 5-CQA
standard was highly effective in the inhibition of NPD mutagen
(30–56%), mainly due to caffeic acid, which has similar antimutagenic
activity (38–41%). Furthermore, feruloylquinic acids
are common phenolic acids found in coffee samples; they are
an ester linkage between a quinic acid and a ferulic acid. Due
to the fact that there are no commercial standards of this chlorogenic
acid, three concentrations of ferulic acid were tested.
The results showed that this compound might also have an
important contribution to the antimutagenic activity of spent
coffee (37–51% protection). Shishu and Kaur (2008) reported that
the methoxy group on the phenyl ring is responsible for the
antimutagenic activity of ferulic acid.