The HPLC-PCD profile of phenolic extracts from the raw Nura
(Fig. 1a) was similar to that of soaked Nura (Fig. 1b). However,
the level of phenolic compounds in the former was higher, as represented
by a higher peak area and PCD responses. Two major
groups of phenolic compounds that eluted at two different regions
in the chromatograms were identified: (i) hydrophilic (eluted in
the first 10 min) and (ii) relatively less hydrophilic (eluted between
10 and 40 min). These two phenolic groups were arbitrary named
the polar and less-polar regions respectively. The phenolic compounds
eluted at the less-polar region as a HPLC ‘hump’ with
inseparable peaks gave a substantial PCD response after reacting
with ABTS+.