3.4. HPLC and TLC analysis
Due to its interesting results, the further study focused on the
active compounds of P. betle leaves extract. The HPLC chromatograms
of the standards, 4-chromanol and eugenol (Fig. 3a), P. betle
extract (Fig. 3b) and the mixture of P. betle extract and the standards
(Fig. 3c) are shown. Peak 1 of Fig. 3aec was identified as 4-
chromanol with retention times of 5.486 ± 0.00 min,
5.654 ± 0.04 min and 5.610 ± 0.00 min, respectively. Peak 2 of
Fig. 3aec was eugenol with retention times of 7.853 ± 0.01 min,
7.966 ± 0.09 min and 7.757 ± 0.01 min, respectively. It indicatedthat at least 4-chromanol and eugenol were the components of
P. betle leaves extract.
There were several bands of P. betle extract components
appeared on the TLC-plate (Fig. 4a). One major band with Rf at 0.38
matched to the standard 4-chromanol gave the large inhibited clear
zone against S. mutans ATCC 25175 in TLC-bioautography assay
(Fig. 4b), and this band also gave inhibited clear zone against
A. actinomycetemcomitans ATCC 33384 (data not shown). Another
minor band with Rf at 0.74 matched to the standard eugenol did not
show any inhibited zone.