Discussion
The obtained results indicated that % yield of
water extracts was higher than ethanolic extracts.
However, ethanolic extracts had better antimicrobial
activity against most tested strains than the water
extracts except water extract of C. micracantha. The
bioactive components in these plants has probably
less polarity. The ethanolic extract of C. micracantha
showed that it had less activity than the water extract
with less concentration. It is suggested that the water
extract of C. micracantha has a potential bioactive
compound resulting in better activity against bacteria
due to higher polarity in the water extract.
The water extracts of Benchalokawichian
remedy, C. petasites and F. racemosa could inhibit none
of the tested strains in the present study. It is possibly
due to the low concentration of water extracts used per
disk. However, the activity was detected in most of the
ethanolic extracts of the remedy and each component.
The Benchalokawichian remedy showed no
activity against all E. coli strains, S. sonnei, S.
Typhimurium and C. albicans compared to individual
component such as T. triandra and C. petasites which
had most effective activity. It revealed that the activity
was reduced resulting from the combination of the five
herbal plants for Benchalokawichian remedy. The
development of medicinal products has to be concerned
for the proportion of each component in order to
produce the products with the most effective activity.
The extract of H. perforata was previously
reported that it showed anti-pyretic, anti-diarrhea and
dysentery(16). The obtained result in the present study
indicated that the ethanolic extract of this component
inhibited not only S. dysenteriae but also all tested
Gram positive bacteria. In addition, the water extract
could inhibit A. baumanii which commonly causes
hospital-acquired infection.