Purpose: To evaluate the anticandidal activity of the ethanol extracts of 12 herbs from Thailand.
Methods: The herbs studied were
Alpinia galanga
,
Curcuma longa
,
Curcuma zedoaria
,
Mentha
cordifolia
,
Ocimum africanum,
Ocimum basilicum
,
Ocimum sanctum
,
Piper betle
,
Piper chaba
,
Piper
nigrum
,
Piper sarmentosum
and
Zingiber officinale
. Various
Candida spp.
were examined for minimal
inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) using microdilution method;
time-kill assay was also used to assess the plants. Antibiofilm activity was investigated using a 3-[4, 5-
dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium-bromide (MTT assay). Gas chromatography mass
spectrometry (GC-MS) analysis, thin layer chromatography (TLC) fingerprinting and TLC-bioautography
were used to determine the active anticandidal compounds.
Results: All tested herbs, except extracts of
P. nigrum and
Limiaceae family, showed varying zones of
inhibition against
Candida albicans
ATCC 90028. P. betle revealed the strongest anticandidal activity
against all tested strains with MIC ranging from 1.56 to 3.13 mg/ml, and MFC from 3.13 to 8.33 mg/ml.
Killing activity depended on time and concentrations of the extract. The concentration of
P. betle extract
required to inhibit ≥ 90 % biofilm formation of
C. albicans ATCC 90028 was 3.13 ± 0.15 mg/ml, while
that to remove ≥ 90 % biofilm growth was 12.50 ± 0.69 mg/ml. The result of GC-MS analysis showed
the major compound of
P. betle extract responsible for anticandidal activity as 4-chromanol.
Conclusion: P. betle extract contains 4-chromanol which is a good potential anticandidal agent for the
treatment of oral infectious diseases caused by certain
Candida spp. 
