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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. November 2005, Volume 4, Number 11, 803-812 |
Structure-Antifungal Activity Relationships of Some Organic Compounds with
Varying Number of Hydroxyl Groups for their Inhibition of Colletotrichum gloeosporioides
Eugene Sebastian J. Nidiry
Internet Electron. J. Mol. Des. 2005, 4, 803-812
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Abstract:
Hydroxyl group(s) is (are) present in some compounds, which are
antifungal as well as in some which promote fungal growth. It was
thought interesting to study the structure-antifungal activity
relationships of some common alcohols, phenols and carboxylic
acids with varying number of hydroxyl groups. Poisoned food
technique was used in the determination of percent mycelial growth
inhibition of Colletotrichum gloeosporioides by the compounds on
potato-dextrose-agar medium and probit analysis was used for the
computation of median effective concentrations. Evaluation of
ClogP values for all compounds was done using Rekker fragment
constants. Multiple regression analysis was used in the QSAR study.
The very large variation in median effective concentrations ranging
from more than 50000 mg/L [pEC50 (moles/L) = 0.19] in the case of
glycerol to less than 50 mg/L [pEC50 (moles/L) = 3.50] in the case of
2-naphthol shows the dramatic effect of the environment within the
molecule on the antifungal activity of compounds with hydroxyl
groups. While monohydroxy alcohols in general exhibit antifungal
activity, the presence of another hydroxyl group has adverse effect
on the activity. Introduction of hydroxyl group appears to have
detrimental effect on the antifungal activity of aliphatic and aromatic
carboxylic acids also. However, substantial differences among the
antifungal activities of dihydroxy and trihydroxy phenols indicate
that the positions of the hydroxyl groups also play their roles in their
activities. The reduction in lipophilicity of the molecule on the
introduction of additional hydroxyl groups can be attributed as the
reason for the detrimental effect on the antifungal activity of
alcohols and carboxylic acids. In the case of phenols, in addition to
reduction in lipophilicity, positions of the hydroxyl groups also play
their roles in the determination of antifungal activity.
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