Inhibitors of Aquatic Hyphomycetes in Dead Conifer Needles

SUMMARYNeedle powders of Pinns leucodermis and Sequoia gigantea were extracted with petroleum ether, ethanol, methanol, or distilled water. After evaporating the solvents, extracts, and extracted powder were added to nutrient medium to examine their effect on linear expansion of five aquatic Hyphomycetes. All extracts depressed fungal growth, the inhibition being strongest with the two alcoholic extracts. The FeC13 test indicated phenolic compounds in the alcohol and water but not in the petroleum-ether extracts. There was no correlation between the colorimetrically determined phenol content of an extract and its antifungal activity. Untreated needle powder strongly inhibited fungal growth, as did petroleum- ether or water-extracted powder. By contrast, alcohol-extracted powder did not inhibit fungal growth. The inhibitory effect of methanol extract was much more pronounced at a pH range of 4.0-4.5 than at 5.5-6.5.